Olfactory dysfunction in downʹs syndrome

Downʹs Syndrome subjects over 40 years old show neuropathology similar to that of Alzheimerʹs disease. The olfactory system is particularly vulnerable in Alzheimerʹs disease, both anatomically and functionally. Several measures of sensory and cognitive functioning were studied in the older Downʹs Syndrome patient, with the hypothesis of significant olfactory dysfunction. Participants were 23 Downʹs subjects, and 23 controls. The Dementia Rating Scale showed mean scores of 103 for Downʹs subjects and 141 for controls. Downʹs subjects showed significant deficits in odor detection threshold, odor identification, and odor recognition memory. Normal performance in a taste threshold task, similar to the olfactory threshold task in subject demands, suggested that the Downʹs syndrome subjectsʹ poor performance was not due to task demands. Deficits in olfaction may provide a sensitive and early indicator of the deterioration and progression of the brain in older subjects with Downʹs Syndrome.