Central and Peripheral Neural Responses in Acromegaly

Abstract

To assess the function of the central and peripheral nervous systems in patients with untreated acromegaly. We recorded the somatosensory evoked potentials (SSEPs) and brain stem auditory evoked potentials (BAEPs) in 10 patients with untreated acromegaly of brief duration and in 20 age- and sex-matched healthy control subjects to evaluate the function of the central nervous system and at least the median and tibial components of the peripheral nerves. Electrophysiologic studies were done at the time of diagnosis and before the initiation of any treatment for acromegaly. We also studied the distal motor latency, nerve conduction velocity, compound muscle action potentials, and F response in the peroneal nerve; the sensory nerve conduction velocity and sensory potential amplitude were measured in the sural nerve. The mean duration of acromegaly (expressed as time elapsed since patients first recognized signs or symptoms) was 2.4 years. The N(9) and N(13) latencies in median SSEPs and the N(22) latency in tibial SSEPs were significantly prolonged in patients with acromegaly in comparison with the control group; however, central nervous system components of SSEPs and all components of BAEPs were normal. We also noted abnormalities in peroneal motor and sural sensory nerves. No correlation was found between the neurophysiologic data and the basal growth hormone level, the fasting blood glucose level, or the duration of disease. Our results suggest that peripheral, but not central, nervous system involvement exists in patients with untreated acromegaly of short duration.