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Olfactory identification in amnestic and non-amnestic mild cognitive impairment and its neuropsychological correlates

Martin Vyhnalek1, Hana Magerova2, Ross Andel3

  • 1International Clinical Research Center, St. Anne's University Hospital Brno, Brno, Czech Republic; Memory Clinic, Department of Neurology, Charles University in Prague, 2nd Faculty of Medicine and Motol University Hospital, Prague, Czech Republic.

Journal of the Neurological Sciences
|January 24, 2015
PubMed
Abstract

Insights

Olfactory identification is impaired in both amnestic and non-amnestic mild cognitive impairment (MCI). This olfactory dysfunction correlates with cognitive decline in amnestic MCI but not non-amnestic MCI.

Area of Science:

  • Neuroscience
  • Gerontology
  • Cognitive Science

Background:

  • Olfactory identification deficits are documented in amnestic mild cognitive impairment (aMCI), linked to Alzheimer's disease (AD) pathology.
  • Evidence for olfactory dysfunction in non-amnestic MCI (naMCI) is less clear.
  • Understanding olfactory impairment in different MCI subtypes is crucial for early AD detection.

Purpose of the Study:

  • To compare olfactory identification abilities across aMCI, naMCI, mild AD dementia, and control groups.
  • To investigate the relationship between olfactory identification and cognitive performance in aMCI versus naMCI.

Main Methods:

  • A cohort of 75 aMCI, 32 naMCI, 26 mild AD, and 27 control participants were assessed.
  • The Motol Hospital Smell Test (18 odors) and a comprehensive neuropsychological examination were administered.
  • Statistical analyses controlled for age and gender.

Main Results:

  • Both aMCI and naMCI groups showed significantly impaired olfactory identification compared to controls (p<0.001).
  • aMCI and naMCI groups performed better than mild AD patients (p<0.001).
  • In aMCI, olfactory ability correlated with cognitive scores (MMSE, memory, visuospatial); this correlation was absent in naMCI.

Conclusions:

  • Olfactory identification dysfunction is comparable in aMCI and naMCI.
  • Olfactory impairment is associated with cognitive decline in aMCI, but not in naMCI.
  • These findings highlight differential relationships between olfactory and cognitive function in MCI subtypes.
Keywords:
Alzheimer's diseaseCognitionMemoryMild cognitive impairmentOlfaction disordersSmell

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