Odor identification deficits in diffuse lewy body disease.

OBJECTIVES: To describe odor identification performance in patients with diffuse Lewy body disease and determine the clinical utility of odor identification tests in distinguishing diffuse Lewy body disease from Alzheimer disease.
BACKGROUND: The presence of olfactory deficits, especially odor identification deficits, has been well established in both Alzheimer disease and Parkinson disease. The presence of olfactory deficits in diffuse Lewy body disease is also likely given the overlap of clinical symptoms and neuropathology with Alzheimer disease and Parkinson disease. However, odor identification abilities have not been described previously in diffuse Lewy body disease.
METHODS: Nine patients from a clinic sample with diffuse Lewy body disease and nine carefully matched patients with Alzheimer disease were administered an odor identification task as part of their neuropsychologic evaluations.
RESULTS: Patients with diffuse Lewy body disease performed significantly worse than patients with Alzheimer disease on the odor identification test.
CONCLUSIONS: Odor identification deficits may be more prevalent and severe in people with diffuse Lewy body disease than in people with Alzheimer disease, and olfactory testing may be useful in antemortem differential diagnosis of the two disorders.