Essential tremor: mild olfactory dysfunction in a cerebellar disorder

Olfactory dysfunction has been reported to occur in patients with cerebellar disorders, including degenerative ataxias and essential tremor (ET). Previous studies have not considered the effects of mild cognitive deficits, which can occur in ET, and could explain the lower olfaction test scores in ET cases. We more than doubled our initial sample (37 ET cases and 37 controls) [Louis ED, Bromley SM, Jurewicz EC, Watner D. Olfactory dysfunction in essential tremor: a deficit unrelated to disease duration or severity. Neurology 2002;59:1631-3. ] and made adjustments for the mini mental status test score. The University of Pennsylvania Smell Identification Test score remained lower in 87 ET cases compared to 92 controls after adjustment for mini mental status test score and other potential confounders (p = 0.04). These findings: suggest that olfactory dysfunction in ET patients occurs independently of mild cognitive deficits and support recent work that the cerebellum may play a role in central olfactory processing.