Predicting recovery of bilateral upper extremity muscle strength after stroke.

Abstract

OBJECTIVE: To investigate the recovery pattern of bilateral upper extremity muscle strength and to predict the recovery of strength early after stroke using a logarithmic regression model. DESIGN: Longitudinal study. SUBJECTS: Twenty-one inpatients with post-stroke hemiparesis were enrolled. The mean time after stroke event was 7.1 days (standard deviation (SD) 3.5 days). METHODS: Bilateral elbow flexion and extension strengths were assessed separately with a hand-held dynamometer.Grip strength was also assessed with a Jamar dynamometer.These measurements were carried out on 4 occasions: baseline assessment within 2 weeks following stroke onset, and at weeks 1, 2 and 3 following baseline evaluation. Recovery off lexion and extension strengths was predicted using a logarithmic model using scores at the initial 2 evaluations. RESULTS: The time course of recovery for bilateral upper extremities resembled a logarithmic function. Moreover, on the basis of a logarithmic regression model, baseline measures of bilateral strengths sampled from 2 time-points during recovery could be applied to predict the pattern of recovery accurately during the subacute stroke phase (R(2) = 0.74–0.95,p < 0.0001). CONCLUSION: Upper extremity muscle strength improved significantly in a similar pattern on the sides contralateral and ipsilateral to the brain lesion. Moreover, a logarithmic regression model accurately predicted both measures.