Clinical Implications of Brain Atrophy by Computed Tomography in Patients with Age-related Dementia

Abstract

The purpose of the present study is to clarify the clinical significance of brain atrophy by computed tomography in age-related dementia. Eighty elderly patients with clinical diagnosis of presenile or senile dementia whose mental states were assessed clinically and by several psychometric test were studied by computed tomography. Patients with suspected cerebrovascular disorders and normal pressure hydrocephalus were excluded.
Three tomographic sections through anterior and posterior horns and cella media of lateral ventricles and cortex with intracranial space of 60-80cm² were evaluated. CSF spaces (%) were measured as a index of brain atrophy. The measurement of CSF spaces (%) was carried out by the computarized planimetric method to avoid visual definition of ventricular borders. In this study, CSF spaces comprised ventricular and subarachnoid spaces.
Hasegawa's dementia scale, Bender-Gestalt test and Kohs' block design test were employed for the cognitive assessment of the subjects.
In two sections through lateral ventricles, significant correlation were obtained between CSF spaces (%) and scores of Hasegawa's dementia scale and Kohs' block design test. Scores of Bender-Gestalt test did not correlate with CSF spaces (%) in these two sections. In the section through cortex, no correlation were found between CSF spaces (%) and scores of any psychometric test. Also, no positive correlations were obtained between age and CSF spaces (%) in the three sections.
The present results suggest that brain atrophy could be one of the significant predictors to screen patients with dementia and to identify patients with so called reversible dementias. Also, it is suggested that ventricular enlargement is more etiological to the intellectual impairment than cortical atrophy. Taking into consideration that the correlation coefficients are fairly low in the present study, it seems quite essential to evaluate etiological factors other than morphological changes such as brain atrophy shown in CT. Finally, the present study will need to be confirmed by both follow-up studies and more extensive inquiries in larger groups of patients.