Cognitive impairment and diffuse white matter atrophy in alcoholics

Objective: Diffuse brain white matter atrophy is often seen in chronic alcoholics, but its relation with cognitive impairment remains to be solved. In order to address this issue, in alcoholics with cognitive impairment at different levels, we studied relations of the central sensory conduction time (CSCT) or brain magnetic resonance imaging (MRI) findings with the cognitive function. Methods: Subjects were 35 alcoholics with mild cognitive impairment (mini-mental state examination score, MMSE, ≥24; mean±SD, 27.7±1.9), 12 with moderate to severe cognitive impairment (MMSE<24; 20.3±2.7), 15 with Alzheimer's disease (AD) (MMSE, 18.9±4.3) (disease control) and 20 healthy volunteers (MMSE, 28.5±1.6) (normal control). Median nerve SEPs were recorded in the all subjects, and the latencies and amplitudes of their N9, N11, P13/14, N20 and P25 components were measured. The ventriculocranial ratio (VCR) and the width of cortical sulci were measured on MRIs. These physiological parameters and MRI findings were compared between the 4 groups of the subject, and correlations between those all features were also analyzed. Results: CSCT and VCR were significantly greater in alcoholics with moderate to severe cognitive impairment than those in the other 3 groups. Pearson's product-moment correlation analyses of the alcoholics disclosed that both the CSCT and VCR had significant negative correlations with the MMSE score. Moreover, the CSCT and VCR were positively correlated. Conclusions: Both physiological and morphological estimates of the white matter function (CSCT and VCR) had a significant correlation with the cognitive dysfunction. Significance: The diffuse white matter atrophy may be one of the factors causing cognitive impairment in chronic alcoholics.