Olfactory sensitivity in early-stage Parkinson patients affected by more marked unilateral disorder.

Two groups of subjects, 6 medicated Parkinson patients at an early stage of disease and affected by more marked right unilateral disorder and 12 normal elderly people, were examined on matching and naming olfactory tasks. On the former, subjects had to recognize among four previously sniffed odours, while on the latter they had to label an odour by choosing among four alternatives proposed by the examiner. Stimuli were administered to both nostrils. Analysis indicated that Parkinson patients were less efficient with the left nostril in the matching task, supporting the hypothesis of a larger compromise in the nostril contralateral to the side of the body more affected by the disease. Such a difference was not observed for the elderly people. Data are discussed with reference to the loss of dopamine in Parkinson patients.