Learning of a novel visuo-postural co-ordination task in adults with multiple sclerosis

Abstract

Objective: A behavioural study was conducted to investigate how cerebellar dysfunction associated with multiple sclerosis affects the ability to learn a novel visuo-postural co-ordination task. Design: A prospective design, 2 group by 1 treatment (4 practice blocks). Subjects: Ten patients with multiple sclerosis diagnosed with cerebellar ataxia and 10 age-matched healthy controls. Methods: Participants stood over a dual force platform (ERBE Balance System) and performed visually guided lateral weight-shifting movements. The task required subjects to gradually transfer weight between sides while maintaining each foot's force vector within visually specified force constraints ranging from 0% to 100% of bodyweight with maximum allowed variation set to ±20%. The time required to complete the task and the number of spatial errors (noted each time the foot's vector exceeded the ±20% force constraint) were recorded. Training consisted of 3 blocks of 5 trials separated by 1-minute intervals and followed by 5 retention trials. Results and Conclusion: Statistics revealed a significant decrease in movement time and spatial errors across trial blocks in both groups; however, the group with multiple sclerosis showed a limited and slower rate of performance improvement characterized by increased within- and between-subject variability. These findings may have important implications in the design of rehabilitation protocols for improving motor skill performance in adults with multiple sclerosis.