Olfactory functions in Parkinson's disease and Alzheimer's disease.

The aim of this investigation was to compare olfactory functions of patients suffering from Parkinson's disease (PD) and Alzheimer's disease (AD). Olfactory threshold, odor identification ability and odor memory performance were assessed in 21 non-demented PD patients and in 22 AD patients. Both patient groups were impaired in relation to an age-matched control group for the measure of odor identification. AD patients showed a higher olfactory threshold and poorer odor memory performance.