Olfaction in the elderly: a cross-sectional analysis comparing Parkinson's disease with controls and other disorders.

Olfactory dysfunction in Parkinson's disease (PD) is an association that has been well documented in the medical literature, although the underlying pathophysiologic mechanism has not been clearly elucidated. In the Sun Health Research Institute Brain and Body Donation Program, subjects were tested for olfactory function. Olfaction was impaired in subjects with clinically probable PD but not those with essential tremor (ET), restless legs syndrome (RLS), or mild cognitive impairment. In the elderly control population there were no differences between genders and the UPSIT score decreased by 3.2 points per decade. These data confirm previous findings in PD, ET, and RLS, and expand the data for an elderly control population.