International consensus statement on allergy and rhinology: Olfaction.

BACKGROUND: The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O). METHODS: Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus. RESULTS: The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies. CONCLUSION: This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.

Clinical validation of the olfactory detection threshold module of the Snap & Sniff® olfactory test system.

BACKGROUND: Quantitative olfactory testing is essential to determine the validity and nature of a patient's complaint, accurately monitor changes in function over time (including influences of pharmacological, surgical, or immunological interventions), detect malingering, and establish disability compensation. This work describes the clinical validation of an advanced rapid odor detection threshold test that standardizes odorant delivery and eliminates unsanitary sniff bottles, the need for blindfolds, and the possibility of touching an odorant stimulus to the nose. METHODS: Snap & Sniff® single-staircase phenyl ethyl alcohol detection thresholds (S&S-Ts) were assessed bilaterally in 736 patients with chemosensory complaints; 421 received both bilateral and unilateral testing. The results were correlated with scores from the University of Pennsylvania Smell Identification Test (UPSIT) and the Smell Threshold Test (STT), a widely-used standardized threshold test. Test-retest reliability data were obtained for 50 patients. RESULTS: S&S-Ts were highly reliable (Spearman r = 0.84), correlated with the other olfactory test measures (rs > 0.65, ps < 0.0001), and required significantly shorter administration times than the STT (<10 minutes). Bilateral thresholds were systematically lower than unilateral thresholds, a phenomenon independent of presentation order but dependent upon the better functioning side of the nose. The S&S-Ts were sensitive to age and sex. No systematic left:right nasal side threshold differences were evident. CONCLUSION: The present study validates the use of Snap & Sniff® technology in the clinic setting. High test-retest reliability and brief administration times were evident. The S&S-T test allows for a reliable, valid, inexpensive, and rapid clinical means for quantitatively assessing human olfactory sensitivity.

Relationship of socioeconomic status to olfactory function.

Socioeconomic status can significantly impact health. To what degree education and other socioeconomic factors influence the chemical sense of olfaction is not clear. Most studies that have assessed such influences come from countries lacking large disparities in education and income and generally view such measures as nuisance variables to be controlled for statistically. In this study, we evaluated the influences of education and income on odor identification in a diverse sample of subjects from Brazil, a society where large disparities in both income and education are present. The 40-item University of Pennsylvania Smell Identification Test (UPSIT) was administered to 1572 healthy Brazilian citizens with no self-reported olfactory or gustatory deficits and for whom detailed socioeconomic and educational status data were obtained. Univariate and multivariate models were employed to examine the influence of socioeconomic status on the test scores. After controlling for age, sex, ethnicity, and smoking behavior, income and educational level were positively and independently related to the olfactory test scores (respective ps < 0.001 & 0.01). Both linear and quadratic functions described the relationship between the UPSIT scores and the levels of education and socioeconomic status. Individuals of lower socioeconomic status performed significantly worse than those of higher socioeconomic status on 20 of the 40 odorant items. This study demonstrates socioeconomic status is significantly associated with influence the ability to identify odors. The degree to which this reflects differential exposures to xenobiotic agents, cultural differences, familiarity with odors or their names, cognitive development, or other factors requires further investigation.

Olfactory assessment using the NIH Toolbox.

The human olfactory system provides us with information about our environment that is critical to our physical and psychological well-being. Individuals can vary widely in their ability to detect, recognize, and identify odors, but still be within the range of normal function. Although several standardized tests of odor identification are available, few specifically address the issues in testing very young children, most of whom are likely to be unfamiliar with many of the odor stimuli used in adult tests and have limited ability to read and identify labels to select among choices. Based on the format of the San Diego Odor Identification Test and the delivery system of the University of Pennsylvania Smell Identification Test, we developed 2 versions of an odor identification test using standardized odor stimuli in a scratch-and-sniff format in which participants match 5 (children) or 9 (adults) odors to pictures representing the odor source. Results from normative testing and validation showed that for most participants, the test could be completed in 5 minutes or less and that the poorer performance among the youngest children and the elderly was consistent with data from tests with larger numbers of items. Expanding on the pediatric version of the test with adult-specific and public health-relevant odors increased the ecological validity of the test and facilitated comparisons of intraindividual performance across developmental stages.

A new cultural adaptation of the University of Pennsylvania Smell Identification Test.

OBJECTIVES: The University of Pennsylvania Smell Identification Test, a test of olfactory function that is widely used by otolaryngologists, geriatricians, and neurologists, has been translated into more than a dozen languages. In some instances, cultural and socioeconomic factors have necessitated changes in the odorant items or the response alternatives to make the test scores congruent with North American norms. The objective of this study was to compare the performance of Brazilian subjects on a new Portuguese language version of the University of Pennsylvania Smell Identification Test with their performance on an earlier Portuguese language version of the test, as well as to assess the influences of gender, age, ethnicity, and economic status on the test scores. METHODS: Based on pilot data, several response alternatives of the earlier Portuguese language version of the test were altered in an effort to improve test performance. Forty-nine healthy Brazilian volunteers, who represented several economic classes, were tested. The test scores of the study cohort who received the newer version of the test were compared with those of a group of 25 subjects who received the earlier version of the test. RESULTS: The mean score for the new version [35 (2.1)] was significantly (p = 0.002) higher than that for the earlier version [32.5 (3.5)]. Although no apparent influence of socioeconomic status was observed, the female participants outperformed the male participants in the current subject cohort. CONCLUSION: The changes made in the new cultural adaptation of the Portuguese version of the University of Pennsylvania Smell Identification Test were effective in increasing the average test scores of the participants. Overall, the female subjects outperformed the male subjects on the test.

A new cultural adaptation of the University of Pennsylvania Smell Identification Test

OBJECTIVES: The University of Pennsylvania Smell Identification Test, a test of olfactory function that is widely used by otolaryngologists, geriatricians, and neurologists, has been translated into more than a dozen languages. In some instances, cultural and socioeconomic factors have necessitated changes in the odorant items or the response alternatives to make the test scores congruent with North American norms. The objective of this study was to compare the performance of Brazilian subjects on a new Portuguese language version of the University of Pennsylvania Smell Identification Test with their performance on an earlier Portuguese language version of the test, as well as to assess the influences of gender, age, ethnicity, and economic status on the test scores. METHODS: Based on pilot data, several response alternatives of the earlier Portuguese language version of the test were altered in an effort to improve test performance. Forty-nine healthy Brazilian volunteers, who represented several economic classes, were tested. The test scores of the study cohort who received the newer version of the test were compared with those of a group of 25 subjects who received the earlier version of the test. RESULTS: The mean score for the new version [35 (2.1)] was significantly (p = 0.002) higher than that for the earlier version [32.5 (3.5)]. Although no apparent influence of socioeconomic status was observed, the female participants outperformed the male participants in the current subject cohort. CONCLUSION: The changes made in the new cultural adaptation of the Portuguese version of the University of Pennsylvania Smell Identification Test were effective in increasing the average test scores of the participants. Overall, the female subjects outperformed the male subjects on the test.

Office procedures for quantitative assessment of olfactory function.

BACKGROUND: Despite the importance of the sense of smell for establishing the flavor of foods and beverages, as well as protecting against environmental dangers, this primary sensory system is commonly ignored by the rhinologist. METHODS: In this article basic issues related to practical measurement of olfactory function in the clinic are described and examples of the application of the two most common paradigms for such measurement--odor identification and detection--are presented. A listing is made of the 27 olfactory tests currently used clinically, along with their strengths and weaknesses. A brief review of common nasosinus-related disorders for which quantitative olfactory testing has been performed is provided. RESULTS: Although many psychophysical tests are available for quantifying olfactory loss, it is apparent that a number are limited in terms of practicality, sensitivity, and reliability. In general, sensitivity and reliability are positively correlated with test length. Given the strengths of the more reliable forced-choice pyschophysical tests and the limitations of electrophysiological tests, the common distinction between "subjective" and "objective" tests is misleading and should not be used. Complete recovery of olfactory function, as measured quantitatively, rarely follows surgical or medical interventions in patients with rhinosinusitis. CONCLUSION: Given the availability of practical clinical olfactory tests, the modern rhinologist can easily quantify cranial nerve (CN) I function. The application of such tests has led to a new understanding of the effects of nasal disease on olfactory function. Except in cases of total or near-total nasal obstruction, olfactory and airway patency measures usually are unrelated, in accord with the concept that rhinosinusitis primarily influences olfactory function by apoptotic pathological changes within the olfactory neuroepithelium.

Objective assessment of terbinafine-induced taste loss.

OBJECTIVES: Terbinafine (Lamisil), a widely prescribed oral antifungal agent, reportedly induces taste loss in 0.6% to 2.8% of those taking the drug. However, many so-called taste problems reflect olfactory problems, and the sole empirical study published on this topic, based on whole-mouth testing of a single subject, found no terbinafine-related deficit. In this study, we quantitatively assessed, using well-validated taste and smell tests, chemosensory function in six patients complaining of taste disturbance after terbinafine treatment and compared their test scores to those of six age-, race-, and sex-matched normal controls. METHODS: Taste function was measured using a 96-trial regional test that assesses sweet, sour, bitter, and salty taste perception within the anterior (cranial nerve [CN] VII) and posterior (CN IX) lingual taste bud fields. Smell function was bilaterally evaluated using the 40-item University of Pennsylvania Smell Identification Test. RESULTS: Taste function for sweet-, sour-, and bitter-tasting stimuli was significantly depressed in both the anterior and posterior lingual regions. For sodium chloride, the decrements were confined to the posterior region. Olfactory function was within normal limits. CONCLUSION: These findings 1) support anecdotal case reports of taste loss after terbinafine use, 2) demonstrate that all four major taste qualities are affected, and 3) suggest that olfactory dysfunction is not involved. Because self-report markedly underestimates chemosensory deficits, more extensive quantitative testing of patients receiving terbinafine will likely reveal a much higher prevalence of terbinafine-induced taste loss than currently reported. Since being older than 65 years of age and having a low body mass index are reportedly risk factors for terbinafine-induced taste loss, physicians should be particularly on the alert for elderly persons taking this medication who may become depressed or alter their food intake in response to decreased taste sensation.

Assessment of upper respiratory tract and ocular irritative effects of volatile chemicals in humans.

Accurate assessment of upper respiratory tract and ocular irritation is critical for identifying and remedying problems related to overexposure to volatile chemicals, as well as for establishing parameters of irritation useful for regulatory purposes. This article (a) describes the basic anatomy and physiology of the human upper respiratory tract and ocular mucosae, (b) discusses how airborne chemicals induce irritative sensations, and (c) reviews practical means employed for assessing such phenomena, including psychophysical (e.g., threshold and suprathreshold perceptual measures), physiological (e.g., cardiovascular responses), electrophysiological (e.g., event-related potentials), and imaging (e.g., magnetic resonance imaging) techniques. Although traditionally animal models have been used as the first step in assessing such irritation, they are not addressed here since (a) there are numerous reviews available on this topic and (b) many rodents and rabbits are obligate nose breathers whose nasal passages differ considerably from those of humans, potentially limiting generalization of animal-based data to humans. A major goal of this compendium is to inform the reader of procedures for assessing irritation in humans and to provide information of value in the continued interpretation and development of empirical databases upon which future reasoned regulatory health decisions can be made.