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ALBERTO FERRARI
COLLABORATORE DI RICERCA
Dipartimento di Ingegneria "Enzo Ferrari"
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Pubblicazioni
2022
- Aquatic Therapy after Incomplete Spinal Cord Injury: Gait Initiation Analysis Using Inertial Sensors
[Articolo su rivista]
Fantozzi, S.; Borra, D.; Cortesi, M.; Ferrari, A.; Ciacci, S.; Chiari, L.; Baroncini, I.
abstract
: Populations with potential damage to somatosensory, vestibular, and visual systems or poor motor control are often studied during gait initiation. Aquatic activity has shown to benefit the functional capacity of incomplete spinal cord injury (iSCI) patients. The present study aimed to evaluate gait initiation in iSCI patients using an easy-to-use protocol employing four wearable inertial sensors. Temporal and acceleration-based anticipatory postural adjustment measures were computed and compared between dry-land and water immersion conditions in 10 iSCI patients. In the aquatic condition, an increased first step duration (median value of 1.44 s vs. 0.70 s in dry-land conditions) and decreased root mean squared accelerations for the upper trunk (0.39 m/s2 vs. 0.72 m/s2 in dry-land conditions) and lower trunk (0.41 m/s2 vs. 0.85 m/s2 in dry-land conditions) were found in the medio-lateral and antero-posterior direction, respectively. The estimation of these parameters, routinely during a therapy session, can provide important information regarding different control strategies adopted in different environments.
2022
- Gait apraxia evaluation in normal pressure hydrocephalus using inertial sensors. Clinical correlates, ventriculoperitoneal shunt outcomes, and tap-test predictive capacity
[Articolo su rivista]
Ferrari, A.; Milletti, D.; Palumbo, P.; Giannini, G.; Cevoli, S.; Magelli, E.; Albini-Riccioli, L.; Mantovani, P.; Cortelli, P.; Chiari, L.; Palandri, G.
abstract
Idiopathic normal pressure hydrocephalus (iNPH) is a neurological condition with gait apraxia signs from its early manifestation. Ventriculoperitoneal shunt (VPS) is a surgical procedure available for treatment. The Cerebrospinal fluid Tap Test (CSF-TT) is a quick test used as selection criterion for VPS treatment. Its predictive capacity for VPS outcomes is still sub judice. This study is aimed to test the hypothesis that wearable motion sensors provide valid measures to manage iNPH patients with gait apraxia.
2022
- Towards a Temperature Compensated Model for a Blood-pH Sensor in Extracorporeal Circulation
[Relazione in Atti di Convegno]
Goldoni, D.; Ferrari, A.; Piccini, M.; Cattini, S.; Rovati, L.
abstract
Under physiological conditions, the body maintains blood pH within the very narrow range [7.36, 7.44] pH. Small deviations from this range can reveal the onset of pathological states. In this work the performances of a real-time, non-invasive pH measuring sysem for extracorporeal circulation (ECC) are analyzed. In particular, this study focuses on the analysis of the effects that temperature of the measurand may have on the error in estimating blood pH. Indeed, the sensor is based on the analysis of the fluorescence produced by HPTS, which is known to vary with temperature. The extent of such a variation, however, depends on various factors, including the chemical environment. Blood temperature in ECC is often thermostated at 37 °C. Nevertheless, there are treatments in which the blood temperature is varied by a few Celsius degrees, generally reduced, from the physiological temperature of 37 °C. Therefore, the first objective of this study was to evaluate whether a modest reduction in temperature, that is a few Celsius degrees, introduce an error such as the measuring system no longer conforms to the maximum permissible measurement error of ±0.04 pH. Once verified that the temperature-induced error could exceed the limit of ±0.04 pH, a correction factor for temperature compensation was investigated and its robustness to unevenness in the sensor production was explored. The results obtained from this preliminary study performed using Phosphate Buffer Saline (PBS) showed how the addition to the measuring system of a temperature sensor can effectively allow to maintain the measurement error within the ±0.04 pH range, even when the temperature of the measurand decreases by a few degrees from the physiological temperature of 37 °C.
2021
- A preliminary investigation of the robustness of a measuring instrument for blood-pCO2 measurement during ECC
[Abstract in Atti di Convegno]
Cattini, Stefano; Accorsi, Luca; Truzzi, Stefano; Ferrari, Alberto; Rovati, Luigi
abstract
2021
- Anterior callosal angle correlates with gait impairment and fall risk in iNPH patients
[Articolo su rivista]
Mantovani, P.; Giannini, G.; Milletti, D.; Cevoli, S.; Valsecchi, N.; Gramegna, L. L.; Albini-Riccioli, L.; Sturiale, C.; Cortelli, P.; Lanzino, G.; Elder, B. D.; Palandri, G.; Agati, R.; Aspide, R.; Calandra-Buonaura, G.; Capellari, S.; Chiari, L.; Ferrari, A.; Magelli, E.; Merola, M.; Oppi, F.; Parchi, P.; Pirina, A.; Piserchia, V. A.; Sambati, L.
abstract
Background: In idiopathic normal pressure hydrocephalus (iNPH), gait and balance impairment is the most frequent symptom, and it is often associated with a higher fall risk. In a prior study, the anterior callosal angle (ACA) was validated as a reliable marker to discriminate iNPH from Alzheimer’s disease and healthy controls. However, the potential correlation between the ACA with clinical symptoms and functional outcomes has not been assessed. The objective of this study is to determine the utility of the ACA in predicting gait improvement after ventriculoperitoneal (VP) shunting. Methods: Patients with probable iNPH who underwent shunt placement at a single institution were prospectively enrolled from May 2015 to May 2019. Patients were assessed preoperatively and at 6 months postoperatively following a standard clinical and MRI protocol. Callosal angle (CA) and ACA were calculated from 3 T MRI preoperatively and at 6 months postoperatively. CA and ACA were tested for correlation with clinical scores. Results: Forty-seven patients with probable INPH who completed 6-month postoperative follow-up were enrolled in the study. Baseline ACA was significantly correlated with preoperative fall risk, gait, and balance impairment assessed with Tinetti POMA scale. Additionally, baseline ACA differentiated patients who experienced improvement at Tinetti POMA scale after surgery. Conclusions: The baseline ACA is a useful neuroradiological marker to differentiate patients by fall risk and has significant correlation with the improvement in gait and balance impairment following surgery. This study demonstrated that the ACA may be a complementary tool to the CA in predicting shunt responsiveness in iNPH.
2021
- Assessing biocompatibility of face mask materials during covid-19 pandemic by a rapid multi-assays strategy
[Articolo su rivista]
Petrachi, T.; Ganzerli, F.; Cuoghi, A.; Ferrari, A.; Resca, E.; Bergamini, V.; Accorsi, L.; Burini, F.; Pasini, D.; Arnaud, G. F.; Piccini, M.; Aldrovandi, L.; Mari, G.; Tomasi, A.; Rovati, L.; Dominici, M.; Veronesi, E.
abstract
During the coronavirus disease 2019 (COVID-19) pandemic, scientific authorities strongly suggested the use of face masks (FMs). FM materials (FMMs) have to satisfy the medical device biocompatibility requirements as indicated in the technical standard EN ISO 10993-1:2018. The biologic evaluation must be confirmed by in vivo tests to verify cytotoxicity, sensitisation, and skin irritation. Some of these tests require an extensive period of time for their execution, which is incompatible with an emergency situation. In this study, we propose to verify the safety of FMMs combining the assessment of 3-[4,5-dimethylthiazolyl-2]-2,5-diphenyltetrazolium bromide (MTT) with quantification of nitric oxide (NO) and interleukin-6 (IL-6), as predictive markers of skin sensitisation or irritation based on human primary fibroblasts. Two hundred and forty-two FMMs were collected and classified according to spectrometer IR in polypropylene, paper, cotton, polyester, polyethylene terephthalate, 3-dimensional printing, and viscose. Of all FMMs tested, 50.8% passed all the assays, 48% failed at least one, and only 1.2% failed all. By a low cost, rapid and highly sensitive multi assays strategy tested on human skin fibroblasts against a large variety of FMMs, we propose a strategy to promptly evaluate biocompatibility in wearable materials.
2021
- Measuring breathability and bacterial filtration efficiency of face masks in the pandemic context: A round robin study with proficiency testing among non-accredited laboratories
[Articolo su rivista]
Tessarolo, F.; Nollo, G.; Benedetti, L.; Helfer, F.; Rovati, L.; Ferrari, A.; Marchetti, G.; Reverberi, F.; Baglio, S.; Tuccitto, N.; Stefani, S.; Stracquadanio, S.; Caraci, F.; Terrasi, A.; Tricomi, A.; Musumeci, M.; Miraglia, A.; Cuttone, G.; Cosentino, S.; Agostino Vitali, L.; Petrelli, D.; Ilaria Ciancia, S.; Mingoia, M.; Castellini, P.; Simoni, S.; Montalto, L.; Baleani, A.; Chiariotti, P.; Paone, N.
abstract
Six Italian non-accredited laboratories participated to an interlaboratory study aimed at measuring Differential Pressure (DP) and Bacterial Filtration Efficiency (BFE) of three face-mask models using methods in-line with EN 14683 standard. Methodological non-conformities were annotated. Repeatability and reproducibility on quintuplicate samples were calculated according to ISO 5725-2. Sample stability was also assessed. Laboratories were ranked according to the total standard deviation over all samples and proficiency was evaluated using z-score according to ISO 13528. Although some non-conformities were present, performances for the DP measurements were always acceptable. One laboratory had to revise the bacterial suspension preparation for the BFE test. Overall, non-accredited laboratories working during pandemic emergency performed satisfactorily. Sample-to-sample variability impacted measurement repeatability. BFE values above 98% showed good repeatability (≤1.0%) and reproducibility (≤6.1%), but high BFE uncertainty was associated to community masks. Our findings suggest that relevant face-mask conformity standards should consider uncertainty of BFE and DP measurements.
2021
- Preliminary investigation of the robustness of a fluorescent measuring system for in-line and real-time monitoring of blood-pH in extracorporeal circulation
[Relazione in Atti di Convegno]
Cattini, S.; Accorsi, L.; Truzzi, S.; Ferrari, A.; Rovati, L.
abstract
The possibility to monitor blood-pH has long been acknowledged to provide significant information for the diagnosis, management and treatment of a variety of diseases and it would be of considerable support for the administration of several treatments such as, for example, extracorporeal (blood) circulation (ECC). During ECC, the patient’s blood flows outside the body in disposable bloodlines and devices for treatments such as blood purification or circulation/ventilation/oxygenation support. Although blood-pH can be measured since the early twentieth century by using ion-selective electrodes (ISEs) and, more recently, also by using point-of-care testing (POCT) instruments, nowadays no measurement method has fully succeeded in providing a cost-effective, reliable and accurate estimate of the blood-pH to be routinely used for its real-time monitoring. In a recent paper, we have proposed and demonstrated a measuring instrument for the in-line and real-time monitoring of blood-pH during ECC. Such a measuring system consists of a low-cost fluorescent disposable sensor that can be integrated into the bloodline and, of a non-disposable reading system that interrogates the sensor without contacting the patient’s blood. In this paper, we investigated the robustness of such a measuring system to variations of blood parameters such as blood flow and hematocrit. The obtained results demonstrate that, although during the tests the pH, flow, and hematocrit values were significantly varied — pH from ≈ 6.8 pH, to ≈ 7.4 pH; hematocrit from 32%, to 40%; flow from 250 ml/min, to 400 ml/min, — the measuring system continued to guarantee a measurement error inferior to ±0.04 pH, thus complying with the metrological requirements for in-line and real-time monitoring of blood-pH during ECC.
2021
- Protocol for the DeFOG trial: A randomized controlled trial on the effects of smartphone-based, on-demand cueing for freezing of gait in Parkinson's disease
[Articolo su rivista]
Zoetewei, Demi; Herman, Talia; Brozgol, Marina; Ginis, Pieter; Thumm, Pablo Cornejo; Ceulemans, Eva; Decaluwé, Eva; Palmerini, Luca; Ferrari, Alberto; Nieuwboer, Alice; Hausdorff, Jeffrey M.
abstract
2021
- Testing surgical face masks in an emergency context: The experience of italian laboratories during the COVID-19 pandemic crisis
[Articolo su rivista]
Tessarolo, F.; Nollo, G.; Maniglio, D.; Rigoni, M.; Benedetti, L.; Helfer, F.; Corradi, I.; Rovati, L.; Ferrari, A.; Piccini, M.; Accorsi, L.; Veronesi, E.; Cuoghi, A.; Baglio, S.; Tuccitto, N.; Stefani, S.; Stracquadanio, S.; Caraci, F.; Terrasi, A.; Tricomi, A.; Musumeci, M.; Miraglia, A.; Cuttone, G.; Cosentino, S.; Muscas, C.; Vitali, L. A.; Petrelli, D.; Angrisani, L.; Colicchio, R.; D'Anna, A.; Iavicoli, I.; De Falco, G.; Di Natale, F.; Di Maio, E.; Salvatore, P.; Quaglia, F.; Mingoia, M.; Castellini, P.; Chiariotti, P.; Simoni, S.; Montalto, L.; Baleani, A.; Paone, N.
abstract
The first wave of the COVID-19 pandemic brought about a broader use of masks by both professionals and the general population. This resulted in a severe worldwide shortage of devices and the need to increase import and activate production of safe and effective surgical masks at the national level. In order to support the demand for testing surgical masks in the Italian context, Universities provided their contribution by setting up laboratories for testing mask performance before releasing products into the national market. This paper reports the effort of seven Italian university laboratories who set up facilities for testing face masks during the emergency period of the COVID-19 pandemic. Measurement set-ups were built, adapting the methods specified in the EN 14683:2019+AC. Data on differential pressure (DP) and bacterial filtration efficiency (BFE) of 120 masks, including different materials and designs, were collected over three months. More than 60% of the masks satisfied requirements for DP and BFE set by the standard. Masks made of nonwoven polypropylene with at least three layers (spunbonded–meltblown–spunbonded) showed the best results, ensuring both good breathability and high filtration efficiency. The majority of the masks created with alternative materials and designs did not comply with both standard requirements, resulting in suitability only as community masks. The effective partnering between universities and industries to meet a public need in an emergency context represented a fruitful example of the so-called university “third-mission”.
2020
- Anterior Callosal Angle: A New Marker of Idiopathic Normal Pressure Hydrocephalus?
[Articolo su rivista]
Mantovani, P.; Albini-Riccioli, L.; Giannini, G.; Milletti, D.; Sorenson, T. J.; Stanzani-Maserati, M.; Oppi, F.; Elder, B. D.; Cevoli, S.; Cortelli, P.; Palandri, G.; Agati, R.; Calandra-Buonaura, G.; Capellari, S.; Chiari, L.; Ferrari, A.; Merola, M.; Parchi, P.; Pirina, A.; Piserchia, V. A.; Ricci, V.; Sambati, L.; Sturiale, C.; Supino, A.
abstract
Objective: Diagnosing idiopathic normal pressure hydrocephalus (iNPH) still remains a clinical challenge. The callosal angle (CA) is a widely used neuroradiologic marker for iNPH. However, the relationship of the CA to clinical features has not been well investigated. We hypothesize that iNPH symptoms might better correlate with a variant of the CA (anterior callosal angle [ACA]). We aim to establish the validity of the ACA measurement for the diagnosis of iNPH and compare it with current radiologic parameters. Methods: The multidisciplinary BOLOGNA PRO-HYDRO Study Group performed a retrospective review of consecutive iNPH patients. Magnetic resonance imaging studies for these patients were collected, as well as magnetic resonance imaging studies from Alzheimer disease and healthy control patients. The CA, ACA, and Evans Index were measured by 2 blinded members of the study team based on magnetic resonance images for each of these populations. Results: The ACA shows high accuracy, sensitivity, and specificity in distinguishing iNPH patients from healthy control and Alzheimer disease patients. The optimal pathologic diagnostic cut-off value for the ACA is 119 degrees. The diagnostic accuracy of the ACA is not significantly different from the CA. Conclusions: The ACA could be a valid radiologic parameter in the diagnostic armamentarium for iNPH.
2020
- The effects of cerebrospinal fluid tap-test on idiopathic normal pressure hydrocephalus: an inertial sensors based assessment
[Articolo su rivista]
Ferrari, A.; Milletti, D.; Giannini, G.; Cevoli, S.; Oppi, F.; Palandri, G.; Albini-Riccioli, L.; Mantovani, P.; Anderlucci, L.; Cortelli, P.; Chiari, L.
abstract
BACKGROUND: Gait disturbances are typical of persons with idiopathic normal pressure hydrocephalus (iNPH) without signs distinctive from other neurodegenerative and vascular conditions. Cerebrospinal fluid tap-test (CSF-TT) is expected to improve the motor performance of iNPH patients and is a prognostic indicator in their surgical management. This observational prospective study aims to determine which spatio-temporal gait parameter(s), measured during instrumented motor tests, and clinical scale(s) may provide a relevant contribution in the evaluation of motor performance pre vs. post CSF-TT on iNPH patients with and without important vascular encephalopathy. METHODS: Seventy-six patients (20 with an associated vascular encephalopathy) were assessed before, and 24 and 72 h after the CSF-TT by a timed up and go test (TUG) and an 18 m walking test (18 mW) instrumented using inertial sensors. Tinetti Gait, Tinetti Balance, Gait Status Scale, and Grading Scale were fulfilled before and 72 h after the CSF-TT. Stride length, cadence and total time were selected as the outcome measures. Statistical models with mixed effects were implemented to determine the relevant contribution to response variables of each quantitative gait parameter and clinical scales. RESULTS AND CONCLUSION: From baseline to 72 h post CSF-TT patients improved significantly by increasing cadence in 18 mW and TUG (on average of 1.7 and 2.4 strides/min respectively) and stride length in 18 mW (on average of 3.1 cm). A significant reduction of gait apraxia was reflected by modifications in double support duration and in coordination index. Tinetti Gait, Tinetti Balance and Gait Status Scale were able to explain part of the variability of response variables not covered by instrumental data, especially in TUG. Grading Scale revealed the highest affinity with TUG total time and cadence when considering clinical scales alone. Patients with iNPH and an associated vascular encephalopathy showed worst performances compared to pure iNPH but without statistical significance. Gait improvement following CSF-TT was comparable in the two groups. Overall these results suggest that, in order to augment CSF-TT accuracy, is key to assess the gait pattern by analyzing the main spatio-temporal parameters and set post evaluation at 72 h. TRIAL REGISTRATION: Approved by ethics committee: CE 14131 23/02/2015.
2019
- A prospective evaluation of clinical and instrumental features before and after ventriculo-peritoneal shunt in patients with idiopathic Normal pressure hydrocephalus: The Bologna PRO-Hydro study
[Articolo su rivista]
Giannini, G.; Palandri, G.; Ferrari, A.; Oppi, F.; Milletti, D.; Albini-Riccioli, L.; Mantovani, P.; Magnoni, S.; Chiari, L.; Cortelli, P.; Cevoli, S.; Agati, R.; Calandra-Buonaura, G.; Capellari, S.; Parchi, P.; Stanzani-Maserati, M.; Marliani, A. F.; Merola, M.; Piserchia, V. A.; Sambati, L.; Sturiale, C.; Supino, A.; Nicola, M.; Urli, T.
abstract
Introduction: Idiopathic Normal Pressure Hydrocephalus (iNPH) is a complex and often misdiagnosed syndrome, whose major challenge is to identify which patients will benefit from surgery. Previous studies reported a variability in positive surgery response. The role of tap test(TT) in screening patients suitable for shunting is controversial. The primary aim of this study was to describe the clinical/instrumental features and their longitudinal progression after surgery in iNPH patients. Secondarily, we aimed to investigate the response of the three iNPH domains and the best time of outcome assessment after TT. Methods: Patients compatible with iNPH underwent a 3-T-MRI and an inpatients program with TT including standardized clinical evaluations, neuropsychological assessments and instrumental gait analysis pre- and after-(24-h and 72-h) TT. The multidisciplinary team selected candidates for surgery. Patients were evaluated 6- and 12-months after surgery. Results: A total of 154 consecutive patients were included from 2015 to 2018, 76 with an iNPH diagnosis (43 underwent surgery, 35 were evaluated after 6-months). Clinical and instrumented quantitative gait measures and urinary symptoms improved over time along with some neuropsychological functions. Concerning pre- and post-TT analyses, the three iNPH domains showed a different response after TT, the delayed motor assessment was more appropriate than the early one and the instrumental measures highlighted the motor improvement. Conclusion: iNPH patients improved after surgery, when accurately selected. A multidisciplinary team focused on this disease and a standardized protocol helped in achieving a correct diagnosis and management of iNPH. Our results could impact the management of this disease.
2019
- Analysis of Biofeedback Effects in Parkinson’s Disease at Multiple Time-Scales
[Relazione in Atti di Convegno]
Corzani, Mattia; Ferrari, Alberto; Ginis, Pieter; Nieuwboer, Alice; Chiari, Lorenzo
abstract
In this study we investigate the effects of motor adaptation and motor learning in persons with Parkinson’s disease during an home-based gait training program built on auditory biofeedback (BF). For this purpose, we assessed the motor response produced immediately after auditory BF messages and analysed it at multiple time-scales, within and between all training sessions. The findings indicate that motor adaptation is possible in a home-based training context for persons with PD using a wearable BF system.
2019
- Gait-Based Diplegia Classification Using LSMT Networks
[Articolo su rivista]
Ferrari, Alberto; Bergamini, Luca; Guerzoni, Giorgio; Calderara, Simone; Bicocchi, Nicola; Vitetta, Giorgio; Borghi, Corrado; Neviani, Rita; Ferrari, Adriano
abstract
Diplegia is a specific subcategory of the wide spectrum of motion disorders gathered under the name of cerebral palsy. Recent works proposed to use gait analysis for diplegia classification paving the way for automated analysis. A clinically established gait-based classification system divides diplegic patients into 4 main forms, each one associated with a peculiar walking pattern. In this work, we apply two different deep learning techniques, namely, multilayer perceptron and recurrent neural networks, to automatically classify children into the 4 clinical forms. For the analysis, we used a dataset comprising gait data of 174 patients collected by means of an optoelectronic system. The measurements describing walking patterns have been processed to extract 27 angular parameters and then used to train both kinds of neural networks. Classification results are comparable with those provided by experts in 3 out of 4 forms.
2019
- Motor Adaptation in Parkinson’s Disease During Prolonged Walking in Response to Corrective Acoustic Messages
[Articolo su rivista]
Corzani, M.; Ferrari, A.; Ginis, P.; Nieuwboer, A.; Chiari, L.
abstract
Wearable sensing technology is a new way to deliver corrective feedback. It is highly applicable to gait rehabilitation for persons with Parkinson’s disease (PD) because feedback potentially engages spared neural function. Our study characterizes participants’ motor adaptation to feedback signaling a deviation from their normal cadence during prolonged walking, providing insight into possible novel therapeutic devices for gait re-training. Twenty-eight persons with PD (15 with freezing, 13 without) and 13 age-matched healthy elderly (HE) walked for two 30-minute sessions. When their cadence varied, they heard either intelligent cueing (IntCue: bouts of ten beats indicating normal cadence) or intelligent feedback (IntFB: verbal instruction to increase or decrease cadence). We created a model that compares the effectiveness of the two conditions by quantifying the number of steps needed to return to the target cadence for every deviation. The model fits the short-term motor responses to the external step inputs (collected with wearable sensors). We found some significant difference in motor adaptation among groups and subgroups for the IntCue condition only. Both conditions were instead able to identify different types of responders among persons with PD, although showing opposite trends in their speed of adaptation. Increasing rather than decreasing the pace appeared to be more difficult for both groups. In fact, under IntFB the PD group required about seven steps to increase their cadence, whereas they only needed about three steps to decrease their cadence. However, it is important to note that this difference was not significant; perhaps future work could include more participants and/or more sessions, increasing the total number of deviations for analysis. Notably, a significant negative correlation, r = −0.57 (p-value = 0.008), was found between speed of adaptation and number of deviations during IntCue, but not during IntFB, suggesting that, for people who struggle with gait, such as those with PD, verbal instructions rather than metronome beats might be more effective at restoring normal cadence. Clinicians and biofeedback developers designing novel therapeutic devices could apply our findings to determine the optimal timing for corrective feedback, optimizing gait rehabilitation while minimizing the risk of cue-dependency.
2018
- Monitoring human activities that might cause work-related musculoskeletal disorders by means of inertial and magnetic sensors
[Relazione in Atti di Convegno]
Chiari, L.; Ferrari, A.
abstract
Activity recognition based on new wearable technologies is considered a key research challenge in the field of applied ergonomics. Deterioration of workers' physical health and loss of workdays impact not only on their wellbeing and quality of life, but also on European countries economy. Musculoskeletal disorders are injuries or pain affecting muscles, joints and tendons. If these disorders are work related are described as Work related Musculoskeletal Disorders (WMSDs). Inertial and magnetic sensor units (IMUs) might open new perspectives in detection and objective measure of WMSDs because they allow to collect data on work activities under free conditions and over extended periods of time. The evolution of technologies has observed not only improvement in measurement accuracy and precision, but also a reduction in intrusiveness and an enhanced fit of the measure technologies.
2018
- Motor Adaptation in Response to Audio-Biofeedback in Parkinson's disease
[Abstract in Rivista]
Corzani, M.; Ferrari, A.; Ginis, P.; Nieuwboer, A.; Chiari, L.
abstract
2017
- External input for gait in people with Parkinson’s disease with and without freezing of gait: One size does not fit all
[Articolo su rivista]
Ginis, Pieter; Heremans, Elke; Ferrari, Alberto; Bekkers, Esther M. J.; Canning, Colleen G.; Nieuwboer, Alice
abstract
Cueing or feedback provided when gait deviates from a predefined goal (intelligent input) can now be provided with wearable technology for Parkinson’s disease (PD). As people with and without freezing of gait (FOG) have distinct cognitive profiles, they may respond differently to various types of input. This study compared the effects of four input modalities during prolonged walking and explored the relationship with cognition, subjective preference, and FOG. Participants (15 with and 13 without FOG) walked 30 min while exposed to continuous cueing; intelligent cueing; intelligent feedback; or no input. Cueing consisted of metronome beats matched to comfortable cadence. Intelligent input represented bouts of ten beats indicating comfortable cadence (intelligent cueing) or an instruction to adapt gait speed (intelligent feedback) when cadence deviated from the comfortable target. Preference for one condition over the other was gathered. Freezers produced most stable gait under continuous cueing, but the majority favored intelligent feedback. Non-freezers showed no differences between conditions, but gait was more stable under intelligent input than in freezers. Interestingly, lower cognitive scores were related to worse gait during intelligent input, most prominently seen in freezers. These results suggest that cognitive ability is an aspect to take into account when deciding on the most appropriate cueing modality in different PD subgroups.
2017
- Focusing on heel strike improves toe clearance in people with Parkinson's disease: An observational pilot study
[Articolo su rivista]
Ginis, Pieter; Pirani, Rudi; Basaia, Silvia; Ferrari, Alberto; Chiari, Lorenzo; Heremans, Elke; Canning, Colleen G.; Nieuwboer, Alice
abstract
Objectives: To investigate differences in toe clearance between people with PD and age-matched healthy elderly (HE) during comfortable walking and to study the effects of dual-tasking and the use of an attentional strategy emphasizing heel strike on toe clearance. Design: Observational cross-sectional study. Setting: Camera-based 3D gait laboratory. Participants: Ten persons with PD (Hoehn and Yahr I to III) having mild gait disturbances and 10 HE. Interventions: Participants walked for two minutes under three conditions at comfortable pace: single-task walking, attending to heel strike during single-task walking, and dual-task walking. Main outcome measures: Minimal and maximal toe clearance; foot strike angle with the ground. Results: People with PD had less maximal toe clearance in the end of the swing phase and a smaller foot strike angle than HE during all three walking conditions. Impairments significantly diminished during heel strike focused walking improving performance to equal the HE. Heel strike focused walking resulted in an increased minimal toe clearance and a longer duration of end swing phase when compared to walking with and without a dual-task. The attentional strategy to focus on heel strike improved the stride length when compared to dual-task walking. Surprisingly, minimal toe clearance did not differ between PD and HE in any of the conditions and there were no dual-task effects on toe clearance. Conclusion: These findings provide evidence favoring the potential incorporation of an attentional strategy focusing on the heel strike in PD gait rehabilitation.
2017
- Prolonged walking with a wearable system providing intelligent auditory input in people with Parkinson's disease
[Articolo su rivista]
Ginis, Pieter; Heremans, Elke; Ferrari, Alberto; Dockx, Kim; Canning, Colleen G.; Nieuwboer, Alice
abstract
Rhythmic auditory cueing is a well-accepted tool for gait rehabilitation in Parkinson's disease (PD), which can now be applied in a performance-adapted fashion due to technological advance. This study investigated the immediate differences on gait during a prolonged, 30 min, walk with performance-adapted (intelligent) auditory cueing and verbal feedback provided by a wearable sensor-based system as alternatives for traditional cueing. Additionally, potential effects on self-perceived fatigue were assessed. Twenty-eight people with PD and 13 age-matched healthy elderly (HE) performed four 30 min walks with a wearable cue and feedback system. In randomized order, participants received: (1) continuous auditory cueing; (2) intelligent cueing (10 metronome beats triggered by a deviating walking rhythm); (3) intelligent feedback (verbal instructions triggered by a deviating walking rhythm); and (4) no external input. Fatigue was self-scored at rest and after walking during each session. The results showed that while HE were able to maintain cadence for 30 min during all conditions, cadence in PD significantly declined without input. With continuous cueing and intelligent feedback people with PD were able to maintain cadence (p = 0.04), although they were more physically fatigued than HE. Furthermore, cadence deviated significantly more in people with PD than in HE without input and particularly with intelligent feedback (both: p = 0.04). In PD, continuous and intelligent cueing induced significantly less deviations of cadence (p = 0.006). Altogether, this suggests that intelligent cueing is a suitable alternative for the continuous mode during prolonged walking in PD, as it induced similar effects on gait without generating levels of fatigue beyond that of HE.
2017
- Signal Processing and Machine Learning for Diplegia Classification
[Relazione in Atti di Convegno]
Bergamini, Luca; Calderara, Simone; Bicocchi, Nicola; Ferrari, Alberto; Vitetta, Giorgio
abstract
Diplegia is one of the most common forms of a broad family of motion disorders named cerebral palsy (CP) affecting the voluntary muscular system. In recent years, various classification criteria have been proposed for CP, to assist in diagnosis, clinical decision-making and communication. In this manuscript, we divide the spastic forms of CP into 4 other categories according to a previous classification criterion and propose a machine learning approach for automatically classifying patients. Training and validation of our approach are based on data about 200 patients acquired using 19 markers and high frequency VICON cameras in an Italian hospital. Our approach makes use of the latest deep learning techniques. More specifically, it involves a multi-layer perceptron network (MLP), combined with Fourier analysis. An encouraging classification performance is obtained for two of the four classes.
2016
- A Mobile Kalman-Filter Based Solution for the Real-Time Estimation of Spatio-Temporal Gait Parameters
[Articolo su rivista]
Ferrari, Alberto; Ginis, Pieter; Hardegger, Michael; Casamassima, Filippo; Rocchi, Laura; Chiari, Lorenzo
abstract
Gait impairments are among the most disabling symptoms in several musculoskeletal and neurological conditions, severely limiting personal autonomy. Wearable gait sensors have been attracting attention as diagnostic tool for gait and are emerging as promising tool for tutoring and guiding gait execution. If their popularity is continuously growing, still there is room for improvement, especially towards more accurate solutions for spatio-temporal gait parameters estimation. We present an implementation of a zero-velocity-update gait analysis system based on a Kalman filter and off-the-shelf shoe-worn inertial sensors. The algorithms for gait events and step length estimation were specifically designed to comply with pathological gait patterns. More so, an Android app was deployed to support fully wearable and stand-alone real-time gait analysis. Twelve healthy subjects were enrolled to preliminarily tune the algorithms; afterwards sixteen persons with Parkinson's disease were enrolled for a validation study. Over the 1314 strides collected on patients at three different speeds, the total root mean square difference on step length estimation between this system and a gold standard was 2.9%. This shows that the proposed method allows for an accurate gait analysis and paves the way to a new generation of mobile devices usable anywhere for monitoring and intervention.
2016
- Feasibility and effects of home-based smartphone-delivered automated feedback training for gait in people with Parkinson's disease: A pilot randomized controlled trial
[Articolo su rivista]
Ginis, Pieter; Nieuwboer, Alice; Dorfman, Moran; Ferrari, Alberto; Gazit, Eran; Canning, Colleen G.; Rocchi, Laura; Chiari, Lorenzo; Hausdorff, Jeffrey M.; Mirelman, Anat
abstract
Background: Inertial measurement units combined with a smartphone application (CuPiD-system) were developed to provide people with Parkinson's disease (PD) real-time feedback on gait performance. This study investigated the CuPiD-system's feasibility and effectiveness compared with conventional gait training when applied in the home environment.
Methods: Forty persons with PD undertook gait training for 30 min, three times per week for six weeks. Participants were randomly assigned to i) CuPiD, in which a smartphone application offered positive and corrective feedback on gait, or ii) an active control, in which personalized gait advice was provided. Gait, balance, endurance and quality of life were assessed before and after training and at four weeks follow-up using standardized tests.
Results: Both groups improved significantly on the primary outcomes (single and dual task gait speed) at post-test and follow-up. The CuPiD group improved significantly more on balance (MiniBESTest) at posttest (from 24.8 to 26.1, SD~5) and maintained quality of life (SF-36 physical health) at follow-up whereas the control group deteriorated (from 50.4 to 48.3, SD~16). No other statistically significant differences were found between the two groups. The CuPiD system was well-tolerated and participants found the tool user-friendly.
Conclusion: CuPiD was feasible, well-accepted and seemed to be an effective approach to promote gait training, as participants improved equally to controls. This benefit may be ascribed to the real-time feedback, stimulating corrective actions and promoting self-efficacy to achieve optimal performance. Further optimization of the system and adequately-powered studies are warranted to corroborate these findings and determine cost-effectiveness.
2016
- Handling gait impairments of persons with Parkinson’s disease by means of real-time biofeedback in a daily life environment
[Capitolo/Saggio]
Ferrari, Alberto; Ginis, Pieter; Nieuwboe, Alice; Greenlaw, Reynold; Muddiman, Andrew; Chiari, Lorenzo
abstract
A smartphone app with telemedicine capability integrating data from foot-mounted inertial measurement units (CuPiD-system) was developed to realize a portable gait analysis system and, on top of it, to provide people with Parkinson’s disease (PD) remote supervision and real-time feedback on gait performance. Eleven persons with PD were recommended to perform gait training for 30 min, three times per week for six weeks. The app offered praising/corrective verbal feedback, encouraging participants to keep the spatio-temporal gait parameters within a clinically determined ‘therapeutic window’. On average, persons performed 20 training sessions of 1.8 km in 24 min and received 28 corrective and 68 praising messages. The mean walking rhythm was 58 strides/min with a stride length of 1.28 m. System’s usability was determined as positive by the users. In conclusion, CuPiD resulted to be effective in promoting gait training in semi-supervised conditions, stimulating corrective actions and promoting selfefficacy to achieve optimal performance.
2015
- Smart Environments and Systems for Maintaining Health and Independent Living: The FARSEEING and CuPiD Projects
[Capitolo/Saggio]
Mellone, Sabato; Ferrari, Alberto; Tacconi, Carlo; Valtolina, E.; Greenlaw, R.; Nawaz, A.; Bourke, A.; Ferriol, P.; Farella, Elisabetta; Rocchi, Laura; Hawley Hague, H.; Chiari, Lorenzo
abstract
Home Control and Automation systems are often modular and offer the flexibility and dependability to make life easier. Wearable sensor systems for health monitoring are an emerging trend and are expected to enable proactive personal health management. Using home-based technology and personal devices the aim is to motivate and support healthier lifestyle; this is a challenge which has been addressed in the framework of FARSEEING and CuPiD EU projects. Contrary to visions that consider home automation and personal health systems as a mean to replace or to simplify the subject control and actions, in the FARSEEING and CuPiD approach smartphones, wearable devices, and home based technology are used to stimulate the user by making life mentally and physically more challenging but without losing comfort.
2015
- Stability study of a wearable audio-feedback system for gait rehabilitation in persons with parkinson's disease
[Relazione in Atti di Convegno]
Ferrari, A.; Ginis, P.; Mirelman, A.; Gazit, E.; Nieuwboer, A.; Dorfman, M.; Hausdorff, J. M.; Rocchi, L.; Chiari, L.
abstract
2014
- A wearable system for gait training in subjects with Parkinson's disease
[Articolo su rivista]
Casamassima, Filippo; Ferrari, Alberto; Milosevic, Bojan; Ginis, Pieter; Farella, Elisabetta; Rocchi, Laura
abstract
In this paper, a system for gait training and rehabilitation for Parkinson’s disease (PD) patients in a daily life setting is presented. It is based on a wearable architecture aimed at the provision of real-time auditory feedback. Recent studies have, in fact, shown that PD patients can receive benefit from a motor therapy based on auditory cueing and feedback, as happens in traditional rehabilitation contexts with verbal instructions given by clinical operators. To this extent, a system based on a wireless body sensor network and a smartphone has been developed. The system enables real-time extraction of gait spatio-temporal features and their comparison with a patient’s reference walking parameters captured in the lab under clinical operator supervision. Feedback is returned to the user in form of vocal messages, encouraging the user to keep her/his walking behavior or to correct it. This paper describes the overall concept, the proposed usage scenario and the parameters estimated for the gait analysis. It also presents, in detail, the hardware-software architecture of the system and the evaluation of system reliability by testing it on a few subjects.
2014
- Step length estimation using shoe-mounted inertial sensors: Application in clinical settings
[Relazione in Atti di Convegno]
Ferrari, Alberto; Chiari, Lorenzo; Ginis, Pieter; Rocchi, Laura
abstract
2014
- Wearable system for auditory feedback based on real-time gait analysis: Application on patients with Parkinson's disease
[Relazione in Atti di Convegno]
Ferrari, A.; Milosevic, B.; Casamassima, F.; Chiari, L.; Rocchi, L.
abstract
2013
- An experimental approach to automatically classify children with cerebral palsy
[Relazione in Atti di Convegno]
Cocconcelli, Marco; Reggiani, G.; Ferrari, A.; Rubini, Riccardo
abstract
This experimental study is aimed at automatically classify the large indistinct group of children affected by diplegic Cerebral Palsy (CP), into four main clinical forms characterized by homogeneous walking patterns as clinically proposed by Ferrari et al. The classification is based on the use of data gathered on 104 patients at LAMBDA (Laboratorio per l’Analisi del Movimento del Bambino DisAbile, S.M.Nuova Hospital, Reggio Emilia, Italy) by means of an 8 cameras optoelectronic system (Vicon, UK) and the Total3Dgait biomechanical protocol. This paper deals with the use of expert systems, such as artificial neural networks (ANN), that are able to learn by examples. ANN has been widely used in mechanics for the resolution of pattern recognition and diagnostic problems. Our aims is to extend the use of these expert systems to classify the four diplegic forms through the analysis of the rotation angles of the lower limb joints along multiple gait cycles. On each walking trial of each patient a set of synthetic statistical parameters representative of joint angles, has been used as input to train a supervised ANN in order to divide patients into the four forms a priori clinically determined. The first attempt consists in a Feed- Forward network trained considering data coming from all the four forms. The effectiveness of the resulting ANN has been proved on a data set acquired by new patiens. In this case, the performace on the form recognition was encouraging but still far from an implementation in clinical routine. In order to improve the efficiency we simplified the recognition problem by creating a network which was asked first to distinguish between two macro- categories, consisting of two forms each. On the basis of the two splitted dataset returned by this first ANN layer, two further network were trained seperately. To these network was finally asked to provide the affinity with one of the original four forms. In this “system of networks” case, the overall performance increased significantly becoming clinically meaningful
2013
- Gait analysis in children with cerebral palsy via inertial and magnetic sensors
[Articolo su rivista]
Van Den Noort, Josien C.; Ferrari, Alberto; Cutti, Andrea G.; Becher, Jules G.; Harlaar, Jaap
abstract
3D kinematic measurements in children with cerebral palsy (CP) to assess gait deviations can only be performed in gait laboratories using optoelectronic systems. Alternatively, an inertial and magnetic measurement system (IMMS) can be applied for ambulatory motion-tracking. A protocol named Outwalk has recently been developed to measure the 3D kinematics during gait with IMMS. This study preliminary validated the application of IMMS, based on the Outwalk protocol, in gait analysis of six children with CP and one typically developing child. Reference joint kinematics were simultaneously obtained from a laboratory-based system and protocol. On average, the root mean square error (RMSE) of Outwalk/IMMS, compared to the reference, was less than 17 in the transversal plane, and less than 10 in the sagittal and frontal planes. The greatest differences were found in offsets in the knee and ankle rotation, and in the hip flexion. These offset differences were mainly caused by a different anatomical calibration in the protocols. When removing the offsets, RMSE was always less than 4. Therefore, IMMS is suitable for gait analysis of major joint angles in a laboratory-free setting. Further studies should focus on improvement of anatomical calibrations of IMMS that can be performed in children with CP. © 2012 International Federation for Medical and Biological Engineering.
2013
- Step length estimation using inertial sensors: Evaluation study
[Relazione in Atti di Convegno]
Ferrari, A.; Rocchi, L.; Van den Noort, J.; Harlaar, J.
abstract
2013
- Toward the use of wearable inertial sensors to train gait in subjects with movement disorders
[Capitolo/Saggio]
Ferrari, A.; Rocchi, L.; van den Noort, J.; Harlaar, J.
abstract
This study presents an algorithm to estimate gait features, from on-body mounted inertial sensors, and preliminary results on two sampling populations. Estimated gait features are compared with gold standard system (camera-based) for gait analysis. Difference of estimated step length and god standard measure is below 5% when considering median values. Results are promising toward the aim of including this approach in a system for training and assessment of gait for people with movement disorders.
2013
- Wearable Audio-feedback System for Gait Rehabilitation in Subjects with Parkinson's Disease
[Relazione in Atti di Convegno]
Casamassima, F.; Ferrari, A.; Milosevic, B.; Rocchi, L.; Farella, E.
abstract
2011
- About the classification of the children with cerebral palsy by means of artificial neural network
[Articolo su rivista]
Reggiani, G.; Ferrari, A.; Cocconcelli, Marco; Rubini, Riccardo
abstract
This preliminary study deals with the classification of thediplegic children affected by cerebral palsy (CP) – based on theprotocol for gait analysis Total3Dgait used in LAMBDA motionanalysis laboratory at S.M. Nuova Hospital of Reggio Emilia– using kinematics data and by means of artificial neural network(ANN). The classification systems for cerebral palsy (CP)need to be continuously updated, according to specific aims andto significant changes observed over the years in the panoramaof CP. Ferrari et al., proposed a classification system where issuggested to divide the diplegic children into four main clinicalforms, according to the patterns of walking observable in thesesubjects
2011
- Use of Neural Networks in Children’s Cerebral Palsy Recognition by Gait Analysis Data
[Capitolo/Saggio]
Reggiani, G.; Cocconcelli, Marco; Rubini, Riccardo; Borghi, C.; Ferrari, A.
abstract
The classification systems for cerebral palsy (CP) need to be continuouslyupdated, according to specific objectives and to significant changes observed over theyears in the panorama of CP. Ferrari et al. [1], recently proposed a classification systemthat aimed at subdividing the diplegic children into four main clinical sub-forms, on thebase of their walking pattern. This preliminary study deals with the classification of thediplegic children affected by CP and it is based on the walking pattern classification systemproposed by Ferrari and utilized in LAMBDA motion analysis laboratory at S. MariaNuova Hospital of Reggio Emilia. Using kinematics data recorded by means of anoptoelectronic system on children affected by CP, an Artificial Neural Network (ANN) wasimplemented to allow an automatic recognition of the form of the palsy. The ANN proposedcorrelates a set of suitable statistical parameters of the kinematics of walking with the typeof diplegic clinical form. The effectiveness of the resulting neural network has been provedon a control set of data
2010
- 'Outwalk': a protocol for clinical gait analysis based on inertial and magnetic sensors
[Articolo su rivista]
Cutti, Ag; Ferrari, Adriano; Garofalo, P; Raggi, M; Cappello, A; Ferrari, A.
abstract
A protocol named Outwalk was developed to easily measure the thorax-pelvis and lower-limb 3D kinematics on children with cerebral palsy (CP) and amputees during gait in free-living conditions, by means of an Inertial and Magnetic Measurement System (IMMS). Outwalk defines the anatomical/functional coordinate systems (CS) for each body segment through three steps: (1) positioning the sensing units (SUs) of the IMMS on the subjects' thorax, pelvis, thighs, shanks and feet, following simple rules; (2) computing the orientation of the mean flexion-extension axis of the knees; (3) measuring the SUs' orientation while the subject's body is oriented in a predefined posture, either upright or supine. If the supine posture is chosen, e.g. when spasticity does not allow to maintain the upright posture, hips and knees static flexion angles must be measured through a standard goniometer and input into the equations that define Outwalk anatomical CSs. In order to test for the inter-rater measurement reliability of these angles, a study was carried out involving nine healthy children (7.9 +/- 2 years old) and two physical therapists as raters. Results showed RMS error of 1.4 degrees and 1.8 degrees and a negligible worst-case standard error of measurement of 2.0 degrees and 2.5 degrees for hip and knee angles, respectively. Results were thus smaller than those reported for the same measures when performed through an optoelectronic system with the CAST protocol and support the beginning of clinical trials of Outwalk with children with CP.
2010
- A new formulation of the coefficient of multiple correlation to assess the similarity of waveforms measured synchronously by different motion analysis protocols
[Articolo su rivista]
Ferrari, A.; Cutti, A. G.; Cappello, A.
abstract
Different 3D motion analysis protocols are currently available, but little is known regarding the level of similarity of their outcomes, e.g. whether a joint-angle waveform from one protocol can be interchanged with that measured by another protocol. Similarity assessments are therefore urgent to ease the comparison of results. In this context, a major issue is how to quantify the similarity between waveforms measured synchronously through different protocols, within each of many movement-cycles (e.g. gait-cycle), when the effect of protocols on waveforms similarity is the only of interest. For this purpose we developed a new formulation of the statistical index called coefficient of multiple correlation (CMC). The CMC measures the overall similarity of waveforms taking into account the concurrent effects of differences in offset, correlation, and gain. The within-day CMC originally proposed by Kadaba et al. [7], was firstly reinterpreted in terms of "excluded factors". Then, the new formulation was set to assess the inter-protocol similarity, removing the between-gait-cycle variability. An example showing the effectiveness of the new formulation is presented regarding the pelvis-trunk and ankle kinematics.
2010
- Detection of the Centre of Pressure for the Double-Contact Problem between Feet and Platform in Gait Analysis
[Capitolo/Saggio]
Cocconcelli, Marco; Rubini, Riccardo; Ferrari, A.; Costi, Stefania
abstract
.
2010
- Dysperceptive forms
[Capitolo/Saggio]
Alboresi, Silvia; Ferrari, Adriano; Ferrari, Alberto
abstract
In over thirty years of clinical observation of cerebral palsied (CP) children, especially among premature babies with bilateral motor damage, we have repeatedly found a group of patients with a unique combination of clinical characteristics which, we believe, could represent a specific group within the CP categorization. For convenience, we have termed them dysperceptive and we have been studying their behavior in a fairly large group of patients in order to see if some phenomena, unmistakably observed in single cases, were recognizable, also in different degrees, in larger groups. We have maintained the term perceptual disturbance or dysperception for the first and most interesting hypothesis that the errors performed by these children could happen during the collection, interpretation, and re-elaboration of information, especially of the sense of movement, even if other fascinating theories can be found especially in the field of psychology. These complex behaviors, for example fear, can be observed during clinical examination or physiotherapeutic treatments. In addition, parents and older children often describe some specific situations, which are recurrent and typical, that take place in everyday life in different settings (at school, on holiday, with friends, etc.), often underlining the limitations produced by these phenomena regarding motor independence and quality of life. These signs can be observed in CP children with diverse motor damage (diplegia, tetraplegia, but not hemiplegia) and at different development levels. In order to explore consistency and recurrence of the more important or frequent dysperceptive signs, describe them in detail and collect evidence by suitable instruments, we have been and are still employing video recording sessions (natural history of these signs). © 2010 Springer-Verlag Milan.
2010
- First in vivo assessment of "Outwalk": a novel protocol for clinical gait analysis based on inertial and magnetic sensors
[Articolo su rivista]
Ferrari, A.; Cutti, A. G.; Garofalo, P.; Raggi, M.; Heijboer, M.; Cappello, A.; Davalli, A.
abstract
A protocol named "Outwalk" was recently proposed to measure the thorax-pelvis and lower-limb kinematics during gait in free-living conditions, by means of an inertial and magnetic measurement system (IMMS). The aim of this study was to validate Outwalk on four healthy subjects when it is used in combination with a specific IMMS (Xsens Technologies, NL), against a reference protocol (CAST) and measurement system (optoelectronic system; Vicon, Oxford Metrics Group, UK). For this purpose, we developed an original approach based on three tests, which allowed to separately investigate: (1) the consequences on joint kinematics of the differences between protocols (Outwalk vs. CAST), (2) the accuracy of the hardware (Xsens vs. Vicon), and (3) the summation of protocols' differences and hardware accuracy (Outwalk + Xsens vs. CAST + Vicon). In order to assess joint-angles similarity, the coefficient of multiple correlation (CMC) was used. For test 3, the CMC showed that Outwalk + Xsens and CAST + Vicon kinematics can be interchanged, offset included, for hip, knee and ankle flexion-extension, and hip ab-adduction (CMC > 0.88). The other joint-angles can be interchanged offset excluded (CMC > 0.85). Tests 1 and 2 also showed that differences in offset between joint-angles were predominantly induced by differences in the protocols; differences in correlation by both hardware and protocols; differences in range of motion by the Xsens accuracy. Results thus support the commencement of a clinical trial of Outwalk on transtibial amputees.
2010
- Functional reaching discloses perceptive impairment in diplegic children with cerebral palsy
[Articolo su rivista]
Adriano, Ferrari; Tersi, Luca; Ferrari, Alberto; Sghedoni, Alice; Chiari, Lorenzo
abstract
The currently accepted definition classifies Cerebral Palsy (CP) as a mere posture andmovement disorder. Conversely, some authors have recently associated the presence of several motordysfunctions exhibited by diplegic children with CP to an impairment in the perceptive system. Theaim of the present study was to investigate the influence of the Perceptive Impairment (PI) on motorcontrol and to appraise if the PI can be revealed by a reaching task.A functional reach and touch experiment was accomplished from sitting posture considering differentdirections and distances. Typically developing and diplegic children with CP were enrolled and, thelatter, a priori divided in two subgroups considering a positive or negative diagnosis of PI. Thereaching trials were quantified by means of centre of pressure analysis in terms of the overall qualityof the task, and accuracy and effectiveness of postural adjustments and Anticipatory PosturalAdjustments (APAs).The three groups showed statistically significant differences in terms of percentage of touched target,and of time spent and maximum distance covered to reach the target. In particular, PI caused a majordifficulty in accomplishing the reaching tasks, thus a lower autonomy level in action. Overall, the PIstrongly affected the anticipatory control system. Children with PI, rarely recruited APAs, each ofwhich was characterized by small amplitude and inaccuracy in direction. The lack of effective APAsindicated how PI strongly influenced the motor control strategy.The present study demonstrates that the PI is a primary syndrome responsible for the long-termprognosis beside the motor and the postural disorders in CP
2010
- Outcome evaluation of surgery treatment by means of gait analysis in children with cerebral palsy: the normality pattern is not an effective term of comparison
[Abstract in Atti di Convegno]
Neviani, R.; Costi, Stefania; Borghi, C.; Ferrari, Adriano; Faccioli, S.; Ferrari, A.
abstract
INTRODUCTION: Among the treatments available for the rehabilitation of the alterations of walking in children affected by Cerebral Palsy (CP), multilevel surgery is one of the most effective and used solutions despite its irreversible nature. Increasingly literature provides evidences of the large benefits afforded by Gait Analysis (GA) in the process of surgery decision making and in the choice of the most appropriate surgery tecnique [1]. However, besides the diagnostic process, GA can be used in order to measure accurately and effectively the outcome of the treatment [1]. The aim of the present study is to demonstrate how deviations in the kinematic pattern of walking provoked by a surgery treatment can determine i) an improvement in the motor performance and ii) an increase in the autonomy level in action, also when they vary in the opposite direction with respect to the normal pattern.METHODS: 15 dipelgic children with purely spastic forms of CP (age range 7 – 17 years) classified in one of the four forms of diplegia proposed by [2] and addressed by a clinical examination to undergo a functional surgery treatment on the lower limbs, participated in the study. The aim of the surgery treatment was to improve the motor performance and the autonomy level in walking. The treatments adopdet included tendon and muscolar lengthenings, and interventions of skeleton correction. The motor performance exhibited by the subjects was measured both by means of the Gross Motor Function Measure 88 (GMFM) by using merely the dimension D and E [3], and of GA, the day before (session PRE) and after six months (session POST) the surgery intervention. The kinematic of at least three gait cycles for each limb was acquired through the protocol Total3DGait [4] by means of an 8 cameras Vicon MX+ system (Vicon Motion System, UK). The 9 kinematic variables relative to the sagittal, frontal and transverse plane rotations of the hip, knee and ankle and the 4 relative to the rotations on the sagittal and frontal plane of the segments pelvis and trunk obtained during the PRE and POST sessions were compared with respect to the normality bands [4]. In particular, for each of the 13 kinematic variables considered, set of 3 mean waveforms were computed from the gait cycles acquired in the two sessions PRE and POST and from the normality bands. For each subject, the approach of the 13 mean waveforms of the POST session towards the normality, with respect to the ones of the session PRE, was computed in terms of offset (Off) and Range of Movement (ROM). In particular, positive values of Off and ROM indicate an approach of the POST mean waveforms to the normal ones in the absolute and range terms. RESULTS: The GMFM values obtained were positive in 13 cases over 15, with a percentage mean value of 3.4 and a standard deviation of 6.1. The following table reports the mean and the standard deviation values relative to Off and ROM obtained from the 13 kinematics variable considered for each of the 15 subjects enrolled. p1p2p3p4p5p6p7p8p9p10p11p12p13p14p15ROMmean-0.3-1.60.4-0.70.22.11.3-0.5-0.31.8-0.50.8-0.91.50.2sd3.36.64.09.04.25.76.12.56.43.73.65.54.62.74.3Offmean0.3-2.00.20.9-0.33.3-0.60.53.23.72.6-0.11.11.4-0.2sd5.85.16.44.95.98.25.53.08.414.96.95.47.66.24.1Table 1: mean and standard deviations (sd) values obtained for Off and ROM over the 13 kinematics variables considered for the 15 subjects (p1 – p15).DISCUSSION: The GMFM data obtained revealed an improvement in the autonomy level in action in 13 cases over 15. On the contrary, the elevated values of the standard deviations together with mean values close to 0 of Off and ROM parameters, demonstrate that the kinematic waveforms obtained in the POST session did not approach the normality pattern homogeneously among the different joints of a single subject. Therefore, the comparison of the GA data with respect to the normality bands was not effective in the asses
2010
- Sul riconoscimento delle forme di spasticità nella paralisi celebrale infantile mediante reti neurali
[Relazione in Atti di Convegno]
Reggiani, G.; Ferrari, A.; Cocconcelli, Marco; Rubini, Riccardo
abstract
Il presente lavoro ha l’intento di presentare uno studio preliminare su un sistema di riconoscimento delle forme di spasticità della Paralisi Cerebrale Infantile (PCI), basato sul protocollo di analisi del movimento Total3Dgait in uso presso il LAMBDA (Laboratorio per l’Analisi del Movimento del Bambino DisAbile) dell’Arcispedale S.M. Nuova di Reggio Emilia [1], a partire dai dati rilevati ed elaborati da sistemi di analisi del cammino e classificati tramite l’utilizzo di reti neurali
2009
- Anticipatory postural control in the diplegic forms of cerebral palsy: influence of the perceptive impairment
[Relazione in Atti di Convegno]
Tersi, Luca; Ferrari, Alberto; Ferrari, A. d.; A., Sghedoni; Chiari, Lorenzo
abstract
Children with Diplegic Infantile
Cerebral Palsy (dICP) frequently show functional
disabilities which cannot be ascribed to motor
dysfunctions but rather directly to an impaired
movement perception. This Perceptive Impairment
(PI) entails the failure of a complex multisensory
process involving the proprioceptive, visual,
somaesthetic, and vestibular systems [1]. Children
with PI recurrently show the following signs: i)
exaggerated and low threshold startle reaction, ii)
freezing posture, iii) blinking or closing eyes, iv)
visual attention shifting, and v) facial grimaces.
Postural adjustments depend on motor reactions as
well as on perception, but perception has a leading
role in anticipation [1]. We aimed to investigate how
PI negatively influences Anticipatory Postural
Adjustments (APAs).
2009
- Development and test of a protocol based on an Inertial and Magnetic Measurement System to measure the 3D kinematics of gait in real-life environment
[Relazione in Atti di Convegno]
Cutti, Andrea Giovanni; Garofalo, Pietro; Ferrari, Alberto; Raggi, Michele; Cappello, Angelo
abstract
2009
- Inter-operator reliability and prediction bands of a novel protocol to measure the coordinated movements of shoulder-girdle and humerus in clinical setting
[Articolo su rivista]
Garofalo, Pietro; Cutti, Ag; Filippi, Mv; Cavazza, S; Ferrari, Alberto; Cappello, Angelo; Davalli, A.
abstract
A clinical motion analysis protocol was developed to measure the coordinated movements of shoulder-girdle and humerus (girdle-humeral rhythm-GD-H-R) during humerus flexion-extension (HFE) and ab-adduction (HAA), through an optoelectronic system. In particular, the protocol describes the GD-H-R with 2 angle-angle plots for each movement: girdle elevation-depression and protraction-retraction vs HFE, and vs HAA. Each of these plots is further divided in two subplots, one for the upward and one for the downward phases of the movement. By involving 11 participants and 2 operators, we measured the protocol's inter-operator reliability which ranged from very-good to excellent depending on the angle-angle plot (median values of the inter-operator coefficient of multiple correlation for the angle-angle plots higher than 0.94). We then computed the subjects' average control patterns, together with statistically meaningful prediction bands. +/-1SD confidence bands were also computed and their width ranged from +/-0.5 degrees to +/-4.6 degrees . Based on these results we could conclude that the method is robust and able to identify even limited differences in the GD-H-R.
2009
- Measure of the 3D gait kinematics in real-life environments through the Outwalk protocol: Development of the end-user clinical software
[Relazione in Atti di Convegno]
Garofalo, Pietro; Raggi, Michele; Ferrari, Alberto; Cutti, Andrea Giovanni; Davalli, Angelo
abstract
2009
- Ortesi modulare astragalo calcaneare (OMAC): Study of its efficacy in the correction of the valgus-pronatus foot in children with cerebral palsy
[Relazione in Atti di Convegno]
Ferrari, Alberto; Costi, Stefania; Ferrari, Adriano; Flori, Gessica; Neviani, Rita; Raggi, Michele; Cutti, Andrea
abstract
2008
- Come il disturbo percettivo influenza la performance motoria in un compito di functional reach and touch nel paziente diplegico pci
[Relazione in Atti di Convegno]
Ferrari, Ad; Sghedoni, A; Ferrari, A; Tersi, L
abstract
2008
- Development of motion analysis protocols based on inertial sensors and fluoroscopy
[Abstract in Atti di Convegno]
Garofalo, Pietro; Fantozzi, Silvia; A. G., Cutti; Tersi, Luca; Ferrari, Alberto; M., Raggi; Stagni, Rita; Cappello, Angelo; A., Davalli
abstract
2008
- Functional Reach and touch: how sense of movement disorders can influence Anticipatory Postural Adjustment?
[Relazione in Atti di Convegno]
Ferrari, Ad; Muzzini, S; Ferrari, A; Tersi, L; Sghedoni, A
abstract
Background: Sense of movement disorders (SMDs), as result
of the failure of a complex multisensorial process involving
the proprioceptive, visual, somaesthetic, and vestibular systems
(A Berthoz 1997), are very frequent in children with
cerebral palsy (CP) and negatively influence motor function-
ing and postural control. The most frequent signs are: exaggerated
and low threshold startle reaction, freezing posture,
blinking or closing eyes, visual attention shifting, and facial
grimaces. Diplegic children with SMDs show panic reactions
to mild postural perturbations and are therefore unable to
execute common tasks successfully, such as reaching and
touching an object. Postural adjustments depend on motor
reactions as well as on perception but perception has a leading
role in anticipation.
Objectives: We wanted to investigate how SMDs negatively
influence anticipatory postural adjustments (APA).
Method: A group of 14 children with diplegia were selected
according to the following criteria: aged 6–15 years, acquired
walking, no major differences at GMFCS, and no major sensorial
or cognitive deficit. Eight were diagnosed positive for
SMDs (according to the mentioned clinical signs), six did not
have SMDs, and five normal participants matched for age
were selected for the control group. The experimental setting
consisted of a functional reach and touch task in the sitting
position on an adjustable stool, a force platform
registered the centre of pressure. A small ball target was
placed at a distance of 120% of arms’ length and at 45˚ of
abduction. The child sat with feet on a foot rest. The stool
was set at two levels: ground and raised.
Results: APAs are indicated by a backward shifting of centre of
pressure with respect to the reaching direction before the
start of the gesture. The presence of APAs according to group
were: SMD, ground 42%, raised 36%; non-SMD ground 83%,
raised 78%; controls, ground 93%, raised 93%.
Discussion: The diplegic group with SMD has significantly
fewer APAs than both the controls and non-SMD group. The
height of the stool seems to influence APAs within the same
group but we did not have enough statistical evidence (ttest).
Data seem to support the hypothesis that SMDs influence
negatively anticipatory postural control and this can
reduce autonomy levels in action.
2008
- Functional reach and touch to evaluate perceptive impairment in diplegic cerebral palsy children
[Relazione in Atti di Convegno]
Tersi, Luca; Ferrari, Alberto; Sghedoni, A.; Pedroni, E.; Ferrari, A. D.
abstract
INTRODUCTION
In 30% of children with Diplegic Cerebral Palsy (CP), disability depends not only on motor aspects, but most of all on perceptual impairments. The Central Nervous System (CNS) cannot collect, elaborate and integrate redundant sensitive and sensorial information in order to obtain coherent representations of reality[1]. Clinical signs that are characteristic of the perceptive impairment consequent to( movement intolerance and to, fear of spaces) seem to be correlated with a visual-kinestesic conflict because of the incoherence between visual and proprioceptive information [1]. We suggest an experimental set up of Functional Reach and Touch (FRT) to establish the presence and to measure the intensity of the perceptive disease by varying the exposition of patients to the empty space.
METHODS
14 patients affected by Spastic Diplegia (SD) (aged 6-15 years) and 5 control subjects (aged 6-14 years) executed FRT while sitting on a height-adjustable chair (0.6 m – low; 1.0 m – high). Subjects were asked to stand steady for 10 seconds, and then, after hearing a whistle, to reach and touch a target (a ball with an accelerometer to sample the touching instant). A force plate under the chair acquired the Centre of Pressure (COP) trajectory. FRT was registered in 18 different positions/conditions, resulting from the combinations of: i) distance to target equal to 120% (near) and 150% (far) of the arm-length (from the acromion to the tip of the medium finger); ii) postero-omolateral (PO), antero-omolateral (AO) or antero-controlateral (AC) directions; iii) high or low chair; iv) presence/absence of perceptive facilitation ‘raised floor’ (highFAC): white sheet stretched at knee level (2.3x2.3m2) hiding the empty space.
RESULTS
All control subjects but one (who failed at high_far_AC) managed to have a positive outcome (target reached). Patients with SD had a positive outcome in 79% of the near, and in 48% of the far trials. Out of the 14 SD, 8 clinically showed the perceptive impairment[1] (perceptual). Only the 17% of these latter obtained a positive outcome far versus the 87% of the remaining 6 (motor). The estimate of the movement smoothness (Normalized Jerk Score – NJS[2]) applied to COP trajectory showed that the highFAC facilitates the performance in perceptuals in a more significant way than in motors. While in the high_far_AO, perceptual subjects worsened (NJS increment) of a factor equal to 24.0, motors of 5.3 and controls of 3.6 in comparison to the relative low trial, in the highFAC trials all the subjects showed similar results (NJS almost triplicated). The facilitation effect appeared also analyzing the Sway Area (SA)[3] during the first 10 s of static posture of all trials. In perceptual subjects a trend was observed: low=159 mm2/s, highFAC=203 mm2/s, high=244 mm2/s, while the effects were absent in controls and motors (about 40 mm2/s).
DISCUSSION
The experimental setup showed here represents a sensitive tool to detect the presence of the perceptive impairment in patients with SD. Although with high variability, results showed different behaviors in patients with motor disability compared to the perceptuals. The presence of perceptive facilitation ‘raised floor’ in the FRT trials yielded to an improvement of the performance only in the perceptual, as measured by movement smoothness during the task (NJS) and of the SA during the static posture. Further experiments and more detailed statistical analysis are needed to characterized the absence and the magnitude of the perceptive impairment in patients with SD in a exhaustive way.
BIBLIOGRAFY
[1] Ferrari A, Cioni G, Le forme spastiche della paralisi cerebrale infantile, Springer, Milano,2005.
[2] Chang JJ, et al., Clin Biomech 2005; 20: 381-388.
[3] Prieto et al., IEEE Trans Biomed Eng 1996, 43(9)
2008
- OUTDOOR GAIT ANALYSIS USING INERTIAL AND MAGNETIC SENSORS: PART 1 - PROTOCOL DESCRIPTION
[Relazione in Atti di Convegno]
Cutti, Ag; Garofalo, P; Ferrari, A; Giovanardi, A; Davalli, A
abstract
2008
- Outdoor gait analysis using inertial and magnetic sensors: Part 2 - preliminary validation
[Relazione in Atti di Convegno]
Ferrari, A; Garofalo, P; Raggi, M; Cutti, Ag; Cappello, A
abstract
2008
- Outwalk: a protocol for ubiquitous gait analysis. A case study on children with cerebral palsy
[Relazione in Atti di Convegno]
Ferrari, A; Raggi, M; Heijboer, M; Cutti, Ag
abstract
2008
- Portable system for gait analysis of children with cerebral palsy
[Abstract in Atti di Convegno]
Ferrari, Alberto; Tersi, Luca; Heijboer, M.; Raggi, Michele; Cutti, ANDREA GIOVANNI
abstract
Introduction
Main concerns about using optoelectronic systems as the standard tool to perform gait analysis in Children with Cerebral Palsy (cCP) are: 1) the unnatural way cCP normally walk in unfamiliar environments, like laboratories; 2) the possibility to acquire only short walking trials, due to limited measuring volume, and 3) difficulty to identify the representative gait cycles among those acquired.
The MTx (Xsens Technologies, NL) is a wearable motion analysis system consisting of lightweight Sensing Units (SU) incorporating 3D accelerometers, gyroscopes and magnetometers. Based on MTx, a new biomechanical protocol was proposed (OutWalk, [1]) which allows to perform 3D kinematic data collection and real-time processing of hundreds of consecutive gait cycles in open space areas.
The aims of this study were to test OutWalk: 1) ease of use in cCP, 2) reliability, and 3) ability to classify the pathological functional strategy used during walking.
Materials and methods
One female diplegic CP child (SI, 10 years old) participated in the experiment. According to [1], 8 SU were applied respectively on thorax, pelvis, thighs, shanks, and feet. To allow estimation of 1) static straight posture and 2) functional knee axis of rotation, SI lied down in supine position. During the static acquisition a therapist assured joints being neither flexed nor hyperextended. Furthermore, the therapist performed passively a pure knee flexion-extension trial on SI. Subsequently, 4 long gait trials consisting of more than 13 gait cycles each were acquired in a pediatric gym.
The 3D kinematics of hip, knee and ankle were online elaborated then offline automatically segmented by using [2]. The protocol reliability was assessed by analyzing the maximum root mean square (RMS) distance between every possible couple of gait cycles. The relation between the clinical diagnosis and the OutWalk gait analysis results was investigated.
Results
It took 18 minutes to perform SU application, the static and functional calibrations, and the acquisition of the gait trails. During walking SI experienced no hindrance caused by Mtx.
Figure 1 reports kinematic gait analysis results of an uninterrupted walk of 15 cycles. For each kinematic variable, the maximum RMS distance between every possible couple of gait cycles is reported in degrees in table 1.
The kinematic report in figure 1 suggests:
- normal pattern of hip movement,
- knees always in flexion, the left with less range of movement,
- ankles always in dorsiflexion but maintaining a good range of movement.
Discussion and conclusions
Clinical investigation on SI found crouch knees, absence of foot equine and an overall good quality of walk. These signs can all be recognized in kinematic report (figure 1), indicating that OutWalk has acquired the representative pathologic synergies of SI’s spontaneous walk. If compared to natural intra-subject variability [3], this protocol appears to have high level of reliability, but its accuracy and precision should be further investigated.
In conclusion, OutWalk based on MTx technology, resulted non constraining measurement device that allowed fast acquisition and on-line elaboration of 3D joint kinematics on the walking of a CP child in a real life environment.
Future developments and visions
Future studies should focus on developing 1) a software upgrade that allows online division of gait into strides and 2) an algorithm able to classify gait deviations and able to suggest the diplegic form of CP with respect to the classification proposed by Ferrari et al. [4].
In order to perform a more comprehensive gait analysis including dynamic information about load distribution on the soles and joint kinetic on lower limbs, the Mtx system should be synchronized and integrated with an in-shoe pressure measuring system.
References
[1] Cutti et al. (2008). Outdoor gait analysis using inertial and m
2008
- Quantitative comparison of five current protocols in gait analysis
[Articolo su rivista]
Ferrari, A; Bnedetti, Mg; Pavan, E; Frigo, C; Bettinelli, D; Rabuffetti, M; Crenna, P; Leardini, A
abstract
2007
- IL DISTURBO PERCETTIVO: COME RILEVARLO NELLE DIPLEGIE SPASTICHE INFANTILI
[Relazione in Atti di Convegno]
Sghedoni, A; Pedroni, E; Tersi, L; Ferrari, A; Alboresi, S; Ovi, A; Ferrari, A
abstract
2007
- Perception disorder: how to identify it in children with spastic diplegia
[Abstract in Atti di Convegno]
Sghedoni, A.; Pedroni, E.; Tersi, L.; Ferrari, Al.; Alboresi, S.; Ovi, A.; Ferrari, Ad.
abstract
INTRODUCTION
It is well known that “movement and perception are the two sides of the same coin in Cerebral Palsy (CP)”. In PC, the alteration of perceptive system represents a crucial element for “palsy development”. Central Nervous System (CNS) isn’t able to collect, elaborate, and integrate sensitive and sensorial information to obtain representations that are coherent among them and corresponding to reality[1]. In particular the altered process of collimation between visual and proprioceptive information may produce visual-kinestesic conflict. In children with CP this is mainly expressed through intolerance to movement, emptiness and depth. It is has been surveyed that in diplegic population, the biggest group in CP, perception disorder influences in a determining way functional abilities, in particular motor autonomy and walking quality[2]. The recognition of this perception disorder represents a basic preliminary assumption for a correct diagnostic framing and for the statement of the most appropriate rehabilitation goals and choices. This study intends to research one or more pathognomonic signs of this pathologic pattern in order to identify the perception disorder in a simple, not invasive setting, easy to be applied in territorial services. From data collected in past observations, the startle resulted as one of the most recurring signs. Therefore we want to investigate its presence in a population of diplegic children walking without support and to verify if it is a pathognomonic sign of perception disorder for the group of selected patients.
METHODS
This is a retrospective blind-randomized study.
We evaluated 41 videos, realised with standard modalities, showing children with spastic diplegia while they are walking. Video are randomly selected among those of patients followed at Child Rehabilitation in RE. The inclusion criteria were: spastic diplegia supported by MRI, age between 5 and 15 years old, no surgical intervention since at least one year and no botulinum injection since at least 6 months, walking without support.
Then the studied population was divided into two groups through video observation of walking. Group A is composed of subjects presenting clinic sign of startle during the march, while Group B by subjects not showing that sign. According to the information regarding the perception disorder found in clinical documentation (realised by gold standard) the sample studied has been divided again into two groups: children with (Group C) or without (Group D) perception disorder.
To identify the importance of the startle clinic sign during walk, we evaluated whether Group A corresponded to Group C and Group B to Group D. We defined motor autonomy level of 41 patients according to the Palisano et al. classification [GMFCS] to assess the possible correlation between this one and the perception disorder.
RESULTS
Among the 14 patients, whose documentation reported the presence of perception disorder (Group C), the 100% shows startle reaction during walk without support. Among the 27 patients without disorder (Group D), only one subject has startle (3,7%). Among subjects of Group C, 6 patients out of 14 (42,86%) belong to level II of GMFCS and the remaining 8 (57,14%) to level III. In Group D, 17 children belong to level I of GMFCS (62,96%) and the remaining 10 to level II (37,04%).
DISCUSSION
Thanks to the results obtained, it is possible to assert that startle represents a pathognomonic sign of perception disorder for population able to walk without support.
It is interesting to underline how clinical documentation of the only subject from group D presenting startle during walk, highlights previous signs of perception disorder which were not relevant in the last years.
The importance of recognizing perception disorder is once again confirmed by the results regarding GMFCS. The presence of the disorder influences in a negative way motor autonomy an
2006
- A SINGLE GAIT CYCLE AS MEASURED BY FOUR CURRENT PROTOCOLS
[Relazione in Atti di Convegno]
Ferrari, A; E, Pavan; Mg, Benedetti; D, Bettinelli; C, Frigo; A, Leardini
abstract
2006
- GAIT ANALYSIS RESULTS FROM FIVE CURRENT PROTOCOLS
[Relazione in Atti di Convegno]
Ferrari, A; Benedetti, Mg; Pavan, E; Frigo, C; Bettinelli, D; Rabuffetti, M; Crenna, P; Leardini, A
abstract