A Study of Comparison of Implicit Learning in Post Stroke and Age-Matched Elderly Subjects

Abstract

Background: A motor skill can be learnt implicitly without awareness of what is being learnt. There is inadequate evidence available whether adults with stroke can learn a motor skill implicitly. Aim: To examine the ability of adults who had unilateral stroke to learn implicitly a perceptual motor task and to compare them with age matched elderly subjects. Settings and Design: This was a prospective experimental study. 30 subjects with unilateral stroke were compared with 30 age -matched elderly subjects for speed of performance of a serial response time task(SRT). Materials and method: Subjects were asked to perform sequences of hand movements in response to target lights in 2 conditions: a patterned sequence and a random sequence. They were not given explicit knowledge of 2 conditions. The SRT to perform both patterned and random sequence activity was measured and comparison was done between both groups. On second day SRT of patterned sequence activity was measured for both groups to test retention. Results: The mean SRT for both groups showed statistically significant decrease with patterned sequence(mean difference-elderly:3.745, stroke:5.108) increase with random sequence (mean difference-elderly:2.792, stroke:3.592) and again decrease with reintroduction of patterned sequence(mean difference-elderly:1.762,stroke:2.423). There was statistically significant retention of implicit learning in both groups. Conclusion: Implicit Learning of Serial Response Time Task is preserved in post Stroke subjects since both the groups showed the similar trend of performance in all the blocks, however, speed of performance of post stroke subjects was slower than that of normal elderly subjects.