Decreased Sense of Smell in a Patient with Dementia or Parkinson's Disease

 

Loss of smell may be associated with:

(1) Parkinson's disease

(2) Alzheimer's disease

(3) other dementias

 

A feature of hyposmia in a neurodegenerative disease is that the patient is either unaware of the loss or significantly underestimates its severity.

 

Screening for loss of smell in a general population has limited utility, but it may be helpful in a high-risk population.

 

The diagnosis of Parkinson's disease should be questioned in a patient with normal smell unless the patient is a female with tremor-dominant disease (Hawkes, 2006).

 

Anosmia is atypical for a patient with progressive suprnuclear palsy or corticobasal degeneration. Its presence should prompt a review of the diagnosis (Hawkes, 2006)>

 

Exclusion of other explanations such as chronic sinusitis or head trauma.