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PubMed1987

Loss of sense of smell in adult, hypothyroid mice.

Adult hypothyroid humans can lose their sense of smell. The present study was designed to investigate whether anosmia follows hypothyroidism in mice. If so, this would provide an animal model in which to study the mechanism for this effect. Adult mice were made hypothyroid with propylthiouracil (PTU) in their drinking water. Their sense of smell was tested before and after treatment by measuring the amount of time they spent sniffing food vs water odours, after a 24-h fast. Thyroid function was assessed histologically or by radioimmunoassay of blood serum for free thyroxine or free triiodothyronine. In Expt. 1 mice treated for 50 days with PTU were hypothyroid and anosmic. Control, euthyroid mice maintained their sense of smell, as did PTU-treated mice which also received daily thyroxine injections. PTU-induced anosmia was reversible: 50 days after removal of treatment previously anosmic mice were euthyroid and had regained their sense of smell (Expt. 3). It was possible that hypothyroidism induced non-specific effects which indirectly affected the olfactory function tests. However, short-term treatment with PTU caused severe hypothyroidism but no anosmia (Expt. 2). Additionally, non-specific effects of hypothyroidism were examined in open-field activity tests after short- and long-term hypothyroidism: euthyroid and hypothyroid animals were similarly active (Expts. 1 and 2). We conclude that chronic hypothyroidism produces anosmia in mice, as it does in humans. This anosmia is prevented by daily injections of thyroxine, and the sense of smell can recover to normal once thyroid function is restored.

Animals↗
PubMedDate not supplied

Taste, smell and neuropsychological performance of individuals at familial risk for Alzheimer's disease.

The purpose of the study was to determine whether there are chemosensory and neuropsychological changes that predate the onset of Alzheimer's disease in individuals at enhanced risk of developing the condition. To study this question, a unique sample of individuals (n = 33) was studied who were genetically at-risk for AD by virtue of documented multigenerational evidence of the disease (so-called multiplex families). The performance of at-risk individuals was evaluated on various smell, taste, and neuropsychological measures at baseline and 18 months later. Their performance was compared to a control group (n = 32) that was matched in age, gender, education, and race. At baseline the at-risk group performed worse than the control group on the chemosensory measures of phenethyl alcohol smell detection, smell memory, and taste memory, and on a memory measure involving recall of narrative information (Logical Memory I from the Wechsler Memory Scale- Revised). Across both sessions, the at-risk group had lower smell memory scores than the control group. At-risk status was not significantly associated with APOE status. The results of this and other studies suggest that individuals who are genetically at risk for developing AD may perform more poorly on memory and smell measures compared to those not at risk. This effect may be separate from one known genetic risk factor of AD, APOE, and supports that multiple genes are likely responsible for the disease and its associated memory and other neurocognitive symptoms.

Aged↗
PubMed2003

Impaired sense of smell in patients with nasal surgery.

The aim of the study was to determine the incidence of olfactory disorders before and following nasal and paranasal sinus surgery. It was a prospective observational study. Over a 6-month period, all patients who had been listed for nasal and paranasal sinus surgery underwent preoperative and postoperative evaluation of their sense of smell. A questionnaire and the 'Smell Diskettes Test' were used to assess olfaction. One hundred and eighty-four patients were studied. Preoperatively, 19 patients (10.3%) had an impaired sense of smell (8.1% before septoplasty, 6.1% before rhinoplasty and 17.1% before endoscopic sinus surgery). Only 16 (84%) of these patients were aware of their impaired sense of smell. Following surgery, four patients (2.5%) who were normal preoperatively developed impaired olfaction on questioning, and this was supported by testing it. In the subgroup that had a septoplasty, no patient developed hyposmia compared to one patient (2.6%) after rhinoplasty and one patient (3%) after endoscopic sinus surgery. No patient developed anosmia. Preoperatively, 10.3% of patients had an altered sense of smell, making it desirable that this is documented in order to avoid postoperative claims that this was caused by surgery. It also helps to audit the results of surgery.

Female↗
PubMed2002

A relationship between smell identification and empathy.

Olfaction is a sense that has close relationships with the limbic system and emotion. Empathy is a vicarious feeling of others' emotional states. The two functions are known to be subserved by common neuroanatomical structures, including orbitofrontal cortex, mediodorsal thalamus, and the amygdala. This study demonstrates a correlation between smell identification and empathy, using the Mehrabian and Epstein Empathy Questionnaire and Alberta Smell Test. Right nostril smell identification correlated with empathy, whereas the left nostril did not. Given the predominantly ipsilateral representation in the olfactory system, this is in accordance with right hemisphere dominance for emotional functions and empathy. Further, the emotional component of empathy (feeling another's emotions) correlated with smell, whereas a cognitive component (comprehending another's emotions) did not. This study is the first to demonstrate a relationship between empathy and smell in normal subjects, suggesting common neural substrates.

Adult↗
PubMed2006

Development of a smell identification test using a novel stick-type odor presentation kit.

The odor identification is strongly influenced by the social and cultural factors; therefore, the odorants used in a smell identification test should be familiar to the test population. In addition, the device used in the test is desired to be simply handled and retain odor quality over time. We developed a novel stick-type odor presentation kit that consists of microcapsules of odorant incorporated into stable cream and the smell identification test using it. Thirteen odorants were selected to be familiar to the test population. In the test, we used two identification methods: one was a modified forced-choice paradigm with "detectable but not recognizable" and "no smell detected" added as choices and the other was a two-step identification paradigm where the participant first selected one of eight odor categories and then chose the specific odor name from the selected category. We verified the performance of the odor stick and the test by stability, using a test-retest paradigm, comparing this test with another smell test, and testing Japanese people from a range of age groups. We conclude that this kit is a useful odor presentation device, and the test using it works effectively as a smell identification test.

Adult↗
PubMed1998

Taste and smell complaints in HIV-infected patients.

OBJECTIVES: To define the scope of taste and smell (chemosensory) complaints amongst HIV-infected persons in the study population; to evaluate the clinical factors associated with chemosensory complaints; and to determine the impact of chemosensory complaints on quality of life. DESIGN: Cross-sectional survey. SETTING: Tertiary care university medical center clinic. PARTICIPANTS: A total of 207 HIV-infected patients. MAIN OUTCOME MEASURES: Chemosensory complaint score from taste and smell questionnaire and quality of life scores from the Medical Outcomes Study HIV Health Survey (MOS-HIV). RESULTS: A total of 144 patients (70%) reported chemosensory complaints, 91 (44%) reported both taste and smell complaints, 47 (23%) reported only taste complaints, and six (3%) reported only smell complaints. Many patients complained that drugs interfered with their sense of taste, or that medications tasted bad. Higher chemosensory complaint scores were associated with a greater number of medications taken, tobacco use, and hay fever. Patients with chemosensory complaints had significantly lower scores in all domains of the MOS-HIV than those without complaints. Quality of life as measured by the MOS-HIV was lower in patients with chemosensory complaints even after controlling for number of AIDS diagnoses, number of medications, CD4 cell count, and HIV-1 viral load. CONCLUSIONS: Chemosensory complaints were common in the patient population and were associated with a poor quality of life. Medications played an important role in chemosensory complaints. Measures to optimize taste and smell function may improve quality of life and medication adherence, and prevent complications such as inadequate oral intake, malnutrition, weight loss, and ultimately wasting.

Adult↗
PubMed1998

Sense of smell in allergic and nonallergic rhinitis.

Hyposmia is a fairly common complaint in patients with long-continuing allergic or nonallergic rhinitis. Other factors such as aging, smoking, or nasal surgery may affect olfaction, but these have been little studied in rhinitis-related hyposmia. The purpose of this study was to measure and compare olfactory thresholds in 105 rhinitis patients and 104 healthy controls and to analyze possible relationships between the sense of smell and rhinitis, age, sex, smoking, prick-test results, nasal resistance, and history of nasal or paranasal surgery. The olfactory threshold was assessed with a commercially available kit of squeeze-bottle pairs. The most important variables associated with the sense of smell were determined with stepwise multiple regression analysis, and intergroup differences were assessed with analysis of variance. The reference interval of olfactory thresholds by age was estimated with regression analysis. Nasal resistance was measured by active anterior rhinomanometry. Age and rhinitis were the only variables with significant effect on the olfactory threshold in the whole series. Both the proportion of hyposmic persons and the degree of the impairment of the sense of smell were significantly higher in the rhinitis group than in the control group. The nonallergic patients' sense of smell was poorer than that of seasonal or perennial allergic rhinitis patients. A history of operations for nasal polyposis was associated with hyposmia, but operations for chronic maxillary sinusitis were not. Neither smoking habits nor sex were related to olfactory thresholds. In conclusion, hyposmia in rhinitis patients is partly attributable to age-related changes, but our results indicate that the disease itself impairs the sense of smell.

Adult↗
PubMedDate not supplied

A polymorphism of the ability to smell urinary metabolites of asparagus.

The urinary excretion of (an) odorous substance(s) after eating asparagus is not an inborn error of metabolism as has been supposed. The detection of the odour constitutes a specific smell hypersensitivity. Those who could smell the odour in their own urine could all smell it in the urine of anyone who had eaten asparagus, whether or not that person was able to smell it himself. Thresholds for detecting the odour appeared to be bimodal in distribution, with 10% of 307 subjects tested able to smell it at high dilutions, suggesting a genetically determined specific hypersensitivity.

Adolescent↗
PubMedDate not supplied

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.

Adult↗
PubMed2004

[Testing the sense of smell using validated procedures].

There is a growing interest into the investigation of smell disorders in both research and clinical practice. For psychophysical ("subjective") investigations related to the sense of smell a variety of test kits are available, namely the various "Sniffin' Sticks" kits, the UPSIT (University of Pennsylvania Smell Identification Test) or the CCSIT (Cross-Cultural Smell Identification Test). Recording of olfactory evoked potentials (OEPs) and respiration olfactometry can be used for diagnosing smell dysfunctions in a more objective way.

Humans↗
PubMed2004

[The 2004 Nobel Prize for Physiology or Medicine for research into smell receptors and the organization of the olfactory system].

The 2004 Nobel Prize for Physiology or Medicine has been awarded to Richard Axel and Linda B. Buck, for their discovery of smell receptors and the organisation of the olfactory system. Their original discovery concerned the identification of some 1000 genes that code for smell receptors in the olfactory epithelium of the rat. They also demonstrated that each receptor can only be activated by a limited number of odourants and that there is some overlap in specificity with other smell receptors. Odourants in inhaled air are specifically recognized and bound by the smell receptors on the olfactory neurones in the nasal epithelium. The activated neurones send an electrical signal to the mitral cells, the dendrites of which lie in the glomeruli of the olfactory bulb. In each olfactory neuron only one smell receptor gene is expressed. Neurones with the same type of receptor are spread throughout the epithelium but converge in the same glomerulus. An olfactory map is formed by means of mitral-cell projections which run to the cerebral cortex as well as to other parts of the brain. Possibly the information gained about odourants will be applied in the areas of physiology and pathophysiology; in the field of pharmacology for example where odourants may be used in the treatment of disorders of fertility, behaviour or mood.

Chemoreceptor Cells↗
PubMed2005

[Smell and taste in drug addicts].

The main objective of this study was to establish the degree of influence of various illicit drugs, taken into the body in different ways, on the senses of smell and taste. Other possible factors, that might have caused disturbances in normal functioning of both senses, were outlined. The studied group consisted of 48 drug addicts, between the age of 16 and 48 years, addicted to various illicit drugs for several years. Olfactory testing included two methods. First quantitative method described by Elsberg and Levy, modified by Pruszewicz, was used to establish the smell detection threshold. Then the University of Pennsylvania Smell Identification Test was used as a method for odor identification. The sense of taste was tested with the use of method described by Krarup and modified by Pruszewicz. The results showed disturbances in olfactory performance (combined in both method) in 52.1% of all drug abusers, and 16.7% of them were diagnosed with ageusia when the sense of taste was tested. The route of administration of illicit drugs proved to be a statistically significant factor that might have caused disturbances of smell perception and identification in the study group. Drug abusers who were taking drugs intravenously and those who smoked and inhaled various drugs had the most significant olfactory problems. Both means for assessing smell function were statistically compared and the results showed that approximately 75% of drug users with olfactory disturbances had olfactory problems in both tests.

Adolescent↗
PubMedDate not supplied

[The use of smells of plant origin as indicators of the extensiveness and intensity of ixodid tick infection with the tick-borne encephalitis virus].

It has been shown that, using a simple olfactometer, through which moist air and smell of vegetative origin penetrate into the centre via different ends of the tube, ticks can be divided into two groups, those infected and not infected with tick-borne encephalitis virus. The method yielding a 100% division, is based on opposite changes in the behaviour of virus infected ticks: the attracting smells become repellent and vice versa. Normal reaction to smell measured by the length of the distance covered by an individual tick towards or from the smell source in the olfactometer tube varies in various groups of control and experimental ticks, but correlates with virus titre of ticks. It is greater in ticks with a higher level of virus reproducibility. The reaction to smell in infected ticks makes it possible to predict the intensity of their infestation.

Animals↗
PubMed1990

[Smell perception in smokers].

The author studied the changes of olfactory function in smokers. He established the fact that the threshold of the perception of smell increases in smokers. By studying the subjective experience of the intensity of smell he established an appearance which he named olfactory recruitment, the increased growth of smelling sensitivity, which points out the changes, not only on the olfactive mucous membranes, but on the olfactive paths as well. The author concludes that smoking influences the decrease of the function of smell and emphasizes the necessity of advising the stopping of smoking in the treatment of all types of smelling disorders, as one of the important elements of treatment.

Humans↗
PubMed1989

ACE inhibitors in hypertension: assessment of taste and smell function in clinical trials.

Taste and smell disturbances are infrequently reported adverse effects of treatment with captopril and are even less frequently reported with other ACE inhibitors. These adverse effects have been attributed to the chemical structure of the drugs used, although this relationship is the matter of some debate. A link between the taste disturbance associated with ACE inhibitors and changes in plasma zinc concentration has also been suggested, but again the evidence for this relationship is equivocal. One problem facing research in this area has been the lack of reliable assessment techniques for the quantitative evaluation of smell and taste function. Three quantitative methods for evaluating taste and smell function are described, together with the results of a pilot study aimed at evaluating the potential ease of application of these techniques in a larger group of patients. In this double-blind, crossover pilot study, 8-week treatment with lisinopril (20-40 mg once daily) was compared with captopril (25-50 mg twice daily) in 12 hypertensive patients. The two drugs produced similar falls in lying and standing blood pressure and neither drug produced a significant alteration in smell recognition, or olfactory or taste threshold. None of the minor changes observed appeared to correlate with either plasma zinc concentrations or intra-erythrocyte zinc levels. This study provides important observations on the use of these new techniques. Based on the wide variability of results obtained, the design of further clinical studies must address and overcome the many factors (age, sex, smoking, etc.) which may confound the study of drug effects on taste and smell.

Angiotensin-Converting Enzyme Inhibitors↗
PubMedDate not supplied

Taste and smell problems: validation of questions for the clinical history.

Complaints of taste and smell dysfunction unaccompanied by symptoms of neurological or nasal problems are not uncommon. However, "I can't taste" is not necessarily an accurate symptom description. Complaints tend to reflect the common confusion between taste sensations (that is, salt, sour, sweet, bitter) and flavor sensations (including taste, smell, temperature, and texture). A number of questions have been identified that help classify symptoms according to the type of dysfunction (taste, smell, or both): whether the problem is quantitative (reduced or absent sensation) or qualitative (distorted sensations); and what might have caused the dysfunction. Directed questioning can yield a clinical history that predicts chemosensory function and identifies the most likely cause of the problem. Questions were assessed by comparing the self-reports of taste and smell symptoms to the clinical evaluation of chemosensory function for 101 new patients seen in the Taste and Smell Center at the University of Connecticut Health Center in 1983.

Adolescent↗
PubMedDate not supplied

[Smell and taste thresholds in older people].

The smell and taste ability of 105 persons at an age of 65 to 93 years was examined by adequate qualitative and semiquantitative chemical and electrogustometric methods. The basic levels of seniors were found above the levels of younger people. For the sense of smelling a significant connection of age and smell sensitivity could be measured. There was no difference between men and women using chemical test methods. With electrogustometry, however, women had a better taste sensitivity than men. At the age of 65 the taste levels are at a fix point. No higher levels could be realized in older persons. A significant reduction of smell ability was recognized in persons with reduction of cerebral blood flow and in smokers. The taste ability was disturbed in cases of diabetes, in persons using dental prostheses and selectively for "salty" in cases of hypertonia and "bitter" in smokers. Loss of taste was recognized in two women who used NaF-drugs, but also some other drugs were able to induce smell and taste alteration.

Aged↗
PubMed1981

Ketone compound smelling ability: study in Hungarian twins.

On the basis of their earlier experiments the authors assumed that the ability to recognize the smell of two ketone compounds, acetone and methylethylketone (MEK), might be determined genetically. In the present work of smelling test was performed in adult Hungarian twins, 61 like sexed DZ pairs and 87 MZ pairs. No connection was found between twin zygosity and intra-pair concordance for MEK, while in the case of acetone smelling some connection may exist. A highly significant correlation was found between the smelling ability to acetone and MEK. Females seemed to be better smellers than males. Comparing the taste perception for PTC to the smell perception for acetone the supposition of a possible genetic linkage between the two traits, put forward by other authors, could not definitely be confirmed.

Acetone↗