Does task complexity influence motor facilitation and visuo-motor memory during mirror therapy in post-stroke patients?

Stroke is one of the most common causes of mortality and reduced disability-adjusted life years worldwide. Hemiparesis due to reduced skeletal-muscle power is an effect of brain lesions. Mirror therapy can significantly improve motor performance among post-stroke patients. To determine if altering the complexity of the mirror task in the mirror therapy paradigm would enhance top-down motor facilitation and visuo-motor memory demand, we conducted a pilot study on four post-stroke patients. Our preliminary results showed that performing complex finger tapping task resulted in enhanced activities in the primary motor cortex and precuneus, ipsilateral to the moving hand in the mirror therapy paradigm. We hypothesise the following: (a) complex finger tapping would result in stronger top-down motor facilitation and higher demand on visuo-motor memory than simple finger tapping in the mirror therapy paradigm, and (b) observing a blurred mirror image would result in increased top-down motor facilitation and higher demand on visuo-motor memory than a clear mirror image. To confirm these hypotheses, we propose a cross-sectional observational study on a large sample of post-stroke patients. This paper reports the findings of the pilot study, the rationale for testing the hypotheses, the experimental set-up, the task design and the assessment protocol for functional near-infrared spectroscopy. Copyright © 2020 Published by Elsevier Ltd.