Effects of unilateral brain damage on contralateral and ipsilateral upper extremity function in hemiplegia

This article describes the long-term effects of unilateral penetrating hemispheric lesions on contralateral and ipsilateral upper extremity motor performance and functional outcome. Activities-of-daily-living skill and gross motor performance contralateral to the lesions were compared among 32 left-sided and 19 right-sided hemiplegic subjects using analysis of variance and chi-square techniques. Ipsilateral to the damaged hemisphere, fine motor tasks of simple visual motor reaction time, grip and pinch strength, finger tapping, and Purdue Pegboard performance were tested. Analysis of covariance compared each ipsilateral task to performance in the corresponding hand of 70 matched controls. Results indicate similar long-term functional ADL outcome in right and left hemisphere-damaged subjects, despite more severe contralateral functional motor deficits following lesions of the left hemisphere. Right hemisphere lesions led to ipsilateral decrements in reaction time, and lesions of either hemisphere diminished grip or pinch strength, finger tapping, and pegboard performance ipsilaterally. These results demonstrate that unilateral brain damage involving the motor areas of either hemisphere has detrimental effects on ipsilateral upper extremity motor function. Findings are discussed and related to the concept that the left hemisphere is specialized or has greater neuronal representation for bilateral motor processes. Physical therapists involved in the treatment of patients with hemiplegia should be aware that motor functions of the ipsilateral, nonparetic upper extremity may also be affected adversely by unilateral brain lesions.