Step to the beat: Auditory-motor coupling during walking to higher and lower tempi with music and metronomes in progressive multiple sclerosis: An observational study.

Background: Many persons with multiple sclerosis (MS) are confronted with fatigue and difficulties with walking and even more so in persons with progressive subtypes of MS. Task-oriented training, and more specifically in the form of auditory-motor coupling, where persons are asked to synchronise their steps to beats in music and metronomes, is promising. However, it is currently not known whether persons with progressive MS (PwPMS) can synchronise their steps to beats in music and metronomes and if they can adapt their gait to slower and higher tempi.

Methods: The study is a case control study where participants with progressive MS (PwPMS) and healthy controls (HCs) were asked to synchronise their steps during overground walking to beats in music and metronomes at five different tempi, ranging from slow (-8%, -4%), baseline (0%) and high (4%, 8%) while synchronisation, spatiotemporal parameters and gait dynamics were recorded. Mixed model analyses were performed on synchronisation outcome measures and spatiotemporal gait parameters. Additionally, a regression analysis was performed to identify clinical factors such as cognition and motor function influencing synchronisation consistency.

Results: In total, 18 PwPMS (mean age = 52.4, median EDSS = 4.24) and 16 healthy controls (HCs) (mean age = 56.5) were included in the study. Results show that both groups were able to synchronise their steps to beats in music and metronomes, but highest synchronisation consistency was reached for metronome conditions compared to music conditions and for HCs compared to persons with progressive MS. Highest synchronisation consistency for persons with progressive MS was found at -4% and 0%. Additionally, more variability in inter-step-intervals and thus a more anti-persistent gait pattern was found for metronome compared to music conditions. Last, lower performance on the Timed Up & Go Test negatively impacted synchronisation consistency.

Conclusion: PwPMS are able to synchronise steps to beats in music and metronomes. Overall, more consistent synchronisation is seen for metronome conditions. All participants are able to adapt their cadence to all tempi, yet, PwPMS struggle to adapt gait speed to high tempi. Noteworthy, participants walk with more random inter-step-interval fluctuations when walking to metronome compared to music conditions. Last, dynamic balance significantly impacted synchronisation consistency. These results show the potential of using auditory-motor coupling for walking related rehabilitation for PwPMS, however, tempo and auditory stimulation should be carefully considered.