Reduced sensory and motor nerve conduction velocities in moderate drinkers

The mechanism responsible for peripheral nerve dysfunction in chronic alcoholism has not been fully elucidated either in terms of its relationship to the quantity of alcohol consumed or to nutritional status. As part of a series of studies to address these issues, the effects of moderate drinking (60-90 g ethanol per day) or heavy drinking (> 100 g ethanol per day) on peripheral nervous function and thiamine status was measured in 73 patients admitted to a detoxification unit. Electromyographic evaluation revealed significant reductions in median and ulnar sensory and motor nerve conduction velocities in both moderate drinkers (n = 30) and heavy drinkers (n = 43) compared to age-matched controls. Twelve moderate drinkers and 25 heavy drinkers manifested clinical neurological signs of peripheral neuropathy. Thiamine deficiency, as revealed by erythrocyte transketolase activation assay, was detected in two moderate drinkers and seven heavy drinkers but was not significantly correlated with electromyographic alterations with the exception of ulnar nerves. These findings provide evidence for significant early peripheral nerve dysfunction in moderate drinkers and a possible contributory role of thiamine deficiency to the ulnar nerve conduction deficits. Whether deficits in other water-soluble vitamins or a direct neurotoxic effect of ethanol are implicated in alcoholic peripheral neuropathy awaits further studies.