Olfactory loss and nigrostriatal dopaminergic denervation in the elderly

Ka Kit Wong, Martijn L.T.M. Muller, Hiroto Kuwabara, Stephanie A. Studenski, Nicolaas I. Bohnen

Research output: Contribution to journalArticlepeer-review

Abstract

Olfactory dysfunction may precede common neurodegenerative disorders in the elderly, such as Alzheimer (AD) or Parkinson disease (PD). However, pathobiological mechanisms of olfactory loss in the elderly are poorly understood. Although nigrostriatal dopaminergic denervation is a key patholobiological feature of PD, age-associated nigrostriatal denervation (AASDD) occurs also with normal aging and can be more prominent in some elderly. We investigated the relationship between AASDD and olfactory performance in community-dwelling subjects. Community-dwelling subjects (n=73, 44 F/29 M, mean age 64.0±16.4, range 20-85) underwent brain dopamine transporter (DAT) [11C]2-β-carbomethoxy-3β-(4-fluorophenyl) tropane (β-CFT) positron emission tomography (PET) imaging and olfactory assessment using the 40-odor University of Pennsylvania Smell Identification Test (UPSIT). Subjects with clinical or DAT PET evidence of Parkinson disease (PD) were not eligible for the study. AASDD was defined based on normative data in young and middle-aged subjects. Compared to a mild and general linear decline in odor identification observed in most subjects (R2=0.18, P=0.0002), there were 13 subjects who deviated below the 5% confidence interval level in age-predicted UPSIT scores. Analysis limited to elderly subjects 60 years and over demonstrated a significant association between poor smell (n=10 out of 49, 20.4%) and AASDD (χ2=4.4, P<0.05). There is a significant association between olfactory dysfunction and more prominent nigrostriatal denervation in the elderly. Olfactory assessment may have potential as a screening tool to detect age-accelerated neurodegeneration in the elderly.

Original languageEnglish (US)
Pages (from-to)163-167
Number of pages5
JournalNeuroscience Letters
Volume484
Issue number3
DOIs
StatePublished - Nov 1 2010

Keywords

  • Aging
  • Basal ganglia
  • Dopamine
  • Nigrostriatal
  • Olfaction
  • Positron emission tomography

ASJC Scopus subject areas

  • Neuroscience(all)

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