Skip to content

Failure to identify odors may be an early sign of cognitive impairment. A recent study included persons aged 65 years or older without dementia (males and females, n = 1037) [1]. They were asked to identify 40 different odors, and their success rate was scored. Also, a brain MRI and a battery of cognitive tests were performed. Follow-up at 2 and 4 years in 757 participants showed that low baseline scores correlated with cognitive decline and the appearance of Alzheimer’s disease. MRI hippocampal volume did not show predictive utility in this cohort. The investigators suggested that the inexpensive smell test could be useful as a predictor of future cognitive impairment.


  • Amos Pines
    Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel


  1. Devanand DP, Lee S, Manly J, et al. Olfactory deficits predict cognitive decline and Alzheimer dementia in an urban community. Neurology 2015;84:182-9
  2. Roberts RO, Christianson TJ, Kremers WK, et al. Association between olfactory dysfunction and amnestic mild cognitive impairment and Alzheimer disease dementia. JAMA Neurol 2016;73:93-101
  3. Fullard ME, Tran B, Xie SX, et al. Olfactory impairment predicts cognitive decline in early Parkinson’s disease. Parkinsonism Relat Disord 2016;25:45-51
  4. Stamps JJ, Bartoshuk LM, Heilman KM. A brief olfactory test for Alzheimer’s disease. J Neurol Sci 2013;333:19-24
  5. Doty RL, Kamath V. The influences of age on olfaction: a review. Front Psychol 2014;5:20
  6. Oleson S, Murphy C. Olfactory dysfunction in ApoE ɛ4/4 homozygotes with Alzheimer’s disease. J Alzheimers Dis 2015;46:791-803
  7. Hughes LF, McAsey ME, Donathan CL, Smith T, Coney P, Struble RG. Effects of hormone replacement therapy on olfactory sensitivity: cross-sectional and longitudinal studies. Climacteric 2002;5:140-50
  8. Doty RL, Tourbier I, Ng V, et al. Influences of hormone replacement therapy on olfactory and cognitive function in postmenopausal women. Neurobiol Aging 2015;36:2053-9
  9. Sundermann EE, Gilbert PE, Murphy C. The effect of hormone therapy on olfactory sensitivity is dependent on apolipoprotein E genotype. Horm Behav 2008;54:528-33
International Menopause Society

Install International Menopause Society - DEV

Install this application on your home screen for quick and easy access when you’re on the go.

Just tap then “Add to Home Screen”