The Effect of Personalized Shoe Insoles on Parkinson's Disease Subjects: A Triple-Blind Randomized Controlled Trial.

Subjects with Parkinson's Disease (PD) display different motor and non-motor symptoms. Different therapies have been shown to be effective, such as plantar foot stimulation, which has proved to be effective for motor symptoms. Different stimulation methods were proposed and tested through specific devices, or insoles. Our aim was to assess the effect of a newly designed custom-made insole called PRO-STEP compared with a flat sham insole on subjects with PD. Subjects were randomized 1:1 into two arms and were asked to wear PRO-STEP or sham insoles for at least 6 h per day for 10 weeks. Participants were evaluated at four timepoints. Forty-two subjects were randomly assigned to the PRO-STEP (EG) or sham group (SG). The comparison of the EG and SG without and with insoles (T0-T1) did not show significant differences in the TUG time and in the 10MWT gait parameters. At T1, T2, and T3 TUG time, BBS, SF12-MC, and SF12-PC did not show significant differences. The satisfaction level with the PRO-STEP or sham insoles was high in both groups. PD patients were satisfied with PRO-STEP insoles; however, plantar foot stimulation is not effective from a functional perspective. Future studies should consider possible modifications to the proposed stimulation to improve its effectiveness in patients with PD.

Uncovering Subtle Gait Deterioration in People with Early-Stage Multiple Sclerosis Using Inertial Sensors: A 2-Year Multicenter Longitudinal Study.

Limited longitudinal studies have been conducted on gait impairment progression overtime in non-disabled people with multiple sclerosis (PwMS). Therefore, a deeper understanding of gait changes with the progression of the disease is essential. The objective of the present study was to describe changes in gait quality in PwMS with a disease duration ≤ 5 years, and to verify whether a change in gait quality is associated with a change in disability and perception of gait deterioration. We conducted a multicenter prospective cohort study. Fifty-six subjects were assessed at baseline (age: 38.2 ± 10.7 years, Expanded Disability Status Scale (EDSS): 1.5 ± 0.7 points) and after 2 years, participants performed the six-minute walk test (6MWT) wearing inertial sensors. Quality of gait (regularity, symmetry, and instability), disability (EDSS), and walking perception (multiple sclerosis walking scale-12, MSWS-12) were collected. We found no differences on EDSS, 6MWT, and MSWS-12 between baseline and follow-up. A statistically significant correlation between increased EDSS scores and increased gait instability was found in the antero-posterior (AP) direction (r = 0.34, p = 0.01). Seventeen subjects (30%) deteriorated (increase of at least 0.5 point at EDSS) over 2 years. A multivariate analysis on deteriorated PwMS showed that changes in gait instability medio-lateral (ML) and stride regularity, and changes in ML gait symmetry were significantly associated with changes in EDSS (F = 7.80 (3,13), p = 0.003, R2 = 0.56). Moreover, gait changes were associated with a decrease in PwMS perception on stability (p < 0.05). Instrumented assessment can detect subtle changes in gait stability, regularity, and symmetry not revealed during EDSS neurological assessment. Moreover, instrumented changes in gait quality impact on subjects' perception of gait during activities of daily living.

Complementary use of statistical parametric mapping and gait profile score to describe walking alterations in multiple sclerosis: a cross-sectional study.

Gait analysis is often used to study locomotor alterations in people with multiple sclerosis (PwMS), but the large number of extracted variables challenges the interpretability. In this paper, we analysed gait alterations by combining the Gait Profile Score (GPS), which summarizes kinematic locomotor deviations, and Statistical Parametric Mapping (SPM), which compares kinematics and kinetics over the whole gait cycle. Eleven PwMS and 11 speed-matched Healthy Controls (HC) underwent overground gait analysis. GPS were compared through independent-samples t-tests; sagittal-plane kinematics and power at hip, knee, and ankle were compared through SPM Hotelling's-T2 and SPM t-tests. Spearman's correlation coefficients (r) between GPS and clinical outcomes were also calculated. PwMS had higher GPS than HC (PwMS = 8.74 ± 2.13°; HC = 5.01 ± 1.41°;p < 0.001). Multivariate SPM found statistically significant differences at 0-49%, 70-80%, and 93-99% of stride (p < 0.05) and univariate analysis showed reduced ankle dorsiflexion, and lower knee flexion during pre-swing and swing. GPS correlated with Expanded Disability Status Scale (r = 0.65; 95%C.I.[0.04,0.91]; p = 0.04) and 2-Minute Walking Test (r = -0.65; 95%C.I.[-0.91,-0.04]; p = 0.04). GPS in conjunction with SPM revealed multi-joint kinematic alterations on sagittal plane involving distal joint angles, ankle and knee, during the stance phase with no changes at the proximal level. Gait deviations were more pronounced in PwMS with higher disability and walking limitations.

Machine learning based estimation of dynamic balance and gait adaptability in persons with neurological diseases using inertial sensors.

Poor dynamic balance and impaired gait adaptation to different contexts are hallmarks of people with neurological disorders (PwND), leading to difficulties in daily life and increased fall risk. Frequent assessment of dynamic balance and gait adaptability is therefore essential for monitoring the evolution of these impairments and/or the long-term effects of rehabilitation. The modified dynamic gait index (mDGI) is a validated clinical test specifically devoted to evaluating gait facets in clinical settings under a physiotherapist's supervision. The need of a clinical environment, consequently, limits the number of assessments. Wearable sensors are increasingly used to measure balance and locomotion in real-world contexts and may permit an increase in monitoring frequency. This study aims to provide a preliminary test of this opportunity by using nested cross-validated machine learning regressors to predict the mDGI scores of 95 PwND via inertial signals collected from short steady-state walking bouts derived from the 6-minute walk test. Four different models were compared, one for each pathology (multiple sclerosis, Parkinson's disease, and stroke) and one for the pooled multipathological cohort. Model explanations were computed on the best-performing solution; the model trained on the multipathological cohort yielded a median (interquartile range) absolute test error of 3.58 (5.38) points. In total, 76% of the predictions were within the mDGI's minimal detectable change of 5 points. These results confirm that steady-state walking measurements provide information about dynamic balance and gait adaptability and can help clinicians identify important features to improve upon during rehabilitation. Future developments will include training of the method using short steady-state walking bouts in real-world settings, analysing the feasibility of this solution to intensify performance monitoring, providing prompt detection of worsening/improvements, and complementing clinical assessments.

Dynamic balance during walking in people with multiple sclerosis: A cross-sectional study.

Dynamic balance disorders are common impairments in People with Multiple Sclerosis (PwMS) leading to gait disorders and a higher risk of falling. However, the assessment of dynamic balance is still challenging and instrumented indexes provide objective and quantitative data of CoM movement and Base of Support, which are considered that are two key factors describing dynamic balance. This study aims at validating recent instrumented indexes based on the inverted pendulum model and characterizing dynamic balance disorders in PwMS. We clinically assessed 20 PwMS and we collected instrumented gait data through an optoelectronic system. Data from 20 Healthy Subjects (HS) were also considered as normative reference. Margin of Stability by HoF (MoS_Hof) and by Terry (MoS_Terry) at midstance, and Foot Placement Estimator (DFPE) at heel strike were calculated in mediolateral (ML) and anteroposterior (AP) directions, for both less affected and most affected sides for PwMS and for dominant and non-dominant side for HS. MoS_HOF well discriminated between PwMS and HS, followed by MoS_TERRY in ML direction (Mos_HOF: PwMS = 130.0 ± 27.2 mm, HS = 106.5 ± 18.6 mm, p < 0.001, MoS_TERRY: PwMS = 75.1 ± 24.3 mm, HS = 56.5 ± 23.4 mm, p < 0.02). MoS_HOF and MoS_TERRY discriminated between sides in both directions in PwMS. DFPE did not discriminate between groups and sides. Moderate correlations were found between all three indexes and clinical balance scales (from r = 0.02 to r = 0.66), energy recovery (from r = -0.77 to r = -0.11), single stance time (from r = -0.11 to r = 0.80) and step length (from r = -0.83 to r = -0.20). MoS_HOF resulted in the best index to describe dynamic balance disorders in PwMS: they keep CoM position far from the lateral and as close as possible to the anterior boundary of the Base of Support as preventive strategies to control balance perturbations. Furthermore, PwMS seem to use different preventive strategies in accordance with the specific lower limb impairments. This alters the physiological gait mechanisms increasing the energy expenditure and decreasing gait quality and dynamic balance.

Balance Impairments in People with Early-Stage Multiple Sclerosis: Boosting the Integration of Instrumented Assessment in Clinical Practice.

The balance of people with multiple sclerosis (PwMS) is commonly assessed during neurological examinations through clinical Romberg and tandem gait tests that are often not sensitive enough to unravel subtle deficits in early-stage PwMS. Inertial sensors (IMUs) could overcome this drawback. Nevertheless, IMUs are not yet fully integrated into clinical practice due to issues including the difficulty to understand/interpret the big number of parameters provided and the lack of cut-off values to identify possible abnormalities. In an attempt to overcome these limitations, an instrumented modified Romberg test (ImRomberg: standing on foam with eyes closed while wearing an IMU on the trunk) was administered to 81 early-stage PwMS and 38 healthy subjects (HS). To facilitate clinical interpretation, 21 IMU-based parameters were computed and reduced through principal component analysis into two components, sway complexity and sway intensity, descriptive of independent aspects of balance, presenting a clear clinical meaning and significant correlations with at least one clinical scale. Compared to HS, early-stage PwMS showed a 228% reduction in sway complexity and a 63% increase in sway intensity, indicating, respectively, a less automatic (more conscious) balance control and larger and faster trunk movements during upright posture. Cut-off values were derived to identify the presence of balance abnormalities and if these abnormalities are clinically meaningful. By applying these thresholds and integrating the ImRomberg test with the clinical tandem gait test, balance impairments were identified in 58% of PwMS versus the 17% detected by traditional Romberg and tandem gait tests. The higher sensitivity of the proposed approach would allow for the direct identification of early-stage PwMS who could benefit from preventive rehabilitation interventions aimed at slowing MS-related functional decline during neurological examinations and with minimal modifications to the tests commonly performed.

Acute Thermoregulatory and Cardiovascular Response to Submaximal Exercise in People With Multiple Sclerosis.

Background: Heat sensitivity occurs in a high percentage of people with multiple sclerosis (PwMS), in response to environmental or exercise-induced increase in body temperature. However, the kinetic and magnitude of adaptation of the internal load and of the core body temperature (CBT) to a submaximal continuous exercise has been poorly addressed in PwMS; this may be relevant for the brief exercise bouts usually occurring in normal daily life. The aim of this work was to evaluate whether multiple sclerosis influences the acute adaptation of the internal load, the CBT and the perceptual load in response to a constant submaximal work step. Methods: CBT has been continuously monitored (0.5 Hz) by a validated wearable heat-flux sensor and electrocardiography was recorded (250 Hz) by a wearable device during a standard 6-minute walk test (6MWT) in 14 PwMS (EDSS, 4.7 ± 1.2; disease duration: 13.0 ± 10.2 years; m ± SD) and 14 age, sex and BMI-matched healthy subjects (HS). The rate of perceived exertion (RPE) of the lower limbs was assessed during the 6MWT by the Borg scale (6-20). Results: As expected, PwMS walked a significantly shorter distance (361 ± 98 m) than the HS group (613 ± 62 m, p<0.001 vs PwMS). However, the kinetics of adaptation of CBT and the magnitude of CBT change from baseline did not differ between groups. Similarly, heart rate (HR) kinetics and HR change from baseline were comparable between groups during the 6MWT. Finally, lower limbs RPE gradually increased during the exercise test, but without significant differences between groups. Conclusion: The internal load, the metabolic heat production, and the perceptive load due to a standard submaximal walking exercise seems to be preserved in PwMS, suggesting a comparable acute heat production and dissipation during exercise. Therefore, it is unlikely that the different distance achieved during the 6MWT may be caused by altered thermoregulatory responses to exercise. Rather, this appears to be a consequence of the known increased energy cost of locomotion in PwMS.

Physical activity in non-disabled people with early multiple sclerosis: A multicenter cross-sectional study.

BACKGROUND: People with Multiple Sclerosis (PwMS) show low levels of physical activity (PA), however there has been limited research on PA in early diagnosed and no/minimally impaired (<5 years, EDSS≤ 2.5) PwMS. The aims of the study were to objectively quantify PA levels in non-disabled PwMS, to compare the time spent daily at different PA levels (No activity (NPA), Light PA (LPA), Moderate PA (MPA), and Vigorous PA (VPA)) with healthy subjects (HS), and to examine the association of PA with disability, and clinical measures in PwMS. METHODS: We assessed 58 PwMS (mean age±standard deviation, SD 39.1 ± 10.6years) and 20 HS (mean age±SD 39.3 ± 8.9 years). Demographic and clinical data were recorded at the hospital during the baseline assessment. Subjects wore the wrist GENEActiv accelerometer for 7-days. Data were collected at 100 Hz and summarized into a motor activity (MA) index using 60 s epochs with the following thresholds: MANPA-LPA: 10mG, MALPA-MPA: 100mG, MAMPA-VPA: 350mG. RESULTS: PwMS show higher NPA and lower VPA compared to matched healthy subjects (NPA: Mean±SD, HS: 7.2 ± 0.9 h/day; PwMS: 8.1 ± 1.2 h/day, p<0.01; VPA: HS: 0.78± 0.42 h/day; PwMS: 0.50± 0.40 h/day, p = 0.01), while no between group differences were observed for LPA and MPA (p>0.05). Bivariate analysis showed that higher NPA was associated with fatigue (Fatigue Severity Scale, FSS score) in PwMS with EDSS 0-1.5 (r = 0.34, p = 0.05). In PwMS with EDSS 2-2.5, NPA was correlated with Six Minute Walk Test (6MWT, r=-0.45, p = 0.02) and CIQ (r=-0.41, p = 0.04), while VPA was more associated with FSS (R= -0.38, p = 0.06). CONCLUSION: The PA level of PwMS differs from that of healthy subjects even in early diagnosed subjects. In PwMS with EDSS 0-1.5 only, fatigue is associated to prolonged inactive behavior. Conversely, in PwMS with EDSS 2-2.5 both inactivity and vigorous activities are modulated by fatigue, endurance and associated with different level of social participation.

Smoothness of movement in idiopathic cervical dystonia.

Smoothness (i.e. non-intermittency) of movement is a clinically important property of the voluntary movement with accuracy and proper speed. Resting head position and head voluntary movements are impaired in cervical dystonia. The current work aims to evaluate if the smoothness of voluntary head rotations is reduced in this disease. Twenty-six cervical dystonia patients and 26 controls completed rightward and leftward head rotations. Patients' movements were differentiated into "towards-dystonia" (rotation accentuated the torticollis) and "away-dystonia". Smoothness was quantified by the angular jerk and arc length of the spectrum of angular speed (i.e. SPARC, arbitrary units). Movement amplitude (mean, 95% CI) on the horizontal plane was larger in controls (63.8°, 58.3°-69.2°) than patients when moving towards-dystonia (52.8°, 46.3°-59.4°; P = 0.006). Controls' movements (49.4°/s, 41.9-56.9°/s) were faster than movements towards-dystonia (31.6°/s, 25.2-37.9°/s; P < 0.001) and away-dystonia (29.2°/s, 22.9-35.5°/s; P < 0.001). After taking into account the different amplitude and speed, SPARC-derived (but not jerk-derived) indices showed reduced smoothness in patients rotating away-dystonia (1.48, 1.35-1.61) compared to controls (1.88, 1.72-2.03; P < 0.001). Poor smoothness is a motor disturbance independent of movement amplitude and speed in cervical dystonia. Therefore, it should be assessed when evaluating this disease, its progression, and treatments.

Identification of modified dynamic gait index cutoff scores for assessing fall risk in people with Parkinson disease, stroke and multiple sclerosis.

BACKGROUND: Balance and gait impairments increase fall rate and injury in people with neurological disorders(PwND). The modified Dynamic Gait Index(mDGI) is a scale assessing dynamic balance during walking, however its ability in identifying Fallers and Recurrent Fallers has not been studied. RESEARCH QUESTION: To evaluate mDGI's ability in identifying retrospective Fallers and Recurrent Fallers establishing cut-off scores for its use in clinical practice. METHOD: In this cross-sectional study, the number of retrospective falls and mDGI scores were collected. PwND were categorised as Non-Fallers or Fallers (falls≥1) and as Recurrent Fallers(falls≥2) or Non-Recurrent/Non-Fallers(falls<2) according to their number of retrospective falls over two months. Two generalised linear logistic models were developed using a machine learning method to detect Fallers (Model 1) and Recurrent Fallers (Model 2) based on mDGI scores. ROC curves were used to identify mDGI cut-off scores to distinguish between different fall categories. RESULTS: 58 PwND (mean ± standard deviation age: 63.4 ± 12 years) including 28 people with Multiple Sclerosis, 15 people with Parkinson's disease and 15 people with Stroke were analysed. The mDGI score(median (IQR)) for Non-Fallers, Fallers, Recurrent Fallers and Non-Recurrent/Non-Fallers was respectively 50(22), 37(22), 26.5(20.25) and 46.5(20.5)points. The cut-off to identify Fallers from Non-Fallers was 49 points(sensitivity:100 %, specificity:50 %, post-test probability with mDGI ≤ cut-off: 53.2 %, post-test probability with mDGI > cut-off: 0%, AUC:0.68), while 29 points(sensitivity:60 %, specificity:79 %, post-test probability with mDGI ≤ cut-off:52.1 %, post-test probability with mDGI > cut-off:16.1 %, AUC:0.70) was the best cut-off to identify Recurrent Fallers. SIGNIFICANCE: People with mDGI score>49 points have low or minimal fall risk, while people with mDGI score≤49 points should be further investigated with other scales before starting a balance-focused rehabilitation intervention. People scoring ≤29 points on the mDGI scale may need a fall prevention intervention, regardless of the results of other balance clinical measures.

Prevalence and patterns of subclinical motor and cognitive impairments in non-disabled individuals with early multiple sclerosis: A multicenter cross-sectional study.

BACKGROUND: Motor and cognitive disorders appear early in the course of multiple sclerosis (MS) and develop gradually over time. OBJECTIVE: To study the frequency and pattern of subtle functional disorders in people with MS (PwMS) with no overt signs of disability in an early phase of the disease and their association with walking impairments in daily activities. METHODS: In this cross-sectional study, we recruited PwMS with an Expanded Disability Status Scale (EDSS) score≤2.5 and disease duration≤5years. Participants were assessed with functional scales rating walking endurance (6-Min Walk Test), perceived walking ability (Twelve-item Multiple Sclerosis Walking Scale), balance (Fullerton Advanced Balance scale_short), manual dexterity (Nine Hole Peg Test), fatigue (Fatigue Severity Scale), and cognitive impairments (Brief International Cognitive Assessment). RESULTS: About 90% of the 82 PwMS (mean [SD] EDSS score 1.5 [0.7] and disease duration 2.2 [1.7] years) showed endurance values below the expected score; almost 30% showed impairment, and for 57%, perceived walking ability score was abnormal. Balance was impaired in 48% of participants, as was manual dexterity (29%) and fatigue (24%), but only a few showed cognitive impairments. Only 11% of PwMS had no abnormal score on the scales used in the assessment. As compared with EDSS score 0 to 1.5, with EDSS score 2 to 2.5, performance was worse for endurance (difference±61.0m, P=0.016), perceived walking ability (-11 points, P=0.002), balance (+1.9 points, P=0.005), manual dexterity (-2.8 s, P=0.004), and fatigue (-1.3 points, P=0.013). Factors that predicted perceived walking ability were balance (B=-1.37, P<0.001) and fatigue (B=5.11, P<0.001) rather than endurance (B=-0.01, P=048). CONCLUSION: Even PwMS with no clinical disability and classified as having "no problem walking" present walking and other functional deficits when assessed with specific functional tests. The addition of specific tools could better identify subtle motor and cognitive deficits. Finally, the assessment of balance disorders and fatigue is important to understand individuals' perceived walking impairments in daily activities.

Minimal clinically important difference of modified dynamic gait index in people with neurological disorders.

BACKGROUND: The minimal clinically important difference (MCID) of modified Dynamic Gait Index (mDGI) has not yet been determined for People with Neurological Disorders (PwND). RESEARCH QUESTION: To establish the MCID of the mDGI to determine clinically meaningful improvement in balance and gait in PwND. METHODS: In this longitudinal study from a randomised clinical trial, 55 participants both in and outpatients with neurological disorders, received fifteen 40-minute rehabilitation sessions. Inpatients received daily treatments over a period of three weeks while outpatients received three treatments/week over a period of five weeks. An anchor-based method using percentage rating of improvement in balance (Activities Balance Confidence scale, ABC) was used to determine the MCID of mDGI. The MCID was defined as the minimum change in mDGI total score (post - pre intervention) that was needed to perceive at least a 10 % improvement on the ABC scale. A Receiver Operating Characteristic curve was used to define the cut-off for the optimal MCID of the mDGI discriminating between improved and not improved participants. RESULTS: The MCID of the mDGI total score was 6 points and Area under the Curve was 0.64. For the mDGI time sub-scores the MCID was 2 points and Area under the Curve was 0.6. SIGNIFICANCE: The MCID of balance and gait improvement measured by mDGI was prudently establish at ≥7 points, meaning that this is the minimum improvement score PwND need to get to perceive a clinically relevant change in their balance and gait confidence. These reference values can be a tool incorporated into clinicians daily practice to interpret mDGI change scores helping to determine whether the intervention is effective; to develop clinical tailored intervention goals and to establish meaningful perceived change in PwND.

Strategies for maintaining dynamic balance in persons with neurological disorders during overground walking.

Maintaining a stable gait requires a dynamic balance control, that can be altered in persons with Multiple Sclerosis (MS), Stroke (ST), and Parkinson's disease (PD). The understanding of the strategy for Center of Mass (CoM) positioning adopted by patients during walking is important to be able to program treatments aimed at improving gait control and preventing falls. Forty-four persons with a mild-to-moderate neurological disorder (20 with MS, 14 with ST, 10 with PD) underwent clinical examination and gait analysis. Ten Healthy Subjects (HS) walking at matched speed provided the normative data. Dynamic balance was assessed using the margin of stability (MoS). It was calculated as the distance between the extrapolated Center of Pressure and the extrapolated CoM at mid-stance. The MoS values for lower limbs were calculated in patients and compared with speed-matched values of HS. Persons with neurological disorder showed increased MoS in the medio-lateral direction with respect to HS. Within-group comparison analysis showed a symmetry between lower limbs in HS (Mean (95%CI) [mm], dominant vs non-dominant limb, 43.3 (31.9-54.6) vs 42.9 (28.8-56.9)) and PD (less affected vs more affected limb, 71.1 (59.8-82.5) vs 72.5 (58.5-86.6)), while a significant asymmetry was found in MS (54.4 (46.4-62.4) vs 81.1 (71.2-91.1)) and ST (52.1 (42.6-61.7) vs 74.7 (62.8-86.6)) participants. The history of falls was comparable among PD, MS, and ST groups, and the MoS in the frontal plane showed a strong correlation with these records. Objective assessment of MoS revealed pathology-specific strategies showing different impacts in MS, ST, and PD on the ability to control CoM information to manage the balance between limbs during gait. MoS evaluation will provide useful information to address a tailored rehabilitation program and to monitor disease progression.

Instrumentally assessed gait quality is more relevant than gait endurance and velocity to explain patient-reported walking ability in early-stage multiple sclerosis.

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.

Walking With Horizontal Head Turns Is Impaired in Persons With Early-Stage Multiple Sclerosis Showing Normal Locomotion.

BACKGROUND: Turning the head while walking (an action often required during daily living) is particularly challenging to maintain balance. It can therefore potentially reveal subtle impairments in early-stage people with multiple sclerosis who still show normal locomotion (NW-PwMS). This would help in identifying those subjects who can benefit from early preventive exercise aimed at slowing the MS-related functional decline. OBJECTIVES: To analyze if the assessment of walking with horizontal head turns (WHHT) through inertial sensors can discriminate between healthy subjects (HS) and NW-PwMS and between NW-PwMS subgroups. To assess if the discriminant ability of the instrumented WHHT is higher compared to clinical scores. To assess the concurrent validity of the sensor-based metrics. METHODS: In this multicenter study, 40 HS and 59 NW-PwMS [Expanded Disability Status Scale (EDSS) ≤ 2.5, disease duration ≤ 5 years] were tested. Participants executed Item-6 of the Fullerton Advanced Balance scale-short (FAB-s) wearing three inertial sensors on the trunk and ankles. The item required to horizontally turn the head at a beat of the metronome (100 bpm) while walking. Signals of the sensors were processed to compute spatiotemporal, regularity, symmetry, dynamic stability, and trunk sway metrics descriptive of WHHT. RESULTS: Mediolateral regularity, anteroposterior symmetry, and mediolateral stability were reduced in NW-PwMS vs. HS (p ≤ 0.001), and showed moderate discriminant ability (area under the receiver operator characteristic curve [AUC]: 0.71-0.73). AP symmetry and ML stability were reduced (p ≤ 0.026) in EDSS: 2-2.5 vs. EDSS: 0-1.5 subgroup (AUC: 0.69-0.70). The number of NW-PwMS showing at least one abnormal instrumented metric (68%) was larger (p ≤ 0.002) than the number of participants showing abnormal FAB-s-Item6 (32%) and FAB-s clinical scores (39%). EDSS: 2-2.5 subgroup included more individuals showing abnormal instrumented metrics (86%) compared to EDSS: 0-1.5 subgroup (57%). The instrumented metrics significantly correlated with FAB-s-Item6 and FAB-s scores (|Spearman's r s | ≥ 0.37, p < 0.001), thus demonstrating their concurrent validity. CONCLUSION: The instrumented assessment of WHHT provided valid objective metrics that discriminated, with higher sensitivity than clinical scores, between HS and NW-PwMS and between EDSS subgroups. The method is a promising tool to complement clinical evaluation, and reveal subclinical impairments in persons who can benefit from early preventive rehabilitative interventions.

Improved Gait of Persons With Multiple Sclerosis After Rehabilitation: Effects on Lower Limb Muscle Synergies, Push-Off, and Toe-Clearance.

Introduction: Persons with MS (PwMS) have markedly reduced push-off and toe-clearance during gait compared to healthy subjects (HS). These deficits may result from alterations in neuromotor control at the ankle. To optimize rehabilitation interventions for PwMS, a crucial step is to evaluate if and how altered neuromotor control, as represented by muscle synergies, improves with rehabilitation. In this study we investigated changes in ankle motor control and associated biomechanical parameters during gait in PwMS, occurring with increase in speed after gait rehabilitation. Methods: 3D motion and EMG data were collected while 11 PwMS (age 50.3 + 11.1; EDSS 5.2 + 1.2) walked overground at self-selected speed before (T0) and after 20 sessions (T1) of intensive treadmill training. Muscle synergies were extracted using non-negative matrix factorization. Gait parameters were computed according to the LAMB protocol. Pearson's correlation coefficient was used to evaluate the similarity of motor modules between PwMS and HS. To assess differences in distal module activations representing neuromotor control at the ankle [Forward Propulsion (FPM) and Ground Clearance modules (GCM)], each module's activation timing was integrated over 100% of the gait cycle and the activation percentage index (API) was computed in six phases. Ten age matched HS provided two separate speed-matched normative datasets for T0 and T1. For speed independent comparison for the PwMs Z scores were calculated for all their gait variables. Results: In PwMS velocity increased significantly from T0 to T1 (0.74-0.90 m/s, p < 0.05). The activation profiles (API) of FPM and GCM of PwMS improved in pre-swing (p < 0.05): FPM (Mean [95% CI] [%]: T0: 12.5 [5.7-19.3] vs. T1: 9.0 [2.7-15.3]); GCM (T0: 26.7 [18.2-35.3] vs. T1: 24.5 [18.2-30.7]). This was associated with an increase in toe clearance (80.3 to 103.6 mm, p < 0.05) and a higher ankle power peak in pre-swing (1.53-1.93 W/kg, p < 0.05). Conclusion: Increased gait speed of PwMS after intensive gait training was consistent with improvements in spatio-temporal gait parameters. The most important finding of this study was the re-organization of distal leg modules related to neurophysiological changes induced by rehabilitation. This was associated with an improved ankle performance.

Local Dynamic Stability of Gait in People With Early Multiple Sclerosis and No-to-Mild Neurological Impairment.

Poor dynamic balance, such as poor walking stability, is a hallmark of multiple sclerosis. Instrumental measures of local dynamic stability (LDS, e.g. short-term Lyapunov's exponents, sLyEs) are genuine measures of walking stability and increasingly used as dynamic balance indicators. The current work aims to investigate if people with multiple sclerosis (PWMS) with no clinical evidence of gait impairment suffer poor LDS of gait. Eighty PWMS with minimal impairment (EDSS ≤2.5) and twenty controls completed the Six-Minute Walk Test (6MWT) at their maximum speed, wearing inertial sensors. sLyEs were calculated from trunk vertical, mediolateral and anteroposterior (sLyEAP) acceleration. PWMS also completed a full clinical assessment including gait, balance and fatigue. Gait speed was lower in PWMS than controls (-15%), while sLyEs were larger in PWMS (+12%), even when adjusting for the different gait speed. High sLyEAP was associated with low gait speed, high impact of disease (including high fatigue) and poor balance, the three variables returned by a principal component analysis of the dataset of clinical measures. PWMS suffer poor LDS of gait, as indicated by large sLyEs. The association between high sLyEAP and poor balance supports the validity of sLyEAP as a dynamic balance measure. The inverse relationship between sLyEAP and gait speed is in line with the view that good balance is decisive for high gait speed. Finally, these findings are in line with the vicious circle linking poor balance and fatigue in PWMS, with fatigue worsening balance and poor balance leading to fatigue.

Assessing balance in non-disabled subjects with multiple sclerosis: Validation of the Fullerton Advanced Balance Scale.

OBJECTIVE: To validate the Fullerton Advanced Balance (FAB) scale for high-functioning non-disabled people with multiple sclerosis (PwMS). DESIGN: Cross-sectional study. PARTICIPANTS: A convenience sample of early-diagnosed PwMS (N = 82; Expanded Disability Status Scale score ≤ 2.5) with disease duration ≤ 5 years and a control group of healthy volunteers (N = 45). MAIN OUTCOME MEASURES: FAB scale, Timed Up and Go test (TUG), 6 Min Walk Test (6MWT) and 25 Foot Walk Test (25FWT). RESULTS: Six of the ten original FAB scale items were selected to represent a unidimensional construct. Only one factor with eigenvalues > 1.0 (1.90) was found. The new version of the scale reported a Cronbach alpha value of 0.65, and it was also statistically significantly correlated with TUG (r = -0.48). The new six-item scale, dubbed the FAB-short scale (FAB-s), discriminated between healthy volunteers and PwMS; moreover, both the FAB-s and the TUG test discriminated between the two PwMS subgroups: EDSS=0-1.5 (no disability) and EDSS=2-2.5 (minimal disability). CONCLUSIONS: FAB-s is a unidimensional clinical tool for assessing balance. The scale is a promising instrument for detecting subtle changes in balance performance in high-functioning PwMS.

Instrumented Version of the Modified Dynamic Gait Index in Patients With Neurologic Disorders.

BACKGROUND: Gait instability is common in adults with neurologic disorders and the modified Dynamic Gait Index (mDGI) was recently introduced to assess dynamic balance. However, instrumental assessment is needed to provide quantitative measures. OBJECTIVE: To develop and validate an instrumented version of the mDGI. DESIGN: Cross-sectional study. SETTING: Clinical setting. PARTICIPANTS: Thirty adults with neurologic disorders (10 with multiple sclerosis, 10 with Parkinson disease, and 10 with stroke) and 20 healthy volunteers. METHODS: Participants were assessed with the Timed Up and Go test (TUG) and with the mDGI. During the assessment of mDGI, data were collected by a single Inertial Measurement Unit (IMU) positioned on the sternum. Principal component analysis (PCA) was performed on the instrumented data extracting eight PC scores (ImPC) describing dynamic balance. The instrumented overall score (ImDGI) was then calculated as the sum of the mPCs. PCA revealed two components associated with stride features and regularity (ImDGI_Gait_Pattern) and trunk movements (ImDGI_Trunk_Sway). Spearman coefficients were calculated between mDGI and ImDGI, whereas Mann-Whitney (U) and Kruskal-Wallis (H) tests assessed differences between groups and neurologic conditions. MAIN OUTCOME MEASUREMENTS: ImDGI. RESULTS: ImDGI did not show ceiling effects, and good correlations were found between ImDGI and mDGI (r = .84), and TUG (r = .84) for people with neurologic disorders (P < .001). Significant differences among pathologies (H test(2) =12.5, P = .002) and between healthy participants and adults with neurologic disorders (U test = 47.0, P = .001) were found. ImDGI_Trunk_Sway discriminated between people using or not using walking aids and among the three pathologies (H(2) = 10.0, P = .007). CONCLUSIONS: The ImDGI test seems to provide valid measures to objectively assess dynamic balance in neurologic conditions and possibly quantify balance deficits also in adults with neurologic disorders.

Instrumental Assessment of Stair Ascent in People With Multiple Sclerosis, Stroke, and Parkinson's Disease: A Wearable-Sensor-Based Approach.

Stair ascent is a challenging daily-life activity highly related to independence. This task is usually assessed with clinical scales suffering from partial subjectivity and limited detail in evaluating different task aspects. In this paper, we instrumented the assessment of stair ascent in people with multiple sclerosis (MS), stroke (ST), and Parkinson's disease (PD) to analyze the validity of the proposed quantitative indexes and characterize subjects' performances. Participants climbed 10 steps wearing a magneto-inertial sensor [magneto-inertial measurement unit (MIMU)] at sternum level. Gait pattern features (step frequency, symmetry, regularity, and harmonic ratios), and upper trunk sway were computed from MIMU signals. Clinical modified dynamic gait index (mDGI) and mDGI-Item 8 "Up stairs" were administered. Significant correlations with clinical scores were found for gait pattern features ( ) and trunk pitch sway ( ) demonstrating their validity. Instrumental indexes showed alterations in the three pathological groups compared to healthy subjects and significant differences, not clinically detected, among MS, ST, and PD. MS showed the worst performance, with alterations of all gait pattern aspects and larger trunk pitch sway. ST showed worsening in gait pattern features but not in trunk motion. PD showed fewer alterations consisting in reduced step frequency and trunk yaw sway. These results suggest that the use of an MIMU provided valid objective indexes revealing between-group differences in stair ascent not detected by clinical scales. Importantly, the indexes include upper trunk measures, usually not present in clinical tests, and provide relevant hints for tailored rehabilitation.