Cognitive impairment and central motor conduction time in chronic alcoholics

The non-invasive technique of transcranial magnetic stimulation (TMS) was used in 62 chronic alcoholics to assess the functional status of descending motor pathways. The main aims of this study were: to investigate asymptomatic upper motor neuron dysfunction in alcoholics as well as to assess its relationship with parameters reflecting the intensity of exposure to alcohol; and to evaluate a possible relationship between central motor conduction time (CMCT) prolongation and neuropsychological measures of alcohol-related brain damage. Compared to control subjects, chronic alcoholics exhibited a significant prolongation of CMCT (23 out of 62 subjects). No significant correlation was found between CMCT prolongation and intensity and duration of abuse, presence of peripheral neuropathy, or brain atrophy on CT scans. Prolongation of CMCT from the upper limb correlated significantly with impairment of frontal skills on neuropsychological testing (p<0.01). These findings suggest that TMS may be a sensitive method for the detection in alcoholics of subtle neurological dysfunction, not confined to motor pathways.