ALZHEIMERS-DISEASE, LEWY BODY DISEASE AND AGING - A COMPARATIVE-STUDYOF THE PERFORANT PATHWAY

The relationship between Alzheimer's disease (AD) and Lewy body diseas e (LBD) is poorly understood. In AD there is severe loss of neurons co mprising the perforant pathway. To assess perforant pathway integrity in pure LBD we compared neuronal counts in layer II of the entorhinal cortex (ERC) in 11 cases of pure LBD that did not meet CERAD pathologi c criteria for AD with ERC neuronal counts from seven AD cases with a similar disease duration and six cognitively normal individuals. We co unted cell bodies/island in layer II of the ERC using formalin-fixed, paraffin-embedded, tau/cresyl violet-stained sections at the level of the rostral-most body of the hippocampus. There was marked variability in neuronal counts among cases in the LBD group; LBD data overlapped with data from both normal and AD groups. Overall, perforant pathway p erikaryal counts in LBD differed significantly from those in AD, but n ot from those in aged normals (mean perikarya/island=30.09+/-8.95, 7.5 7+/-6.08, and 38.83+/-8.98, respectively; F=26.131, P<0.001). The perc ent of remaining neurons bearing neurofibrillary tangles in LBD also o verlapped with AD and control groups (16.17+/-13.85%, 87.86+/-11.81%, and 24.36+/-13.30% of remaining neurons, respectively, F=65.62, P<0.00 1). We conclude that although perforant pathway neuronal loss may occu r in LBD, it is more often milder and more variable than that seen in AD. (C) 1997 Elsevier Science B.V.