Quantitative olfactometry in the measurement of posttraumatic hyposmia. A simple method.
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Craniocerebral Trauma↗
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Intranasal meningoencephalocele.
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Adult↗
Biopsy of human olfactory mucosa. An instrument and a technique.
We have developed an instrument that obtains small biopsy specimens of human olfactory mucosa suitable for electron microscopy. Following local anesthesia of the patient, the instrument is introduced through the naris and advanced 60 to 70 mm between the septum and middle turbinate. The cutting edge is pressed against the olfactory area and then is withdrawn with the mucosal specimen. This procedure has been performed successfully on 12 people with no substantial adverse effects. We have provided the indications for the use of this technique and its possible applications.
Biopsy↗
Electron microscopy of olfactory epithelia in two patients with anosmia.
Ultrastructural alterations were present in biopsy specimens of olfactory epithelia taken from two patients with anosmia. In both cases, the olfactory epithelia presented a disorganized appearance when viewed by transmission electron microscopy. The number of ciliated olfactory receptors was reduced; few olfactory vesicles were present at the epithelial surface. Where present, the olfactory vesicles usually lacked cilia. Since both patients had a history of head trauma, we speculate that the fila olfactoria may have been severed at the level of the cribriform plate. The histopathologic changes in the olfactory receptors that were revealed by electron microscopy may have resulted from the inability of regenerating axons to reach their normal site of synaptic contact--the second-order neurons (mitral cells) in the olfactory bulb of the brain.
Adult↗
Changes in olfactory acuity induced by total inferior turbinectomy.
The short-term and long-term effects of total inferior turbinectomy on smell acuity was assessed in two groups of patients. Olfactory thresholds were determined by a three-way forced-choice method, using four odorants. Resection of obstructive inferior turbinates resulted in a decrease in olfactory thresholds in 22 of 24 tested patients. No deleterious effect on smell acuity was observed in 16 patients tested 2 1/2 years or more after surgery. Subjective assessment of olfactory acuity is unreliable. It is our intention to focus attention on an aspect of intranasal surgery not frequently reported.
Adolescent↗
Characterization of olfactory dysfunction.
Management of dysosmic patients frequently is hampered by an incomplete description of their chief complaint and sometimes inadequate qualitative analysis of their symptoms. Qualitative analysis of olfactory dysfunction by an Odorant Confusion Matrix helps to characterize more fully sense of smell in the dysosmic patient. It is well grounded in psychophysical theory, thereby permitting physiological inferences about specific neural dysfunctions. The quantitative measure derived from the matrix correlates well with another quantitative measure of olfactory ability, the Smell identification Test, and provides the opportunity for valid comparisons among and within patients. Examination of illustrative case reports demonstrates that the qualitative features of the Odorant Confusion Matrix offer additional insights to support etiologic diagnoses of disturbances in sense of smell.
Adult↗
Steroid-dependent anosmia.
In steroid-dependent anosmia (nasal polyps, inhalant allergy, anosmia), high doses of steroids will temporarily restore the sense of smell, a diagnostic test. Appropriate surgery can then be carried out, followed by low-dose, long-term steroid therapy to maintain the sense of smell. Olfactory biopsy specimens taken during the course of evaluation and treatment show electron-optically normal olfactory receptors, meaning that the probable pathogenesis of the sensory deficit is an obstruction, mechanical and possibly biochemical. Two cases of steroid-dependent anosmia are presented to detail a fully reversible anosmia using state-of-the-art techniques.
Adrenal Cortex Hormones↗
Caution urged in treating 'steroid-dependent anosmia'.
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Adrenal Cortex Hormones↗
Vocal cord adduction while sniffing.
The movement of vocal cords while sniffing was observed by fiberscope and electromyogram. Nasal airflow rate was compared while sniffing and during normal respiration. Fiberscopic and electromyographic observations revealed that the vocal cords adduct while the subject is sniffing. The olfactory sense was not needed. It also was different from the defensive laryngeal reflex closure. The nasal airflow rate during sniffing was less during inspiration than during normal respiration. Inhalation while sniffing was different from that of respiration. It is concluded that the vocal cords adduct while sniffing, and that the nasal airflow rate might be less during sniffing than during normal respiration.
Adolescent↗
Magnetic resonance imaging of the olfactory apparatus.
The magnetic resonance imaging visualization of the olfactory apparatus is reported in this article. We used a superconductor-type magnetic resonance device (Siemens Magnetom H15 (1.5 T) with a surface coil. The subjects were patients with posttraumatic anosmia. The olfactory bulbs were clearly visualized in the frontal plane magnetic resonance images, the olfactory bulbs and the foramina of the cribriform plate were visualized in the sagittal section, and the olfactory bulbs, tracts, and other structures were visualized in the coronal sections. The olfactory nerves could not be seen.
Brain Diseases↗
Long-term follow-up of olfactory loss secondary to head trauma and upper respiratory tract infection.
OBJECTIVE: To determine the extent to which olfactory function can improve after loss induced by head trauma or a previous upper respiratory tract infection (URI) and the time for this improvement for more effective patient counseling. DESIGN: Patients initially evaluated at the University of Cincinnati (Ohio) Taste and Smell Center were reevaluated for olfactory loss with the University of Pennsylvania (Philadelphia) Smell Identification Test 1 to 5 years after initial testing. Changes in score on this test were used to indicate improvement in sensory function. Subjective information on olfactory ability and olfactory symptoms was also collected. SETTING: University-based tertiary care center. PATIENTS AND OTHER PARTICIPANTS: Forty-one patients with olfactory loss induced by head trauma (20) or previous URI (21). RESULTS: Seven (35%) of 20 patients with head trauma improved on the smell test by 4 points or more. Fourteen of 21 (67%) patients with a previous URI had improved scores of this magnitude or more. A statistically significant correlation was noted between the amounts of improvement and length of follow-up for URI patients. Thirteen of these patients also reported improved olfactory function. CONCLUSION: These findings for patients with head trauma are consistent with other reports of recovery of (or improvement in) olfactory function after trauma-induced loss. For patients with previous URI, these data indicate that improvement in olfactory function occurs, but the improvement may take several years.
Adult↗
Topical corticosteroid treatment of anosmia associated with nasal and sinus disease.
OBJECTIVE: To establish the efficacy of topical corticosteroid nasal spray treatment of severe olfactory loss associated with severe nasal and sinus disease. DESIGN: Efficacy before and after open-label trial of topical corticosteroid nasal spray used exclusively in the head-down-forward position. SETTING: Taste and smell clinic of a university teaching hospital and research facility. PATIENTS: Taste and smell clinic patients with anosmia or severe hyposmia associated with paranasal sinus disease and nasal polyposis including 39 of 45 patients recruited from 1988 to 1994 who completed the topical corticosteroid treatment course and returned for subsequent testing. INTERVENTION: At least 8 weeks of treatment with flunisolide (Nasalide), 2 sprays in each nostril twice a day, with concurrent antibiotic treatment of any bacterial infection. MAIN OUTCOME MEASURES: Subjective olfactory symptoms, objective olfactory function tests, and otolaryngological evaluation (including endoscopic examination). RESULTS: Olfactory scores significantly improved following treatment (P < .001); signs of nasal and sinus disease significantly decreased (P < .001); and 26 (66%) of the patients reported a subjective improvement in their sense of smell. CONCLUSION: Topical corticosteroid nasal spray administered in a head-down-forward position is an effective treatment of severe olfactory loss associated with severe nasal and sinus disease.
Administration, Topical↗
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↗
Father-to-son transmission of hypogonadism with anosmia: Kallmann's syndrome.
Gonadal and olfactory features of Kallmann's syndrome, usually considered to be inherited as an X-linked recessive trait, were found in a father and son who both had cryptorchidism, hypogonadism, and hyposmia. The father's fertility had been induced with chorionic gonadotropin, leading to the birth of three children. Olfactory and gonadal functions were normal in the mother and two siblings. The father had low basal plasma testosterone and subnormal follicle stimulating hormone (FSH) response to luteinizing hormone-releasing hormone (LH-RH). The affected son and his healthy brother were prepubertal. Their basal plasma total and free testosterone, serum FSH and luteinizing hormone (LH), and response to LH-RH were similar. The clinical presentation and formal olfactory function studies were considered most helpful for the suggestive diagnosis of Kallmann's syndrome in children. The occurrence of this syndrome in this family is consistent with autosomal dominant inheritance.
Child↗
Decrements in volume of anterior ventromedial temporal lobe and olfactory dysfunction in schizophrenia.
CONTEXT: Patients with schizophrenia exhibit olfactory deficits, but it is unclear whether these represent a specific abnormality. The link between olfactory impairments and regional brain abnormalities has yet to be established. OBJECTIVES: To determine whether patients with schizophrenia exhibit volumetric deficits in the anterior ventromedial temporal lobe, the target for neuronal inputs from the olfactory bulb, and whether these are related to olfactory performance deficits. DESIGN: A cohort study of patients and healthy control subjects who underwent both 1-mm spoiled-gradient echo magnetic resonance imaging and behavioral tests of olfaction and memory. SETTING: Schizophrenia Research Center at the University of Pennsylvania, Philadelphia. PARTICIPANTS: Fifty-two patients with a DSM-IV diagnosis of schizophrenia and 38 healthy control subjects. Individuals were excluded for history of head trauma, significant substance abuse, and medical conditions affecting brain function or olfactory capacity. MAIN OUTCOME MEASURES: Gray matter volumes of the left and right temporal poles and the perirhinal and entorhinal cortexes; olfactory threshold detection sensitivity and identification test scores; composite indexes of verbal and spatial memory ability. RESULTS: Patients had reduced volumes, relative to cranial size, in left (P =.003) and right (P =.01) perirhinal and left (P =.002) and right (P =.002) entorhinal cortexes, but not in the temporal pole. Perirhinal, but not entorhinal, cortical volume decrement was associated with decreased olfactory threshold sensitivity. Neither region was associated with impaired memory performance. CONCLUSIONS: Patients with schizophrenia have reduced cortical volumes in brain regions that receive afferents directly from the olfactory bulb. Behavioral olfactory deficits are related to structural brain abnormalities in these regions.
Adolescent↗
Olfaction and social drive in schizophrenia.
BACKGROUND: The neurobiology of social dysfunction in schizophrenia is unknown, but smell identification deficits (SIDs) exist in schizophrenia, and olfaction is related to social affiliation in other mammals. The SIDs have been linked with negative symptoms and the deficit syndrome, but any specificity of SIDs for social dysfunction is unstudied. Low intelligence might explain this relationship, if it is associated with both negative symptoms and SIDs. We examined whether SIDs in schizophrenia were related broadly to negative symptoms, as are a number of other neuropsychological measures, or whether they might show a more specific relationship with social drive. METHODS: Smell Identification Test scores, Wechsler Adult Intelligence Scale-Revised IQ, symptomatology assessed with the Positive and Negative Syndrome Scale, and the deficit syndrome were determined in 70 patients with DSM-IV schizophrenia. RESULTS: The SIDs were related to negative symptoms and the deficit syndrome, but the association of SIDs with diminished social drive explained both relationships. Smell identification was also related to Wechsler Adult Intelligence Scale-Revised IQ, but intelligence was independent of the relationship of SID and social drive. The worse Smell Identification Test scores in male patients were attributable to a greater preponderance of men with the deficit syndrome. CONCLUSIONS: These analyses demonstrated independent relationships of Smell Identification Test scores to social drive and intelligence that together accounted for almost 50% of the variance in Smell Identification Test scores. There may be common neural substrates for the low social drive and SIDs in schizophrenia.
Drive↗
Prevalence of olfactory impairment in older adults.
CONTEXT: Older adults represent the fastest-growing segment of the US population, and prevalences of vision and hearing impairment have been extensively evaluated. However, despite the importance of sense of smell for nutrition and safety, the prevalence of olfactory impairment in older US adults has not been studied. OBJECTIVE: To determine the prevalence of olfactory impairment in older adults. DESIGN, SETTING, AND PARTICIPANTS: A total of 2491 Beaver Dam, Wis, residents aged 53 to 97 years participating in the 5-year follow-up examination (1998-2000) for the Epidemiology of Hearing Loss Study, a population-based, cross-sectional study. MAIN OUTCOME MEASURES: Olfactory impairment, assessed by the San Diego Odor Identification Test and self-report. RESULTS: The mean (SD) prevalence of impaired olfaction was 24.5% (1.7%). The prevalence increased with age; 62.5% (95% confidence interval [CI], 57.4%-67.7%) of 80- to 97-year-olds had olfactory impairment. Olfactory impairment was more prevalent among men (adjusted prevalence ratio, 1.92; 95% CI, 1.65-2.19). Current smoking, stroke, epilepsy, and nasal congestion or upper respiratory tract infection were also associated with increased prevalence of olfactory impairment. Self-reported olfactory impairment was low (9.5%) and this measure became less accurate with age. In the oldest group, aged 80 to 97 years, sensitivity of self-report was 12% for women and 18% for men. CONCLUSIONS: This study demonstrates that prevalence of olfactory impairment among older adults is high and increases with age. Self-report significantly underestimated prevalence rates obtained by olfaction testing. Physicians and caregivers should be particularly alert to the potential for olfactory impairment in the elderly population.
Aged↗
Kallmann syndrome gene (KAL-X) is not mutated in schizophrenia.
Kallmann syndrome and schizophrenia share several clinical features, including dysfunctional olfactory ability, hypogonadotrophic hypogonadism, an excess of affected males, and psychiatric presentation. Because of this congruence, it has been proposed that up to 70% of male schizophrenics might have mutations affecting the function or expression of the gene mutated in Kallmann syndrome, KAL-X. We identified and studied 9 unrelated males with schizophrenia (as defined by DSM-IIIR criteria) who also have severe anosmia (first percentile of normal range) and low sex drive (seventh percentile of the normal range), and we sequenced the exons and the intron-exon junctions of the KAL-X gene for each. We found no mutations, and conclude that schizophrenia is rarely, if ever, due to a mutation in the coding sequence or splice junctions of KAL-X.
Extracellular Matrix Proteins↗