Smell Ability Research Articles

A Retrospective Cohort Study of Glossopharyngeal Nerve Taste in Children with Recurrent Acute Tonsillitis.

Objective To compare glossopharyngeal taste between healthy children and those with recurrent acute tonsillitis. Study Design Retrospective cohort study. Setting Pediatric clinics in a tertiary care medical center and satellite location. Subjects and Methods Smell and taste testing was administered to 80 well children and 64 children with recurrent acute tonsillitis (age range, 6-17 years). Smell testing was performed with the NIH Toolbox Odor Identification Test, with scores based on national averages for age and sex. Validated Taste Strips were placed on the midline of the tongue at the circumvallate papillae in random tastant order and in increasing concentrations to test sweet, salty, sour, and bitter. Ordinal logistic regression was used for multivariate analysis. Results The healthy and tonsillitis groups were similar, with mean ages of 11.3 and 10.8 years ( P = .34), respectively. The tonsillitis group had fewer boys (n = 18 vs 43, P = .002), higher mean body mass index (BMI) percentile (n = 72.2 vs 59.8, P = .01), and more subjects with public or no insurance (n = 24 vs 13, P = .004). Univariate analysis revealed no statistically significant differences in rate of normal overall taste (67.2% vs 60%, P = .39) and in sweet (79.7% vs 82.5%, P = .67), salty (85.9% vs 82.8%, P = .82), sour (64.1% vs 70%, P = .48), and bitter (90.6% vs 86.3%, P = .45). In multivariate analysis, smell ability, sex, BMI percentile, parent BMI, and insurance type did not affect overall taste or sweet, salty, sour, or bitter alone. Conclusion Despite controlling for potential intrinsic (sex, smell, BMI) and extrinsic (parent BMI, insurance type) confounders, there was no statistically significant difference in taste among children with recurrent acute tonsillitis as compared with healthy children.

Optimal economic load dispatch based on wind energy and risk constrains through an intelligent algorithm

This article focus on optimal economic load dispatch based on an intelligent method of shark smell optimization (SSO). In this problem, the risk constrains has been considered which has root in uncertainity and unpredictable behavior of wind power. Regarding to increasing of this clean energy in power systems and un‐dispatchable behavior of wind power, its conditional value at risk index considered in this article which consists of loss from load and "spilling" wind energy connected with unpredictable imbalances among generation and load. This problem has been considered as an optimization problem based on SSO that evaluate the balance between cost and risk. This algorithm is based on distinct shark smell abilities for localizing the prey. In sharks' movement, the concentration of the odor is an important factor to guide the shark to the prey. In other words, the shark moves in the way with higher odor concentration. This characteristic is used in the proposed SSO algorithm to find the solution of an optimization problem. Effectiveness of the proposed method has been applied over 30‐bus power system in comparison with other techniques. © 2016 Wiley Periodicals, Inc. Complexity 21: 494–506, 2016

Dogs'olfactory diagnostics applied on human species: state of the art and clinical perspectives.

Dogs'smell ability is about 10000-100000 more developed than humans' one. Dogs smell is usually exploited in forensic medicine, to find missing people and specific substances showing peculiar sensorial features. In clinic, there is the possibility to take advantage of dogs smell, which are conveniently trained, for the screening of cancers and other diseases. The common feature is the presence of molecules in organic samples that may be considered as biomarkers of a specific pathology. In cancer, scientific evidences exist about screening of melanoma, lung, breast, rectum, ovarian, prostate and bladder cancer. Instead, other pathologies manifest the presence of organic volatile compounds in biologic materials, such as spit, faeces and urine that may be studied by dogs smell in order to identify the presence of a specific disease. This review shows the state of the art of actual dogs' olfactory ability based on scientific principles and the advantages and the disadvantages of this method. The authors also reveal some potential pathologies joined by the presence of organic volatile compounds, which may be investigated by dogs smell.

Olfactory impairment in patients with the fibromyalgia syndrome and systemic sclerosis.

Patients with autoimmune diseases often present with olfactory impairment. The aim of the study was to assess the olfactory functions of female patients with fibromyalgia (FM) compared with patients with systemic sclerosis (SSc) and with healthy female controls. Olfactory functions were assessed in 24 patients with FM, 20 patients with SSc and 21 age-matched healthy controls. The sense of smell was evaluated using the Sniffin' Sticks test including the three stages of smell: threshold, discrimination, and identification (TDI) of the different odors. The severity of fibromyalgia was assessed using the fibromyalgia impact questionnaire (FIQ). The short form 36 (SF-36) questionnaire was also completed in order to seek a relationship between the patients perception of quality of life and the different aspects of the smell sense. Depression was evaluated in both FM and SSc patients utilizing the Beck depression inventory-II (BDI-II) questionnaire. Patients with FM had significantly lower TDI smell scores compared with both SSc patients and healthy controls (p < 0.005, One-Way ANOVA). Hyposmia (defined as TDI scores below 30) were observed in 14 of 24 (42 %) patients with FM compared to 3 of 20 (15 %) patients with SSc and 1 of the healthy controls (4.3 %) (p < 0.02). FM patients had significantly lower thresholds of smell compared to both healthy controls and patients with SSc (p < 0.001), whereas for patients with SSc only the ability to discriminate between odors was impaired (p < 0.006). We could not detect any statistical correlation between smell abilities and clinical manifestation of SSc or the FIQ and SF-36 scores among FM patients. However the correlation between depression, defined by the BDI-II score, and the sense of smell differed between patients with FM and patients with SSc. As only among SSc patients a lower sense of smell correlated with a higher BDI-II score (p = 0.02). Our findings suggest that there is a decrease in the sense of smell both in FM and SSc patients compared with healthy controls. However these impairments differ between patients group and might represent different mechanisms that affect the sense of smell.

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

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. 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. 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. 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. Our findings should inform self-rated measures that screen for severe olfactory dysfunction in clinical/community settings where testing is not routine.

Radiofrequency Inferior Turbinate Reduction Improves Smell Ability of Patients with Chronic Rhinitis and Inferior Turbinate Hypertrophy

Radiofrequency inferior turbinate reduction (RFITR) of inferior turbinate hypertrophy (ITH) is an effective way to treat patients with intractable nasal mucosal obstruction. The objective of this study was to assess smell ability, nasal symptoms, inferior turbinate grading (ITG), peak nasal inspiratory flow (PNIF) of patients with chronic rhinitis (CR), and ITH before and after RFITR. Patients with CR and ITH, aged 18–60 years, who underwent RFITR, were prospectively recruited. Smell ability (measured by smell detection threshold [SDT]), visual analog scale (VAS) of nasal symptoms, ITG, and PNIF before and 6–10 weeks after RFITR were compared. Forty-eight subjects were included. All nasal symptoms were significantly decreased after RFITR. After surgery, SDT (tested by phenyl ethyl alcohol) was worsened in 7 patients (14.6%), improved in 8 patients (16.7%), and did not change in 33 patients (68.7%). SDT after RFITR of six patients in the worsened SDT group were still within normal range (> −6.5). There was only one patient whose SDT changed from normosmia to mild hyposmia (−7.25 to −5.38). In the improved SDT group, two of eight patients had obviously better SDT after RFITR, which changed from moderate hyposmia to normosmia (−3.65 to −10; −3.73 to −10), whereas six of eight patients had little better SDT after RFITR. RFITR also significantly reduced ITG and improved PNIF. In conclusion, the treatment of patients with CR and ITH with RFITR significantly improved PNIF, ITG, and nasal symptoms assessed by VAS, although SDT after RFITR could be the same or improved or worsened.

Do the blinds smell better?

If people lose a sense organ, there is thought to be an increase in the remaining sensory functions. Previous studies showed ambiguous results on this topic. In a prospective matched pair case-control study on 46 blind and 46 normal-sighted subjects, the olfactory performance was examined using the Sniffin' Sticks Test [threshold-discrimination-identification (TDI) test], determining the olfactory threshold, the identification and the discrimination performance. There was no significant difference between the groups. Neither the overall olfactory performance (TDI score) nor any of its subtests did correlate with the vision or with the duration of blindness. The study could not detect any superior smell abilities of blind subjects as compared to sighted subjects.

Smell and Taste in Inflammatory Bowel Disease

ObjectiveTo investigate the olfactory/gustatory functions of patients with inflammatory bowel disease (IBD) by smell/taste tests, and to determine if disease activity or medication might influence the olfactory/gustatory functions of patients.Patients and MethodsIn total, 59 IBD patients (37 Crohn's disease (CD) and 22 ulcerative colitis (UC) patients) were studied using “Sniffin' sticks” and “taste strips” for olfactory and gustatory tests, respectively, and compared to healthy controls and published normative data.ResultsAmong IBD (CD and UC) patients, the values for odor threshold, but not for odor identification or discrimination, were significantly lower than that of the normative data. Further, these patients showed lower values than the normative taste values and the control group for all tastes, except sour; 57.6% of the IBD patients were hyposmic, while 30.5% were hypogeusic. Subjective self-assessments showed that the patients were not aware of their reduced olfactory/gustatory functions. There were no relevant differences in taste and smell abilities between the CD and UC patients. Disease activity and treatment did not influence the olfactory/gustatory functions.ConclusionIBD (CD and UC) patients exhibited significant reductions in the olfactory and gustatory functions. Therefore, patients should be tested by smell/taste tests, in order to be adequately informed of their olfactory/gustatory functions and provided an understanding of how to overcome their limitations, and thus improve their quality of life.

Association between underweight and taste sensitivity in middle‐ to old‐aged nursing home residents in Sri Lanka: a cross‐sectional study

Low taste sensitivity may be one factor related to undernutrition, which is a major problem in developing countries. The purpose of this cross-sectional study was to examine the association between underweight, one indicator of undernutrition, and taste sensitivity in middle- to old-aged Sri Lankan nursing home residents. Participants were 946 residents with BMI of <25·0 from 25 nursing homes. Data were obtained on height, weight, taste sensitivity, subjective taste ability, sex, age, ethnicity, number of years in nursing homes, activities of daily living (ADL), frequency of exercise, bowel movements, smoking status, drinking status, current number of chronic diseases, number and kinds of medications used, self-reporting questionnaire 20 (SRQ20), subjective smell ability, number of teeth present, Eichner index and flow rate of saliva. Low sensitivity to bitter taste, being male, old age, low ADL, smoking experience, drinking experience, fewer medications used and no use of medication for hypertension and diabetes were each associated with underweight (P<0·05). In a multilevel Poisson regression model adjusted for sex, age, ADL, smoking status, drinking status, number of medications used, use of medication for hypertension and diabetes and flow rate of saliva, subjects with low sensitivity (>0·003% quinine hydrochloride dihydrate) to bitter taste had a significant 1·70 times higher prevalence ratio (95% confident interval 1·04-2·80) for underweight compared with those with high sensitivity (0·0001% quinine hydrochloride dihydrate). These results suggest that low taste sensitivity to bitter taste may be one factor related to underweight.

Riechvermögen nach Medialisierung der mittleren Nasenmuschel bei der endonasalen Siebbeinoperation

Endoscopic sinus surgery usually requires a move of the middle nasal turbinate into the midline to achieve a better sight into the ethmoidal sinuses. In this procedure damages of the turbinate are possible, which later can lead to a scarred fixation of the turbinate. Fixing of the turbinate to the septum can avoid this effect, but could reduce smell ability by blocking of the upper nasal duct. In a prospective study with 83 patients with chronic sinusitis (55% CRS with polyps, 45% CRS without polyps) at the end of the operation the middle nasal turbinates were fixed at the nasal septum with a 4 × 0 stitch. Before the operation and 6 weeks, 3 and 5 months after operation the smell was tested using the "sniffin'sticks" threshold test. After operation the ethmoidal area remained open without developing of relevant synechiae or scars. The smell ability decreased after surgery due to the obstruction of the upper nasal duct, but improved again later. After 5 months the average threshold of smell was better than before operation. Testing of the threshold values with the t-test showed a significant difference (p<0.001) between the pre- and postoperative status. The method of medialization and temporary septal fixation of the middle nasal turbinate allows a sufficient ventilation and drainage of the paranasal sinuses after sinus surgery. Due to only temporary fixation of the turbinate at the septum, a permanent obstruction of the upper nasal duct and the olfactory area is prevented. Thus the threshold of smell is not reduced.

Effects of pyridine inhalation exposure on olfactory epithelium in mice

Olfactory neurons in the nasal mucosa have the capacity to regenerate continuously along the lifespan by neurogenesis processes starting with progenitor cells close to the basal lamina. The cellular turnover into olfactory neuroepithelium may be modified by environmental stimuli insofar as nasal mucosa is directly in contact with airborne chemicals. However, few studies have been focused on selective changes, especially those concerning mature olfactory neurons and basal cells during specific inhalation exposure. Among chemicals, solvents are known to induce changes in smell abilities and concomitant histological and cellular modifications related to the type of molecule, concentration and time of exposure. This study was designed to characterize smell sensitivity (using behavioral tests) and immunohistochemical effects on olfactory neuroepithelium induced by pyridine exposure in mice. Olfactory marker protein (OMP) and proliferating cell nuclear antigen (PCNA) were used to characterize respectively mature olfactory neurons and basal cells. Results showed that inhalation exposure to pyridine had no impact on smell sensitivity whatever the concentration used and the time of exposure. These findings were in agreement with immunohistochemical measurements showing the same cellular kinetic whatever the condition of exposition to pyridine. Indeed, OMP-positive cells increased and PCNA-positive cells decreased as early as the beginning of exposure and cell amounts remained stable at this level until the end of exposure. These findings suggest that pyridine could have the property to rapidly activate a cellular turnover from basal cell progenitors. Rather than toxic effects, the present findings suggest that the metabolites of pyridine might have cell cycle activation properties.

Evaluation of the efficacy of the ‘nasal airflow‐inducing manoeuvre’ for smell rehabilitation in laryngectomees by means of the Sniffin′ Sticks test

To determine the efficacy of the nasal airflow-inducing manoeuvre (NAIM) as a method for olfactory rehabilitation in laryngectomees by the means of the Sniffin' Sticks test. Prospective open interventional trial. Tertiary academic hospital. Thirty-seven patients after laryngectomy have been screened and 25 patients have been included into the study. The participant's sense of smell was tested with the Sniffin' Sticks test before and after learning the nasal airflow inducing manoeuvre. The individual level of threshold, discrimination and identification (TDI) was determined and the individual threshold, discrimination and identification score was used to classify the patients as being anosmic, hyposmic or normosmic. The primary endpoint was the change of the threshold, discrimination and identification score before and after learning the nasal airflow inducing manoeuvre. The secondary endpoint was a change in the diagnostic group (normosmic, hyposmic and anosmic) after learning of the nasal airflow inducing manoeuvre. There was a statistically significant increase in the total threshold, discrimination and identification score (P < 0.001) and the three sub-scores (P ≤ 0.02) before and after the learning of the nasal airflow inducing manoeuvre. Patients gained seven points on average in the threshold, discrimination and identification score. Twenty of 25 patients showed an increase of five or more point in the threshold, discrimination and identification score. In the classification of the smell ability, 15 of 25 patients showed a change to a higher class (hyposmic to normosmic or from anosmic to hyposmic or normosmic). The nasal airflow inducing manoeuvre is a method for the successful rehabilitation of the sense of smell in laryngectomees. The evaluation with the Sniffin' Sticks tests showed a clinically relevant increase of olfaction in 80% of patients. The teaching of the nasal airflow inducing manoeuvre should be included in post-laryngectomy rehabilitation programmes.

Modulation of Spontaneous and Odorant-Evoked Activity of Rat Olfactory Sensory Neurons by Two Anorectic Peptides, Insulin and Leptin

In mammals, the sense of smell is modulated by the status of satiety, which is mainly signaled by blood-circulating peptide hormones. However, the underlying mechanisms linking olfaction and food intake are poorly understood. Here we investigated the effects of two anorectic peptides, insulin and leptin, on the functional properties of olfactory sensory neurons (OSNs). Using patch-clamp recordings, we analyzed the spontaneous activity of rat OSNs in an in vitro intact epithelium preparation. Bath perfusion of insulin and leptin significantly increased the spontaneous firing frequency in 91.7% (n = 24) and 75.0% (n = 24) of the cells, respectively. When the activity was electrically evoked, both peptides shortened the latency to the first action potential by approximately 25% and decreased the interspike intervals by approximately 13%. While insulin and leptin enhanced the electrical excitability of OSNs in the absence of odorants, they surprisingly reduced the odorant-induced activity in the olfactory epithelium. Insulin and leptin decreased the peak amplitudes of isoamyl acetate-induced electroolfactogram (EOG) signals to 46 and 38%, respectively. When measured in individual cells by patch-clamp recordings, insulin and leptin decreased odorant-induced transduction currents and receptor potentials. Therefore by increasing the spontaneous activity but reducing the odorant-induced activity of OSNs, an elevated insulin and leptin level (such as after a meal) may result in a decreased global signal-to-noise ratio in the olfactory epithelium, which matches the smell ability to the satiety status.

Taste in dementing diseases and Parkinsonism

Like with many sensory abilities a reduction of taste and smell occurs during aging. Since there are hints to an additional reduction in dementing diseases, we assessed 52 patients, 26 women and 26 men, who were presented to a memory clinic, using the Sniffin' Sticks, Whole Mouth and Taste Strip Tests. While smoking, alcohol consumption, intake of drugs and sex exerted only minor impact, age and the severity of cognitive impairment were of major importance. There was a moderate but significant correlation between the severity of dementia, taste and smell, even if the age effect was partialled out. Notably, patients with Parkinson syndrome showed worse taste and smell abilities than those without. Here the differences were indeed marked enough to play a possible role in making the diagnosis. This exploratory study confirms a mild reduction of gustatory function in dementing diseases over and beyond that of normal aging which–in addition to a reduction of smell–seems to be especially marked in Parkinson syndromes.

Episodic odor memory: Influences of handedness, sex, and side of nose

It is not known whether, or to what degree, odor memory is influenced by lateralized brain processes. In this study, we administered a 12-item match-to-sample odor memory test separately to the left and right sides of the nose of 30 left- and 30 right-handed subjects of equivalent age, sex distribution, and overall general smell ability. For each test item, one of three delay intervals (10-, 30-, and 60-s) was interspersed between smelling the target stimulus and smelling the first of four response alternatives. Women, but not men, performed significantly better on the left than on the right side of the nose, conceivably reflecting greater reliance upon left-hemisphere semantic processes. Subjects who received the first test on the right side of the nose outperformed those who received the first test on the left side of the nose. As in previous work, an age-related decrement in odor memory test scores was present. These data contribute to the debate on the role of lateralized brain processes in episodic odor memory, and suggest that performance on a standardized match-to-sample odor memory task is influenced by a number of interacting factors.

Are there olfactory evoked alterations of breathing patterns?

It is controversially discussed whether strictly olfactory stimuli are able to evoke changes of breathing patterns. A number work groups argue that the more or less noticeable irritative component of odors are responsible for a respiratory response. Other work groups regard changes of breathing pattern as an indicator for an intact smell ability during "pure" olfactory stimulation. 12 normosmic young volunteers were repeatedly challenged with hydrogensulfide (H (2)S) for two seconds on inspiration in concentrations just above the threshold using a flow olfactometer. Clean air stimuli were presented randomly as control blanks. The breathing patterns were registered with a differential pressure transducer occluding one nostril via a tube. The signals were digitized and recorded on a PC. Nine parameters were calculated for each breath using a custom made LabView (R) software. The breath during stimulation was compared to the average of five breathing cycles prior to stimulation. An increase or reduction of each parameter was equally regarded by means of their absolute value. The sum was termed respiration index (RI). The mean RI (all trials of each test person) stimulated with H (2)S varied from 201 to 570; stimulated with clean air from 85 to 188. The difference was significant (p < 0,001). A significant group-difference for each single trial was seen as well. There was no significant increase or decrease of RI during 15 successive stimulations with H (2)S. Detectable short H (2)S-stimuli are able to evoke alterations of breathing patterns which can be identified by computer. Respiration-olfactometry is suitable to objectify odor perception.

Sniffing out a link with Alzheimer's

A growing body of evidence suggests that Alzheimer's disease is associated with a diminished sense of smell. Initially deficits are apparent in the identification and recognition of smells; later thresholds for smell detection are affected and brain areas associated with olfactory information processing and memory show decreased metabolic activity. The olfactory dysfunction might predate onset of the cognitive decline associated with Alzheimer's disease. As early diagnosis of the condition is difficult, impaired performance on olfactory tasks with memory demands could be useful in predicting who will develop the disease.In a recent study, Schiffman et al. assessed neuropsychological and chemosensory performance in individuals at high genetic risk for developing late-onset Alzheimer's disease [1xTaste, smell and neuropsychological performance of individuals at familial risk for Alzheimer's disease. Schiffman, S.S. et al. Neurobiol. Aging. 2002; 23: 397–404Abstract | Full Text | Full Text PDF | PubMed | Scopus (62)See all References][1]. Participants (mean age 60 years) were not cognitively impaired and were matched by controls for age, gender, race and education. Smell and taste functions were assessed using a variety of stimuli at concentrations determined at pretesting to have the same intensity rating. Tests of detection threshold, memory, discrimination and identification of standardized odors and tastes were carried out. Subjects also completed a battery of neuropsychological measures. All measures were repeated approximately 18 months after the initial assessment and the experimental group was evaluated for cognitive change yearly for up to 8 years. There were apparent differences on the smell detection and memory tasks. At baseline, the ‘at-risk’ group performed worse than controls on measures of phenylethyl alcohol smell detection, smell memory and taste memory. The at-risk group also performed poorly on a recall of narrative information task, but were better than controls on a simple attentional task. At follow-up, many subjects showed improvement on the cognitive, but not on the chemosensory, measures. At both assessment times the at-risk subjects had poorer smell memory. The decrement in smell ability was odor-specific (for example, sensitivity to menthol, an odorant with a large trigeminal component, was not related to at-risk status).Of the at-risk participants (n = 33), seven subjects (21%) changed in cognitive status 2–8 years after the baseline session; five subjects developed mild cognitive impairment and two developed Alzheimer's disease. The data therefore suggest a modest effect of smell memory but the conclusions are constrained by the small number of affected individuals. A larger-scale study might reveal whether smell detection could be a useful early diagnostic tool for Alzheimer's.

On Possible Impairment of Smell and Taste Ability in Posttraumatic Hypopituitarism

On Possible Impairment of Smell and Taste Ability in Posttraumatic Hypopituitarism

A study of the relationship between the T&T olfactometer and the University of Pennsylvania Smell Identification Test in a Japanese population.

The University of Pennsylvania Smell Identification Test (UPSIT) and a smell ability questionnaire were administered to 167 Japanese volunteers ranging in age from 20 to 59 years. Of these subjects, 80 also received the T&T olfactometer threshold test. Of the latter subjects, 36 were patients tested before endoscopic nasal surgery for sinusitis and polyposis. The patients exhibited decreased smell function, as measured by the T&T olfactometer, the UPSIT, and a 30-item version of the UPSIT in which the 10 least familiar items were removed (ps < 0.001). Spearman correlations ranging from 0.53 to 0.70 were found between (i) scores on the 30- and 40-item UPSITs and (ii) the T&T detection and recognition threshold values. Significant correlations were found between scores on the smell ability questionnaire and the olfactory test measures (UPSIT30 r = 0.56; UPSIT40 r = 0.58; T&T detection r = 0.56; T&T recognition r = 0.69, p < 0.001), indicating that subjects are relatively accurate in assessing their olfactory ability. This study suggests that the 30 and 40-item UPSITs correlate well with measures derived from the T&T olfactometer, and that all three tests are sensitive to the smell loss of Japanese sinusitis/polyposis patients.

Bilateral detection thresholds in dextrals and sinistrals reflect the more sensitive side of the nose, which is not lateralized.

Several fundamental questions remain enigmatic concerning human olfactory sensitivity, including (i) whether detection threshold differences exist between the two sides of the nose (and, if so, whether such differences are influenced by handedness) and (ii) whether bilateral (i.e. binasal) stimulation leads to lower thresholds than unilateral stimulation (and, if so, whether the degree of facilitation is inversely related to general olfactory ability). In this study, and well-validated single staircase procedure was used to establish bilateral and unilateral detection thresholds for the cranial nerve I stimulant phenyl ethyl alcohol in 130 right- and 33 left-handed subjects. No differences in sensitivity between the left and right sides of the nose were observed in either group. Bilateral thresholds were lower, on average, than unilateral thresholds when the latter were categorized in terms of left and right nares. However, the bilateral thresholds did not differ significantly from those of the side of the nose with the lower threshold. Overall smell ability, as measured by the University of Pennsylvania Smell Identification Test, did not interact with any of the test measures. These data imply that (i) the left and right sides of the nose do not systematically differ in detection threshold sensitivity for either dextrals or sinistrals and (ii) if central integration of left:right olfactory threshold sensitivity occurs, its effects do not exceed the function of the better side of the nose.