Normative Performance on the Brief Smell Identification Test (BSIT) in a Multi-Ethnic Bilingual Cohort: A Project FRONTIER Study¹

Abstract

The Brief Smell Identification Test (BSIT) is a commonly used measure of olfactory functioning in elderly populations. Few studies have provided normative data for this measure, and minimal data are available regarding the impact of sociodemographic factors on test scores. This study presents normative data for the BSIT in a sample of English- and Spanish-speaking Hispanic and non-Hispanic Whites. A Rasch analysis was also conducted to identify the items that best discriminated between varying levels of olfactory functioning, as measured by the BSIT. The total sample included 302 older adults seen as part of an ongoing study of rural cognitive aging, Project FRONTIER. Hierarchical regression analyses revealed that BSIT scores require adjustment by age and gender, but years of education, ethnicity, and language did not significantly influence BSIT performance. Four items best discriminated between varying levels of smell identification, accounting for 59.44% of total information provided by the measure. However, items did not represent a continuum of difficulty on the BSIT. The results of this study indicate that the BSIT appears to be well-suited for assessing odor identification deficits in older adults of diverse backgrounds, but that fine-tuning of this instrument may be recommended in light of its items’ difficulty and discrimination parameters. Clinical and empirical implications are discussed.

New chemosensory component in the U.S. National Health and Nutrition Examination Survey (NHANES): first-year results for measured olfactory dysfunction

“…These differences could have resulted from procedure effects, although the NHANES pilot testing and modifications of the PST to ensure cultural appropriateness aimed to minimize procedural differences. The parent forms of the PST, the 12-item B-SIT and 40-item UPSIT, have been shown to perform well in testing olfaction across diverse groups including Hispanics [74, 78] and Asians [79]. Other population-based studies also have reported differences in olfactory testing across race/ethnic groups [63, 80].…”

Comparative effectiveness of medical and surgical therapy on olfaction in chronic rhinosinusitis: a prospective, multi‐institutional study

“…7 Furthermore, the B-SIT is not as effective at discriminating various levels of smell identification. 25 This potential lack of discrimination may lead to an under reporting of olfactory dysfunction which may bias effect estimates of change towards null hypotheses and limit our ability to detect true differences between treatment modalities. The high level of normosmics led to the evaluation of the cohort in sub-groups of normal olfaction and impaired olfaction.…”

Intact global cognitive and olfactory ability predicts lack of transition to dementia

“…The 12‐item B‐SIT is a subset of the 40‐item UPSIT and may have similar accuracy for the prediction of dementia . For this report, B‐SIT scores were computed from the twelve B‐SIT items within the UPSIT.…”

“…Distributions and group differences in demographic and clinical variables were examined by χ 2 , t‐test, and general linear models as appropriate. B‐SIT score of 11 or 12 of 12 indicates no odor identification deficit in a broad range of individuals and BOMC score ≤5 of 28 is in the normative range for middle‐aged to older adults . Therefore, these cutoff points, which represent stringent criteria, were used in the main analyses.…”