Sensitivity and Specificity of Self-Reported Olfactory Function in a Home-Based Study of Independent-Living, Healthy Older Women

Abstract

Introduction The 2011–14 US National Health and Nutrition Examination Survey chemosensory protocol asks adults to self-rate their orthonasal (via nostrils) and retronasal (via mouth) smell abilities for subsequent odor identification testing. From data collected with a similar protocol, we aimed to identify a self-reported olfactory index that showed the best sensitivity (correctly identifying dysfunction) and specificity (correctly indentifying normosmia) with measured olfaction. Methods In home-based testing, 121 independent-living older women (age 73±7 years) reported their olfactory function by interviewer-administered survey. Olfactory function was measured orthonasally via composite (odor threshold, identification task) or identification task alone. Results Only 16 % of women self-rated “below average” smell function. More women perceived loss of smell (38 %) or flavor (30 %) with aging. The rate of measured dysfunction was 30 % by composite (threshold and identification) and 21.5 % by identification task, the latter misclassifying some mild dysfunction as normosmia. An index of self-rated smell function and perceived loss yielded the most favorable sensitivity (65 %) and specificity (77 %) to measured function. Self-rated olfaction showed better agreement with severe measured dysfunction; mild dysfunction was less noticed. Conclusions Self-reported indices that query about current and perceived changes in smell and flavor with aging showed better sensitivity estimates than those previously reported. Specificity was somewhat lower—some older adults may correctly perceive loss unidentified in a single assessment, or have a retronasal impairment that was undetected by an orthonasal measure. Implications Our findings should inform self-rated measures that screen for severe olfactory dysfunction in clinical/community settings where testing is not routine.

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

“…The questionnaire was adapted from previous research, including a community-based study of self-rated olfaction in older adults [10], the olfaction and taste questionnaire used in the Beaver Dam Studies [11, 12], and the self-reported chemosensory questionnaire used in the Disability Supplement to the 1994 National Health Interview Survey [13]. The CSQ was content-validated by a nationwide team of chemosensory experts and cognitively tested for response problems and cultural appropriateness to ensure that respondents could understand, process, and interpret the questions in a consistent manner as intended.…”

“…Self-reported smell function typically has not been considered to be a sensitive indicator of measured impairment [10]. However, previously reported low sensitivities of self-reported smell function may have resulted from the use of a single question, which simply asked participants to rate their current smell ability [11, 15].…”

“…However, previously reported low sensitivities of self-reported smell function may have resulted from the use of a single question, which simply asked participants to rate their current smell ability [11, 15]. In a home-based community study [10], self-reported indices of olfactory function that included the CSQ question on smell loss with age (in addition to ‘current smell ability’) showed better sensitivity and specificity to measured function than had been previously reported. Another laboratory-based study [14] showed that individuals reporting smell problems or smell loss with age in the CSQ scored significantly lower in odor identification tests.…”

“…The gLMS scale provides data similar to magnitude matching, the gold standard procedure for assessing perceived intensity [21], is reliable [10, 22] while enjoying the advantage of being much quicker and adaptable to population-based samples. The gLMS has been used in multiple clinical [23, 24] and population-based studies [25, 26] to study variation in taste perception.…”

“…Participants also answered questions on common conditions (e.g., sinonasal, head/orofacial injury) that have been previously shown to increase risk of chemosensory alterations. Validity and reliability estimates of some CSQ questions have been reported from two studies with community-based samples [10, 14]. …”