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[Olfaction disturbances in general ORL practice].
Analysis of smell disturbances in the ENT outpatients department of in a General Hospital. A retrospective and descriptive study. We include all patients with olfactory alterations as the main reason for consultation. The sample was 38 patients. Viral, postraumatic, toxic, drug-induced and inflammatory. We performed anamnesis, nasal endoscopic and scan images on all patients. Olfactory disturbances were more frequent in women older than 55 (2:1). The viral cause was the most frequent aethiology (55.3%). Nasal endoscopic exploration was normal in 68.4% patients. The CT scan was the main imaging study used (68.4%). The younger patients recovered better than the older ones. Smell disorders provoked by virus, toxic and medical drugs do have a better.
[The Connecticut Chemosensorial Clinical Research Center olfaction test: values in healthy volunteers].
OBJECTIVE: To know the values of the olfactory test (CCCRC) performed in healthy people. To analyse how the age and sex affect the test. MATERIAL AND METHODS: Descriptive study in 100 volunteers with no olfactory disorders. We used CCCRC olfactory test, which it has an odor threshold component, an odor identification component and a composite score. We analysed how age and sex variables affect olfactory test data, listing a t-Student test. The size sample is calculated to 0.05 alfa error. RESULTS: Threshold test data mean was 5.8. Identification test data mean was 7.5. Composite score mean was 6.7. CONCLUSION: Age is a significant factor in our study but not sex. Sample size is sufficient to analyze normal values. Our results are similar to other authors.
Social olfaction: a review of the ontogeny of olfactory influences on vertebrate behavior.
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Clinical evaluation of olfaction.
An odor identification test and an odor threshold test offered satisfactory quantitative information on olfactory function in patients with chemosensory complaints. The threshold test used various concentrations of butanol presented in an ascending sequence. On each trial, the participant had to choose between stimulus and blank (two-alternative forced-choice procedure). The identification test used common odorous items (e.g., baby powder and ground coffee) and pungent items (e.g., ammonia) to test trigeminal function. A list of odor names and use of corrective feedback during testing overcame word-finding difficulty in odor identification. Each test readily distinguished between patients and control subjects. At present, a score that reflects the combined outcome of the tests is used to indicate five categories of functioning: normal osmesis, mild hyposmia, moderate hyposmia, severe hyposmia, and anosmia.
Clinical tests of olfaction.
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A Scandinavian adaptation of the Multi-Clinic Smell and Taste Questionnaire: evaluation of questions about olfaction.
OBJECTIVE: A Scandinavian adaptation of the Multi-Clinic Smell and Taste Questionnaire (MCSTQ-Sc) was evaluated with respect to comprehension and test-retest reliability for responses to questions about olfactory dysfunction (abnormal sensitivity, parosmia and phantosmia) and related questions about medical history and consequences of olfactory dysfunction. MATERIAL AND METHODS: Comprehension was evaluated in a first study in 20 patients with chief complaints of olfactory dysfunction by comparing questionnaire- and interview-based responses. Test-retest reliability was evaluated in a second study in 30 other patients with olfactory complaints. RESULTS: Data from the two studies suggest that the vast majority of the questions evaluated from the MCSTQ-Sc are comprehensible and generate responses with very good reliability. Distinct exceptions were poor agreement between the questionnaire- and interview-based responses for questions about the number of cigarettes smoked and the pleasantness and typical episode length of phantosmia; the test-retest reliability regarding the nostril side of phantosmia also showed poor agreement. The results suggest the importance of probing these areas further in the clinical interview. CONCLUSION: The findings imply that, with a few caveats, the MCSTQ-Sc is a useful tool for the clinical assessment of olfactory dysfunction and its consequences.
Interactions between olfaction and the trigeminal system: what can be learned from olfactory loss.
The olfactory and the trigeminal systems have a close relationship. Most odorants also stimulate the trigeminal nerve. Further, subjects with no sense of smell exhibit a decreased trigeminal sensitivity with unclear underlying mechanisms. Previous studies indicated that single stages of trigeminal processing may differently be affected by olfactory loss. A better knowledge of adaptive and compensatory changes in the trigeminal system of subjects with acquired anosmia (AA) will improve the understanding of interactive processes between the 2 sensory systems. Thus, we aimed to assess trigeminal function on different levels of processing in subjects with AA. Subjects with AA showed larger electrophysiological responses to irritants obtained from the mucosa than healthy controls. On central levels, however, they exhibited smaller event-related potentials and psychophysical measures to irritants. Over 9 months, they exhibited an increase in trigeminal sensitivity. Subjects with recovering olfactory function showed an even more increased peripheral responsiveness to irritants. These data suggest dynamic mechanisms of mixed sensory adaptation/compensation in the interaction between the olfactory and trigeminal systems, where trigeminal activation is increased on mucosal levels in subjects with AA and amplified on central levels in subjects with a functioning olfactory system.
Clinical studies of olfaction.
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Rapid imaging of olfaction by functional MRI (fMRI): identification of presence and type of hyposmia.
PURPOSE: Our goal was to develop a rapid, simple, near-real-time method of functional MRI (fMRI) to measure brain activation in response to olfactory stimuli, to use it to identify patients with smell loss (hyposmia), and to differentiate their types of hyposmia. METHOD: fMRI was obtained in 16 patients with Type I hyposmia (who could detect but not recognize odors), 5 patients with Type II hyposmia (who could both detect and recognize odors, albeit with less than normal acuity), and 2 volunteers with normal olfactory acuity by use of a rapid echo planar imaging technique in which one coronal brain section from the anterior cortical region was studied and a single olfactory stimulus was used. Actual scanning time performed by a variation of methods previously published required 26 s. Three patients with Type I hyposmia were treated with theophylline 250-500 mg for 4-6 months and were studied before and after treatment. RESULTS: Brain activation in response to olfactory stimuli was demonstrated using a new, rapid, and simple fMRI technique. Patients with Type I hyposmia had less activation than patients with Type II hyposmia. Both patient groups had less activation than normal volunteers. Activation in patients with Type I hyposmia was essentially absent from regions of the middle frontal, orbitofrontal, and temporal cortex and was totally absent in regions of inferior frontal, insular, and cingulate cortex. Activation in patients with Type II hyposmia was greatest in the middle frontal cortex and the orbitofrontal cortex bilaterally and was present in regions of inferior frontal, temporal, and cingulate cortex. Each patient with Type I hyposmia treated with theophylline had improved smell function to Type II hyposmia and after treatment demonstrated activation in inferior frontal and cingulate cortex bilaterally, whereas before treatment, no activation in these regions was apparent. CONCLUSION: We describe a simple, rapid technique that can be used in a practical clinical setting to identify patients with hyposmia and to differentiate patients with different types of olfactory loss. These studies confirm the presence and classification of patients with Type I and Type II hyposmia. Results of this study suggest that regions of the frontal cortex may act to guide or direct olfactory signals to other brain areas such as temporal and cingulate regions. Although these latter regions are involved with olfactory recognition, their role in olfactory memory, olfactory meaning, and attention needs to be considered.
Olfaction in migraineurs.
Many investigators have described olfactory dysfunction among migraineurs. Olfactory stimuli can precipitate migraine, and olfactory hallucinations can occur as auras of migraines or as part of the symptom complex. Despite many reports linking olfactory phenomena and migraine, no evaluations of the olfactory abilities of migraineurs have been documented. To begin such assessments, sixty-seven consecutive migraine patients were given Pyridine odor threshold tests. Twelve of them (18%) scored as hyposmic or anosmic. In comparison, 1% of the general population of the U.S. is hyposmic or anosmic. Aside from possible diagnostic or methodological error, several possibilities may account for our result: migraine may induce olfactory pathology; olfactory pathology may induce migraine, or; a common pathogen may induce both olfactory dysfunction and migraine. The association of migraine with the emotional component of the limbic system has long been recognized, and our results strengthen its association with the olfactory component as well. Headache patients should be tested for olfactory loss and warned of such risks as inability to detect gas leaks and spoiled food.
Newer insights into the role and modifications of olfaction in man through clinical studies.
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Olfaction.
The main and accessory olfactory systems have received considerable attention on the part of scientists and clinicians during the last decade, largely because of (a) quantum advances in understanding their genetically expressed receptor mechanisms, (b) evidence that their receptor cells undergo neurogenesis and both programmed and induced cell death, and (c) important technical and practical developments in psychophysical measurement. The latter developments have led to the proliferation of standardized olfactory testing in laboratories and clinics, and to the discovery that smell loss is among the first signs of a number of neurodegenerative diseases, including Alzheimer's disease and idiopathic Parkinson's disease. Recent controversial claims that humans possess a functioning vomeronasal system responsive to "pheromones" has added further interest in intranasal chemoreception. This review focuses on recent progress made in understanding olfactory function, emphasizing transduction, measurement, and clinical findings.
Impaired olfaction predicts cognitive decline in nondemented older adults.
In 1992, the twelve-item Brief Smell Identification Test((R)) and, in 1992 and 1996, a variety of measures of verbal learning and memory, executive control, and global function were administered to a total of 359 individuals (286 men and 73 women; mean age in 1992 74.3 years). Individuals with a history of stroke or impaired cognition at baseline were excluded from analyses. Impaired olfactory function (present or absent) was related to a greater 4.5-year decline on several indices of verbal memory, but not to a decline on measures of executive control or of global functioning after adjustment for baseline cognitive performance, age, education, gender, and history of smell difficulties. Olfactory loss remained associated with a decline in components of verbal memory, independently of the apolipoprotein E epsilon4 status. The predictive utility of impaired smell identification in older adults appears to be specific to a decline in components of verbal memory.
Olfaction in neurodegenerative disorder.
There has been gradual increase of interest in olfactory dysfunction since it was realised that anosmia was a common feature of idiopathic Parkinson's disease (IPD) and Alzheimer-type dementia. It is an intriguing observation that a premonitory sign of a disorder hitherto regarded as one of movement or cognition may be that of disturbed sense of smell. In this review of aging, IPD, parkinsonian syndromes, tremor, Alzheimer's disease (AD), motor neuron disease (MND), Huntington's chorea (HC) and inherited ataxia, the following observations are made: (1) olfactory senescence starts at about the age of 36 years in both sexes and accelerates with advancing years, involving pleasant odours preferentially; (2) olfactory dysfunction is near-universal, early and often severe in IPD and AD developing before any movement or cognitive disorder; (3) normal smell identification in IPD is rare and should prompt review of diagnosis unless the patient is female with tremor-dominant disease; (4) anosmia in suspected progressive supranuclear palsy and corticobasal degeneration is atypical and should likewise provoke diagnostic review; (5) subjects with hyposmia and one ApoE4 allele have an approximate 5-fold increased risk of later AD; (6) impaired sense of smell may be seen in some patients at 50% risk of parkinsonism, and possibly in patients with unexplained hyposmia; (7) smell testing in HC and MND where abnormality may be found is not likely to be of clinical value, and (8) biopsy of olfactory nasal neurons reveals non-specific changes in IPD and AD and at present will not aid diagnosis.