Association between cognitive function and olfactory identification ability in community-dwelling older individuals.
Masashi Yoshitake, Etsuko Maeshima, Shinichiro Maeshima and 2 others
PMID 35698550WHAT IT FOUND
Smell test scores correlated with MoCA-J scores but not MMSE-J scores in older adults.
Many people had low MoCA-J scores without smell loss, and some had smell loss without low MoCA-J scores. Smell testing alone does not reliably flag early cognitive decline.
Key findings
01Olfactory identification scores correlated significantly with MoCA-J scores but not with MMSE-J scores.
0221.8% of participants showed cognitive decline on the MoCA-J despite normal olfactory identification scores.
0310.9% of participants had normal MoCA-J scores but impaired olfactory identification, suggesting possible future risk rather than current decline.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
Participants were not medically diagnosed with MCI or dementia; classification relied solely on screening test cutoffs, so some participants labelled as cognitively normal may have had undiagnosed conditions and vice versa. The study used a cross-sectional design, so it cannot establish whether olfactory decline precedes, follows, or co-occurs with cognitive decline over time. The sample size was small (55 participants) and drawn from a single community salon, limiting generalisability. The age range was narrow (62–82 years), which may explain why no age effect was found on olfactory scores, unlike studies with wider age ranges. No information is provided on whether participants had other conditions affecting smell or cognition beyond the exclusion of diagnosed MCI/dementia and causative smell disease.
Declared interests
No conflicts of interest or funding sources are declared in the provided text.
The easy way to misread this
Do not interpret the significant MoCA-J and smell correlation as evidence that olfactory testing can replace cognitive screening. The MMSE-J showed no correlation with smell scores, and nearly a quarter of participants with cognitive decline on the MoCA-J had normal smell. Using smell tests to rule out early cognitive impairment would miss those individuals.