NEUROPATHOLOGY OF WHITE-MATTER CHANGES IN ALZHEIMERS-DISEASE AND VASCULAR DEMENTIA

Morphological white matter changes were investigated in clinically and neuropathologically diagnosed cases of Alzheimer's disease (AD; 60 ca ses) and vascular dementia (VaD, 40 cases). In 33 of 60 AD cases, a wh ite matter disease (WMD) characterized by tissue rarefaction, mild gli osis and a non-amyloid small-vessel sclerosis occurred in the central, preferentially frontal deep white matter. The mean vessel density was significantly lower than in normal control case frontal white matter. The presence of WMD did not parallel the severity of grey matter Alzh eimer encephalopathy. In 25 of 60 AD cases, white matter degeneration with signs of both condensation and rarefaction of tissue elements was seen subjacent to advanced cortical degeneration in the temporal lobe s. It concurred with WMD in only 13 cases and was judged to be of ante rograde, Wallerian type and not related to angiopathy. In VaD, similar changes occurred, accompanied by several types of focal and topograph ically related lesions. For diffuse white matter pathology of similar appearance in vascular and neurodegenerative disease with dementia, th ere may be various at least partly contrasting aetiologies, which can be differentiated by the presence of even minor focal lesions in some cases. For the recognition of such subtle variations in the spectrum o f WMD modem imaging techniques are crucial for detailed clinical diagn osis and attempts at therapeutic intervention.