Robotic and clinical evaluation of upper limb motor performance in patients with Friedreich's Ataxia: an observational study

Instrumented Upper Limb Functional Assessment Using a Robotic Exoskeleton: Normative References Intervals

Upper-limb rehabilitation exoskeletons offer a valuable solution to support and enhance the rehabilitation path of neural-injured patients. Such devices are usually equipped with a network of sensors that can be exploited to evaluate and monitor the performances of the users. In this work, we assess the normality ranges of different motor-performance indicators on a group of 15 healthy participants, computed with the benchmark toolbox of AGREE, an upper limb motorized exoskeleton. The toolbox implements a benchmarking scheme for the evaluation of the upper limb, used to test anterior reaching at rest position height and hand-to-mouth motor skills. We selected kinematic and electromyography performance indicators to assess the different motor abilities. We performed a pilot evaluation on three neurological patients, to verify if the AGREE benchmark toolbox was able to distinguish patients from healthy subjects on the basis of the selected performance indicators. Through a comparison between results obtained by the healthy and the small group of motor-impaired users, we successfully calculated the normality ranges for the selected performance indicators, and we pilot-showed how data gathered from AGREE can be used to evaluate the current status of the patients.

Real-life ankle submovements and computer mouse use reflect patient-reported function in adult ataxias

Novel disease-modifying therapies are being evaluated in spinocerebellar ataxias and multiple system atrophy. Clinician-performed disease rating scales are relatively insensitive for measuring disease change over time, resulting in large and long clinical trials. We tested the hypothesis that sensors worn continuously at home during natural behaviour and a web-based computer mouse task performed at home could produce interpretable, meaningful and reliable motor measures for potential use in clinical trials. Thirty-four individuals with degenerative ataxias (spinocerebellar ataxia types 1, 2, 3 and 6 and multiple system atrophy of the cerebellar type) and eight age-matched controls completed the cross-sectional study. Participants wore an ankle and wrist sensor continuously at home for 1 week and completed the Hevelius computer mouse task eight times over 4 weeks. We examined properties of motor primitives called 'submovements' derived from the continuous wearable sensors and properties of computer mouse clicks and trajectories in relationship to patient-reported measures of function (Patient-Reported Outcome Measure of Ataxia) and ataxia rating scales (Scale for the Assessment and Rating of Ataxia and the Brief Ataxia Rating Scale). The test-retest reliability of digital measures and differences between ataxia and control participants were evaluated. Individuals with ataxia had smaller, slower and less powerful ankle submovements during natural behaviour at home. A composite measure based on ankle submovements strongly correlated with ataxia rating scale scores (Pearson's r = 0.82-0.88), strongly correlated with self-reported function (r = 0.81), had high test-retest reliability (intraclass correlation coefficient = 0.95) and distinguished ataxia and control participants, including preataxic individuals (n = 4) from controls. A composite measure based on computer mouse movements and clicks strongly correlated with ataxia rating scale total (r = 0.86-0.88) and arm scores (r = 0.65-0.75), correlated well with self-reported function (r = 0.72-0.73) and had high test-retest reliability (intraclass correlation coefficient = 0.99). These data indicate that interpretable, meaningful and highly reliable motor measures can be obtained from continuous measurement of natural movement, particularly at the ankle location, and from computer mouse movements during a simple point-and-click task performed at home. This study supports the use of these two inexpensive and easy-to-use technologies in longitudinal natural history studies in spinocerebellar ataxias and multiple system atrophy of the cerebellar type and shows promise as potential motor outcome measures in interventional trials.

Identification of Gait Unbalance and Fallers Among Subjects with Cerebellar Ataxia by a Set of Trunk Acceleration-Derived Indices of Gait

This study aimed to assess the ability of 25 gait indices to characterize gait instability and recurrent fallers among persons with primary degenerative cerebellar ataxia (pwCA), regardless of gait speed, and investigate their correlation with clinical and kinematic variables. Trunk acceleration patterns were acquired during the gait of 34 pwCA, and 34 age- and speed-matched healthy subjects (HS_matched) using an inertial measurement unit. We calculated harmonic ratios (HR), percent recurrence, percent determinism, step length coefficient of variation, short-time largest Lyapunov exponent (sLLE), normalized jerk score, log-dimensionless jerk (LDLJ-A), root mean square (RMS), and root mean square ratio of accelerations (RMSR) in each spatial direction for each participant. Unpaired t-tests or Mann-Whitney tests were performed to identify significant differences between the pwCA and HS_matched groups. Receiver operating characteristics were plotted to assess the ability to characterize gait alterations in pwCA and fallers. Optimal cutoff points were identified, and post-test probabilities were calculated. The HRs showed to characterize gait instability and pwCA fallers with high probabilities. They were correlated with disease severity and stance, swing, and double support duration, regardless of gait speed. sLLEs, RMSs, RMSRs, and LDLJ-A were slightly able to characterize the gait of pwCA but failed to characterize fallers.

Reliability and validity of digital health metrics for assessing arm and hand impairments in an ataxic disorder

OBJECTIVES

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is the second most frequent recessive ataxia and commonly features reduced upper limb coordination. Sensitive outcome measures of upper limb coordination are essential to track disease progression and the effect of interventions. However, available clinical assessments are insufficient to capture behavioral variability and detailed aspects of motor control. While digital health metrics extracted from technology-aided assessments promise more fine-grained outcome measures, these have not been validated in ARSACS. Thus, the aim was to document the metrological properties of metrics from a technology-aided assessment of arm and hand function in ARSACS.

METHODS

We relied on the Virtual Peg Insertion Test (VPIT) and used a previously established core set of 10 digital health metrics describing upper limb movement and grip force patterns during a pick-and-place task. We evaluated reliability, measurement error, and learning effects in 23 participants with ARSACS performing three repeated assessment sessions. In addition, we documented concurrent validity in 57 participants with ARSACS performing one session.

RESULTS

Eight metrics had excellent test-retest reliability (intraclass correlation coefficient 0.89 ± 0.08), five low measurement error (smallest real difference % 25.4 ± 5.7), and none strong learning effects (systematic change η -0.11 ± 2.5). Significant correlations (ρ 0.39 ± 0.13) with clinical scales describing gross and fine dexterity and lower limb coordination were observed.

INTERPRETATION

This establishes eight digital health metrics as valid and robust endpoints for cross-sectional studies and five metrics as potentially sensitive endpoints for longitudinal studies in ARSACS, thereby promising novel insights into upper limb sensorimotor control.

Rehabilitation in patients with cerebellar ataxias

ABSTRACT Cerebellar ataxias comprise a heterogeneous group of diseases characterized by motor and non-motor symptoms, which can be acquired, degenerative, or have a genetic cause, such as spinocerebellar ataxias (SCA). Usually, the genetic and neurodegenerative forms of cerebellar ataxias present a progressive and inevitable worsening of the clinical picture so that rehabilitation treatment is fundamental. Rehabilitation treatment includes physical therapy, respiratory therapy, speech, voice and swallowing therapy, occupational therapy, and new technologies, such as the use of exergames. The current treatment of patients with cerebellar ataxias, especially neurodegenerative forms, genetic or not, should include these different forms of rehabilitation, with the main objective of improving the quality of life of patients.

Assessing Smoothness of Arm Movements With Jerk: A Comparison of Laterality, Contraction Mode and Plane of Elevation. A Pilot Study

Measuring the quality of movement is a need and a challenge for clinicians. Jerk, defined as the quantity of acceleration variation, is a kinematic parameter used to assess the smoothness of movement. We aimed to assess and compare jerk metrics in asymptomatic participants for 3 important movement characteristics that are considered by clinicians during shoulder examination: dominant and non-dominant side, concentric and eccentric contraction mode, and arm elevation plane. In this pilot study, we measured jerk metrics by using Xsens^® inertial measurement units strapped to the wrists for 11 different active arm movements (ascending and lowering phases): 3 bilateral maximal arm elevations in sagittal, scapular and frontal plane; 2 unilateral functional movements (hair combing and low back washing); and 2 unilateral maximal arm elevations in sagittal and scapular plane, performed with both arms alternately, right arm first. Each arm movement was repeated 3 times successively and the whole procedure was performed 3 times on different days. The recorded time series was segmented with semi-supervised algorithms. Comparisons involved the Wilcoxon signed rank test (p < 0.05) with Bonferroni correction. We included 30 right-handed asymptomatic individuals [17 men, mean (SD) age 31.9 (11.4) years]. Right jerk was significantly less than left jerk for bilateral arm elevations in all planes (all p < 0.05) and for functional movement (p < 0.05). Jerk was significantly reduced during the concentric (ascending) phase than eccentric (lowering) phase for bilateral and unilateral right and left arm elevations in all planes (all p < 0.05). Jerk during bilateral arm elevation was significantly reduced in the sagittal and scapular planes versus the frontal plane (both p < 0.01) and in the sagittal versus scapular plane (p < 0.05). Jerk during unilateral left arm elevation was significantly reduced in the sagittal versus scapular plane (p < 0.05). Jerk metrics did not differ between sagittal and scapular unilateral right arm elevation. Using inertial measurement units, jerk metrics can well describe differences between the dominant and non-dominant arm, concentric and eccentric modes and planes in arm elevation. Jerk metrics were reduced during arm movements performed with the dominant right arm during the concentric phase and in the sagittal plane. Using IMUs, jerk metrics are a promising method to assess the quality of basic shoulder movement.

Reliability and agreement of the Nine Hole Peg Test in patients with unilateral spastic cerebral palsy

Upper extremity involvement is one of the most common motor impairments in children with unilateral spastic cerebral palsy (CP). One tool for the assessment of manual function in CP is the Nine Hole Peg Test (NHPT). However, the reliability of the NHPT in patients with unilateral CP is unknown. This study aimed to analyze the intra-rater inter-session reliability of the NHPT in unilateral spastic CP, for its use in clinical practice and research. A total of 27 participants with spastic unilateral CP were included. Reliability was verified by the intraclass correlation coefficient (ICC), standard error of measurement, and minimum detectable change. The agreement was analyzed by the Bland-Altman method. An excellent intra-rater reliability was observed for the non-affected side (ICC = 0.94) and the affected side (ICC = 0.96). The minimal detectable change was 4 and 12 s for the non-affected and affected side, respectively. There were no significant biases between repetitions.   Conclusions: The NHPT showed excellent intra-rater inter-session reliability in patients with spastic unilateral CP. In addition, the test shows adequate agreement and proportionally small errors to assess manual dexterity. What is Known: • The Nine Hole Peg Test (NHPT) is widely used to assess dexterity in patients with neurological conditions. • The NHPT has demonstrated appropriate measurement properties in healthy children and adults with neurological conditions. What is New: • The NHPT presents excellent reliability, small measurement errors, and adequate agreement for the assessment of patients with cerebral palsy. • The measurement error of the NHPT in unilateral cerebral palsy may be up to 13% of the total time to perform it.

Evaluation of upper extremity ataxia through image processing in individuals with multiple sclerosis

BACKGROUND

Impaired dexterity is a frequently reported disability among people with ataxic multiple sclerosis (MS).

OBJECTIVE

To quantify and standardize the evaluation of upper extremity coordination disorder among patients with multiple sclerosis (MS), using the Tablet Ataxia Assessment Program (TAAP).

METHODS

The X and Y axis movements of 50 MS patients and 30 healthy individuals who were evaluated using the International Cooperative Ataxia Rating Scale (ICARS) were also assessed using TAAP. The functional times of the participants' right and left hands were recorded using the nine-hole peg test (NHPT). The upper extremity coordination of individuals with MS was evaluated using the upper extremity kinetic functions section of ICARS.

RESULTS

The deviations for the X and Y axis movements of the MS group were greater than those of the control group (p<0.05). Significant correlations were shown between TAAP scores and NHPT and ICARS scores. The strongest correlation was found between NHPT and ICARS in the dominant hand (rnhpt=0.356, pnhpt=0.001; ricars=0.439, picars=0.000). In correlating the Y axis with ICARS, the deviations in the Y axis were found to be greater in the non-dominant hand than those in the X axis (ryright=0.402, pyright=0.004; ryleft=0.691, pyleft=0.000).

CONCLUSION

Measurement using TAAP is more sensitive than other classical and current methods for evaluating ataxia. We think that TAAP is an objective tool that will allow neurorehabilitation professionals and clinicians to evaluate upper extremity coordination.

Objective Assessment of Progression and Disease Characterization of Friedreich Ataxia via an Instrumented Drinking Cup: Preliminary Results

The monitoring of disease progression in certain neurodegenerative conditions can significantly be quantified with the help of objective assessments. The severity assessment of diseases like Friedreich ataxia (FRDA) are usually based on different subjective measures. The ability of a participant with FRDA to perform standard neurological tests is the most common way of assessing disease progression. In this feasibility study, an Ataxia Instrumented Measurement-Cup (AIM-C) is proposed to quantify the disease progression of 10 participants (mean age 39 years, onset of disease 16.3 years) in longitudinal timepoints. The device consists of a sensing system with the provision of extracting both kinetic and kinematic information while engaging in an activity closely associated with activities of daily living (ADL). A common functional task of simulated drinking was used to capture features that possesses disease progression information as well as certain other features which intrinsically correlate with commonly used clinical scales such as the modified Friedreich Ataxia Rating Scale (mFARS), the Functional Staging of Ataxia score and the ADL scale. Frequency and time-frequency domain features allowed the longitudinal assessment of participants with FRDA. Furthermore, both kinetic and kinematic measures captured clinically relevant features and correlated 85% with clinical assessments.

Differentiating Motor Coordination in Children with Cerebral Palsy and Typically Developing Populations Through Exploratory Factor Analysis of Robotic Assessments

General motor and executive functions are integral for tasks of daily living and are typically assessed when quantifying impairment of an individual. Robotic tasks offer highly repeatable and objective measures of motor and cognitive function. Additionally, robotic tasks and measures have been used successfully to quantify impairment of children with cerebral palsy (CP). Many robotic tasks include multiple performance parameters, so interpretation of results and identification of impairment can be difficult, especially when multiple tasks are completed. This study used exploratory factor analysis to investigate a potential set of quantitative models of motor and cognitive function in children, and compare performance of participants with CP to these models. The three calculated factors achieved strong differentiation between participants with mild CP and the typically developing population. This demonstrates the feasibility of these factors to quantify impairment and track improvements related to therapies.Clinical Relevance- This establishes a method to differentiate atypical motor performance related to CP using a robotic reversed visually guided reaching task.

Tools and Techniques Used With Robotic Devices to Quantify Upper-Limb Function in Typically Developing Children: A Systematic Review

Background:

Robotic devices have been used to quantify function, identify impairment, and rehabilitate motor function extensively in adults, but less-so in younger populations. The ability to perform motor actions improves as children grow. It is important to quantify this rate of change of the neurotypical population before attempting to identify impairment and target rehabilitation techniques.

Objectives:

For a population of typically developing children, this systematic review identifies and analyzes tools and techniques used with robotic devices to quantify upper-limb motor function. Since most of the papers also used robotic devices to compare function of neurotypical to pathological populations, a secondary objective was introduced to relate clinical outcome measures to identified robotic tools and techniques.

Methods:

Five databases were searched between February 2019 and August 2020, and 226 articles were found, 19 of which are included in the review.

Results:

Robotic devices, tasks, outcome measures, and clinical assessments were not consistent among studies from different settings but were consistent within laboratory groups. Fifteen of the 19 articles evaluated both typically developing and pathological populations.

Conclusion:

To optimize universally comparable outcomes in future work, it is recommended that a standard set of tasks and measures is used to assess upper-limb motor function. Standardized tasks and measures will facilitate effective rehabilitation.

Validation of low-cost system for gait assessment in children with ataxia

BACKGROUND

Ataxic syndromes include several rare, inherited and acquired conditions. One of the main issues is the absence of specific, and sensitive automatic evaluation tools and digital outcome measures to obtain a continuous monitoring of subjects' motor ability.

OBJECTIVES

This study aims to test the usability of the Kinect system for assessing ataxia severity, exploring the potentiality of clustering algorithms and validating this system with a standard motion capture system.

METHODS

Gait evaluation was performed by standardized gait analysis and by Kinect v2 during the same day in a cohort of young patient (mean age of 13.8±7.2). We analyzed the gait spatio-temporal parameters and we looked at the differences between the two systems through correlation and agreement tests. As well, we tested for possible correlations with the SARA scale as well. Finally, standard classification algorithm and principal components analysis were used to discern disease severity and groups.

RESULTS

We found biases and linear relationships between all the parameters. Significant correlations emerged between the SARA and the Speed, the Stride Length and the Step Length. PCA results, highlighting that a machine learning approach combined with Kinect-based evaluation shows great potential to automatically assess disease severity and diagnosis.

CONCLUSIONS

The spatio-temporal parameters measured by Kinect cannot be used interchangeably with those parameters acquired with standard motion capture system in clinical practice but can still provide fundamental information. Specifically, these results might bring to the development of a novel system to perform easy and quick evaluation of gait in young patients with ataxia, useful for patients stratification in terms of clinical severity and diagnosis.

Measurements of Hand Function in Degenerative Cerebellar Disease: A Case-Control Pilot Study

OBJECTIVE

The aim of the study was to determine the association of Nine Hole Peg Test, Box and Block Test, Jebsen-Taylor Hand Function Test, and kinematic measures of a simple reaching task with ataxia severity in adults with degenerative cerebellar disease.

DESIGN

Fourteen adults with cerebellar degeneration were recruited, and ataxia severity was determined using the Scale for the Assessment and Rating of Ataxia. The median Scale for the Assessment and Rating of Ataxia score was used to divide participants into less and more severe ataxia groups. The two groups' average scores on the hand function tests were compared, and correlation of each test with ataxia severity was determined.

RESULTS

The Nine Hole Peg Test, Box and Block Test, and Jebsen-Taylor Hand Function Test all differentiated between less and more severe ataxia groups, and the Nine Hole Peg Test performed with the participant's dominant hand had the highest correlation with ataxia severity (rs = 0.92, P < 0.01). Although accuracy, precision, and number of submovements were statistically different between healthy individuals and the more ataxic participant group, most kinematic measures were not significantly different between the less and more severe ataxic groups.

CONCLUSION

Overall, our results indicate that all three clinical tests correlate with ataxia severity. Larger future studies should examine the reliability and validity of these hand function measures in adults with degenerative cerebellar disease.

Development of SaraHome: A novel, well-accepted, technology-based assessment tool for patients with ataxia

BACKGROUND AND OBJECTIVE

Early onset ataxias (EOAs) are a heterogeneous group of neurological conditions, responsible for severe motor disability in paediatric age, which still lack reliable outcome measures. Available scales to assess ataxia, such as the Scale for Assessment and Rating of Ataxia (SARA), are based on subjective assessment of specific motor and language tasks by an examiner, and therefore is age dependent and lacks accuracy in detecting small variations in disease severity. In last years, novel technologies, including computer interfaces and videogames, have emerged for clinical applications and the advent of Internet of Medical Things and of Information Communication Technology have allowed the remote control of such technologies. This pilot study describes a newly developed tool (SaraHome) for the assessment at home of EOA evaluating its feasibility and acceptability on a small sample of children.

METHODS

Ten EOA children and ten caregivers have been enrolled for a preliminary outpatient evaluation. The Microsoft Kinect 2.0 and Leap Motion Controller (LMC) connected to a personal computer with an ad hoc software have been set-up, for the acquisition of standardized motor tasks performed by the patients with the caregivers' assistance. Acceptance and practicability have been tested by QUEST 2.0 and IMI questionnaires in caregivers and patients respectively.

RESULTS

The SaraHome software was developed, based on a collection of services provided by a complex architecture that consists of a Restful interface, which enables to access a series of plugins for the execution of different tasks. A graphical user interface allows the acquisition of the patient movements while performing a motor task. A protocol of standard tasks inspired by SARA was established, and a system of video-assisted instruction provided. The set-up for the optimal acquisition of such protocol by Kinect and LMC has been defined. Both patients and caregivers accomplished the SaraHome assessment with good feedback at the technology acceptance questionnaires.

CONCLUSIONS

SaraHome represents a newly developed tool for the assessment of ataxia in patients, resulting from the integration of low-cost and easy-accessible technologies. This pilot application highlighted the feasibility and the acceptability of the system, suggesting the potential use in clinical practice.

Temporal but not spatial dysmetria relates to disease severity in FA

Friedreich's ataxia (FA) is an inherited disease that causes degeneration of the nervous system. Features of FA include proprioceptive and cerebellar deficits leading to impaired muscle coordination and, consequently, dysmetria in force and time of movement. The aim of this study is to characterize dysmetria and its association to disease severity. Also, we examine the neural mechanisms of dysmetria by quantifying the EMG burst area, duration, and time-to-peak of the agonist muscle. Twenty-seven individuals with FA and 13 healthy controls (HCs) performed the modified Functional Ataxia Rating Scale and goal-directed movements with the ankle. Dysmetria was quantified as position and time error during dorsiflexion. FA individuals exhibited greater time but not position error than HCs. Moreover, time error correlated with disease severity and was related to increased agonist EMG burst. Temporal dysmetria is associated to disease severity, likely due to altered activation of the agonist muscle.NEW & NOTEWORTHY For the first time, we quantified spatial and temporal dysmetria and its relation to disease severity in Friedreich's ataxia (FA). We found that FA individuals exhibit temporal but not spatial dysmetria relative to healthy controls. Temporal dysmetria correlated to disease severity in FA and was predicted from an altered activation of the agonist muscle. Therefore, these results provide novel evidence that FA exhibit temporal but not spatial dysmetria, which is different from previous findings on SCA6.

Using an ankle robotic device for motor performance and motor learning evaluation

In this paper we performed the evaluation of ankle motor performance and motor learning during a goal-directed task, executed using the pediAnklebot robot. The protocol consisted of 3 phases (Familiarization, Adaptation, and Wash Out) repeated one time for each movement direction (plantarflexion, dorsiflexion, inversion, and eversion). During Familiarization and Wash out subjects performed goal-directed movements in unperturbed environment, whereas during Adaptation phase, a curl viscous force field was applied and it was randomly removed 10 times out of 200. Ankle motor performance was evaluated by means of a set of indices grouped into: accuracy, smoothness, temporal, and stopping indices. Learning Index was calculated to study the motor learning during the adaptation phase, which was subdivided into 5 temporal intervals (target sets). The outcomes related to the ankle motor performance highlighted that the best performance in terms of accuracy and smoothness of the trajectories was obtained in dorsiflexion movements in the sagittal plane, and in inversion rotations in the frontal plane. Differences between movement directions revealed an anisotropic behavior of the ankle joint. Results of the Learning index showed a capability of the subjects to rapidly adapt to a perturbed force field depending on the magnitude of the perceived field.

Scoping review of symptoms in children with rare, progressive, life-threatening disorders

BACKGROUND

Q3 conditions are progressive, metabolic, neurological or chromosomal childhood conditions without a cure. Children with these conditions face an unknown lifespan as well as unstable and uncomfortable symptoms. Clinicians and other healthcare professionals are challenged by a lack of evidence for symptom management for these conditions.

AIMS

In this scoping review, we systematically identified and mapped the existing literature on symptom management for children with Q3 conditions. We focused on the most common and distressing symptoms, namely alertness, behavioural problems, bowel incontinence, breathing difficulties, constipation, feeding difficulties, sleep disturbance, temperature regulation, tone and motor problems and urinary incontinence. For children with complex health conditions, good symptom management is pertinent to ensure the highest possible quality of life.

METHODS

Scoping review. Electronic database searches in Ovid MEDLINE, Embase and CINAHL and a comprehensive grey literature search.

RESULTS

We included 292 studies in our final synthesis. The most commonly reported conditions in the studies were Rett syndrome (n=69), followed by Cornelia de Lange syndrome (n=25) and tuberous sclerosis (n=16). Tone and motor problems were the most commonly investigated symptom (n=141), followed by behavioural problems (n=82) and sleep disturbance (n=62).

CONCLUSION

The evidence for symptom management in Q3 conditions is concentrated around a few conditions, and these studies may not be applicable to other conditions. The evidence is dispersed in the literature and difficult to access, which further challenges healthcare providers. More research needs to be done in these conditions to provide high-quality evidence for the care of these children.

Improving the Efficiency of Robot-Mediated Rehabilitation by Using a New Organizational Model: An Observational Feasibility Study in an Italian Rehabilitation Center

Robotic rehabilitation is a promising way to restore upper limb function, but new organizational models are crucial in order to improve its sustainability. We aimed to analyze the feasibility of a robot-Assisted REhabilitation Area (robotAREA) equipped with four devices, using a new organizational model in which one physiotherapist supervises up to four patients. In 33 days, 60 patients were treated in the robotAREA. Two hundred fifty-five rehabilitation sessions were analyzed, each including two, three, or four patients supervised by one physiotherapist (the R2, R3, and R4 group, respectively). For each session, the duration of (a) setup, (b) training, (c) supervision, (d) session closure, and participant satisfaction were measured. For each patient, upper limb impairment, disability, mobility, and comorbidity were recorded. The time of training in the R4 group was lower by only 2 and 3 min compared to the R2 and R3 groups, respectively, while the supervision significantly changed between the R2, R3, and R4 groups. No differences were observed in satisfaction. Moreover, according to the logistic regression analysis, when the mean disability of the group is moderate, four patients can be supervised by one physiotherapist. These results suggest that the proposed model is feasible, and the mean disability of the group could influence the proper physiotherapist/patient ratio.

Perturbed Point-to-Point Reaching Tasks in a 3D Environment Using a Portable Haptic Device

In this paper, we propose a new protocol, integrating Virtual Reality with the Novint Falcon, to evaluate motion performance during perturbed 3D reaching tasks. The protocol consists of six 3D point-to-point reaching tasks, performed using Falcon with six opposing force fields. Twenty subjects were enrolled in the study. During each task, subjects reached 80 targets and the protocol was repeated over three different days. The trajectories of the end-effector were recorded to calculate: duration of movement, length ratio, lateral deviation, aiming angle, speed metric, and normalized jerk. The coefficient of variation was calculated to study the intra-subject variability and the intra-class correlation coefficient to assess the reliability of the indices. Two-way repeated measurement ANOVA tests were performed for all indices in order to ascertain the effects of force and direction on the trajectories. Duration of movement, length ratio and speed metric have proven to be the most repeatable and reliable indices. Considering the force fields, subjects were able to optimize the trajectory in terms of duration and accuracy but not in terms of smoothness. Considering the directions, the best motor performance occurred when the trajectories were performed in the upper quadrant compared to those performed in the lower quadrant.

Current behavioral assessments of movement disorders in children

Pediatric movement disorders (PMDs) are common and have recently received increasing attention. As these disorders have special clinical features, the selection of appropriate behavioral assessment tools that can clearly distinguish movement disorders from other diseases (eg, epilepsy and neuromuscular disorders) is crucial for achieving an accurate diagnosis and treatment. However, few studies have focused on behavioral assessments in children. The present report attempts to provide a critical review of the available subjective and objective assessment tests for common PMDs. We believe that the principles of objectification, multi-purpose use, and simplification are also applicable to the selection and development of satisfactory pediatric behavioral assessment tools. We expect that the development of wearable sensors, virtual reality, and augmented reality will lead to the establishment of more reliable and simple tests. In addition, more rigorous randomized controlled trials that have been specifically designed to evaluate behavioral testing in children are also expected in the future.

Reliability, validity and discriminant ability of the instrumental indices provided by a novel planar robotic device for upper limb rehabilitation

BACKGROUND

In the last few years, there has been an increasing interest in the use of robotic devices to objectively quantify motor performance of patients after brain damage. Although these robot-derived measures can potentially add meaningful information about the patient's dexterity, as well as be used as outcome measurements after the rehabilitation treatment, they need to be validated before being used in clinical practice. The present work aims to evaluate the reliability, the validity and the discriminant ability of the metrics provided by a novel robotic device for upper limb rehabilitation.

METHODS

Forty-eight patients with sub-acute stroke and 40 age-matched healthy subjects were involved in this study. Clinical evaluation included: Fugl-Meyer Assessment for the upper limb, Action Research Arm Test, and Barthel Index. Robotic evaluation of the upper limb performance consisted of 14 measures of motor ability quantifying the dexterity in performing planar reaching movements. Patients were evaluated twice, one day apart, to assess the reliability of the robotic metrics, using the Intraclass Correlation Coefficient. Validity was assessed by analyzing the correlation of the robotic metrics with the clinical scales, by means of the Spearman's Correlation Coefficient. Finally, the ability of the robotic metrics to distinguish between patients with stroke and healthy subjects was investigated with t-tests and the Effect Size.

RESULTS

Reliability was found to be excellent for 12 measures and from moderate to good for the remaining 2. Most of the robotic indices were strongly correlated with the clinical scales, while a few showed a moderate correlation and only one was not correlated with the Barthel Index and weakly correlated with the remain two. Finally, all but one the provided metrics were able to discriminate between the two groups, with large effect sizes for most of them.

CONCLUSION

We found that all the robotic indices except one provided by a novel robotic device for upper limb rehabilitation are reliable, sensitive and strongly correlated both with motor and disability clinical scales. Therefore, this device is suitable as evaluation tool for the upper limb motor performance of patients with sub-acute stroke in clinical practice.

TRIAL REGISTRATION

NCT02879279 .

Quantitative assessment of paretic limb dexterity and interlimb coordination during bilateral arm rehabilitation training

In neuro-rehabilitation after stroke, the conventional constrained induced movement therapy (CIMT) has been well-accepted. Existing bilateral trainings are mostly on mirrored symmetrical motion. However, complementary bilateral movements are dominantly involved in activities of daily living (ADLs), and functional bilateral therapies may bring better skill transfer from trainings to daily life. Neurophysiological evidence is also growing. In this work, we firstly introduce our bilateral arm training system realized with a haptic interface and a motion sensor, as well as the tasks that have been designed to train both the manipulation function of the paretic arm and coordination of bilateral upper limbs. Then, we propose quantitative measures for functional assessment of complementary bilateral training performance, including kinematic behavior indices, smoothness, submovement and bimanual coordination. After that, we describe the experiments with healthy subjects and the results with respect to these quantitative measures. Feasibility and sensitivity of the proposed indices were evaluated through comparison of unilateral and bilateral training outcomes. The proposed bilateral training system and tasks, as well as the quantitative measures, have been demonstrated effective for training and assessment of unilateral and bilateral arm functions.

Virtual Sensors for Advanced Controllers in Rehabilitation Robotics

In order to properly control rehabilitation robotic devices, the measurement of interaction force and motion between patient and robot is an essential part. Usually, however, this is a complex task that requires the use of accurate sensors which increase the cost and the complexity of the robotic device. In this work, we address the development of virtual sensors that can be used as an alternative of actual force and motion sensors for the Universal Haptic Pantograph (UHP) rehabilitation robot for upper limbs training. These virtual sensors estimate the force and motion at the contact point where the patient interacts with the robot using the mathematical model of the robotic device and measurement through low cost position sensors. To demonstrate the performance of the proposed virtual sensors, they have been implemented in an advanced position/force controller of the UHP rehabilitation robot and experimentally evaluated. The experimental results reveal that the controller based on the virtual sensors has similar performance to the one using direct measurement (less than 0.005 m and 1.5 N difference in mean error). Hence, the developed virtual sensors to estimate interaction force and motion can be adopted to replace actual precise but normally high-priced sensors which are fundamental components for advanced control of rehabilitation robotic devices.

Robot Training With Vector Fields Based on Stroke Survivors' Individual Movement Statistics

The wide variation in upper extremity motor impairments among stroke survivors necessitates more intelligent methods of customized therapy. However, current strategies for characterizing individual motor impairments are limited by the use of traditional clinical assessments (e.g., Fugl-Meyer) and simple engineering metrics (e.g., goal-directed performance). Our overall approach is to statistically identify the range of volitional movement capabilities, and then apply a robot-applied force vector field intervention that encourages under-expressed movements. We investigated whether explorative training with such customized force fields would improve stroke survivors' (n = 11) movement patterns in comparison to a control group that trained without forces (n = 11). Force and control groups increased Fugl-Meyer UE scores (average of 1.0 and 1.1, respectively), which is not considered clinically meaningful. Interestingly, participants from both groups demonstrated dramatic increases in their range of velocity during exploration following only six days of training (average increase of 166.4% and 153.7% for the Force and Control group, respectively). While both groups showed evidence of improvement, we also found evidence that customized forces affected learning in a systematic way. When customized forces were active, we observed broader distributions of velocity that were not present in the controls. Second, we found that these changes led to specific changes in unassisted motion. In addition, while the shape of movement distributions changed significantly for both groups, detailed analysis of the velocity distributions revealed that customized forces promoted a greater proportion of favorable changes. Taken together, these results provide encouraging evidence that patient-specific force fields based on individuals' movement statistics can be used to create new movement patterns and shape them in a customized manner. To the best of our knowledge, this paper is the first to directly link engineering assessments of stroke survivors' exploration movement behaviors to the design of customized robot therapy.

A novel protocol to evaluate ankle movements during reaching tasks using pediAnklebot

The aim of the study is to design a novel protocol to characterize the ankle movements during dorsal and plantar flexion reaching tasks using the pediAnklebot. Five healthy children were instructed to control a pointer and hit targets appearing on the monitor, by moving their ankle alternatively up and down. The protocol consisted of 60 targets, 30 up and 30 down, reachable via dorsiflexion and plantarflexion movements, respectively. Ankle angular displacements and torques were gathered by encoders and load cells embedded in the robot. Ankle motor performance was evaluated by means of kinematic, submovements and dynamic indices. Results suggest that (i) plantarflexion movements are faster and more accurate than the dorsiflexion ones, but children are able to perform with a higher level of smoothness the latter ones; (ii) children are able to stop the ankle movement more easily at the end of dorsiflexion rather than plantarflexion; (iii) the central nervous system plans plantarflexion and dorsiflexion movements with the same efficiency; (iv) children apply different torque levels during the two motor tasks and they cannot balance the inversion and eversion moments during dorsiflexion. These findings provide an important starting point for the assessment of a reference baseline of motor indices for the ankle joint.