The epidemiology of aphasic and cognitive impairment in stroke: age, sex, aphasia type and laterality differences.

Sex differences and age distribution are examined in various types of aphasia and in right hemisphere-damaged patients due to acute infarct. The language and performance deficits were measured by a standardized test allowing us to group patients meaningfully. The higher male to female ratio of aphasia is shown to relate to a similar sex distribution in infarcts rather than to sex differences in cerebral organization. Broca's aphasics were somewhat younger than the other groups and the slight difference may be related to pathophysiological factors favouring embolic strokes in the anterior territory of the middle cerebral artery. Sex and aphasia types were not significantly different in various age groups except about 50 years of age where the female aphasics reversed the ratio.