The relationship between enlargement of the temporal horns of the lateral ventricles and dementia in aging patients with Down syndrome.

Head CT studies of patients with Alzheimer's disease (AD) show global atrophic changes. Tissue loss is especially prominent in the temporal lobes, with widening of the temporal horns of the lateral ventricles and, usually, widening of the temporal sulci. Some recent studies have found a familial form of AD to be mapped to chromosome 21. Down syndrome (DS) results from the inheritance of three chromosomes 21, and it has been shown that after the age of 35 the brains of patients with DS commonly show neuropathological changes similar to those in patients with AD. CT studies of 25 patients with DS (ages 29-64 years) were examined for tissue loss in the temporal regions, and this was compared to the findings commonly seen in patients with AD. The widths of CSF spaces varied considerably in patients with DS, but after the age of 50 most of them showed significant widening of the temporal horns. In some patients the horns were large enough to suggest obstructive hydrocephalus. Because of a new trend toward deinstitutionalization of patients with DS, radiologists will be seeing more studies on these patients and should familiarize themselves with the unique ways in which they manifest the aging process.