Topography of callosal atrophy reflects distribution of regional cerebral volume reduction in Alzheimer's disease

It has been suggested that regional corpus callosum atrophy in Alzheimer's disease (AD) may serve as an in vivo index of neuronal loss in the neocorte x. In this study total and regional size of the corpus callosum was evaluat ed with respect to the volumes of the frontal, temporal, and parietal lobes in 38 patients with AD (NINCDS-ADRDA criteria) using quantitative magnetic resonance imaging. Twenty healthy subjects matched for age and gender serv ed as a control group. Al quantitative measurements were performed by manua l tracing using personal computer-based software. Both total size and the f ive measured regional subsections were significantly smaller in AD when com pared to the control subjects. The severity of dementia was significantly c orrelated with the size of the middle sections of the corpus callosum (rost ral body and midbody). Within the AD group, the rostral body of the corpus callosum was significantly correlated with the frontal lobe volumes, the mi dbody was correlated with the temporal lobe volumes, and size of the spleni um was correlated with the parietal lobe volumes. We conclude that callosal atrophy in AD reflects the severity and pattern of cortical neuronal damag e. Correlations between regional callosal atrophy and severity of dementia indicate that interhemispheric cortico-cortical disconnection may contribut e to the dementia syndrome. (C) 1999 Elsevier Science Ireland Ltd. All righ ts reserved.