Alzheimer's disease or Alzheimer's syndrome?: a longitudinal computed tomography neuroradiological follow-up study of 56 cases diagnosed clinically as Alzheimer's disease.

BACKGROUND: Some 200 patients, including those with Alzheimer's disease and other types of dementia, stay year-round in Yokohama - Houyuu Hospital. They undergo computed tomography (CT) neuroradiological examination at least once or twice a year. For this study, the accumulative data, including clinical and neuroradiological, were analyzed. METHODS: Differential diagnoses of Alzheimer's disease were performed in accordance with the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer's Disease and Related Disorders Association criteria. The 56 patients (15 men, 41 women) included in this study underwent in-hospital observation on average for 4.4 years (range: 1-10 years). The patients were classified into four groups according to the age of disease onset. The CT findings were summarized for each group and then compared among the groups to determine if there were any differences related to age of onset and, if so, to identify and analyze them. RESULTS: (1) The duration of deceased cases' total clinical course (in years) compared among the four groups. In general, the degree of dementia was more severe among those with earlier disease onset. (2) In cases admitted within 2 years from onset (n =14), the suspected initiating focus of cortical atrophy occurred in the frontal lobe (n = 6), the temporal lobe (n = 6), or the fronto-temporal lobes (n = 2). (3) Although CT findings generally showed that the more severe cases had earlier onset, serial CT examinations in each case showed widely different pathologies in degree, nature and manner of progression, regardless of group classification. (4) The earliest sites of brain atrophy, sites of its severest involvement within the brain, and neuroradiological development of the cerebral cortex pathology in combination with hemispheric white matter, lateral ventricles, and third ventricles varied among the four groups and between case within each group. Alzheimer's disease could not be subclassified simply by the age of clinical onset. CONCLUSION: Cases of so-called Alzheimer's disease, as observed through continued clinical follow-up and serial CT examinations, appear so diverse in symptomatology and radiological pathomorphology that it is difficult to consider them a single nosological entity. The pathology of Alzheimer's disease has to be reconsidered in accordance with the variety observed in the sequential development of neuroradiological findings. The pathology must be reconstructed in terms of topographical dimensions and chronological developments. The diagnosis of Alzheimer's disease appears to be not so simple based on any conventional diagnostic operational standards.

Regional quantitative analysis of NFT in brains of non-demented elderly persons: comparisons with findings in brains of late-onset Alzheimer's disease and limbic NFT dementia.

Brains of non-demented elderly people were divided into two groups according to the presence or absence of senile plaques (SP(+) and SP(-)). The regional number of NFT in each group were then quantitatively investigated and compared with that in the late-onset Alzheimer's disease (AD) group and the limbic NFT dementia (LNTD) group. NFT were divided into type 1, type 2 and type 3 according to the developmental stage. In addition, polymorphism of the apolipoprotein E (Apo E) gene was analyzed in all groups. The most frequent regions of NFT common to all groups were the transentorhinal cortex, the entorhinal cortex, the subiculum and cornu ammonis (CA)1 of the hippocampus. In the SP(+) group the proportion of type 3 was high in the transentorhinal cortex and entorhinal cortex, while type 1 or 2 were high in the subiculum and CA1, suggesting that NFT formation progresses from the parahippocampal cortex to the hippocampus. In the SP(-) group the proportion of type 3 was higher in the subiculum and CA1 than in the transentorhinal cortex and entorhinal cortex, suggesting that NFT formation is accelerated in the hippocampus. The late-onset AD group and LNTD group showed the patterns of NFT formation similar to those of the SP(+) group and SP(-) group, respectively. The frequency of the epsilon4 allele of the Apo E gene was significantly higher in the late-onset AD group and SP(+) group than in the LNTD group and SP(-) group, respectively. From these findings it is suggested that persons in the SP(+) group are likely to remain non-demented elderly persons or become a developmental matrix of late-onset AD with a risk factor of the epsilon4 allele, while those in the SP(-) group are likely to remain non-demented elderly persons or pass into LNTD without a risk factor of the epsilon4 allele.