LEWY BODIES ARE LOCATED PREFERENTIALLY IN LIMBIC AREAS IN DIFFUSE LEWY BODY DISEASE

Lewy bodies (LBs) are found throughout the brain stem, limbic and neoc ortical areas in Parkinson's disease. Lewy bodies are also associated in these areas with dementia and the substrate of 'dementia with Lewy bodies' is thought to include Lewy body pathology in limbic and neocor tical areas with or without Alzheimer-type changes. In order to determ ine whether dementia with Lewy bodies is characterised primarily by co rtical or limbic LB pathology, we have measured the density of Lewy bo dies, neuritic plaques and neurofibrillary tangles in 12 neocortical, limbic and brain stem sites in 10 patients who were pathologically dia gnosed with diffuse Lewy body disease (DLBD) (64.7+/-2.7 years). The m ean LB density in limbic areas (3.00+/-0.61/mm(2)) was significantly g reater than that of neocortical areas (1.13+/-0.22/mm(2); P < 0.001). The greatest density of LBs was found in the amygdala (4.1+/-0.7/mm(2) ) and the lowest in the occipital cortex (0.3+/-0.1/mm(2)). In limbic areas, LB formation positively correlated with neuritic plaque formati on (r=0.51, P < 0.01) but not with neurofibrillary tangle densities. T hese data indicate that dementia with Lewy bodies is characterised pri marily by limbic, and secondly by neocortical, LB pathology. It remain s to be determined why limbic areas are selectively vulnerable to LB p athology in dementia with Lewy bodies.