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Electrogustometric-threshold assessment demonstrated excellent test-retest reliability, good bilateral correspondence and age-related differences. Tactile and stimulus-related descriptors of the sensation elicited at detection threshold, as well as a lack of correlation between whole-mouth chemical thresholds and anterior tongue electrogustometric thresholds, raise questions for future research.

Olfactory-evoked potentials (OEPs) were recorded monopolarly at the Fz, Cz and Pz electrode sites in young adults and elderly subjects with an amyl acetate stimulus presented olfactometrically. Psychophysical odor thresholds for amyl acetate were determined using a two-alternative, forced-choice detection procedure. These demonstrated a decreased odor detection sensitivity in the elderly relative to tye young subjects. In accordance with the threshold findings, elderly subjects produced significantly smaller N1 and P2 amplitudes, and a trend towards longer latencies than younger subjects. Moreover, odor threshold was found to correlate with amplitude magnitude. The OEP findings, which are discussed in the context of previous OEP studies, offer promise as an objective, non-invasive measure of sensory function in both clinical and non-clinical settings.

The chemical sensitivity scale for sensory hyperreactivity (CSS-SHR) is used to quantify affective reactions to and behavioral disruptions by odorous/pungent substances in the environment and has documented good metric properties. However, normative data have not been available. The main objective of the present study was therefore to establish normative data for reference by means of a large-scale population-based study.From a random sample of 8,520 reachable inhabitants in the county of Västerbotten in Sweden, aged 18-79 years, stratified for age and gender, 3,406 individuals agreed to participate.The results show fairly high internal consistency (Cronbach's α = 0.78-0.83) of the CSS-SHR and that it generates scores with approximately normal distributions (skewness: 0.045-0.454; kurtosis: -0.314 to 0.230), irrespective of age group and gender. Mean scores, standard deviations, confidence intervals, and proportions of individuals who met the diagnostic cutoff score for the CSS-SHR were obtained for reference of normality.CSS-SHR can be recommended for quantification of affective reactions to and behavioral disruptions by odorous/pungent environmental substances, and with the advantage of comparing scores with normality.

CONCLUSIONS: Results from prior studies of quality of life (QoL) in heterogeneous patient groups (regarding disorder type and etiology) with olfactory disorders may be useful also for understanding QoL in homogeneous patient groups. Diagnosis and treatment of smell loss should be given high priority in polyposis with asthma, and coping strategies can be suggested to these patients. OBJECTIVES: To investigate the effects of smell loss on daily life and coping strategies in patients with smell loss without dysosmia and with nasal polyposis with asthma as the only primary etiology, and to compare these results with those from a prior study of a patient group with heterogeneous olfactory disorders and etiology. METHODS: Fifty patients with smell loss and with nasal polyposis and asthma responded to questions about consequences of smell loss, QoL, psychological well-being and distress, and coping strategies. RESULTS: Negative consequences of smell loss, associated risks, and diminished food enjoyment were commonly reported, and various aspects of QoL were rated as being deteriorated. Psychological well-being was found to be poorer than normal, and use of both problem- and emotion-focused strategies was common. The results from this homogeneous patient group are very similar to those previously obtained from a heterogeneous group.

To study coping strategies, social support and responsibility for improvement in chemical intolerance (CI).Limited knowledge of CI among health professionals and lay persons places demands on the chemically intolerant individual's coping strategies and perception of social support and ability to take responsibility for improvement. However, there is sparse literature on these issues in CI.A cross-sectional, questionnaire-based, quasi-experimental study.Fifty-nine persons with mild, 92 with moderate and 31 with severe CI participated by rating (i) usage and effectiveness of six problem- and six emotion-focused coping strategies, (ii) emotional, instrumental and informative support provided by various sources and (iii) society's and the inflicted individual's responsibility for improvement.The participants reported that the most commonly used and effective coping strategies were avoiding odorous/pungent environments and asking persons to limit their use of odorous/pungent substances (problem-focused strategies) as well as accepting the situation and reprioritising (emotion-focused strategies). High intolerance severity was associated with problem-focused coping strategies and relatively low intolerance with emotion-focused strategies. More emotional than instrumental and informative support was perceived, predominantly from the partner and other family members. Responsibility attributed to society was also found to increase from mild to moderate/severe intolerance.Certain coping strategies are more commonly used and perceived as more effective than others in CI. However, intolerance severity plays a role regarding both coping strategies and responsibility. Emotional support appears to be the most available type of support.For improved care, certain coping strategies may be suggested by nurses, the healthcare system needs to provide better social support to these patients and the issue of responsibility for improvement may be discussed with the patient.

For studying changes in the sensory sensitivities, psychophysical methods offer a variety of models. The psychophysical approach also holds for applications on indoor air quality. The human senses can be used for characterizing environments in terms of effects on health and comfort, and have been used by the WHO for determining recommended exposure limits. The use of psychophysical methods for air pollution applications is illustrated by two studies on effects on sensory functions in smokers and passive smokers. Olfactory as well as auditory effects were found. Furthermore, methodological findings are presented, such as obtaining information on detectability and perceived intensity in the very same estimation procedure. The results also demonstrate the need for calibrating scales with regard to individual scaling behavior in perceived intensity measurements as well as the capability of the master scale principle for performing such a calibration.

Olfactory impairments are present in common neurodegenerative disorders and predict conversion to dementia in non-demented individuals with cognitive impairment. In cognitively intact elderly, evidence is sparse regarding the role of olfactory deficits in predicting cognitive impairment. The present study investigated predictors of 5-year prospective decline in the Mini-Mental State Examination (MMSE) in a large (n = 501), population-based sample of elderly (65-90 years) individuals. All participants were genotyped for the ApoE gene, assessed for health factors, and were non-demented at the baseline assessment. After partialling out the influences of demographic and health-factors at baseline and dementia at follow-up, poor odor identification ability in combination with older age and the ApoE-epsilon4 allele predicted larger prospective global cognitive decline. This effect could not be produced by a vocabulary test. In sum, the findings suggest that an olfactory deficit can dissociate between benign and malign global cognitive development in non-demented, very old epsilon4-carriers, who are at high risk of developing dementia.

This work investigated perceived air quality and health effects from exposure to low to high levels of volatile organic compounds (VOCs) emitted from damp building materials and a mixture of molds growing on the materials. A mixture of Wallemia sebi, Fusarium culmorum, Penicillium chrysogenum, Ulocladium botrytis, and Aspergillus versicolor was inoculated on pine wood and particle board. In Study 1, each of 27 participants took part in two exposure conditions, one with air from molds growing on building materials (low levels of emissions from the building materials and the mold mixture) and one with blank air, both conditions during 60 min. In Study 2, each of 24 participants was exposed (10 min) four times in a 2 x 2 design randomly to air from moldy building materials (high levels) and blank, with and without nose-clip. The participants rated air quality and symptoms before, during, and after each exposure. Self-reported tear-film break-up time and attention and processing speed (Study 1) was also measured. Exposure to high VOC levels increased the reports of perceived poor air quality, and in the condition without nose-clip enhanced skin symptoms were also noted. No such outcome was observed when exposing the participants to low VOC levels.Emissions from building materials caused by dampness and microbial growth may be involved in indoor air health problems. This study showed that exposure to high levels of VOC emitted from damp building materials and a mixture of mold may cause perceived poor air quality. It also indicated that stimulation of chemical warning systems (the nasal chemosensory part of the trigeminal system and the olfactory system) may enhance skin symptoms.

The aim was to develop and evaluate a seven-point category scale, called the Environmental Annoyance Scale (EAS), with semantic descriptors and ratio-scale properties. Six studies were conducted that involved ratings of perceived magnitude of descriptors, selection of seven descriptors with semantic coherency, and ratings of various environmental issues. Seven semantically coherent descriptors with subjective equidistance and small interindividual variability were selected for the EAS. Environmental ratings on the EAS were linearly related to magnitude estimations, and the two rating procedures generated very similar exponents of the psychophysical power function. The used selection procedure was found to be reliable and not likely affected by the respondent's educational level, and the reliability of the EAS per se was found to be satisfying. The EAS appears to have properties that approach those of a ratio scale, and to be reliable and valid for assessment of environmental annoyance.

To enhance understanding of neuropsychological processing underlying chemosensory event-related potentials (CSERPs), the objective of the present study was to compare CSERPs with auditory (AERPs) and visual event-related potentials (VERPs), and to approach the question of similarities in neuropsychological processing by means of correlation and cluster analyses. A multisensory ERP protocol was used, in which olfactory/chemosomatosensory (pyridine), auditory (1000-Hz tone) and visual (white circle) stimuli were presented in a pseudo-randomized sequence to 18 young, healthy adults. The results show (1) a morphological relation between P2 and P3 components that is different for the chemosensory than for the auditory and visual modalities, (2) a relatively weak association between the chemosensory and auditory/visual modalities for P3 in terms of both correlation and cluster, and (3) a P2/P3 cluster for the chemosensory but not auditory or visual modality. This supports the claim that the chemosensory P2 and P3 components reflect similar neuropsychological processes.

The study investigated whether the P600/SPS component is sensitive to the richness of semantic content in sentences. ERPs were recorded while 30 native Swedish speakers read sentences, of which half were syntactically correct and half contained a syntactic violation. Both kinds of sentences came in one of three types of descending semantic completeness: semantically coherent sentences, sentences which were incoherent due to violations of selectional restrictions, or sentences of pseudo words, hence void of lexical content. In the semantically coherent sentences a P600/SPS was found for the syntactic violation. A less salient positivity was found for the violation in the semantically incoherent sentences. No P600/SPS was found for the syntactic violation in the pseudo word sentences and no LAN component in any sentence type. The results are interpreted as supporting the hypothesis that the P600/SPS component reflects a semantically based reanalysis process.

Recent studies illuminate the difficulties that patients with olfactory disorder face in daily life, which underlines the need to understand its prevalence, and to diagnose and treat these patients. The purpose of the present review is to characterize olfactory disorders and describe associated complaints, present recent insights into epidemiology, suggest procedures to assess these disorders, and discuss clinical implications.A compilation of previous and new studies of olfactory disorders suggests associated complaints of poor quality of life, depression, and various specific consequences. Epidemiological studies show that loss in odor sensitivity is common in both general and clinical populations, whereas dysosmia is less common in general populations but frequent in clinical populations. The most common etiologies are post-upper respiratory infection, nasal/sinus disease and head trauma.Procedures to diagnose olfactory disorders and to identify etiologies are available. Depending on etiology, certain types of treatment are often successful, such as endoscopic sinus surgery and corticosteroid administration in nasal/sinus disease. In post-upper respiratory infection and head trauma, spontaneous recovery is fairly high. In any case, it is advisable to counsel the patient with regards to strategies to cope with olfactory disorders.

This is a report from the International Symposium on “Adverse Effects of Aircraft Noise” held at the University of Stockholm, Sweden, April 6–8, 1987. The purpose of the report is to summarize the concerns and interests of the scientific community as represented by the participants about interested in the control of noise pollution and in environmental health, It may also serve as a basis for priorities in research programs.

The prevalence of chemical sensitivity (CS) and sensory hyperreactivity (SHR) was assessed in a teenage population. Among a random sample of 401 teenagers, 326 (81.3%) answered questionnaires assessing sensitivity to chemicals and noise, anxiety and depression. A subgroup of 85 teenagers conducted a capsaicin inhalation test. The estimated prevalence was 15.6% for general self-reported CS, 3.7% for CS with affective and behavioral consequences, about 1% for SHR. Sensitivity variables were positively intercorrelated. Risk factors for general CS were noise sensitivity (OR: 2.1), probable anxiety (OR: 2.5) and female sex (OR: 2.0). CS problems seem to be present also in teenagers, although less so than in adults. Furthermore, CS seems to be related to other environmental sensitivities.

The ApoE gene is expressed in olfactory brain structures and is believed to play a role in neuronal regenerative processes as well as in development of Alzheimer's disease (AD), the most common form of dementia. The varepsilon4 allele has been reported to be associated with compromised odor identification ability in the elderly, and this deficit has been interpreted as a sign of pre-diagnostic AD. However, because it has not been demonstrated that the relationship between the varepsilon4 allele and odor identification is mediated by dementia, it is possible that the varepsilon4 allele may have an effect on odor identification over and above any effects of dementia. The present study investigated effects of ApoE-status on odor identification in a large, population-based sample (n=1236) of adults (45-80 years), who were assessed for dementia at time of testing and 5 years later. The results showed that the varepsilon4 allele was associated with an odor identification deficit among elderly participants (75-80). Critically, this effect remained after current and pre-diagnostic dementia, vocabulary, global cognitive status and health variables were partialled out. The present results suggest that the ApoE gene plays a role in olfactory functioning that is independent of dementia conversion within 5 years.

Sensory hyperreactivity (SHR) with predominantly airway symptoms is a subgroup of chemical intolerance to various environmental substances with pungent/odorous properties. The hallmark of SHR is sensitivity to capsaicin inhalation, resulting in extensive coughing likely to be mediated by a C-fiber hyperreactivity of the airway sensory neurons. However, it is not clear whether capsaicin sensitivity implies a greater sensitivity to chemosomatosensory substances in general. Therefore, the present study tested the hypothesis of an association between capsaicin cough sensitivity and sensitivity to CO(2) with respect to detection sensitivity and electrophysiological brain response.A correlational study was employed to investigate the relation between capsaicin cough sensitivity and detection thresholds and chemosomatosensory event-related potentials (ERPs) for CO(2) presented in the nasal cavity in 35 persons varying in capsaicin cough sensitivity.Number of coughs were found to correlate negatively with CO(2) threshold and tended to correlate negatively also with N1 and P2 latencies of the chemosomatosensory ERP for CO(2). No tendencies of correlations were found between number of coughs and latencies for olfactory and auditory ERPs, recorded for comparison, but, unexpectedly, were found between number of coughs and auditory N1 amplitude.The results imply that capsaicin cough sensitivity, such as in SHR, is related to higher detection sensitivity, and tends to be related to faster cortical processing of other chemosomatosensory substances, at least of CO(2).

Adverse reactions to ambient odorous and pungent substances in daily activities among pregnant women who are half-way through pregnancy, and changes in odor perception at predominantly an early stage of pregnancy motivated the present study of odor intolerance at an early pregnancy stage. Ninety-five women averaging gestational week 11 and 102 non-pregnant women were compared with the Chemical Sensitivity Scale for Sensory Hyperreactivity (CSS-SHR). General environmental intolerance was assessed with items from the Noise Sensitivity Scale that are analogous to the CSS-SHR (“NSS-SHR”). Pregnant women were found to have higher scores on the CSS-SHR, but not on the “NSS-SHR”. This suggests an odor intolerance that affects pregnant women's daily activities, which appears not to be due to a general environmental intolerance. The effect size of pregnancy on CSS-SHR score is larger in the present study of early pregnancy than in the previous study of women half-way through pregnancy.

Objectives The number of employees on sick leave due to stress-related syndromes has increased drastically in many industrialized countries. Cognitive dysfunction is a common complaint among patients suffering from chronic stress. Previous research on chronic stress has mainly focused on its interpersonal, attitudinal, psychological, organizational, and physical effects. Less attention has been allocated to effects of chronic stress on cognitive functioning. Hence the aim of the present study was to investigate the relationship between chronic stress and cognition. Methods The cognitive performance of 19 chronic stress outpatients and 19 matched controls was studied. A battery of standard and experimental cognitive tests assessing processing speed, attention, working memory, and episodic and semantic memory were administered. Results Performance deficits of the chronic stress patients relative to the performance of the controls were found for some but not all cognitive tasks, indicating a selective deficit. Deficits were found for episodic memory, particularly for learning across repeated trials and for tasks requiring divided attention during either the encoding or retrieval of words. Performance differences were also found for aspects of working memory, mental tempo, semantic access, and prospective memory, but not for basic perceptual speed measures. Conclusions These findings may suggest suboptimal executive functioning (eg, strategic or attentional control) among chronic stress patients. Particularly, poor performance in letter fluency and prospective memory were significantly associated with chronic stress, the finding suggesting the usefulness of these tests as clinical tools in evaluations of chronic stress states.

Parosmia can be defined as a qualitative odor distortion. Despite the consequences of this condition for quality of life, the scientific literature lacks information about the prevalence of parosmia in the general population, which was the objective of the present study.Random samples of 1,900 adult and 401 teenage inhabitants, stratified for age and gender, were drawn from the municipal population register of Skövde, Sweden. In total, 1,713 individuals (74% of the samples) agreed to participate, of which 1,387 (73%) were adults and 326 (81%) were teenagers. They responded to a question about parosmia by means of either a structured interview (adults) or a questionnaire (teenagers).The overall prevalence of parosmia was 3.9% (4.0% in adults and 3.4% in teenagers), which was stable across gender, but differed somewhat between age groups, with highest prevalence in the age group 20-29 years.The rather high overall prevalence, 3.9%, does indeed suggest that parosmia deserves attention when attempting to better understand olfactory dysfunction in clinical settings and in the general population of both adults and teenagers.

A special consulting team for patients with olfactory disorders would be able to verify, describe, and explain the characteristics of the disorders, also in cases where a patient experiences a disorder, but has a normal sense of smell.The general purpose of this paper was to present our experience with patients seeking medical attention for olfactory disorders, and to describe how quantitative and qualitative olfactory disorders are diagnosed, what the etiologies are, and how quality of life is compromised in patients with olfactory disorders.This investigation was performed prospectively over a 10-year period by one physician responsible for the consulting team for patients with olfactory disorders. Based on a standardized clinical examination, a structured interview, and assessment of olfactory function, its aim was to diagnose quantitative and qualitative disorders in 303 consecutive patients. Health-related quality of life was assessed with the Nottingham Health Profile (NHP) in about one-third of patients.In the majority of patients, a reduced sense of smell was found after testing. Often, but not always, this was combined with qualitative disorders. Dominating etiologies were infections, nasal polyposis, head trauma, and aging. Patients complaining of olfactory disorders experience a significantly reduced quality of life regarding the impact of their health problem on paid employment, household work, and social and family life.

In experimental practice, odors are commonly applied to only one nostril for recordings of olfactory event-related potentials (OERPs), but the lateralization aspect of the OERP response is unclear regarding both stimulated nostril and cortical topography. The purpose of the present study was to investigate whether stimulated-nostril side affects OERP amplitudes and latencies and whether these potentials indicate lateralization of brain response in healthy, right-handed, young adults. OERPs were recorded from nine electrode sites in response to monorhinal stimulation with amyl acetate in 28 participants. The results showed a general increase in amplitude from frontal to parietal electrode sites (in particular for N1/P3) and generally larger amplitudes on the left hemisphere and midline than on the right hemisphere. There was no main effect of stimulated-nostril side on amplitude. Interactions indicated that N1/P2 amplitude was larger for left- than right-nostril stimulation and larger on the left hemisphere and midline than on the right hemisphere in left-nostril stimulation. No main effect or interactions of stimulated-nostril side over latencies were found and no effects on latencies of sagittal or coronal sites. These findings suggest a general parietal, left-hemisphere predominance in response amplitude to odorous stimulation and imply that either the left or the right nostril may be sufficient for accurate assessment of OERP latency in right-handed, young adults.

The aim of this study was to investigate the relationship between the behavioral consequences of self-reported odor sensitivity with the chemical sensitivity scale for sensory hyperreactivity (CSS-SHR) and cough sensitivity to inhaled capsaicin. We also wanted to estimate the prevalence of airway sensory hyperreactivity (SHR), which was defined as a positive CSS-SHR score in combination with a positive capsaicin inhalation test result.A general population-based study with randomly selected individuals after stratification for age and gender.Skövde Central Hospital, Departments of Lung Medicine and Otorhinolaryngology, Sweden.A total of 693 randomly selected individuals from a population-based study in which 595 persons (86%) responded to the CSS-SHR questionnaire.The individuals were divided into four groups with different odor sensitivity according to their CSS-SHR score. Of these, 137 individuals were randomly recruited for the capsaicin inhalation test. Capsaicin inhalation was performed with concentrations of 0.4 and 2.0 mumol/L in a randomized order. The number of coughs were registered and counted for 10 min from the start of each inhalation.Of the 137 individuals who were recruited for the capsaicin inhalation test, 103 (75%) participated. Sixteen individuals had increased cough sensitivity and fulfilled the criteria for a positive capsaicin inhalation test result. Of the individuals with a positive capsaicin inhalation test result,80% also had a positive CSS-SHR score. Only 5% of the individuals with a negative CSS-SHR score had a positive capsaicin inhalation test result. The order of inhaled capsaicin concentration was found to influence the results. The prevalence of SHR with the definition given above was estimated to be 6.3% in this general population.A high CSS-SHR score was found to be directly related to the sensitivity for inhaled capsaicin, which made it possible to relate subjective data to objective findings.

Physiological anorexia, decreased dietary variation, and weight loss associated with poor health are common conditions in the elderly population, with changes in chemosensory perception as important contributing causes. The present study of age-related taste loss aimed to investigate the question whether this loss is generalised and unspecific, or whether it exhibits differences in relation to certain tastants and/or differences in the topographical distribution of age-related loss. Impregnated "taste strips" with four concentrations of each of the tastants sucrose, NaCl, quinine-hydrochloride, and citric acid were applied on the tip, midlateral and posteromedial tongue regions to be identified as either sweet, salty, bitter, or sour by 30 young and 26 elderly adults. The results showed more pronounced age-related loss in identification for citric acid and quinine-hydrochloride than for sucrose and NaCl at both the tip and midlateral regions, but not at the posteromedial region where both age groups performed close to chance level. These findings may have implications for food preferences, and thus, the diets of elderly people.

The aims of this study were to investigate the effects of loss of smell as regards the quality of life and the coping strategies used.Seventy-two patients with anosmia (46%) or hyposmia (54%) filled in the validated Multi-Clinic Smell and Taste Questionnaire, the validated General Well-being Schedule (GWBS), and answered other questions shown to be of good validity.Several kinds of negative effects, risks associated with the loss, interference with daily routines and deteriorations in well-being were common. Physical health, financial security, profession, partnership, friendship, emotional stability and leisure were also deemed to be negatively affected and GWBS scores show compromised psychological well-being. The importance of olfaction seemed to be more noticeable after the loss of smell, and several kinds of problem- and emotion-focused coping strategies were adopted by these patients.We found that the loss of smell had substantial adverse effects on the quality of life and that high priority should be given to its diagnosis and treatment and to further research in this field. Furthermore, a combination of problem- and emotion-focused coping strategies may be suggested to patients who have recently lost the sense of smell.

The present study investigated chemosensory gender differences by means of ratings of total nasal chemosensory intensity, unpleasantness and sensory irritation and simultaneous recordings of chemosensory event-related potentials (CSERPs) for three concentrations of the olfactory/trigeminal stimulus pyridine in 19 women and 17 men, all young adults. Results show that, compared to men, women gave higher intensity and unpleasantness ratings, in particular for the highest stimulus concentration. The gender differences in perceived intensity are reflected in the signal-to-noise ratio of the individual CSERP averages, revealing more identifiable early components (P1, N1) in women than in men. The late positive component, labeled P2/P3, displayed larger amplitudes at all electrode sites and shorter latencies at Cz, in women compared to men. The effects of increased pyridine concentration on perception (larger in women) and CSERPs (similar across gender) imply that the two measures involve partially different neural processing. CSERP component identifiability is proposed here as a general means of assessing signal-to-noise ratio of the CSERPs.

This study investigated demographic and cognitive correlates of cued odor identification in a population-based sample from the Betula project: 1906 healthy adults varying in age from 45 to 90 years were assessed in a number of tasks tapping various cognitive domains, including cognitive speed, semantic memory and executive functioning. The results revealed a gradual and linear deterioration in cued odor identification across the adult life span. Overall, females identified more odors than men, although men and women performed at the same level in the oldest age cohort (85-90 years). Hierarchical regression analyses revealed that age, sex, education, cognitive speed and vocabulary were reliable correlates of performance in the odor identification task. In addition, age-related deficits in the included demographic and cognitive variables could not fully account for the observed age-related impairment in identification, suggesting that additional factors are underlying the observed deterioration. Likely candidates here are sensory abilities such as olfactory detection and discrimination.

Patients with olfactory dysfunction appear repeatedly in ear, nose, and throat practices, but the prevalence of such problems in the general adult population is not known. Therefore, the objectives were to investigate the prevalence of olfactory dysfunction in an adult Swedish population and to relate dysfunction to age, gender, diabetes mellitus, nasal polyps, and smoking habits.Cross-sectional, population-based epidemiological study.A random sample of 1900 adult inhabitants, who were stratified for age and gender, was drawn from the municipal population register of Skövde, Sweden. Subjects were called to clinical visits that included questions about olfaction, diabetes, and smoking habits. Examination was performed with a smell identification test and nasal endoscopy.In all, 1387 volunteers (73% of the sample) were investigated. The overall prevalence of olfactory dysfunction was 19.1%, composed of 13.3% with hyposmia and 5.8% with anosmia. A logistic regression analysis showed a significant relationship between impaired olfaction and aging, male gender, and nasal polyps, but not diabetes or smoking. In an analysis of a group composed entirely of individuals with anosmia, diabetes mellitus and nasal polyps were found to be risk factors, and gender and smoking were not.The sample size of the population-based study was adequate, with a good fit to the entire population, which suggests that it was representative for the Swedish population. Prevalence data for various types of olfactory dysfunction could be given with reasonable precision, and suggested risk factors analyzed. The lack of a statistically significant relationship between olfactory dysfunction and smoking may be controversial.

Anormal chemosensory perception has been identified as a possible mechanism underlying odor intolerance, but research in this domain has yet been rather limited. The main objective of the present study was to investigate total perceived intensity, unpleasantness, sensory irritation, and cortical activity assessed with chemosensory event-related potentials (ERPs) for three concentrations of pyridine ranging from predominantly olfactory to trigeminal in activation. Results from 19 individuals with self-reported chemical hypersensitivity and 19 controls with self-reported normal chemical sensitivity show that the hypersensitive group, compared to controls, rated the pyridine stimuli to be more intense and unpleasant, and that these group differences increased with pyridine concentration. Sensory irritation was also the perceptual dimension found to correlate strongest with score on the chemical sensitivity scale. However, no group differences were found in ERP amplitudes or latencies. These findings suggest that self-reported chemical hypersensitivity (1) can be associated with anormal chemosensory perception, (2) may be more closely related to trigeminal function than to olfaction, and (3) has a neural basis at a higher cortical level than that captured by chemosensory ERPs.

Impaired taste sensation in the aging person may affect the appreciation of food and beverages and compromise nutritional status. Changes in flavor perception may be due to altered ability to discriminate between intensities of suprathreshold taste stimuli. An interesting question is whether all taste qualities (sweet, salty, sour, bitter) show similar age-associated decline in intensity discrimination. Taste intensity discrimination has been shown to be significantly poorer in elderly than in young women for the bitter stimulus caffeine, but not for the sweet stimulus sucrose. The present experiment investigated effects of taste substance and age on taste intensity discrimination by assessing Weber ratios (WRs) for citric acid and sodium chloride (NaCl) in 60 people, half elderly, and half women. Results indicate a significant effect of age on WRs for citric acid and NaCl, suggesting the importance of suprathreshold intensity discrimination for taste perception in the elderly.

A short version of the 21-item Chemical Sensitivity Scale (CSS), called the Chemical Sensitivity Scale for Sensory Hyperreactivity (CSS-SHR), was developed and evaluated for the quantifying of self-reported affective reactions to and behavioral disruptions in daily activities by odorous/pungent substances among patients with sensory hyperreactivity (SHR) for clinical and epidemiological studies.Twenty-two patients with clinically diagnosed SHR and 124 control participants responded to the CSS and to additional questions about chemical sensitivity for the evaluation of the CSS-SHR.Eleven of the 21 items of the CSS were selected, on statistical grounds, to constitute the CSS-SHR, which was found to generate approximately normal distributions, have good test-retest reliability (r(xy)=0.87), satisfying internal consistency (r(alpha)=0.76-0.84) and predictive and concurrent validity, and to be uni-dimensional. The metric properties of the CSS-SHR were, despite its few items, comparable with those of the CSS. A proposed diagnostic cut-off score for SHR demonstrated a high correct classification rate (92%) for the CSS-SHR.The favorable metric properties of the CSS-SHR and its sensitivity/specificity suggests that it is useful for clinical diagnosis and epidemiological study of sensory hyperreactivity in combination with other diagnostic tools.

Unlike the clinical usages of evoked potentials (e.g. brain stem auditory evoked potentials for the assessment of auditory function), normative data for the olfactory event-related potential (OERP) have been unavailable. The principal objective was to establish normative data across the human life span for OERPs with a given set of parameters. Participants were 140 persons from seven age groups (16–19, 20–29, 30–39, 40–49, 50–59, 60–69 and 70–79 years of age), with equal numbers of males and females, screened for nasal health and dementia. The odor stimulus was amyl acetate, presented at nasal temperature in a humidified airstream delivered by an air-dilution olfactometer at a constant flow rate, using a 60-s inter-stimulus interval. OERPs were recorded at Fz, Cz, and Pz electrode sites, amplified and averaged over trials. Amplitudes of the N1/P2 and P3 and latencies of the P2 and P3 were analyzed. Processing speed decreased at a constant rate over decades for the sensory (P2 latency) as well as cognitive (P3 latency) components. Decline in amplitude over decades was also apparent. Normative data will be useful in research on olfactory function and in clinical assessment of olfactory functional status.

The Scandinavian Odor-Identification Test (SOIT) was developed to address the need for a culturally valid odor-identification test for clinical use on the Scandinavian population that (i) has good ability to generalize performance to olfactory status, (ii) assesses olfactory and trigeminal function separately, (iii) requires only limited cognitive demands, (iv) has normative data and good sensitivity and specificity, and (v) is fast, easy to administer and inexpensive. Sixteen odorous test stimuli were selected that were relatively identifiable, familiar, strong in intensity and pleasant according to healthy participants. Four response alternatives were then selected for each test stimulus based on a confusion matrix of identification rates obtained from healthy participants, in a manner that controlled for task difficulty. Results on the SOIT from healthy persons and hyposmic patients showed satisfactory test-retest reliability, split-half reliability and validity. Cut-off scores for olfactory diagnosis (normosmia, hyposmia, anosmia) based on normative data obtained from 171 healthy persons showed a satisfactory sensitivity and specificity of the SOIT. Assessment of 22 anosmic patients with the SOIT revealed that three of the test stimuli were significant trigeminal stimulants.

The prevalence of parosmia and phantosmia among 363 chemosensory and nasal/sinus patients was studied, as was the accuracy with which our clinical questionnaire could assess these dysfunctions. We then investigated whether patients with parosmia or phantosmia, matched for odor intensity, perform poorer on odor identification than do patients with no dysosmia. More than 40% of the study group evidenced either parosmia (18.7%) and/or phantosmia (25.6%), a finding that suggests that more attention should be paid by the medical practitioner in addressing qualitative olfactory dysfunction. Furthermore, it appears that assessment of these dysfunctions may aid in differential diagnosis, and that questionnaires can be used with reasonable validity irrespective of the patient's age. Finally, the results imply that parosmia may be reflected in a discrepancy between odor identification and detection.

The impact of lexical functioning and detection sensitivity on the deficit of odor identification in Alzheimer's disease (AD) was studied in persons diagnosed with probable and questionable AD. Tests consisted of lexical-based odor identification, lexical-based picture identification, picture-based odor identification, and odor-detection threshold. Results suggest (1) that odor identification is poorer than picture identification in probable and questionable AD, (2) that odor identification continues to be poor even when lexical demands are eliminated, (3) that odor detection does contribute to the odor-identification deficit, but does not account for it completely, and (4) that odor identification tests have a correct classification rate of 83 – 100%. Odor identification tests can be very useful tools in diagnosing AD and should be considered an important addition to existing diagnostic test batteries.

Awareness of loss in smell sensitivity was assessed in 80 normal elderly subjects, 80 patients with probable Alzheimer's disease (AD), and 80 patients with sinusitis by comparing measured smell sensitivity to questionnaire-based, self-reported sensitivity. Both AD patients and sinusitis patients had significantly poorer diagnosed smell sensitivity than the normal elderly. Both patient groups had thresholds which on average were about nine times more concentrated than those of the normal elderly. However, 74% of the AD patients and 77% of the normal elderly with smell loss reported normal smell sensitivity. In contrast, only 8% of the sinusitis patients with loss reported normal smell sensitivity.

Context effects, intraindividual variability, and internal consistency of intermodal joint scaling with magnitude estimation (“magnitude matching”) were studied by instructing 12 subjects to judge the three pairs of odor intensity, loudness, and brightness on a common scale of perceived intensity as well as to judge odor intensity separately (unimodal magnitude estimation). Significant context effects were found by comparing odor intensity judgments obtained by separate versus intermodal joint scaling as well as across different modalities (loudness vs. brightness) in joint scaling. But no such effects were found for loudness or brightness when compared across modality of joint scaling. Intraindividual variability in the estimates imply about equal reliability in intermodal joint scaling and separate scaling. Good internal consistency was found, indicating that subjects are successful in expressing perceived intensities of different modalities on a common scale.

The aim of the study was to investigate odor identification performance in patients one year after hospital admittance due to stroke. Predictors for olfactory dysfunction were investigated as well as self-reported olfactory function and pleasantness of olfactory items.A 1-year prospective study was performed. Stroke location, classification and comorbidities were registered at hospital admission. One year after admission, olfactory function was assessed using standardized olfactory methods (screening for loss of detection sensitivity and an odor identification test). A group of matched controls was derived from a population-based study to compare odor identification performance between groups. Patients were asked for their personal judgment regarding their olfactory function and pleasantness of odorous items. In addition, global cognitive function and symptoms of depression were assessed.A total of 78 patients were enrolled (46 males, 32 females; mean age 68 years) of which 28.2% exhibited reduced olfactory function (hyposmia) and 15.4% exhibited loss of olfactory function (10.3% functional anosmia, 5.1% complete anosmia). Patients showed significantly lower olfactory performance compared to age- and sex-mated matched controls. Predictors of impaired olfactory function were age and NIHSS score. Self-reports indicated no significant differences between patients with normal olfactory function and those with reduced function. Yet, patients having an olfactory dysfunction rated odorous items as significantly less pleasant compared to patients without dysfunction.Olfactory dysfunction seems to occur frequently after stoke even one year after initial admission. The deficits seem to relate to hyposmia and functional anosmia, and less to a complete loss of smell sensitivity.

This study investigated differences in olfactory cognitive functions, in 40 healthy young right-handed participants, with respect to side of rhinal stimulation. The targeted functions were: perceived familiarity, episodic recognition memory, free identification and repetition priming in identification. The results showed that odors presented to the right nostril were rated as more familiar than odors presented to the left nostril and also showed significant effects of repetition priming in identification. However, no differences were found between nostrils in episodic recognition memory or free identification. These latter results indicate a rather extensive inter-hemispheric interaction in higher-order cognitive functions.