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IMPORTANCE: Olfactory dysfunction (OD) is increasingly recognized as a robust marker of frailty and mortality. Despite broad recognition of frailty as a critical component of head and neck cancer (HNC) care, there is no standardized frailty assessment. OBJECTIVE: To assess the prevalence of OD and its association with frailty and postoperative outcomes in HNC. DESIGN, SETTING, AND PARTICIPANTS: In this prospective cohort study with enrollment between February 17, 2021, to September 29, 2021, at a tertiary academic medical center, 85 eligible adult patients with primary, treatment-naive HNC of mucosal or cutaneous origin were included. Patients with a history of COVID-19, neurocognitive, or primary smell/taste disorders were excluded. EXPOSURES: Prospective olfactory assessments (self-reported, visual analog scale [VAS] and psychophysical, University of Pennsylvania Smell Identification Test [UPSIT]) with concurrent frailty assessment (Risk Analysis Index [RAI]) were used. Olfactory-specific quality of life (QOL) was examined with brief Questionnaire of Olfactory Disorders–Negative Statements (QOD-NS). MAIN OUTCOME(S) AND MEASURE(S): The primary outcome was the prevalence of OD as assessed by VAS (0-10, no to normal smell) and UPSIT (0-40, higher scores reflect better olfaction) and its association with frailty (RAI, 0-81, higher scores indicate greater frailty). For surgical patients, secondary outcomes were associations between OD and postoperative length of stay (LOS), 30-day postoperative outcomes, and QOD-NS (0-21, higher scores indicate worse QOL). RESULTS: Among 51 patients with HNC (mean [SD] age, 63 [10] years; 39 [77%] male participants; 41 [80%] White participants), 24 (47%) were frail, and 4 (8%) were very frail. Despite median (IQR) self-reported olfaction by VAS of 9 (8-10), 30 (59%) patients demonstrated measured OD with psychophysical testing. No meaningful association was found between self-reported and psychophysical testing (Hodges-Lehmann, <0.001; 95% CI, −2 to 1); a total of 46 (90%) patients did not report decreased olfaction-specific QOL. Median UPSIT scores were lower in frail patients (Hodges-Lehmann, 6; 95% CI, 2-12). Multivariate modeling demonstrated severe microsmia/anosmia was associated with 1.75 (95% CI, 1.09-2.80) times odds of being frail/very frail and approximately 3 days increased LOS (β, 2.96; 95% CI, 0.29-5.62). CONCLUSIONS AND RELEVANCE: Although patients with HNC are unaware of olfactory changes, OD is common and may serve as a bellwether of frailty. In this prospective cohort study, a dose-dependent association was demonstrated between increasing degrees of OD and frailty, and the potential utility of olfaction was highlighted as a touchstone in the assessment of HNC frailty.

Millions of people will now suffer from long-term smell loss as a result of infection with the SARS-CoV-2 virus. Smell is an integral component of the flavor of foods, which is one of the primary drivers of ingestive behavior. When individuals lose their sense of smell, they find food to be less flavorful and less enjoyable, which negatively impacts their quality of life. To compensate, many individuals alter their diet by focusing on tastes, chemesthesis (e.g., chili pepper heat, menthol cooling), and the texture of foods to make it more palatable. Some diet alterations, such as increasing salt use, can result in a lower diet quality, and an increased risk for chronic disease. Sensory nutrition is an area of research that focuses on how the chemical senses (e.g. taste, smell, chemesthesis) and oral somatosensation) affect dietary choices and health. Sensory nutrition strategies designed for individuals with smell loss may help improve the flavor and liking of foods while improving diet quality, and are a necessary area of future research to help improve health and quality of life in the growing population with smell loss.

The fear of producing malodours that can be detected by others is a daily cause of anxiety for millions of people with incontinence. For many, the risk—whether real or imagined—that leaked waste products will be detectable by odour is sufficiently concerning to result in limitations on many types of activities. However, worry about personal odours can sensitise our olfactory system and cause us to be more aware of odours that may otherwise not be perceptible. In addition, heightened olfactory attention can often lead to odour misattributions, such as when we erroneously identify our body as the source of an odour that may simply be present in the environment. Odours produced by our bodies (endogenous odours) do enjoy a greater access to emotional brain centers and are processed faster than general odours. Here we provide examples from both everyday life and laboratory studies to explain how and why the olfactory system is unique among our sensory systems and how this knowledge can provide insights to our concerns about smell and incontinence and inform the development of products and solutions for incontinence.

ABSTRACTThis study developed and tested a protocol for monitoring odors near a Concentrated Animal Feeding Operation (CAFO). The Nasal Ranger, a portable field olfactometry instrument, was used by a panel of trained individuals to conduct the monitoring near a swine CAFO. Monitors were selected based on olfactory sensitivity, scheduling availability, and lack of association with the CAFO or residential neighbors of the CAFO. Monitors were trained to use the Nasal Ranger, collect and record weather data, and characterize any odors detected. Data were collected over a 3-year period (2007-2009) for approximately 9 months each year. The data recorded included odor intensity, a description of the odor, date and time of the reading, and weather conditions.Of more than 50,000 readings, forty-one (0.1%) odor readings had a dilution to threshold ratio (D/T) of ≥ 7:1 and were attributed to hog manure. The frequency of odor readings attributed to hog manure with D/T ≥7:1 was found to negatively correlate with log wind speed and positively correlate with wind from the direction of the farm. Other meteorological variables (temperature, precipitation, cloud cover) and time of day did not influence the frequency.IMPLICATIONSThe use of a portable field olfactometry instrument can provide an assessment of the intensity, frequency and duration of odor in real time. Along with descriptors of the odors being detected, such data can provide a basis for the evaluation of odor complaints.

There is mounting evidence that the presence of airborne chemicals that produce odor and irritation can be a significant impediment to a productive and healthy workforce, even among individuals without chemical sensitivity.

Characterize the expression and glucuronidation activities of the human uridine 5′-diphospho (UDP)-glucuronosyltransferase (UGT) 2A2.

Background Mechanical obstruction of odorant flow to the olfactory neuroepithelium may be a primary cause of olfactory loss in nasal-sinus disease patients. Surgical removal of nasal obstruction may facilitate the recovery of olfactory ability. Unfortunately, quantifying the functional impact of nasal obstruction and subsequent surgical outcomes using acoustic rhinometry, rhinomanometry, or CT scans is inadequate.Methods Using computational fluid dynamics (CFD) techniques, we can convert patient CT scans into anatomically accurate 3D numerical nasal models that can be used to predict nasal airflow and odorant delivery rates. These models also can be rapidly modified to reflect anatomic changes, e.g., surgical removal of polyps.Results CFD modeling of one patient's nose pre- and postsurgery showed significant improvement in postsurgical ortho- and retronasal airflow and odorant delivery rate to olfactory neuroepithelium (<1000 times), which correlated well with olfactory recovery.Conclusion This study has introduced a novel technique (CFD) to calculate nasal airflow dynamics and its effects on olfaction, nasal obstruction, and sinus disease. In the future, such techniques may provide a quantitative evaluation of surgical outcome and an important preoperative guide to optimize nasal airflow and odorant delivery.

The increased incidence of Type I and Type II diabetes among adults and adolescents is a growing public health concern worldwide. The primary objective of diabetes mellitus management involves keeping glycemia levels within the euglycemic range to prevent a variety of serious health complications. Unfortunately, daily self-monitoring is both a requirement and a problem for many patients with diabetes, particularly children and adolescents. Studies have shown that as many as 43% of adolescents and 30% of children (<14 years old) regularly forget to use glycemic tests and are significantly poorer at recognizing and reporting symptoms and signs of hypoglycemia/hyperglycemia. For this reason, methods for noninvasive, continuous monitoring that can signal glycemic status to a parent, teacher, or other caregiver would improve the care and management of symptoms of diabetes among these individuals. The goal of this review is to describe and evaluate electronic olfaction technology ("electronic nose") for monitoring the presence and levels of volatile chemicals from human body and breath that can be used to evaluate status of diabetes. The review is organized in four sections. The first section reviews the chemistry of the volatile signals that are produced by the body that are indicative of metabolic status. The second section provides an overview of novel sensor technology, e.g., "electronic olfaction," that mimics the biological olfactory system and can be used to monitor and identify complex plumes of volatiles that are signatures of metabolic states. The third section reviews studies that have employed electronic "nose" technology for diagnosis and monitoring of diabetes via urine and breath, and the final section discusses needed future directions for the development of olfactory-based metabolic monitoring, particularly among noncompliant populations.

This study was undertaken in conjunction with an evaluation of the olfactory function of 52 persons exposed to styrene vapors to provide quantitative styrene exposure histories of each subject for use in the interpretation of the results of olfactory function testing. Current and historic exposures were investigated. Historic exposures were reconstructed from employment records and measurements of styrene exposure made in the subject facilities over the last 15 years. Current exposures were estimated for every exposed subject though personal air sampling and through pre- and post-shift measurements of urinary metabolites of styrene. The study population had been employed in the reinforced-plastics industry for an average of 12.2 ± 7.4 years. Their mean 8-hr time weighted average (TWA) respirator-corrected annual average styrene exposure was 12.6 ± 10.4 ppm; mean cumulative exposure was 156 ± 80 ppm-years. The current respirator-corrected 8-hr TWA average exposure was 15.1 ± 12.0 ppm. The mean post-shift urinary mandelic and phenylglyoxylic acid (PGA) concentrations were 580 ± 1,300 and 170 ± 360 mg/g creatinine, respectively and were highly correlated with air concentrations of styrene. This quantitative exposure evaluation has provided a well-characterized population, with documented exposure histories stable over time and in the range suitable for the purposes of the associated study of olfactory function. Am. J. Ind. Med. 44:12–23, 2003. © 2003 Wiley-Liss, Inc.

Impairment of olfactory function in humans has been associated with occupational exposure to volatile chemicals. To investigate whether exposure to styrene was associated with olfactory impairment, olfactory function was examined in workers with a minimum of 4 years exposure to styrene in the reinforced-plastics industry (current mean exposure: 26 ppm, range: 10–60 ppm; historic mean dose: 156 ppm-years, range: 13.8–328 ppm-years) and in a group of age- and gender-matched, unexposed controls. Olfactory function was assessed using a standardized battery that included tests of threshold sensitivity for phenylethyl alcohol (PEA), odor identification ability, and retronasal odor perception. Odor detection thresholds for styrene were also obtained as a measure of specific adaptation to the work environment. No differences were observed between exposed workers and controls on tests of olfactory function. Elevation of styrene odor detection thresholds among exposed workers indicated exposure-induced adaptation. The present study found no evidence among a cross-section of reinforced-plastics industry workers that current or historical exposure to styrene was associated with impairment of olfactory function. Taken together with anatomical differences between rodent and human airways and the lack of evidence for styrene metabolism in human nasal tissue, the results strongly suggest that at these concentrations, styrene is not an olfactory toxicant in humans. Am. J. Ind. Med. 44:1–11, 2003. © 2003 Wiley-Liss, Inc.

Although animal models of sensory irritation have led to the development of useful assays for evaluating the potency of chemical irritants, the importance of conducting human exposure studies to model and understand the human response to sensory irritants cannot be minimized. In recent years a series of tests have been developed for humans that can be safely conducted and that can provide excellent data on which to base occupational exposure limits. This article delineates the major issues involved in the evaluations of sensory irritation in humans. Among these issues are the differences between odor and irritation, irritation and slight toxicity, adaptation and habituation, as well as personal expectation about discomfort and the reported irritation. The article also describes psychophysiological and electrophysiological methods for assessing sensory irritation. Some of the possible confounders that can influence the results of human tests involving sensory irritants are addressed.

This article describes the fundamentals of olfaction and irritation perception and the dominant psychophysical methods for the assessment of olfaction and respiratory tract irritation. It also discusses factors that determine the olfactory and irritant response (ranging from the physicochemical properties of the stimulus to the physiological and cognitive characteristics of the individual). Because the vast majority of volatile chemicals stimulate the olfactory system at concentrations well below that at which they will elicit trigeminal activation, the evaluation of irritation from volatiles is often confounded by the perception of odor. Several methods have been used for studying the perception of irritation, without the influence of olfaction. The perception and reports of acute adverse effects of odor, annoyance, and irritation from volatile chemicals have multiple determinants. Understanding the perceptual impact of chemicals under environmentally realistic conditions requires attending to both the sensory and the psychological impact of those exposures. The review, which is largely based on presentations given by Dr. Richard Doty and Dr. William Cain, concludes by discussing the importance of the psychophysical approach, which considers physiochemical, subject, experimental, and cognitive/psychological factors, for research in the chemical senses.

Odor and irritation sensitivity for methyl isobutyl ketone (MIBK) was evaluated by obtaining olfactory detection thresholds and irritation (lateralization) thresholds, as well as perceived odor intensity and irritation ratings for three predetermined concentrations of MIBK, acetone, and phenylethyl alcohol. Subsequently, perceived annoyance ratings for the three concentrations were measured for 25 of the 40 volunteers. The mean odor detection threshold for MIBK was 10 ppm, and mean lateralization threshold was 8874 ppm. Calculating the fifth percentile for lateralization thresholds revealed that 95% of the sample population did not experience sensory irritation at or below 1802 ppm. Thus, while odor thresholds were well below the current recommended exposure limits (50 ppm, threshold limit value; 75 ppm short-term exposure limit, American Conference of Governmental Industrial Hygienists), irritation thresholds were significantly higher. Odor and irritation intensity ratings for the chemicals increased with increasing concentrations and were higher for MIBK than for acetone. However, when the affective component of the irritation response (annoyance) was rated separately from the sensory component (perceived irritation), no significant differences were found between the irritancy of MIBK and acetone, suggesting that negative hedonic evaluations of MIBK (perhaps based on odor unfamiliarity) contributed to ratings of perceived irritation. These results validate coupling affective and sensory ratings to more effectively examine the human response to volatile stimuli. Results indicate that intranasal sensory irritation from MIBK will not be experienced at or near current exposure levels. Notably, the best predictors of perceived irritation to high concentrations of MIBK were those measures related to its odor, not to the threshold for sensory irritation, suggesting that negative responses to MIBK involve reactions to olfactory properties.

The subjectivity of irritancy judgments can bias attempts to establish exposure guidelines that protect individuals from the sensory irritation produced by volatile chemicals. At low to moderate chemical concentrations, naive and occupationally exposed individuals often show considerable variation in the reported levels of perceived irritation. Such variation could result from differences in exposure history, differences in the perceived odor of a chemical, or differences in generalized response tendencies to report irritation, or response bias. Thus, experimental evaluation of sensory irritancy must dissociate sensory irritation from response bias. To this end, judgments of perceived irritation from 800 ppm acetone were obtained from acetone-exposed workers and age- and gender-matched naive controls. To assess the role of response bias during exposure to odorants, subjects were also exposed to phenylethyl alcohol (PEA), an odorant that does not produce sensory irritation. Following exposure, subjects completed a subjective symptom survey that included symptoms that have been associated with long-term solvent exposures and symptoms that have not. Acetone-exposed workers and naive controls reported large differences in the perceived intensity of odor and irritation from acetone, yet no differences in the perception of PEA. However, for both groups, the most significant factors mediating reported irritancy and health symptoms from acetone were the perceived intensity of its odor and an individual's bias to report irritation from PEA. The perception of odor intensity and degree of response bias will differ between and within groups of exposed and naive individuals; hence, an assessment of the influence of these factors in experimental and workplace studies of chemical irritancy is warranted. Am. J. Ind. Med. 31:558–569, 1997. © 1997 Wiley-Liss, Inc.

The subjectivity of irritancy judgments can bias attempts to establish exposure guidelines that protect individuals from the sensory irritation produced by volatile chemicals. At low to moderate chemical concentrations, naive and occupationally exposed individuals often show considerable variation in the reported levels of perceived irritation. Such variation could result from differences in exposure history, differences in the perceived odor of a chemical, or differences in generalized response tendencies to report irritation, or response bias. Thus, experimental evaluation of sensory irritancy must dissociate sensory irritation from response bias. To this end, judgments of perceived irritation from 800 ppm acetone were obtained from acetone‐exposed workers and age‐ and gender‐matched naive controls. To assess the role of response bias during exposure to odorants, subjects were also exposed to phenylethyl alcohol (PEA), an odorant that does not produce sensory irritation. Following exposure, subjects completed a subjective symptom survey that included symptoms that have been associated with long‐term solvent exposures and symptoms that have not.