Motor memory impairments in people with Parkinson’s Disease.
What is it about?
Parkinson’s Disease (PD), the second most common neurodegenerative disease affecting approximately 7 million people worldwide, leads to major motor dysfunctions and, with time, loss of functional independence. Motor rehabilitation therapies targeting functional motor skills essential for daily living activities are thus of great importance for this clinical population. Critically, the effectiveness of these motor therapies relies on successful motor learning, which is the ability to permanently retain (i.e., consolidate) and perform newly acquired motor skills. While previous research in PD has mostly focused on motor skill acquisition, defined as the ability to improve performance during practice, this study concentrated on motor skill retention. We systematically reviewed 46 trials and conducted meta-analysis and meta-regression to determine the extent to which people with PD have motor memory consolidation deficits in comparison to neurotypical individuals, and which factors may modulate these impairments.
Why is it important?
People with PD need to constantly learn new sensory motor skills and sequential movements and/or adapt pre-existing motor routines to cope with major motor dysfunctions. They also suffer from gait abnormalities, postural instability, and speech and voice disorders. The results of this review confirm that people with mild to moderate PD have deficits in motor memory consolidation processes, although the magnitude of these deficits varies among different motor skills. Remarkably, extended practice and augmented feedback appear to be valuable strategies to mitigate some of the observed motor learning deficits. Overall, our novel findings underline the importance of developing more targeted rehabilitative interventions to enhance motor memory consolidation processes to support long-term motor skills retention in people with PD.