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Screening and rehabilitation of olfaction after total laryngectomy in Swedish patients: results from an intervention study using the Nasal Airflow-Inducing Maneuver.

OBJECTIVES: To examine the olfactory function in patients with laryngectomy and to assess the results of the Nasal Airflow-Inducing Maneuver (NAIM) odor-rehabilitation technique. DESIGN: A prospective intervention study. SETTING: University hospital. PATIENTS: Twenty-four patients, 21 men and 3 women, mean age 68 years, who underwent laryngectomy at least 5 months prior to intervention. INTERVENTION: Speech therapists trained patients in the NAIM technique: simultaneous lowering of the jaw, floor of the mouth, tongue, base of the tongue, and soft palate while the lips are closed. Three interventions were given within 6 weeks. MAIN OUTCOME MEASURE: Olfactory testing with semistructured interview, the Questionnaire on Olfaction, Taste, and Appetite (QOTA), and the Scandinavian Odor-Identification Test (SOIT). Quality of life was measured with European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-H&N35 questionnaires. The patients were categorized as smellers or nonsmellers based on the SOIT results. RESULTS: Before the treatment, 10 patients (42%) were smellers (ie, 6 had normosmia and 4 hyposmia), while 14 patients (58%) were nonsmellers (ie, all had anosmia). Thus, 18 patients had impaired olfaction. Using the NAIM technique, 13 (72%) of 18 patients with impaired olfaction showed improvement. Of the 14 nonsmellers, 7 converted to smellers after only 1 intervention session, giving us a success rate of 50% in anosmic patients after 1 session. CONCLUSIONS: Olfactory impairment is common in patients who underwent laryngectomy. The NAIM method is easy to learn and rapidly improves smell and taste. A single intervention session is sometimes sufficient, but many patients benefit from repeated training. The SOIT test is an effective and simple test for the assessment of olfaction acuity after laryngectomy.

Aged↗

The effect of chronic cocaine abuse on human olfaction.

Cocaine has been used for many decades as both a stimulant and as a topical anesthetic/vasoconstrictor. Illicit "snorting" or freebase smoking has increased markedly in recent years. Decreased olfaction has been an often reported subjective complaint of cocaine abusers, but quantification of smell loss using sensitive psychophysical tests has not yet been done, leading to the present study. Eleven cocaine abusers were recruited from a drug treatment clinic. Olfaction was assessed using a butanol threshold test, the UPSIT, and a 7-item discrimination test. One patient tested anosmic, one had a mild discrimination problem, and one had a large septal perforation but was normosmic. From the present study, it appears that most cocaine abusers, even heavy users or those with intranasal damage, do not develop permanent olfactory dysfunction. It is not clear what factors may have resulted in complaints of olfactory loss in previous studies.

Adult↗

Rapid clinical evaluation of anosmia. The alcohol sniff test.

BACKGROUND: Smell impairment affects 1% to 2% of Americans and leads to frequent physician visits. Olfactory testing is available in chemosensory centers, but not as part of a routine cranial nerve examination. The alcohol sniff test (AST), which uses the standard 70% isopropyl alcohol pad, was developed as a quick, reliable measure of olfactory function. METHODS: Sixty-four patients and 36 healthy control subjects (N = 100) were tested with the AST and with a standard butanol threshold test. RESULTS: The AST reliably, consistently, and correctly measured olfactory function. CONCLUSIONS: The AST is a rapid, reliable olfactory test that can be used for screening olfactory function and should be incorporated in the routine cranial nerve examination.

1-Propanol↗

Patients with seasonal affective disorder have lower odor detection thresholds than control subjects.

BACKGROUND: Behavioral changes in patients with seasonal affective disorder resemble seasonal changes in photoperiodic animals. Because the olfactory system has a modulatory role in seasonal photoperiodic responses in certain species, we hypothesized that olfactory function may differ between patients with seasonal affective disorder and healthy control subjects. METHODS: Fourteen patients who had winter seasonal affective disorder and 16 healthy volunteers were studied once in winter and once in the subsequent summer. We administered a phenyl ethyl alcohol detection threshold test to each side of the nose in a counterbalanced order, with the nostril contralateral to the tested site occluded. Patient and control data were compared using a 4-way repeated measure analysis of covariance (with group and gender as between-subjects factors, season and side-of-the-nose as within-subjects factors, and age as a covariate). RESULTS: The patients exhibited lower thresholds than did the controls (F(1,25) = 9.2; P =.006). There was no main effect of season. CONCLUSION: In humans, marked seasonal behavioral rhythms with recurrent winter depression may be associated with a more acute sense of smell.

Adult↗

Characterization of aroma volatiles in tomatoes by sensory analyses.

Using gas chromatography-olfactometry and aroma extract dilution analysis 34 aroma compounds were found with flavour dilution factors > or = 4. (Z)-3-hexenal, hexanal, 1-octen-3-one, methional, 1-penten-3-one and 3-methylbutanal belonged to the most odour-active aroma volatiles in fresh tomatoes. Smell, taste and aftertaste of different tomato cultivars were evaluated by quantitative descriptive analysis. By applying principal component analysis to both sensory attributes and chemical compounds (odour-active aroma volatiles, titratable acid and reducing sugars) the first three components explained 70% of the total variance. The data set was reduced to the sensory attributes intensive, tomato, sour, fruity, sweet and bitter as well as to important chemical compounds. Relations between chemical compounds and sensory attributes were found.

Chromatography, Gas↗

Olfactory dysfunction in anorexia and bulimia nervosa.

Fifty-five eating-disordered women and 16 normal controls participated in this study to determine whether olfactory function is altered in patients with food-restricting anorexia, anorexia with bulimic features, and bulimia nervosa. Olfactory function was assessed using the University of Pennsylvania Smell Identification Test and by determining phenyl ethyl alcohol odor detection thresholds. Only the very low-weight anorexics showed impairments in their identification and detection of odors. This group's olfactory function did not improve from admission to discharge despite significant weight gain. Although, overall, smoking had only a minor influence on olfactory function, the very low-weight anorexic smokers had the lowest scores of all subjects. Since higher-weight anorexics did not show such impairments, the results suggest that the severe and prolonged starvation experienced by the very low-weight anorexics caused or contributed to intractable deficits in the olfactory system and that these deficits are compounded by smoking.

Adolescent↗

Solvent-associated decrements in olfactory function in paint manufacturing workers.

To assess the effects of low-level organic solvent exposure on olfactory function, a cross-sectional study in paint manufacturing workers was undertaken. Workers in two paint manufacturing facilities (N = 187) were tested using the University of Pennsylvania Smell Identification Test (UPSIT), a standardized, quantitative test of olfactory function. Industrial hygiene air samples over the past 13-15 years revealed that average solvent exposures in these plants were 2-40% of the existing threshold limit values for the three chemicals measured. Stratification by smoking status revealed evidence of dose-related decrements in olfactory function (p = .01) only in non-smokers. Furthermore, those nonsmoking workers in the highest exposure category had UPSIT scores below the fifth percentile for their age. These results suggest that solvents may cause nervous system dysfunction at lower levels than previously suspected, and that the olfactory system may be a critical target organ for the neurotoxic effects of solvents and other chemicals.

Adult↗

Measurement precision of an olfactory perception threshold test for use in field studies.

Changes in olfactory function have been associated with workplace exposure to a variety of substances. In the workplace, smell can be particularly important, since it is commonly used to detect potentially hazardous situations or as an indicator of mask cartridge breakthrough. Sensitive quantitative measures of olfactory loss would be useful in epidemiological studies and workplace surveillance. The objective of the present study was to determine the reproducibility of an olfactory perception threshold test and variations with age, gender, and smoking status. The test was a standard olfactory kit (Olfactolab No. 11), including 18 serial dilutions of PM-carbinol, with an equal number of blanks. The forced choice method was used, with both tester and subject blinded as to which bottle contained the odorant. Olfactory perception threshold was recorded when the subject identified the same dilution three times. To assess reproducibility, testing was repeated four times over a period of 4 weeks, on the same weekday and the same time of day. Subjects (n = 63) ranged in age from 20 to 60 years (mean age: 39.7 +/- 12.5 years), 47.6% were women, 29.5% currently smoked, and 27.9% were former smokers. Results showed no inter-week differences in olfactory perception threshold (Analysis of variance for repeated measures: F = 0.59; p much greater than 0.05). Inter-class correlation for assessment of agreement of continuous variables was 0.76. Inter-week concordance of hyposmia showed fair to good agreement (0.55 greater than or equal to kappa less than or equal to 0.66). Three-way analysis of variance (ANOVA) revealed significant differences with respect to age category (F = 7.36; p less than 0.001) and current smoking status (F = 4.54; p less than 0.05), but not for gender (F = 2.32; p greater than 0.05). The multiple regression model with age and smoking as independent variables was highly significant (F = 13.03; p less than 0.001), explaining 28% of the variance; olfactory threshold increased 0.47 ds/year (t = 4.01; p less than 0.001) and 0.27 ds/cigarettes/day (t = 2.46; p less than 0.05). The findings of this study indicate that this test is reproducible and sensitive to expected changes with age and smoking status. It corresponds well to criteria for testing in the field and should be considered for studies characterizing olfactory functions and sensory loss among working populations.

Adult↗

Use of spatial, visual, and olfactory information during foraging in wild nocturnal and diurnal anthropoids: A field experiment comparing Aotus, Callicebus, and Saguinus.

Early in their evolution, the ancestors of anthropoid primates radiated from a nocturnal to a diurnal niche. Foraging during the night differs from foraging during the day in terms of the availability of light and color cues, and in the movement of odor molecules through the canopy. In this study, we compared the ability of nocturnal and diurnal New World monkeys to use perceptual cues (i.e., the sight or smell of food) and spatial information (place predictability) in within-patch foraging decisions. An experimental field study was conducted on wild groups of night monkeys (Aotus nigriceps), tamarins (Saguinus imperator imperator and S. fuscicollis weddelli), and titi monkeys (Callicebus cupreus) at the Zoobotanical Park/UFAC, Rio Branco, Brazil. Our research design included the construction of feeding stations located in the home range of the study groups. Each feeding station consisted of eight visually identical feeding platforms located in a circular arrangement. In all test settings, two platforms at each feeding station contained a food reward (banana), and the remaining six platforms contained a sham reward (yellow plastic or inaccessible banana). In the night-monkey experiments, each feeding platform was illuminated by a 40-W red bulb to aid the researcher in observing their behavior. When the location of reward sites was predictable over time, individuals in all four species successfully relocated food rewards based solely on spatial information. Each species was also successful in using visual information to distinguish real from sham food rewards. However, only night monkeys and one group of emperor tamarins used olfactory information alone to locate food rewards. Overall, the species' performances did not clearly differentiate Aotus from diurnal New World primates in these experiments.

Animals↗

Accessory chemosignaling mechanisms in primates.

Accessory olfaction is defined as the chemoreceptive system that employs the vomeronasal complex (VNC) and its distinct central projections to the accessory olfactory bulb (AOB) and limbic/cortical systems. Comparisons of the structural and functional features of primate accessory olfaction can now be made at many levels. Advances in the understanding of molecular mechanisms of odorant transfer and detection, physiological analyses of signal processing, and appreciation of ontogenetic timetables have clarified the contribution of accessory chemoreception to the sensory map. Two principal functions dominate: the decoding of social information through the uptake of signals (often fluid-borne), and the provision of an essential pathway for the "migration" of presumptive neurocrine (GnRH) cells from the olfactory placode to the hypothalamus. VN "smelling" (vomerolfaction) is now seen to overlap with primary olfaction. Both systems detect signal compounds along the spectrum of volatility/molecular weight, and neither is an exclusive sensor. Both main and accessory chemoreception seem to require collaborative molecular devices to assist in odorant transfer (binding proteins) and (for the VNO) signal recognition (MHC1 proteins). Most adaptive-selective features of primate chemocommunication variously resemble those of other terrestrial mammals. VN function, along with its genome, has been maintained within the Strepsirrhines and tarsiers, reduced in Platyrrhines, and nearly extinguished at the Catarrhine up to hominin levels. It persists as an intriguing ancient sense that retains key features of past evolutionary events.

Animals↗

[123I]-FP-CIT-SPECT demonstrates dopaminergic deficit in orthostatic tremor.

There is increasing evidence of a potential role of the dopaminergic system in orthostatic tremor (OT): Association with parkinsonism and treatment effects of L-dopa and dopamine agonists have been reported. Eleven patients with isolated OT had single-photon emission computed tomography (SPECT) using (123)I-FP-CIT ([(123)I]-2 beta-carbomethoxy-3beta-(-4-iodophenyl)-N-(3-fluoropropyl)-nortropane) as dopamine transporter tracer. Results were compared with 12 age-matched normal controls and 12 patients with Parkinson's disease (PD). A marked reduction in striatal tracer binding was found in OT compared to normal controls (p < 0.001). Tracer uptake was significantly higher and more symmetrical than in PD, and caudate and putamen were equally affected. L-dopa challenges, performed in seven patients, showed a small but non-significant improvement on EMG and a small but significant improvement in clinical parameters on blinded video rating. Two-month open-label L-dopa treatment (600 mg/day) led to a small improvement in two of five patients but no significant overall change. Olfactory function on University of Pennsylvania Smell Identification Test was normal. Our finding of a marked tracer uptake reduction on dopamine transporter SPECT supports a role of the dopaminergic system in OT. Lack of evidence of a clinically relevant therapeutic response to L-dopa suggests that other mechanisms must also be involved in the pathogenesis.

Aged↗

Paroxysmal unilateral dysosmia: a cured patient.

A 31-year-old woman with an 11-year history of unilateral paroxysmal olfactory hallucinations was cured by resection of the homolateral olfactory bulb, which was believed to be the site of origin of the noxious smell.

Adult↗

Lack of major olfactory dysfunction in MPTP-induced parkinsonism.

The olfactory function of 6 patients whose parkinsonism was the result of intravenous administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was compared to that of 12 age-matched patients with idiopathic Parkinson's disease (PD) and 10 age-matched normal control subjects. Unlike their PD counterparts, the olfactory test scores of patients with MPTP-induced parkinsonism did not differ significantly from those of control subjects. These findings suggest that MPTP-induced parkinsonism, unlike idiopathic PD, is unaccompanied, on average, by major alterations in the ability to smell.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

Odor and (bio)diversity: single enantiomers of chiral fragrant substances.

Our sense of smell is enantioselective. This review reports interesting examples of single stereoisomers of natural and synthetic odorants, prepared via bioorganic routes, that support this statement. This article is the summary of a talk given at the Flavours & Fragrances 2004 conference in Manchester at the MCC/UMIST, 12-14 May, 2004.

Animals↗

Effects of double and triple bonds on the spatial representations of odorants in the rat olfactory bulb.

Many naturally occurring volatile chemicals that are detected through the sense of smell contain unsaturated (double or triple) carbon-carbon bonds. These bonds can affect odors perceived by humans, yet in a prior study of unsaturated hydrocarbons we found only very minor effects of unsaturated bonds. In the present study, we tested the possibility that unsaturated bonds affect the recognition of oxygen-containing functional groups, because humans perceive odor differences between such molecules. We therefore compared spatial activity patterns across the entire glomerular layer of the rat olfactory bulb evoked by oxygen-containing odorants differing systematically in the presence, position, number, and stereochemistry of unsaturated bonds. We quantified activity patterns by mapping [(14)C]2-deoxyglucose uptake into anatomically standardized data matrices, which we compared statistically. We found that the presence and number of unsaturated bonds consistently affected activity patterns, with the largest effect related to the presence of a triple bond. Effects of bond saturation included a loss of activity in glomeruli strongly activated by the corresponding saturated odorants and/or the presence of activity in areas not stimulated by the corresponding saturated compounds. The position of double bonds also affected patterns of activity, but cis vs. trans configuration had no measurable impact in all five sets of stereoisomers that we studied. These results simultaneously indicate the importance of interactions between carbon-carbon bond types and functional groups in the neural coding of odorant chemical information and highlight the emerging concept that the rat olfactory system is more sensitive to certain types of chemical differences than others.

Analysis of Variance↗

Correlation between cardiac 123I-MIBG and odor identification in patients with Parkinson's disease and multiple system atrophy.

We investigated an association between olfaction and cardiac (123)I-metaiodobenzylguanidine (MIBG) uptake in patients with Parkinson's disease (PD) and multiple system atrophy (MSA). There was a significant positive correlation between cardiac MIBG uptake and the Cross-Cultural Smell Identification (CCSI) score in patients with PD (r = 0.56; P = 0.003) independent of the disease duration or clinical rating of motor status. However, patients with MSA did not show a significant correlation between cardiac MIBG uptake and the CCSI score. Our findings suggest that the functional losses of the olfactory and cardiac sympathetic systems are closely coupled in PD.

3-Iodobenzylguanidine↗

Olfactory function in restless legs syndrome.

Restless leg syndrome (RLS) is usually idiopathic but may occur in patients with Parkinson's disease (PD). Both respond to dopaminergic medications. Whether these disorders share a common pathophysiology is unclear. Because PD is associated with a loss of olfactory function, we compared the olfactory function of patients with RLS with control and PD patients. Using the University of Pennsylvania Smell Identification Test (UPSIT), olfactory function was found to be normal in patients with idiopathic RLS and significantly reduced in patients with PD. This suggests that the pathophysiology of RLS differs from PD, and that RLS likely is not a "forme fruste" or a preclinical sign of PD.

Aged↗

Pinocchio, a novel protein expressed in the antenna, contributes to olfactory behavior in Drosophila melanogaster.

Most organisms depend on chemoreception for survival and reproduction. In Drosophila melanogaster multigene families of chemosensory receptors and putative odorant binding proteins have been identified. Here, we introduce an additional distinct protein, encoded by the CG4710 gene, that contributes to olfactory behavior. Previously, we identified through P[lArB]-element mutagenesis a smell impaired (smi) mutant, smi21F, with odorant-specific defects in avoidance responses. Here, we show that the smi21F mutant also exhibits reduced attractant responses to some, but not all, of a select group of odorants. Furthermore, electroantennogram amplitudes are increased in smi21F flies. Characterization of flanking sequences of the P[lArB] insertion site, complementation mapping, phenotypic reversion through P-element excision, and expression analysis implicate a predicted gene, CG4710, as the candidate smi gene. CG4710 produces two transcripts that encode proteins that contain conserved cysteines and which are reduced in the smi21F mutant. Furthermore, in situ hybridization reveals CG4710 expression in the third antennal segment. We have named this gene of previously unknown function and its product "Pinocchio (Pino)".

Amino Acid Sequence↗