The effect of knowledge of results frequency on motor learning in individuals with stroke
Background and Aim: Reduced augmented feedback leads to motor learning. However, it is unknown whether these findings can be applied in stroke patients who may have impaired internal feedback mechanisms. The purpose of this study was to determine if stroke-related brain damage affects the use of extrinsic feedback and if these patients benefit from practice with reduced frequency of knowledge of results.
Materials and Methods: Participants were sixteen patients aged 45-65 years (mean: 57.56 ± 6.47 years) with middle cerebral artery (MCA) stroke (under 6monthes). They were randomly assigned in two groups of 8. Group one received 100% knowledge of results (KR) and group two received 25% KR about their actual force. During 6 blocks of acquisition (48 trials), participants practiced a grip force production task with upper limb ipsilateral to the lesion. Then performed retention test on the next day without receiving KR. Accuracy and consistency were assessed over acquisition and retention and compared between groups.
Results: A significant decrease in VE was found in the 25% group in acquisition (p: 0.004) and retention (p: 0.001). TE in the 25% group in acquisition phase was significant (p: 0.016) as well. There were no significant differences in these variables for the 100% group. Significant decrease of AE (p: 0.035), TE (0.039) and nearly significant decrease of VE (0.058) were found in the 100% group compared with the 25% group in acquisition. However, no significant difference between groups was found in retention.
Conclusion: Although group received 25% KR was more consistent during practice, group received 100% KR was significantly more accurate and consistent at the end of the practice in acquisition. In retention test there were no significant differences between groups of feedback condition. As a conclusion in our study, individuals with stroke related brain damage benefit from 100% KR, in acquisition phase.
Key Words: motor learning, augmented feedback, knowledge of results frequency, stroke