We appreciate the interest shown by Dr Derakhshan in our article on improving hand function in patients with chronic stroke. Focusing on the principal point, he makes the criticism that our understanding of a competition between proximal and distal musculature in preventing the recovery of distal function does not jibe well with the data in the literature.
Based on numerous neurophysiologic, neuroanatomic, and neuroimaging studies conducted during the past decades worldwide, our understanding of brain plasticity is that there is active competition among body parts for territory in the brain cortex. For example, evidence shows that practice results in an increased cortical representation of the training body part (in competition with the untrained)1 and that sensory deprivation of a body part increases the spatial extent of the surrounding body representations (in competition with each other).2 Using this basic principle of competition, we have developed a new therapeutic strategy that combines practice with sensory deprivation and have found that this can help improve hand function in patients with chronic stroke.
Muellbacher W, Hallett M. Improving Hand Function in Chronic Stroke: Topography of the Lesion and Role of the Corpus Callosum—Reply. Arch Neurol. 2003;60(4):640-641. doi:10.1001/archneur.60.4.640-a