Limbic lobe involvement in presenile dementia

Limbic lobe involvement in presenile dementia was studied from a neuropathological and neuropsychiatric viewpoint. The material consisted of seven cases of Alzheimer's disease, four cases of Pick's disease, and four cases of Jacob-Creutzfeldt's disease. These three groups showed different patterns of distribution of the degeneration characteristic for each group, in particular for the first two. Among the groups, these patterns differed with regard to involvement both of nonlimbic and limbic areas. Thus the Alzheimer group had a mainly temporoparieto-occipital and posterior cingulate gyrus involvement. The Pick group in many respects showed an inverse distribution with frontotemporal and anterior cingulate gyrus accentuation of the damage. Basal temporal limbic areas were involved in both groups. The Jacob-Creutzfeldt group had a less schematic lesion pattern, without involvement of limbic areas. From a neuropsychiatric aspect, these differences were reflected in symptoms that could be referred both to areas spared and those more pronouncedly destroyed by the degenerative process. Thus the Alzheimer group long retained emotional qualities that were lost early in the Pick group. The possible relationship between neurotransmitters and regional accentuation of the degeneration is discussed.