We welcome the observation offered by Singh and Schwankhaus of a patient likely to have dementia with Lewy bodies, in which they extend the spectrum of neurodegenerative conditions associated with olfactory hallucinations. Besides phantosmia as an early symptom, their case shows distinct features compared with the cases described thus far, ie, the perceived odor was unpleasant and did not disappear with the onset of motor symptoms. In fact, in our reply to Hirsch1 and in the initial article, we already acknowledged that the pleasantness of the phantosmia may not be a mandatory criterion for the diagnosis of Parkinson disease. Whether disappearance of the phantosmia has to be concomitant with the onset of motor symptoms and whether this is a key element of Parkinson disease–related olfactory distortions remain open questions.
Landis BN, Burkhard PR. Olfactory Disturbance in Parkinson Disease—Reply. Arch Neurol. 2009;66(6):805-806. doi:10.1001/archneurol.2009.88