Reduced sensory and motor nerve conduction velocities in moderate drinkers

The mechanism responsible for peripheral nerve dysfunction in chronic alcoh olism has nor been fully elucidated either in terms of its relationship to the quantity of alcohol consumed or to nutritional status. As parr of a ser ies of studies to address these issues, the effects of moderate drinking (6 0-90g ethanol per day) or heavy drinking (> 100 g ethanol pet. day) on peri pheral nervous function and thiamine status was measured in 73 patients adm itted to a detoxification unit. Electromyographic evaluation revealed signi ficant reductions in median and ulnar sensory and motor nerve conduction ve locities in both moderate drinkers (n = 30) and heavy drinkers (n = 43) com pared to age-matched controls. Twelve moderate drinkers and 25 heavy drinke rs manifested clinical neurological signs of peripheral neuropathy. Thiamin e deficiency, as revealed by erythrocyte transketolase activation assay, wa s detected in two moderate drinkers and seven heavy drinkers but was not si gnificantly correlated with electromyographic alterations with the exceptio n of ulnar nerves. These findings provide evidence for significant early pe ripheral nerve dysfunction in moderate drinkers and a possible contributory role of thiamine deficiency to the ulnar nerve conduction deficits. Whethe r deficits in other water-soluble vitamins or a direct neurotoxic effect of ethanol are implicated in alcoholic peripheral neuropathy awaits further s tudies.