|Budget Amount *help
¥1,200,000 (Direct Cost : ¥1,200,000)
Fiscal Year 1998 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1997 : ¥700,000 (Direct Cost : ¥700,000)
Early detection, treatment and prevention of dementia have become increasingly important as the population ages. I have performed a follow-up study of changes in the brains of healthy elderly persons with computed tomography (CT) and magnetic resonance imaging (MRI) since 1982. One hundred thirty-three healthy elderly volunteers were first examined in 1982 with CT or MRI, electroencephalography, the Benton Visual Retention Test (BVRT), blood pressure measurement, and interview. Subsequent examinations were done in 1986, 1989, and 1992. On CT, microinfarctions were found in 15.0% of subjects in 1982 and in 13.0% in 1986, and periventricular lucency (PVL) was found in 6.0% and 8.3%. The most frequent findings were vascular changes, which were observed in six persons (5.6%). followed by PVL, which was found in four persons (3.7%). Thus, vascular changes became more pronounced during the follow-up period. Lesions with high signal intensity on T_2-weighted images (T_2HSI) were found in 69.5% of subjects and increased in prevalence with age in the 1989 study. Such T_2HSI lesions were found most frequently, in the basal ganglia (61.9%), followed by the thalamus (39.0%), parietal lobe (37.0%), temporal lobe (12.7%) and the pons (8.5%). Of these lesions, lacunar infarctions showed low signal intensity on T1-weighted images and were found in 24.6% of subjects ; their prevalence also increased with age. Results of BVRT were closely correlated with T_2HSI lesions, suggesting that T_2HSIs lesions may affect cognitive function. By 1992, 10 years after the start of the study, 34 (25.6%) of subjects had died and 19 (14.3%) had become demented. Subjects were divided into surviving and dead groups and dementia and non-dementia groups. Findings on CT and BVRT in this study have provided clear clinical indices of death and dementia, especially maximal width of third ventricule in impairment of the diagnosis of dementia.