Differences in olfactory test performance between normal aged, Alzheimer and vascular type dementia individuals

Abstract

Abstract A comparison was made between 3 groups of elderly subjects — normal controls aged 69–79 years, patients with vascular dementia aged 64–84 years and patients with probable senile dementia of Alzheimer type (SDAT) aged 70–90 years — by means of several tests of olfactory functions. Significant group differences were found at all levels assessed — olfactory thresholds, smell recognition, smell identification, naming of smells — with the normal aged performing best and the SDAT group scoring lowest throughout. The differences were most pronounced with regard to smell recognition and smell identification where minimal or no overlap at all between controls and SDAT patients was found. Differences in age and severity of dementia did not fully account for the findings, suggesting that differential diagnosis of Alzheimer ‐ type dementia could be facilitated and improved by the use of olfactory tasks. Neurophysiological and ‐ pathological findings support a close association or even identity of brain structures involved in olfaction and affected in Alzheimer's disease.