Disproportionate atrophy of cerebral white matter in chronic alcoholics

Morphometric analysis of postmortem brains from chronic ethyl alcohol abusers and controls was performed to determine the regional distribution and extent of atrophy in the cerebral hemispheres of alcoholics. This study was performed by digitizing photographs of coronal slices of the brains to compute the cross-sectional area of the cerebrum, cerebral cortex, subcortical nuclei, cerebral white matter, and the ventricular system at five standardized levels. Although the alcoholics and controls had similar demographic features and mean brain weights, brains from the alcoholic group showed mild but consistent atrophy of the cerebral cortex (2.5% to 4.2% reductions in cross-sectional area at all five levels), moderate atrophy of cerebral white matter (6.1% to 17.5% reductions), and enlargement of the ventricular system (31.8% to 71.9% increases). There were no differences in the sizes of subcortical nuclei. The absolute increase in the size of the ventricles in the alcoholic group was roughly equal to the amount of tissue lost in cerebral white matter, thereby representing hydrocephalus ex vacuo. The disproportionate loss of cerebral white matter relative to cerebral cortex suggests that a major neurotoxic effect of chronic alcohol intoxication in the central nervous system is axonal degeneration.