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.

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.

Detrended fluctuation analysis of gait dynamics when entraining to music and metronomes at different tempi in persons with multiple sclerosis.

In persons with multiple sclerosis (PwMS), synchronizing walking to auditory stimuli such as to music and metronomes have been shown to be feasible, and positive clinical effects have been reported on step frequency and perception of fatigue. Yet, the dynamic interaction during the process of synchronization, such as the coupling of the steps to the beat intervals in music and metronomes, and at different tempi remain unknown. Understanding these interactions are clinically relevant, as it reflects the pattern of step intervals over time, known as gait dynamics. 28 PwMS and 29 healthy controls were instructed to walk to music and metronomes at 6 tempi (0-10% in increments of 2%). Detrended fluctuation analysis was applied to calculate the fractal statistical properties of the gait time-series to quantify gait dynamics by the outcome measure alpha. The results showed no group differences, but significantly higher alpha when walking to music compared to metronomes, and when walking to both stimuli at tempi + 8, + 10% compared to lower tempi. These observations suggest that the precision and adaptation gain differ during the coupling of the steps to beats in music compared to metronomes (continuous compared to discrete auditory structures) and at different tempi (different inter-beat-intervals).

Walking to Music and Metronome at Various Tempi in Persons With Multiple Sclerosis: A Basis for Rehabilitation.

Background. Mobility dysfunctions are prevalent in persons with multiple sclerosis (PwMS), thus novel rehabilitation mechanisms are needed toward functional training. The effect of auditory cueing is well-known in Parkinson's disease, yet the application of different types of auditory stimuli at different tempi has not been investigated yet. Objectives. Investigating if PwMS, compared with healthy controls (HC), can synchronize their gait to music and metronomes at different tempi during walking and the effects of the stimuli on perceived fatigue and gait. Additionally, exploring if cognitive impairment would be a factor on the results. Methods. The experimental session consisted of 2 blocks, music and metronomes. Per block, participants walked 3 minutes per tempi, with instructions to synchronize their steps to the beat. The tempi were 0%, +2%, +4% +6%, +8%, +10% of preferred walking cadence (PWC). Results. A total of 28 PwMS and 29 HC participated. On average, participants were able to synchronize at all tempi to music and metronome. Higher synchronization was obtained for metronomes compared with music. The highest synchronization for music was found between +2% and +8% of PWC yet pwMS perceived less physical and cognitive fatigue walking to music compared with metronomes. Cognitive impaired PwMS (n = 9) were not able to synchronize at tempi higher than +6%. Conclusion. Auditory-motor coupling and synchronization was feasible in HC and PwMS with motor and cognitive impairments. PwMS walked at higher tempi than their preferred walking cadence, and lower fatigue perception with music. Coupling walking to music could be a promising functional walking training strategy.

A model of different cognitive processes during spontaneous and intentional coupling to music in multiple sclerosis.

Evidence for using auditory-motor coupling in neurological rehabilitation to facilitate walking is increasing. However, the distinction between spontaneous and intended coupling and its underlying mechanisms is yet to be investigated. In this study, we include 30 persons with multiple sclerosis and 30 healthy controls (HCs) in an experiment with two sessions in which participants were asked to walk to music with various tempi, matching their preferred walking cadence (PWC) up to 10% above in incremental steps of 2%. In the first session, no instructions were given to synchronize. In the second, participants were instructed to synchronize steps to the beats. Spontaneous synchronization was possible at 0% and +2% of the PWC, and fewer persons with multiple sclerosis were able to do so compared with HCs. Instruction was needed to synchronize at above +2% tempo in all participants. In the instructed session, the +6% condition marked a cutoff for cognitively impaired persons, as they were no longer able to synchronize. Based on our findings, we constructed a model illustrating that spontaneous entrainment is limited, operating during spontaneous coupling at only 0% and +2% of the PWC, and that at a higher tempo, entrainment requires intentional synchronization, with an active cognitive control mechanism.

Effectiveness of music-based interventions on motricity or cognitive functioning in neurological populations: a systematic review.

BACKGROUND: Motor and cognitive symptoms are frequent in persons with neurological disorders and often require extensive long-term rehabilitation. Recently, a variety of music-based interventions have been introduced into neurological rehabilitation as training tools. EVIDENCE ACQUISITION: This review aims to 1) describe and define music-based intervention modalities and content which are applied in experimental studies; and 2) describe the effects of these interventions on motor and/or cognitive symptoms in the neurological population. The databases PubMed and Web of Science were searched. Cited references of included articles where screened for potential inclusion. A systematic literature search up to 20th of June 2016 was conducted to include controlled trials and cohort studies that have used music-based interventions for ≥3 weeks in the neurological population (in- and outpatients) targeting motor and/or cognitive symptoms. No limitations to publication date was set. EVIDENCE SYNTHESISː Nineteen articles comprising thirteen randomized controlled trials (total participants Nexp=241, Nctrl=269), four controlled trials (Nexp=59, Nctrl=53) and two cohort studies (N.=27) were included. Fourteen studies were conducted in stroke, three in Parkinson's disease, and two in multiple sclerosis population. Modalities of music-based interventions were clustered into four groups: instrument-based, listening-based, rhythm-based, and multicomponent-based music interventions. Overall, studies consistently showed that music-based interventions had similar or larger effects than conventional rehabilitation on upper limb function (N.=16; fine motricity, hand and arm capacity, finger and hand tapping velocity/variability), mobility (N.=7; gait parameters), and cognition (N.=4; verbal memory and focused attention). CONCLUSIONSː Variety of modalities using music-based interventions has been identified and grouped into four clusters. Effects of interventions demonstrate an improvement in the domains assessed. Evidence is most available for improving motricity in stroke. More studies are warranted to investigate cognition as well as motor and cognition dysfunctions in combination. Instrument-based music interventions can improve fine motor dexterity and gross motor functions in stroke. Rhythm-based music interventions can improve gait parameters of velocity and cadence in stroke, Parkinson's disease and multiple sclerosis. Cognition in the domains of verbal memory and focused attention can improve after listening-based music interventions in stroke.