[Chemosensory evoked potentials. Applications and significance in routine clinical practice].
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Chemoreceptor Cells↗
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[Sniffin'Sticks: a new system for olfactory assessment in routine clinical practice].
INTRODUCTION: The Sniffin'Sticks test battery consists of a short screening test and tests for odor detection thresholds (using n-butanol), odor discrimination and odor identification. We evaluated the usefulness of this new test in clinical practice and propose normative values. MATERIAL AND METHODS: In the present study 30 normosmic and 15 anosmic volunteers as well as 35 patients with various olfactory dysfunctions were examined. RESULTS: All four Sniffin'Sticks tests were able to separate normosmics and anosmics in a highly significant manner. Even a small decrease in olfactory performance was detectable in elderly patients. For practical purposes the sensitivity of the test for screening test was found to be too low. The good correlation between the individual Sniffin'Sticks tests and the correlation between the Sniffin'Sticks test battery and the "University of Pennsylvania Smell Identification Test" (UPSIT) test battery and the "University of Pennsylvania Smell Identification Test" (UPSIT) document the reliability of these tests. CONCLUSIONS: Our findings show that the Sniffin'Sticks are well suited to assess olfactory performance in clinical practice.
Adult↗
[Olfactory testing with "sniffin' sticks" for clinical diagnosis of Parkinson disease].
Olfactory dysfunction seems to be one of the most frequent symptoms in idiopathic parkinsonian syndrome (IPS). In contrast to the increasing number of studies providing evidence of the usefulness of olfactory tests in the diagnosis of IPS, clinical assessment of olfactory function is rarely performed. This may be due to the lack of an easy-to-use, inexpensive, standardized, and reliable test. In this study, we administered the newly developed "sniffin' sticks" test to a group of 40 nondemented IPS patients and compared the results with 40 healthy controls matched for age, gender, and smoking habits. In all three subtests including odor identification, odor detection threshold, and odor discrimination, the control group scored significantly better than the IPS group, yielding a specificity and sensitivity of 90% each. Our results indicate that olfactory disturbances in IPS can be found at early stages of the disease, appear bilaterally, and do not correlate with the dominant side of parkinsonism. Therefore, we emphasize that olfactory testing may be a useful tool in the diagnosis of IPS.
Age Factors↗
[Hyposmia and epistaxis. Esthesioneuroblastoma (olfactory neuroblastoma)].
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Diagnosis, Differential↗
Chemosensory additivity in trigeminal chemoreception as reflected by detection of mixtures.
A series of experiments probed into the degree of chemosensory detection additivity exhibited by mixtures of ethyl propanoate and heptanoate in terms of their trigeminal detectability via nasal pungency (i.e., irritation) and eye irritation. Nasal pungency was tested in subjects lacking a functional sense of smell (i.e., anosmics) to avoid olfactory biases. First, we built concentration-detection functions for each chemical and sensory endpoint. Second, we used the data from the functions to prepare mixtures of the two compounds in complementary proportions, and suitable single-chemical standards, all of which should be equally detectable under a rule of complete additivity, i.e., independence of detection. Third, we compared the experimentally obtained detectability with that expected under such rule. The outcome revealed that, at a low detectability level (but still above chance), the mixtures showed complete additivity for both trigeminal endpoints. At a high detectability level (but below perfect detection), the mixtures showed complete additivity for nasal pungency but less than complete additivity for eye irritation. In the context of previous studies, the results consolidate a picture of higher degree of detection additivity at perithreshold levels in trigeminal than in olfactory chemoreception. The outcome presents another line of evidence suggesting broader chemical tuning in chemesthesis compared to olfaction.
Adult↗
Olfactory mucosa histological findings in laryngectomees.
After total laryngectomy, the patients often report immediate and marked olfactory deficit. The aim of this study was to determine whether hyposmia in laryngectomees reflects olfactory epithelial damage. Ten laryngectomized patients and ten rhinologically normal subjects were subjected to olfactory testing, after which histological examination of biopsied olfactory mucosa was performed. Olfactory testing in laryngectomees revealed a marked reduction in odor perception. Histological examination of olfactory mucosa specimens showed that in laryngectomees some neuroepithelial structural features were comparable with those found in normal subjects. However, additional signs of damage were also observed, consisting mainly of various degrees of epithelial degeneration, above and beyond those that are characteristic of physiological epithelium turnover. These different degenerative features consisted of severe damage to the neuroepithelium, culminating in complete topical loss. Bowman's glands were also observed to be involved in the degenerative process. Laryngectomy-induced hyposmia seems to be correlated with the almost complete loss of nasal airflow due to the disconnection between the upper and lower airways, which prevents odor molecules from reaching the olfactory area, together with degenerative phenomena, which affect the neuroepithelium, and consequent failure in neurosensorial performance.
Aged↗
Clinical presentation of qualitative olfactory dysfunction.
Many patients with olfactory dysfunction not only experience quantitative reduction of olfactory function, but also suffer from distorted olfactory sensations. This qualitative dysfunction is referred to as parosmia (also called "troposmia") or phantosmia, with the major difference that distorted olfactory sensations are experienced in the presence or absence of an odor, respectively. Our clinical observations corroborate the literature in terms of a general underestimation of the incidence of olfactory distortions. Based on selected cases we try to show that olfactory distortions exhibit a large variance in their clinical appearance. Further, emphasis is placed on the fact that only a detailed and directed history of the patient can provide cues to the correct diagnosis.
Adult↗
A study on the prognostic significance of qualitative olfactory dysfunction.
We investigated the frequency and prognostic significance of qualitative olfactory dysfunction (parosmia, phantosmia) in a retrospective patient based study. A total of 392 patients with impairment of olfaction were tested at least two times for their olfactory function using the "Sniffin' Sticks". The mean interval between the first and the last test was 11 months. At the first visit 34% of all patients reported parosmia. Parosmia was most frequent in patients with postinfectious olfactory loss (56%), and less frequent in idiopathic, posttraumatic, sinunasal disease with frequencies of 10, 14, and 28%, respectively. In contrast, only 12% of all patients had phantosmias, with no significant differences between the patient groups. Improvement of olfactory function was found in 23% of all patients (n = 90). Pre-existing parosmia or phantosmia had no significant effect on recovery rate. Regarding qualitative olfactory dysfunction, 29% of those patients reporting parosmia reported relief of this symptom after an average of 12 months, whereas 53% of phantosmic patients lost phantosmia during the observation period. Although it has been suggested that olfactory distortion s could be regarded as an indicator of early recovery of decreased olfactory sensitivity, the current data indicate that occurrence of parosmia or phantosmia has little prognostic value. Phantosmia disappears at a faster rate than parosmia. These insights into qualitative olfactory dysfunction are regarded to be significant in the counseling of patients with olfactory loss.
Adolescent↗
Normative data for the "Sniffin' Sticks" including tests of odor identification, odor discrimination, and olfactory thresholds: an upgrade based on a group of more than 3,000 subjects.
"Sniffin' Sticks" is a test of nasal chemosensory function that is based on pen-like odor dispensing devices, introduced some 10 years ago by Kobal and co-workers. It consists of tests for odor threshold, discrimination, and identification. Previous work established its test-retest reliability and validity. Results of the test are presented as "TDI score", the sum of results obtained for threshold, discrimination, and identification measures. While normative data have been established they are based on a relatively small number of subjects, especially with regard to subjects older than 55 years where data from only 30 healthy subjects have been used. The present study aimed to remedy this situation. Now data are available from 3,282 subjects as compared to data from 738 subjects published previously. Disregarding sex-related differences, the TDI score at the tenth percentile was 24.9 in subjects younger than 15 years, 30.3 for ages from 16 to 35 years, 27.3 for ages from 36 to 55 years, and 19.6 for subjects older than 55 years. Because the tenth percentile has been defined to separate hyposmia from normosmia, these data can be used as a guide to estimate individual olfactory ability in relation to subject's age. Absolute hyposmia was defined as the tenth percentile score of 16-35 year old subjects. Other than previous reports the present norms are also sex-differentiated with women outperforming men in the three olfactory tests. Further, the present data suggest specific changes of individual olfactory functions in relation to age, with odor thresholds declining most dramatically compared to odor discrimination and odor identification.
Adolescent↗
Clinical validation of a new olfactory test.
A new approach to clinical olfactometry is presented using nasal sprays. A special dosage valve was used to standardize an aerosol size to 40 microns. For evaluation a 6 x 6 matrix (substance/olfactory quality) with verbal associative clues was used according to test psychological findings. Validation took place in three steps after determining smell-associated thresholds in preliminary examinations. Recognition of different aromas administered either by spraying into the open mouth from a distance of 5 cm using nasal sprays or sniffing opened bottles was compared in 50 subjectively normosmic subjects. Findings showed that the correspondence between the two procedures was relatively high, with global identification of odorous substances as high as 98.4% in the spray test. The number of substances used was next reduced to those six substances providing the most reproducible results in an investigation with 56 normosmic and 55 hyposmic subjects. Verbal associative clues were also tested. In a last step 50 patients with hyposmia of various origin and 110 normosmic subjects were tested, allowing previous results to be reproduced regardless of the cause of hyposmia. The spray test was shown to be easily performed and was suitable as a screening test, with a sensitivity of 88% and a specificity of 100%.
Administration, Intranasal↗
A threshold-like measure for the assessment of olfactory sensitivity: the "random" procedure.
Many tests of olfactory dysfunction are either too complex, too expensive, or too time-consuming to be of use in routine clinical testing. Thus, the present multicenter study was undertaken to investigate a new approach, the so-called "random" test. In this test different concentrations of citronellal and phenyl ethyl alcohol are applied according to a pre-established order; patients are asked to identify the odor if possible. The test score is the sum of correctly identified odors. Test administration takes about 10 min. Two studies were performed. Basic characteristics of the test were explored in experiment 1 in 176 healthy subjects (76 male, 100 female; age 12-85 years, mean age 30 years), namely test-retest reliability, correlation with other measures of olfactory sensitivity, and sensitivity of the test to differences in age and gender. In the second experiment the test was tried in 97 patients (45 male, 52 female; age 19-78 years, mean age 47 years) in a clinical environment to investigate its usefulness in diagnosing olfactory loss. The "random"-test was found (1) to exhibit a test-retest reliability similar to that reported for established measures of olfactory function (r = 0.71; P < 0.001), (2) to correlate with other measures of olfactory sensitivity (0.82 > r > 0.60; P < 0.001), (3) to differentiate between expected differences in olfactory sensitivity in relation to gender (t > 2.602, P < 0.011), and (4) to discriminate between different degrees of olfactory loss (F > 36.6, P < 0.001). Based on these data, and the fact that the new test requires little time and is easy to use, this approach can be expected to suit clinical needs.
Adolescent↗
Olfactory impairment in monozygotic twins discordant for schizophrenia.
OBJECTIVE: Several studies demonstrated olfactory dysfunction in patients with schizophrenia, some reported deficient olfaction in unaffected relatives of schizophrenics as well. This study differentially assessed olfactory acuity as well as smell identification and smell discrimination in monozygotic twins discordant for schizophrenia and healthy, monozygotic control twins, to determine the genetic basis of different olfactory modalities and their association to schizophrenia. METHOD: The Sniffin'Sticks test,a comprehensive and standardized olfactory test, was employed to assess the olfactory function of 10 monozygotic twin pairs discordant for schizophrenia versus 10 age- and sexmatched healthy,monozygotic twin pairs. RESULTS: Olfaction of affected monozygotic twins was globally impaired. Partial olfactory impairment of their unaffected co-twins may point to a genetic cause of olfactory impairment in schizophrenia. The influence of genetic factors was most evident for olfactory acuity and least evident for smell identification. All olfactory functions declined with duration of illness. Side of stimulus presentation did not influence olfactory performance. CONCLUSIONS: Genetic factors associated with olfactory dysfunction may contribute to schizophrenia. The degree of the genetic influence on olfaction depends on the olfactory domain under examination.
Adult↗
Orofacial apraxia in corticobasal degeneration, progressive supranuclear palsy, multiple system atrophy and Parkinson's disease.
OBJECTIVES: To determine whether the assessment of orofacial praxis is useful for the differential diagnosis of parkinsonian syndromes and to understand the neural mechanisms underlying OFA, searching for the respective roles of cortical and subcortical structures. METHODS: Forty-four patients were assessed: 12 with idiopathic Parkinson's disease (IPD), 8 with multiple system atrophy (MSA), 12 with progressive supranuclear palsy (PSP) and 12 with corticobasal degeneration (CBD). An easy bedside scale was used, exploring single gestures, gestures with noise production and multiple sequential gestures. We searched for group and task effects. RESULTS: Patients with CBD were significantly more impaired than those with IPD, MSA or PSP (p<0.001). Our assessment was unable to distinguish between the IPD, MSA and PSP groups. There was a clear task effect in CBD with a major impairment in multiple sequential gestures (p<0.0001). CONCLUSION: Assessment of orofacial praxis helps in the clinical diagnosis of CBD. Patients with IPD, MSA and PSP did not present with OFA. We suggest that the deficit in multiple sequential gestures in CBD is related to simultaneous lesions of the parietal lobule and the supplementary motor area.
Adult↗
Spinocerebellar ataxia type 2 olfactory impairment shows a pattern similar to other major neurodegenerative diseases.
Olfactory function is affected in different neurodegenerative diseases. Recently, it has been found that some hereditary ataxias are also associated with significant olfactory impairment. However, the initial findings did not examine the nature of the olfactory impairment associated with these ataxias. In the present article the effect of spinocerebellar ataxia type 2 (SCA2) on olfactory function was studied in 53 SCA2 patients and 53 healthy control subjects from Holguín, Cuba. Several tests were applied to evaluate olfactory threshold, description, identification and discrimination. The results show significant impairment in SCA2 patients on all olfactory measurements, and the pattern of olfactory deficits found suggests that they have much in common with those reported for other neurodegenerative diseases such as Parkinson's and Alzheimer's diseases.
Adult↗
Early diagnosis of Parkinson's disease.
The clinical methods of olfactory testing and color discrimination as well as apparative methods such as transcranial ultrasound, dopamine transporter imaging and MIBG scintigraphy reveal a high sensitivity concerning the diagnosis of idiopathic Parkinson's disease (PD). The specificity of the presented methods, in particular of the dopamine transporter imaging--seems to be limited. All these methods and primarily their combination allow the detection of PD in early and--probably--preclinical stages. This requires sufficient therapeutic strategies to prevent and treat preclinical and early PD.
Humans↗
Olfactory dysfunction and its measurement in the clinic and workplace.
OBJECTIVES: To provide an overview of practical means for quantitatively assessing the sense of smell in both the clinic and workplace. To address basic measurement issues, including those of test sensitivity, specificity, and reliability. To describe and discuss factors that influence olfactory function, including airborne toxins commonly found in industrial settings. METHODS: Selective review and discussion. RESULTS: A number of well-validated practical threshold and suprathreshold tests are available for assessing smell function. The reliability, sensitivity, and specificity of such techniques vary, being influenced by such factors as test length and type. Numerous subject factors, including age, sex, health, medications, and exposure to environmental toxins, particularly heavy metals, influence the ability to smell. CONCLUSIONS: Modern advances in technology, in conjunction with better occupational medicine practices, now make it possible to reliably monitor and limit occupational exposures to hazardous chemicals and their potential adverse influences on the sense of smell. Quantitative olfactory testing is critical to establish the presence or absence of such adverse influences, as well as to (a) detect malingering, (b) establish disability compensation, and (c) monitor function over time.
Air Pollutants, Occupational↗
Editorial: Evaluation of chemosensory effects due to occupational exposures.
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Air Pollutants, Occupational↗
Trigeminal and olfactory sensitivity: comparison of modalities and methods of measurement.
OBJECTIVE: The principal objective was to chart sensitivity for human nasal irritation by alternative psychophysical methods, namely, a common detection procedure versus a nasal lateralization procedure that required the subject to indicate whether a vapor had stimulated the left or right nostril. This objective relates to the broader issues as to (a) whether subjects with normal olfaction (normosmics) can yield, through novel methodology, an index of sensitivity to nasal irritation comparable with that obtained from subjects without olfaction (anosmics) and (b) whether both types of subjects have similar irritation sensitivity in general. This study sought to gauge interconvertability both between types of subjects and between modes of stimulus presentation for irritative and, where appropriate, olfactory stimulation. METHODS: Static dilution series of four n-aliphatic alcohols, chosen to represent volatile organic compounds (VOCs), provided the source of calibrated olfactory and irritative vapors emitted from their squeezable containers into the nose or eye either by a mechanical device or by hand. Standard psychophysical methodology (forced-choice; ascending strength of stimulation) served to chart detection thresholds for irritation and odor and an analogous procedure served to chart the threshold for localization of stimulation. RESULTS: Within the limits of resolution, detection thresholds and nasal localization thresholds yielded comparable indices of the potency of the VOCs to evoke nasal irritation. The thresholds agreed well with those for detection of eye irritation, though only the eyes proved to be capable of detecting irritation from l-octanol. The method of emitting the stimulus had little material effect on measures of either irritative or olfactory detection. CONCLUSIONS: The threshold for nasal localization offers a suitable way to measure nasal irritation in normosmic persons. Olfactory stimulation does not interfere with the measure since subjects cannot localize on that basis. Anosmic and normosmic persons have comparable sensitivity to nasal and ocular irritation. If anosmic persons have any lower sensitivity, as sometimes claimed, it would seem to have only trivial consequences for estimates of the irritative potency of VOCs.
Adult↗