The advantage of being broad-minded: Brain diameter and neuropsychological test performance in elderly war veterans

The study aimed to find out if brain width and anteroposterior (AP) diameter are related to neuropsychological test performance. Computerized tomography (CT) scans and neuropsychological testing were carried out on 201 elderly veterans of World War II, half of whom were former prisoners of war (POWs). Brain width and AP diameter were measured at the level of the third ventricle. Brain width was related to performance on tests of verbal ability and to education, but AP diameter was unrelated to any of the tests. These results held whether or not demented Ss were excluded, and whether or not the effect of body size was partialled out. The former POWs did not differ on brain width or any of the neuropsychological tests, but they had a shorter mean AP diameter. This difference may be due to selective survival under conditions of starvation. An unexpected finding was that extraversion was related to brain width independent of verbal ability. The relationship of brain width to verbal ability and education may be relevant to hypotheses that education and brain size are protective for dementia.