The H-reflex of the flexor carpi radialis muscle; a study in controls and radiation-induced brachial plexus lesions.

H-reflexes of the flexor carpi radialis muscle were studied in 52 controls and 25 cancer patients with radiation-induced brachial plexopathy. It was found that H-reflex conduction velocity (H-RCV) decreased with increasing age. This was not true for H-reflex latency (H-RL) and inter-latency times. There were no H-RCV and latency differences between age-matched male and female subjects. In the affected arm the reflex was absent in nine patients and delayed in 16 patients in whom H-RCV was decreased in 13 patients. Three patients showed large H-RL differences which were also notable features in median nerve disease in the region of the brachial plexus.