Utility of olfactory identification test for screening of cognitive dysfunction in community-dwelling older adults

Satoshi Nogi; Kentaro Uchida; Jumpei Maruta; Hideo Kurozumi; Satoshi Akada; Masatsugu Shiba; Koki Inoue

doi:10.7717/peerj.12656

Utility of olfactory identification test for screening of cognitive dysfunction in community-dwelling older adults

PeerJ. 2021 Dec 20:9:e12656. doi: 10.7717/peerj.12656. eCollection 2021.

Authors

Satoshi Nogi¹, Kentaro Uchida¹, Jumpei Maruta^{1

2}, Hideo Kurozumi¹, Satoshi Akada¹, Masatsugu Shiba³, Koki Inoue^{1

4}

Affiliations

¹ Neuropsychiatry, Osaka City University Graduate School of Medicine, Osaka, Japan.
² Medical Center for Dementia, Osaka City Kosaiin Hospital, Osaka, Japan.
³ Medical Statistics, Osaka City University Graduate School of Medicine and Faculty of Medicine, Osaka, Japan.
⁴ Center for Brain Science, Osaka City University Graduate School of Medicine and Faculty of Medicine, Osaka, Japan.

Abstract

Background: There is a need for a large-scale screening test that can be used to detect dementia in older individuals at an early stage. Olfactory identification deficits have been shown to occur in the early stages of dementia, indicating their usefulness in screening tests. This study investigated the utility of an olfactory identification test as a screening test for mild cognitive dysfunction in community-dwelling older people.

Methods: The subjects were city-dwelling individuals aged over 65 years but under 85 years who had not been diagnosed with dementia or mild cognitive impairment. The Japanese version of the Mild Cognitive Impairment Screen was used to evaluate cognitive function. Based on the results, the subjects were divided into two groups: healthy group and cognitively impaired group. Olfactory identification abilities based on the Japanese version of the University of Pennsylvania Smell Identification Test were compared between the groups.

Results: There were 182 participants in total: 77 in the healthy group and 105 in the cognitively impaired group. The mean olfactory identification test score of the cognitively impaired group was significantly lower than that of the healthy group. The cognitive impairment test score was significantly correlated with the olfactory identification test score.

Conclusions: Cross-sectional olfactory identification deficits at baseline in community-dwelling older adults reflected cognitive dysfunction. Assessing olfactory identification ability might be useful as a screening test for mild cognitive dysfunction in community-dwelling older people.

Keywords: Community-dwelling older adults; Dementia; Early diagnosis; Mass screening; Olfaction disorders; Olfactory identification.

Grants and funding

This work was funded by the Wellness Open Living Lab (No. G191000006) in joint research. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.