A study of the clinical and the neuroradiological findings in multi-infarct dementia and Alzheimer type dementia

In forty patients with dementia, a comparison of the clinical and the neuroradiological findings between 15 Alzheimer type dementia (ATD) and 21 multi-infarct dementia (MID) were made. MID had significantly (p<0.01) higher Hachinski's Ischemic Score (HIS) (mean ±S.D., 9.7±1.8) compared with ATD (3.6±1.5). The HIS was a useful diagnostic aid in differential diagnosis between the two groups. MID significantly (p<0.01) had cerebrovascular risk factors such as hypertension, diabetes mellitus and increase of platelet aggregation. The morphometric analysis of the ratios of the ventricular dilatation, the cortical atrophy, and the white matter changes was performed on the CT scan and the magnetic resonance imaging. This was the first time the method of having the cortical atrophy analyzed by the ratio of the area of the sylvian sulci and the area of the whole brain had been used. It was found that the degrees of the ventricular dilatation, the cortical atrophy, and the white matter changes were more increased in MID than in ATD (p<0.01∼0.05). In ATD, there was a positive correlation between Hasegawa's Dementia Scale and both the ratios of the ventricular dilatation, and the cortical atrophy (r=-0.62, p<0.05, r=-0.63, p<0.05, respectively). Also a comparative study between MID and 9 patients with multiple infarction, without dementia (MI). MID had the mean infarct numbers of 6.5±2.5, and MI had 4.1±2.2. The white matter changes were more increased in MID than MI (p<0.05). The incidence of the dementia was significantly higher in cases with left lenticular nucleus (p<0.01) or main lesions of the white matter in the left frontal lobe (p<0.05), and in cases with bilateral lenticular nucleus (p<0.01), compared to cases without lesions. (J.P.N.)