BACKGROUND: Hand motor deficits are known to occur ipsilateral to stroke, but their cause and impact remain uncertain. Here we examined these issues by exploring associations with acute hand motor deficits ipsilateral to stroke, including genetic and neuroanatomical factors. We hypothesized that severity of hand motor deficits ipsilateral to stroke in the acute setting would 1 reflect interhemispheric interactions and so correlate with extent of injury to corpus callosum, but not corticospinal tract (CST) or primary motor cortex (M1); 2 persist but improve over time; and 3 be related more strongly to motor rather than cognitive deficits. METHODS: A total of 763 patients with a new stroke were studied longitudinally over 1 year across 28 US sites. Genetic data were collected in each, and neuroimaging data were available in 448. Acutely, grip strength was measured in the hand ipsilateral to stroke, and NIHSS was scored. At the 3-mo visit, grip strength testing was repeated. RESULTS: Acutely, deficits in grip strength ipsilateral to stroke were common: patients on average were 0.39 SD below normative values that accounted for age, gender, and body side; in 16.3% of patients, values were >1 SD below normal. Extent of these deficits was associated with acute NIHSS total score (r=-.11, p=0.002) and affected arm motor score (r=-0.07, p1 SD below normal; gains over time were significant (p<0.002). CONCLUSIONS: Deficits in grip strength ipsilateral to stroke measured acutely are associated with stroke severity and with contralateral arm weakness. These ipsilateral deficits improve but persist over time, and correlated with motor but not language or hemineglect symptoms. Common genetic polymorphisms were unrelated. Imaging results favor a model based on interhemispheric interactions in the pathogenesis of hand motor deficits ipsilateral to acute stroke.
Cramer et al. (Thu,) studied this question.