Summary

Among 290 demented subjects in a consecutive autopsy series of elderly individuals with or without parkinsonian signs, 41 cases or 14.1% showed abundant subcortical and cortical Lewy bodies satisfying the diagnosis of Lewy body dementia (LBD) they represented 35.7% of demented patients with parkinsonism (54% of those with idiopathic Parkinson's disease) (IPD) and 26.1% of confirmed cases of Alzheimer's disease (AD) with parkinsonism. Both elderly subjects without clinical parkinsonism (n = 83) and IPD patients (” = 39) showed significant negative correlations between Mini-Mental State and neuritic Alzheimer stages, while 10 of 18 LBD cases clinically presenting with IPD and dementia did not satisfy the CERAD criteria for AD but represented ‘plaque-only’ type of AD. The 41 cases of autopsy-proven LBD showed a female preponderance (31/10), mean age at death of 76 + 10.8 years and mean duration of 5.2 + 4.1 years. Among 31 clinically well documented LBD cases, all except 4 were severely demented, with initial cognitive impairment in 58%, parkinsonian symptoms in 26%, and later combination of both in 84%. Neuropathology revealed LBD without AD pathology in one, LBD with ‘plaque-predominant’ AD and CERAD-definite AD in 15 cases each. Morphometric analyses showed about 70% neuronal loss in the cholinergic nucleus basalis of Meynert in LBD, demented IPD, and AD cases. While these data suggest the importance of both cortical AD pathology and dysfunction of the ascending cholinergic system for mental decline in these disorders, both the significance of cortical Lewy bodies and the pathogenic relationships between IPD, LBD and LBD + AD await further elucidation.