This paper describes a method to extract upper limb intention tremor from gyroscope data, through the Hilbert-Huang transform (HHT), a technique suitable for the study of nonlinear and non-stationary ...processes. The aims of the study were to: (i) evaluate the method's ability to discriminate between healthy controls and MS subjects; (ii) validate the proposed procedure against clinical tremor scores assigned using Fahn's tremor rating scale (FTRS); and (iii) compare the performance of the HHT-based method with that of linear band-pass filters.
HHT was applied on gyroscope data collected on 20 MS subjects and 13 healthy controls (CO) during finger-to-nose tests (FNTs) instrumented with an inertial sensor placed on the hand. The results were compared to those obtained after traditional linear filtering. The tremor amplitude was quantified with instrumental indexes (TIs) and clinical FTRS ratings.
The TIs computed after HHT-based filtering discriminated between CO and MS subjects with clinically-detected intention tremor (MS_T). In particular, TIs were significantly higher in the final part of the movement (TI2) with respect to the first part (TI1), and, for all components (X, Y, Z), MS_T showed a TI2 significantly higher than in CO subjects. Moreover, the HHT detected subtle alterations not visible from clinical ratings, as TI2 (Z-component) was significantly increased in MS subjects without clinically-detected tremor (MS_NT). The method's validity was demonstrated by significant correlations between clinical FTRS scores and TI2 related to X (rs = 0.587, p = 0.006) and Y (rs = 0.682, p < 0.001) components. Contrarily, fewer differences among the groups and no correlation between instrumental and clinical indexes emerged after traditional filtering.
The present results supported the use of the HHT-based procedure for a fully-automated quantitative and objective measure of intention tremor in MS, which can overcome the limitations of clinical scales and provide supplementary information about this sign.
Step climbing is a demanding task required for personal autonomy in daily living. Anticipatory Postural Adjustments (APAs) preceding gait initiation have been widely investigated revealing to be ...hypometric in Parkinson's disease (PD) with consequences in movement initiation. However, only few studies focused on APAs prior to step climbing. In this work, a novel method based on wearable inertial sensors for the analysis of APAs preceding gait initiation and step climbing was developed to further understand dynamic balance control. Validity and sensitivity of the method have been evaluated.
Eleven PD and 20 healthy subjects were asked to perform two transitional tasks from quiet standing to level walking, and to step climbing respectively. All the participants wore two inertial sensors, placed on the trunk (L2-L4) and laterally on the shank. In addition, a validation group composed of healthy subjects and 5 PD patients performed the tasks on two force platforms. Correlation between parameters from wearable sensors and force platforms was evaluated. Temporal parameters and trunk acceleration from PD and healthy subjects were analyzed.
Significant correlation was found for the validation group between temporal parameters extracted from wearable sensors and force platforms and between medio-lateral component of trunk acceleration and correspondent COP displacement. These results support the validity of the method for evaluating APAs prior to both gait initiation and step climbing. Comparison between PD subjects and a subgroup of healthy controls confirms a reduction in PD of the medio-lateral acceleration of the trunk during the imbalance phase in the gait initiation task and shows similar trends during the imbalance and unloading phase of the step climbing task. Interestingly, PD subjects presented difficulties in adapting the medio-lateral amplitude of the imbalance phase to the specific task needs.
Validity of the method was confirmed by the significant correlation between parameters extracted from wearable sensors and force platforms. Sensitivity was proved by the capability to discriminate PD subjects from healthy controls. Our findings support the applicability of the method to subjects of different age. This method could be a possible valid instrument for a better understanding of feed-forward anticipatory strategies.
In multiple sclerosis (MS) exercise improves upper limb functions, but it is unclear what training types are more effective.
This study compares robot-assisted training based on haptic or ...sensorimotor exercise.
41clinically definite MS subjects with upper limb impairment were randomised into two groups: (i) Haptic and (ii) Sensorimotor. Subjects in the Haptic performed a robot-assisted training protocol designed to counteract incoordination and weakness. The task –interaction with a virtual mass-spring system against a resistive load– requires coordination skills. Task difficulty and magnitude of resistive load were automatically adjusted to the individual impairment. Subjects in the Sensorimotor performed reaching movements under visual control; the robot generated no forces. Both groups underwent eight training sessions (40 min/session, 2 sessions/week). Treatment outcome were 9HPT and ARAT scores.
The average 9HPT score decreased from 74±9 s to 61±8 s for the Haptic and from 49±6 s to 44±6 s. We found a significant Treatment (p=.0453) and Time differences (p=.005), but no significant Treatment×Time interactions although we found that the absolute change was only significant in the Haptic group (p=.011). We observed no significant changes in the ARAT score.
Participants tolerated treatments well with a low drop-out rate. In the subjects evaluated at after 12 week (11 subject in sensory-motor and 17 in haptic group) no retention of the effect was found.
Task oriented training may improve upper limb function in persons with MS especially in prevalent pyramidal impaired subjects without maintain the effects after three months.
Clinical trial registration number: NCT02711566 (clinicaltrial.gov).
•Comparison between robot-assisted training based on haptic or sensorimotor exercise•Task oriented training may improve upper limb function in persons with MS expecially in prevalent pyramidal impaired subjects1•Robot-mediated training protocol may provide exercises for upper limb deficits tailored to specific subjects impairments, adapting task parameters after each sessions and a very low rate of drop-out
Highlights • Our new method is intended for Gait Initiation (GI) examination in OFF state. • PD subjects in OFF state showed reduced spatio-temporal parameters during GI. • PD subjects took more time ...than controls to perform the unloading phase. • A difference between the durations of the GI phases was limited to the PD group.
Background and purpose
People with multiple sclerosis (PwMS) often report walking limitations even when the gold standard Expanded Disability Status Scale (EDSS) indicates normal walking ...endurance/autonomy. The present multicenter study on early‐stage PwMS aims at analyzing which aspects are associated with patient‐reported walking limitations measured with the 12‐item Multiple Sclerosis Walking Scale (MSWS‐12).
Methods
Eighty‐two PwMS (EDSS ≤ 2.5) were assessed using the Fullerton Advanced Balance Scale—short (FAB‐s), the Fatigue Severity Scale (FSS) and the 6‐min Walk Test (6MWT), the latter administered also to 21 healthy subjects. Participants performed the 6MWT wearing three inertial sensors on ankles and trunk. Instrumented metrics describing gait velocity (stride length and frequency) and quality (regularity, symmetry, instability) were computed from sensor data. Fatigue (FSS), balance (FAB‐s), walking endurance (6MWT) and instrumented metrics were entered in a multiple regression model with MSWS‐12 as dependent variable.
Results
Gait symmetry, gait instability, fatigue and balance were significantly associated with self‐rated walking ability, whilst walking endurance and velocity were not. Fatigue, balance, gait symmetry and instability were more impaired in participants reporting mild‐to‐moderate (MSMM‐PWL, 25 ≤ MSWS‐12 < 75) compared to those reporting none‐to‐minimal (MSnm‐PWL, 0 ≤ MSWS‐12 ≤ 25) perceived walking limitations. Compared to healthy subjects, gait symmetry and stability were reduced in MSnm‐PWL and MSMM‐PWL, even in those participants with EDSS ≤ 1.5.
Conclusion
Instrumentally assessed gait quality aspects (symmetry and instability) are associated with patient‐reported walking ability in early‐stage PwMS and seem sensitive biomarkers to detect subtle impairments even in the earliest stages of the disease (EDSS ≤ 1.5). Future studies should assess their ability to follow walking change due to MS progression or pharmacological/rehabilitation interventions.
People with multiple sclerosis often report walking limitations even when the Expanded Disability Status Scale indicates normal walking endurance/autonomy. Instrumentally assessed gait symmetry and instability and clinically assessed fatigue and balance were associated with perceived walking limitations, whilst walking endurance and velocity were not. Fatigue, balance, gait symmetry and instability were more impaired in participants reporting mild‐to‐moderate (MSMM‐PWL) compared to those reporting none‐to‐minimal (MSnm‐PWL) perceived walking limitations. Compared to healthy subjects, gait symmetry and stability were reduced in MSnm‐PWL and MSMM‐PWL, suggesting that these measures could be sensitive biomarkers to detect subtle impairments even in the earliest stages of the disease.
Inertial measurement units (IMUs) allow accurate quantification of gait impairment of people with multiple sclerosis (pwMS). Nonetheless, it is not clear how IMU-based metrics might be influenced by ...pragmatic aspects associated with clinical translation of this approach, such as data collection settings and gait protocols. In this study, we hypothesised that these aspects do not significantly alter those characteristics of gait that are more related to quality and energetic efficiency and are quantifiable via acceleration related metrics, such as intensity, smoothness, stability, symmetry, and regularity. To test this hypothesis, we compared 33 IMU-based metrics extracted from data, retrospectively collected by two independent centres on two matched cohorts of pwMS. As a worst-case scenario, a walking test was performed in the two centres at a different speed along corridors of different lengths, using different IMU systems, which were also positioned differently. The results showed that the majority of the temporal metrics (9 out of 12) exhibited significant between-centre differences. Conversely, the between-centre differences in the gait quality metrics were small and comparable to those associated with a test-retest analysis under equivalent conditions. Therefore, the gait quality metrics are promising candidates for reliable multi-centric studies aiming at assessing rehabilitation interventions within a routine clinical context.
Emotional states have been shown to influence cognitive processes including visual-spatial learning. Parkinson's Disease (PD), besides manifesting with the cardinal motor symptoms, presents cognitive ...and affective disturbances. Here we aimed at investigating whether manipulation of the emotional state by means of music was able to influence the performance of a visual-spatial learning task in a group of PD participants.
Ten PD patients and 11 healthy elderly (ELD) were asked to perform a visual-spatial learning task while listening two musical pieces evoking a neutral emotion or fear. Targets were presented on a screen in a preset order over four blocks and subjects were asked to learn the sequence order by attending to the display. At the end of each block, participants were asked to verbally recall the sequence and a score was assigned (Verbal Score, VS).
Analysis of variance-type statistic test on the VS disclosed a significant effect of Music and sequence Blocks (p = 0.01 and p < 0.001, respectively) and a significant interaction between Group and sequence Blocks. Sequence learning occurred across the training period in both groups, but PD patients were slower than ELD and at the end of the training period learning performance was worse in PD with respect to ELD. In PD patients, like in ELD, fear-inducing music has a detrimental effect on visual-spatial learning performances, which are slower and decreased.
These findings confirm an impairment in visual-spatial learning in PD and indicates that the emotional state influences this learning ability similarly to healthy controls.
•We studied emotion effects on visuospatial learning in Parkinson's disease and elders.•Music-evoking emotions influence the visuospatial learning in both groups.•Learning is improved after training regardless of evoked emotion type in both groups.•Fearful music worsened visuospatial learning performance in both groups.
Abnormalities of body-weight transfer occur during several motor tasks in people with Parkinson's disease (PwPD). In this paper, a novel robotic paradigm for assessment and training of dynamic ...balance was developed and applied to twelve healthy subjects (HS) and ten PwPD to verify its feasibility and to assess the capability of PwPD to counteract the postural perturbations through body-weight shifts. At variance with other robotic paradigms, subjects had to react as fast as possible to the perturbation, bringing the platform back to the horizontal and keeping it until the end of the task. Four randomized perturbations, obtained varying the platform equilibrium angle from 0 to ±6° in sagittal (backward, forward) and frontal (right, left) planes, were repeated 3 times. Compared to HS, PwPD showed, in all perturbation directions, increased delay in counteraction phase onset (p <;= 0.01), prolonged time to stabilize the platform (p <;= 0.02), and higher deviation of the final plate inclination from the horizontal (p <;= 0.04), the deviation being larger during sagittal perturbations. PwPD also showed a larger (p = 0.01) postural sway around the stabilization angle following the frontal perturbations. Results are in keeping with the known hypo- and bradykinesia as well as the proprioceptive and kinesthetic impairments in PD. We suggest that the proposed approach is feasible and might be included in balance evaluation and training in PD.
Functional recovery of the plegic upper limb in post-stroke patients may be enhanced by sequentially applying a myoelectrically controlled FES (MeCFES), which allows the patient to voluntarily ...control the muscle contraction during a functional movement and robotic therapy which allows many repetitions of movements.
Evaluate the efficacy of MeCFES followed by robotic therapy compared to standard care arm rehabilitation for post-stroke patients.
Eighteen stroke subjects (onset ⩾ 3 months, age 60.1 ± 15.5) were recruited and randomized to receive an experimental combination of MeCFES during task-oriented reaching followed by robot therapy (MRG) or same intensity conventional rehabilitation care (CG) aimed at the recovery of the upper limb (20 sessions/45 minutes). Change was evaluated through Fugl-Meyer upperextremity (FMA-UE), Reaching Performance Scale and Box and Block Test.
The experimental treatment resulted in higher improvement on the FMA-UE compared with CG (P= 0.04), with a 10 point increase following intervention. Effect sizes were moderate in favor of the MRG group on FMA-UE, FMA-UE proximal and RPS (0.37-0.56).
Preliminary findings indicate that a combination of MeCFES and robotic treatment may be more effective than standard care for recovery of the plegic arm in persons > 3 months after stroke. The mix of motor learning techniques may be important for successful rehabilitation of arm function.
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