Neural entrainment underpins sensorimotor synchronization to dynamic rhythmic stimuli.

Neural entrainment, defined as unidirectional synchronization of neural oscillations to an external rhythmic stimulus, is a topic of major interest in the field of neuroscience. Despite broad scientific consensus on its existence, on its pivotal role in sensory and motor processes, and on its fundamental definition, empirical research struggles in quantifying it with non-invasive electrophysiology. To this date, broadly adopted state-of-the-art methods still fail to capture the dynamic underlying the phenomenon. Here, we present event-related frequency adjustment (ERFA) as a methodological framework to induce and to measure neural entrainment in human participants, optimized for multivariate EEG datasets. By applying dynamic phase and tempo perturbations to isochronous auditory metronomes during a finger-tapping task, we analyzed adaptive changes in instantaneous frequency of entrained oscillatory components during error correction. Spatial filter design allowed us to untangle, from the multivariate EEG signal, perceptual and sensorimotor oscillatory components attuned to the stimulation frequency. Both components dynamically adjusted their frequency in response to perturbations, tracking the stimulus dynamics by slowing down and speeding up the oscillation over time. Source separation revealed that sensorimotor processing enhanced the entrained response, supporting the notion that the active engagement of the motor system plays a critical role in processing rhythmic stimuli. In the case of phase shift, motor engagement was a necessary condition to observe any response, whereas sustained tempo changes induced frequency adjustment even in the perceptual oscillatory component. Although the magnitude of the perturbations was controlled across positive and negative direction, we observed a general bias in the frequency adjustments towards positive changes, which points at the effect of intrinsic dynamics constraining neural entrainment. We conclude that our findings provide compelling evidence for neural entrainment as mechanism underlying overt sensorimotor synchronization, and highlight that our methodology offers a paradigm and a measure for quantifying its oscillatory dynamics by means of non-invasive electrophysiology, rigorously informed by the fundamental definition of entrainment.

Physical Activity in Multiple Sclerosis: Meeting the Guidelines at the Time of the COVID-19 Pandemic.

BACKGROUND AND PURPOSE: Regular physical activity (PA) helps to reduce the severity of physical and mental symptoms and improves quality of life in people with multiple sclerosis (PwMS). Based on current evidence and expert opinion, the recent multiple sclerosis guidelines recommend at least 150 minutes/week of PA. This study presents the results of a survey analyzing whether and how PwMS met the guidelines before and during the pandemic. METHODS: We developed and disseminated an international online survey between December 2020 and July 2021, investigating changes in self-reported PA type, duration, frequency, and intensity due to the COVID-19 outbreak in PwMS with differing disability levels. RESULTS: Among respondents (n = 3810), 3725 were eligible. The proportion of those who conducted at least one activity decreased with increasing disability level at both time points (pre and during). Overall 60% of respondents met the guidelines before the pandemic (mild: 64.43%; moderate: 51.53%; severe: 39.34%; χ 2(2) = 109.13, P < 0.01); a reduction of approximately 10% occurred during the pandemic in all disability groups (mild: 54.76%; moderate: 42.47%; severe: 29.48%; χ 2(2) = 109.67, P < 0.01). Respondents with higher disability participated more in physical therapy and less in walking, cycling, and running at both time points. Most respondents reported practicing PA at a moderate intensity at both time points; frequency and duration of sessions decreased as disability level increased. DISCUSSION AND CONCLUSIONS: The percentage of those meeting the guidelines reduced with increasing disability level and during the pandemic. PA type and intensity varied widely across the disability categories. Interventions accounting for disability level are required to enable more PwMS to reap the benefits of PA.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A415 ).

Application of step and beat alignment approaches and its effect on gait in progressive multiple sclerosis with severe cerebellar ataxia: A proof of concept case study.

BACKGROUND: In a case report of a progressive multiple sclerosis with cerebellar impairments, we reported that synchronisation of steps to beats was possible only at -12% of usual walking cadence during 1 minute of walking. OBJECTIVES AND METHODS: Here, we investigate the effect of synchronisation using two different alignment approaches on the patient's gait pattern over 2 minutes of walking, compared to walking in silence. RESULTS AND CONCLUSION: This proof of concept showed that the adaptive approach was successful resulting in an improved gait pattern compared to the other conditions, providing preliminary evidence to support a full-scale intervention study.

Impact of the COVID-19 Pandemic on Physical Activity and Associated Technology Use in Persons With Multiple Sclerosis: An International RIMS-SIG Mobility Survey Study.

OBJECTIVE: To investigate the impact of the COVID-19 pandemic on physical activity in persons with multiple sclerosis (PwMS). DESIGN: Multicenter international online survey study. SETTING: The survey was conducted within 11 participating countries. Each country launched the survey using online platforms from May to July 2021. PARTICIPANTS: This was an electronic survey study targeting PwMS (N=3725). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: The survey ascertained physical activity performance and its intensity, the nature of the activities conducted, and the use of technology to support home-based physical activity before and during the pandemic. RESULTS: A total of 3725 respondents completed the survey. Prepandemic, the majority (83%) of respondents reported being physically active, and this decreased to 75% during the pandemic. This change was significant for moderate- and high-intensity activity (P<.0001). Activities carried out in physiotherapy centers, gyms, or pools decreased the most. Walking was the most frequently performed activity prepandemic (27%) and increased during the pandemic (33%). A total of 24% of those inactive during the pandemic had no intention of changing their physical activity behavior post pandemic. A total of 58% of the respondents did not use technology to support physical activity during the pandemic. Of those who did use technology, wearables were most used (24%). Of those currently nonactive (25%) expressed a preference for an in-person format to conduct physical activity post pandemic. CONCLUSIONS: Physical activity performance, especially activities at moderate and high intensities, decreased during the pandemic in PwMS compared with prepandemic. Walking and using wearables gained popularity as ways to stay active. As we move toward an endemic COVID-19, a call for action to develop interventions focused on walking programs with specific emphasis on increasing physical activity of PwMS is proposed.

Cognitive-motor Interference in Individuals With a Neurologic Disorder: A Systematic Review of Neural Correlates.

BACKGROUND: Performing a cognitive task and a motor task simultaneously is an everyday act that can lead to decreased performance on both tasks. OBJECTIVE: To provide insight into the neural correlates associated with cognitive-motor dual tasking in individuals with a neurologic disorder. METHOD: We searched the PubMed and Web of Science databases for studies that had been published up to January 16th, 2019. Studies investigating the neural correlates of cognitive-motor dual task performance in individuals with a variety of neurologic disorders were included, independently from whether the study included healthy controls. Clinical and imaging data were abstracted for the comparison between single tasks and a dual task in the individuals with a neurologic disorder and for the comparison between the healthy controls and the individuals with a neurologic disorder. RESULTS: Eighteen studies met the inclusion criteria. Study populations included individuals with Parkinson disease, multiple sclerosis, mild cognitive impairment, Alzheimer disease, traumatic brain injury, and stroke. Neuroimaging types used to study the neural correlates of cognitive-motor dual tasking during upper limb or gait tasks included fMRI, functional near-infrared spectroscopy, EEG, and PET. CONCLUSION: Despite large heterogeneity in study methodologies, some recurrent patterns were noted. Particularly, in neurologic patients, an already higher brain activation during single tasks was seen compared with healthy controls, perhaps compromising the patients' ability to further adapt brain activation with increasing load during dual tasking and resulting in reduced behavioral dual task performance.

A pilot study of the effects of running training on visuospatial memory in MS: A stronger functional embedding of the hippocampus in the default-mode network?

BACKGROUND/OBJECTIVE: Endurance exercise can improve memory function in persons with multiple sclerosis (pwMS), but the effects on hippocampal functioning are currently unknown. We investigated the effects of a running intervention on memory and hippocampal functional connectivity in pwMS. METHODS/RESULTS: Memory and resting-state functional magnetic resonance imaging (fMRI) data were collected in a running intervention (n = 15) and waitlist group (n = 14). Visuospatial memory improvement was correlated to increased connectivity between the hippocampus and the default-mode network (DMN) in the intervention group only. CONCLUSION: As a result of endurance exercise, improvements in visuospatial memory may be mediated by a stronger functional embedding of the hippocampus in the DMN.

Effects of an individual 12-week community-located "start-to-run" program on physical capacity, walking, fatigue, cognitive function, brain volumes, and structures in persons with multiple sclerosis.

BACKGROUND: Exercise therapy studies in persons with multiple sclerosis (pwMS) primarily focused on motor outcomes in mid disease stage, while cognitive function and neural correlates were only limitedly addressed. OBJECTIVES: This pragmatic randomized controlled study investigated the effects of a remotely supervised community-located "start-to-run" program on physical and cognitive function, fatigue, quality of life, brain volume, and connectivity. METHOD: In all, 42 pwMS were randomized to either experimental (EXP) or waiting list control (WLC) group. The EXP group received individualized training instructions during 12 weeks (3×/week), to be performed in their community aiming to participate in a running event. Measures were physical (VO2max, sit-to-stand test, Six-Minute Walk Test (6MWT), Multiple Sclerosis Walking Scale-12 (MSWS-12)) and cognitive function (Rao's Brief Repeatable Battery (BRB), Paced Auditory Serial Attention Test (PASAT)), fatigue (Fatigue Scale for Motor and Cognitive Function (FSMC)), quality of life (Multiple Sclerosis Impact Scale-29 (MSIS-29)), and imaging. Brain volumes and diffusion tensor imaging (DTI) were quantified using FSL-SIENA/FIRST and FSL-TBSS. RESULTS: In all, 35 pwMS completed the trial. Interaction effects in favor of the EXP group were found for VO2max, sit-to-stand test, MSWS-12, Spatial Recall Test, FSMC, MSIS-29, and pallidum volume. VO2max improved by 1.5 mL/kg/min, MSWS-12 by 4, FSMC by 11, and MSIS-29 by 14 points. The Spatial Recall Test improved by more than 10%. CONCLUSION: Community-located run training improved aerobic capacity, functional mobility, visuospatial memory, fatigue, and quality of life and pallidum volume in pwMS.

Interlimb coordination and spatiotemporal variability during walking and running in children with developmental coordination disorder and typically developing children.

BACKGROUND: A different interlimb coordination and higher variability in movement patterns is evident in children with Developmental Coordination Disorder (DCD). The impact of DCD on interlimb coordination during walking and running is unknown. AIM: To assess interlimb coordination and spatiotemporal variability during overground walking and running in children with and without DCD. METHODS: Children with DCD and typically developing children (TDC), from 8 to 12 years participated. Children were equipped with portable sensors. Participants walked and ran for 3 min in an oval-path at their comfortable pace. Interlimb coordination, expressed by the phase coordination index (PCI), and spatiotemporal variability (coefficient of variance (CoV)) were collected. RESULTS: Twenty-one children with DCD and 23 TDC participated. During walking, PCI showed similar values in both groups, but a higher spatiotemporal variability was observed in children with DCD. During running, PCI was higher (reduced coordination) in children with DCD than TDC and a higher spatiotemporal variability was shown. CONCLUSIONS AND IMPLICATIONS: Only during running, interlimb coordination of children with DCD was lower than TDC. During both walking and running tasks, spatiotemporal variability was higher in DCD. Current results implicate that difficulties in children with DCD is more prominent when motor coordination is more challenged. WHAT THIS PAPER ADDS: This paper adds to the literature on coordination and gait pattern in children with Developmental Coordination Disorder (DCD) through a cross-sectional analysis of interlimb coordination and variability of spatiotemporal measures of overground walking and running. Overground walking and running were performed in a large oval-path allowing the assessment of coordination and gait patterns in an ecological valid set-up. Our results indicate that during a more demanding task, namely running, children with DCD display a less coordinated running pattern, expressed by a significantly higher phase coordination index, than typically developing peers. During walking, the interlimb coordination was similar between both groups. The current result is in accordance with the hybrid model of DCD that states that motor coordination difficulties in DCD are dpendent on the interaction of the task, individual and environment. This highlights the importance of implementing running assessments in children with DCD and the need for task-oriented running training in clinical practice The study also supports previous findings that children with DCD show a higher variability in their gait pattern of both walking and running, expressed by higher coefficient of variance of spatiotemporal measures, than typically developing peers. Further understanding in the normal development of interlimb coordination during walking and running from childhood into adulthood will enhance interpretations of the phase coordination index in children with and without DCD.

Interlimb Coordination and Auditory-Motor Synchronization in Children with Developmental Coordination Disorder: Examining Antiphase Knee Movements with Auditory Metronomes While Seated.

Background: Children with developmental coordination disorder (DCD) exhibit reduced interlimb coordination compared to typically developing children (TDC) during complex tasks like running, which requires dynamic postural control. However, the extent of interlimb coordination difficulties in DCD during tasks that demand minimal dynamic balance, such as self-paced and externally auditory-paced tasks, remains unclear. This study aimed to compare interlimb coordination and auditory-motor synchronization between children with DCD and TDC during a seated antiphase coordination task of the lower limbs, which has minimal postural control requirements. Methods: Twenty-one children with DCD and 22 TDC performed an antiphase knee flexion and extension task while seated, in three conditions (baseline silence, metronome discrete, and metronome continuous), for three minutes. The interlimb coordination, synchronization, and spatiotemporal movement parameters were analyzed using a mixed model analysis; Results: Children with DCD displayed less coordinated interlimb movements compared to TDC (p = 0.0140), which was the result of the greater variability in coordinating antiphase knee flexion-extension movements (p < 0.0001). No group differences in spatiotemporal movement parameters were observed. Children with DCD, compared to TDC, had a lower synchronization consistency to metronomes (p = 0.0155). Discrete metronomes enhanced interlimb coordination compared to the baseline silence condition (p = 0.0046); Conclusions: The study highlights an inferior interlimb coordination and auditory-motor synchronization in children with DCD compared to TDC. Implementing metronomes with a discrete temporal structure improved the interlimb coordination of both groups during the used fundamental seated interlimb coordination task, supporting theorical frameworks of event-based timing.

Auditory-motor synchronization in developmental coordination disorder: Effects on interlimb coordination during walking and running.

Developmental coordination disorder (DCD) presents challenges in motor control. DCD affects tasks such as walking and running and is characterized by poor interlimb coordination and increased spatiotemporal variability compared to typically developing children (TDC). While auditory rhythm synchronization has shown to have benefits for gait performance in adults, its impact on children with DCD during walking and running remains unclear. This study investigated auditory-motor synchronization and interlimb coordination during walking and running in children with and without DCD. Twenty-one DCD and 23 TDC participants aged 8-12 years walked and ran to two different auditory metronomes (discrete and continuous). Synchronization consistency was the primary outcome, with interlimb coordination and spatiotemporal variability as secondary outcomes. Results showed that children with DCD exhibited significantly lower synchronization consistency than TDC, particularly during running. The metronome structure did not influence synchronization ability. Additionally, interlimb coordination differed significantly between DCD and TDC during running and was not impacted by auditory-motor synchronization. Spatiotemporal variability was higher in DCD during both walking and running than in TDC, and accentuated during running. Variability of cadence was influenced by the use of continuous metronomes, which may offer potential benefits in reducing cadence variability.

Assessment and tailored physical rehabilitation approaches in persons with cerebellar impairments targeting mobility and walking according to the International Classification of Functioning: a systematic review of case-reports and case-series.

PURPOSE: Cerebellar impairment (CI) manifests from different etiologies resulting in a heterogenic clinical presentation affecting walking and mobility. Case-reports were reviewed to provide an analytical clinical picture of persons with CI (PwCI) to differentiate cerebellar and non-cerebellar impairments and to identify interventions and assessments used to quantify impact on walking and mobility according to the International Classification of Functioning, Disability and Health (ICF). MATERIALS AND METHODS: Literature was searched in PubMed, Web Of Science and Scopus. Case-reports conducting physical rehabilitation and reporting at least one outcome measure of ataxia, gait pattern, walking or mobility were included. RESULTS: 28 articles with a total of 38 different patients were included. Etiologies were clustered to: spinocerebellar degenerations, traumatic brain injuries, cerebellar tumors, stroke and miscellaneous. The interventions applied were activity-based, including gait and balance training. Participation based activities such as tai chi, climbing and dance-based therapy had positive outcomes on mobility. Outcomes on body function such as ataxia and gait pattern were only reported in 22% of the patients. CONCLUSIONS: A comprehensive test battery to encompass the key features of a PwCI on different levels of the ICF is needed to manage heterogeneity. Measures on body function level should be included in interventions.

This review reports on 38 cerebellar cases from 14 different aetiologies.Distinguishing cerebellar and non-cerebellar symptoms and categorising patients within the three cerebellar syndromes can assist with heterogeneity.Reporting of assessment on the body function level of ICF in terms of ataxia and gait pattern was only present in a minority of reports and thus increased reporting is encouraged.Multimodal and patient-tailored strategies are promising for targeting walking and mobility in persons with cerebellar impairment.

Auditory attention measured by EEG in neurological populations: systematic review of literature and meta-analysis.

Sensorimotor synchronization strategies have been frequently used for gait rehabilitation in different neurological populations. Despite these positive effects on gait, attentional processes required to dynamically attend to the auditory stimuli needs elaboration. Here, we investigate auditory attention in neurological populations compared to healthy controls quantified by EEG recordings. Literature was systematically searched in databases PubMed and Web of Science. Inclusion criteria were investigation of auditory attention quantified by EEG recordings in neurological populations in cross-sectional studies. In total, 35 studies were included, including participants with Parkinson's disease (PD), stroke, Traumatic Brain Injury (TBI), Multiple Sclerosis (MS), Amyotrophic Lateral Sclerosis (ALS). A meta-analysis was performed on P3 amplitude and latency separately to look at the differences between neurological populations and healthy controls in terms of P3 amplitude and latency. Overall, neurological populations showed impairments in auditory processing in terms of magnitude and delay compared to healthy controls. Consideration of individual auditory processes and thereafter selecting and/or designing the auditory structure during sensorimotor synchronization paradigms in neurological physical rehabilitation is recommended.

Effects of Peripheral Cooling on Upper Limb Tremor Severity and Functional Capacity in Persons with MS.

Upper limb intention tremor in persons with multiple sclerosis (pwMS) affects the ability to perform activities of daily life and is difficult to treat. The study investigated the effect of peripheral upper limb cooling on tremor severity and functional performance in MS patients with intention tremor. In experiment 1, 17 patients underwent two 15 min cooling conditions for the forearm (cold pack and cryomanchet) and one control condition. In experiment 2, 22 patients underwent whole arm cooling for 15 min using multiple cold packs. In both experiments, patients were tested at four time points (pre- and post-0, -25 and -50 min cooling) on unilateral tasks of the Test Evaluant les Membres supérieurs des Personnes Agées (TEMPA), Fahn's tremor rating scale (FTRS), Nine Hole Peg Test (NHPT). In experiment 1, the mean FTRS ranged from 13.2 to 14.1 across conditions. A two-way ANOVA showed mainly time effects, showing that cooling the forearm significantly reduced the FTRS, the performance on the NHPT, and three out of four items of the TEMPA, mostly independent of the cooling modality. In experiment 2, the mean FTRS was 13.1. A repeated measures ANOVA showed that cooling the whole arm reduced the FTRS and time needed to execute two out of four items of the TEMPA. These effects occurred immediately after cooling lasting at least 25 min. Cooling the whole upper limb led to a clinically noticeable effect on tremor severity and improved functional performance, which was pronounced during the first half-hour after cooling.

Changes in physiotherapy services and use of technology for people with multiple sclerosis during the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic has led to reorganization or reduction of neurorehabilitation services for people with multiple sclerosis (PwMS). The aim of this study was to explore the changes in the organizational framework and technology usage in physiotherapy services for PwMS during the COVID-19 pandemic. METHODS: This international cross-sectional survey study was designed, developed, and disseminated by RIMS European Network for Best Practice and Research in Multiple Sclerosis Rehabilitation. Physiotherapists from nine countries (Australia, Belgium, Czech Republic, Ireland, Israel, Italy, Norway, Spain, Turkey) who provided physiotherapy services to PwMS, were invited to complete an online survey to compare physiotherapy delivery to PwMS prior to and during the pandemic period. RESULTS: The survey was completed by 215 physiotherapists. Accessibility, the average number, length and perceived effectiveness of physiotherapy sessions provided to PwMS were significantly reduced during the COVID-19 pandemic (p=0.001). Physiotherapists increased the advice of mobile apps, recorded videos for rehabilitation and exercise websites during the pandemic (p<0.001) while the use of telerehabilitation and virtual reality technology did not change. CONCLUSION: There was of a reduction in the number, duration and perceived effectiveness of rehabilitation sessions for people with multiple sclerosis during the COVID-19 pandemic while use of remote technologies for physiotherapy did not change. To ensure the continuity of physiotherapy for PwMS with complex healthcare needs also during pandemics, the provision of guidelines and training in telehealth technologies in professional education becomes crucial.

Motor sequence learning in a goal-directed stepping task in persons with multiple sclerosis: a pilot study.

Motor sequence learning in persons with multiple sclerosis (pwMS) and healthy controls (HC) under implicit or explicit learning conditions has not yet been investigated in a stepping task. Given the prevalent cognitive and mobility impairments in pwMS, this is important in order to understand motor learning processes and optimize rehabilitation strategies. Nineteen pwMS (the Expanded Disability Status Scale = 3.4 ± 1.2) and 18 HC performed a modified serial reaction time task by stepping as fast as possible on a stepping tile when it lit up, either with (explicit) or without (implicit) knowledge of the presence of a sequence beforehand. Motor sequence learning was studied by examining response time changes and differences between sequence and random blocks during the learning session (acquisition), 24 h later (retention), and in three dual-task (DT) conditions at baseline and retention (automaticity) using subtracting sevens, verbal fluency, and vigilance as concurrent cognitive DTs. Response times improved and were lower for the sequenced compared with the random blocks at the post- and retention tests (P's < 0.001). Response times during DT conditions improved after learning, but DT cost improved only for the subtracting sevens DT condition. No differences in learning were observed between learning conditions or groups. This study showed motor sequence learning, by acquisition and retention, in a stepping task in pwMS with motor impairments, to a similar degree as HC and regardless of learning conditions. Whether automaticity increased remains unclear.

Embodied learning in multiple sclerosis using melodic, sound, and visual feedback: a potential rehabilitation approach.

Given the prevalence of motor and cognitive functions in persons with multiple sclerosis (PwMS), we proposed that the theoretical framework of embodiment could provide a rehabilitation avenue to train these functions as one functional unit. PwMS (n = 31) and age- and gender-matched healthy controls (n = 30) underwent an embodied learning protocol. This involved learning a cognitive sequence while performing it through bodily stepping movement under three feedback conditions (melody, sound, and visual). Cognitive and movement performance was assessed by a delayed recall 15 min after undergoing the embodied learning protocol. Half of participants correctly recalled the sequence in all three conditions, while 70% of healthy controls achieved correct recall within the melody condition. Balance impairment predicted the speed of executing the sequence irrespective of learning, most apparent in the melody condition. Information processing speed predicted the speed of executing the sequence in the melody and sound conditions between participants as well as over time. Those who learned performed the sequence faster in the melody condition only and overall were faster over time. We propose how embodied learning could expand the current context of rehabilitation of cognitive and motor control in PwMS.

The impact of the COVID-19 pandemic on physical therapy practice for people with multiple sclerosis: A multicenter survey study of the RIMS network.

BACKGROUND: The impact of the COVID-19 pandemic on physical therapy services for people with multiple sclerosis (pwMS) is unknown. Therefore, the Special Interest Group for Mobility (SIG Mobility) of the European Network for Best Practice and Research in Multiple Sclerosis Rehabilitation (RIMS) has undertaken the initiative to examine the impact of the COVID-19 outbreak on physical therapy services and physical activity participation in pwMS across Europe, Israel and Australia. OBJECTIVE: To describe the impact of the COVID-19 outbreak on physical therapy practice from the perspective of the therapist. METHODS: An online survey was developed and conducted from December 2020 to July 2021. The survey (50 questions), included multiple-choice questions and open-ended responses. RESULTS: In total, 215 physical therapists (PT's) from 9 countries (Australia, Belgium, the Czech Republic, Ireland, Israel, Italy, Norway, Spain, and Turkey) participated in the study. The therapy most affected during the pandemic was aerobic training/conditioning exercises; 33.5% reported that these activities were either reduced or unavailable. In contrast, 15% of the PTs reported increased use of relaxation/mind body techniques and/or fatigue management programs during the pandemic. PTs reported a mixture of positive and negative feelings about the therapeutic sessions offered during the pandemic. Most reported positive feelings included "positive" (26.5%), and "optimistic" (24.7%). Negative feelings most frequently reported included "worried" (30.7%), and "hesitant" (20.9%). The PTs reported a 10% decrease in the use of hands-on techniques and a 10% increase in the use of oral instructions when treating moderately and severely pwMS during as compared to before the pandemic. CONCLUSION: The COVID-19 pandemic has affected physical therapy services in pwMS internationally in terms of content, frequency of use and format.

Neural Entrainment Meets Behavior: The Stability Index as a Neural Outcome Measure of Auditory-Motor Coupling.

Understanding rhythmic behavior in the context of coupled auditory and motor systems has been of interest to neurological rehabilitation, in particular, to facilitate walking. Recent work based on behavioral measures revealed an entrainment effect of auditory rhythms on motor rhythms. In this study, we propose a method to compute the neural component of such a process from an electroencephalographic (EEG) signal. A simple auditory-motor synchronization paradigm was used, where 28 healthy participants were instructed to synchronize their finger-tapping with a metronome. The computation of the neural outcome measure was carried out in two blocks. In the first block, we used Generalized Eigendecomposition (GED) to reduce the data dimensionality to the component which maximally entrained to the metronome frequency. The scalp topography pointed at brain activity over contralateral sensorimotor regions. In the second block, we computed instantaneous frequency from the analytic signal of the extracted component. This returned a time-varying measure of frequency fluctuations, whose standard deviation provided our "stability index" as a neural outcome measure of auditory-motor coupling. Finally, the proposed neural measure was validated by conducting a correlation analysis with a set of behavioral outcomes from the synchronization task: resultant vector length, relative phase angle, mean asynchrony, and tempo matching. Significant moderate negative correlations were found with the first three measures, suggesting that the stability index provided a quantifiable neural outcome measure of entrainment, with selectivity towards phase-correction mechanisms. We address further adoption of the proposed approach, especially with populations where sensorimotor abilities are compromised by an underlying pathological condition. The impact of using stability index can potentially be used as an outcome measure to assess rehabilitation protocols, and possibly provide further insight into neuropathological models of auditory-motor coupling.

Rhythmic interlimb coordination of the lower limbs in multiple sclerosis during auditory pacing to three different frequencies.

BACKGROUND: Multiple sclerosis (MS) is a demyelinating disorder of the central nervous system with heterogeneous symptoms. Persons with MS (PwMS) show reduced walking capacity with changes in their gait pattern. It is unknown to which extent coordination deficits are present in PwMS, which can be measured by seated lower leg interlimb coordination tasks, and to which extent they are related to motor and cognitive function. RESEARCH QUESTION: How is the control of interlimb coordination of the lower limbs characterized in PwMS compared to healthy controls (HC) during a seated rhythmical coordination task and what is the relationship between interlimb coordination, motor or cognitive function? METHODS: Rhythmical interlimb coordination was assessed during a single session in 38 PwMS and 13 HC, using a seated rhythmical coordination task, comprising of antiphase flexion-extension of the lower limbs, to metronomes at 0.75 Hz, 1.00 Hz, 1.50 Hz. Outcomes were phase coordination index (PCI), movement amplitude and movement frequency. Correlations between interlimb coordination, motor, and cognitive function were examined. RESULTS: PwMS showed impaired walking capacity but preserved cognitive function. Mixed model analysis revealed a significant effect of group and metronome frequency for PCI, attenuated by the variability in generating knee (antiphase flexion-extension) movements. Movement amplitude was highest at metronome frequency 1.00 Hz. In PwMS significant correlations were found between PCI and cognitive function when performing the task at metronome frequencies 0.75 Hz and 1.50 Hz, as well as motor function at 1.50 Hz. SIGNIFICANCE: PwMS had a higher variability in interlimb coordination compared to HC. The most stable interlimb antiphase coordination mode was performed at 1.00 Hz. Significant correlations support the existence of a relationship between information processing speed, as well as walking impairment, with interlimb coordination. While cognitive and motor control are always needed for interlimb coordination movements, associations are strongest in the deviant higher and lower metronome rhythms.