Is Implicit Motor Learning Preserved after Stroke? A Systematic Review with Meta-Analysis

Area of Science:

• Neurorehabilitation
• Motor Learning
• Stroke Recovery

Background:

• Stroke survivors often struggle with dual-tasking, impacting daily function.
• Implicit motor learning is a potential intervention to improve movement automaticity post-stroke.
• Existing evidence on preserved implicit motor learning after stroke requires systematic evaluation.

Purpose of the Study:

• To systematically review the evidence for preserved implicit motor learning in stroke patients.
• To compare the effectiveness of implicit versus explicit motor learning strategies post-stroke.

Main Methods:

• Comprehensive search of conventional and grey literature databases.
• Inclusion of 20 studies from 2177 identified reports.
• Two independent reviewers screened studies, extracted data, and assessed risk of bias.

Main Results:

• Implicit motor learning was evident in the unaffected limb (MD = 69 ms, p < .00001) but not the affected limb (SMD = -.11, p = .56).
• Implicit motor learning appeared equally effective as explicit motor learning (SMD = -.54, p = .20).
• Most studies utilized the serial-reaction time paradigm, with limited investigation of complex, whole-body tasks.

Conclusions:

• Current evidence suggests implicit motor learning may not be reliably preserved in the affected limb post-stroke.
• The effectiveness of implicit versus explicit motor learning post-stroke remains inconclusive.
• High risk of bias, small sample sizes, and limited clinical relevance of existing studies necessitate high-quality research.