Clinical significance of olfactory event-related potentials related to orthonasal and retronasal olfactory testing

OBJECTIVE: The purpose of this study was to evaluate the likelihood of recording olfactory event-related potentials (OERPs) in patients with an olfactory dysfunction and to correlate the electrophysiological responses to orthonasal and retronasal olfactory testing. DESIGN/MATERIALS AND METHODS: This was a prospective study of 65 patients with different origins of their olfactory loss. Orthonasal olfactory function was assessed with the "Sniffin' Sticks" test (orthonasal score; maximal score 48) and retronasal olfactory function with odorized powders presented intraorally (retronasal score; maximal score 20). The OERPs were obtained after presentation of 2-phenyl ethyl alcohol, the selected olfactory stimulus. Causes of olfactory dysfunction included postinfectious olfactory loss (n = 15), head trauma (n = 26), nasal polyposis (n = 15), and mixed causes (idiopathic, toxic, drug induced) (n = 9). RESULTS: Based on orthonasal testing, 32 and 33 patients were diagnosed with anosmia and hyposmia, respectively. Twenty-two patients from the hyposmic group demonstrated reliable OERPs. No OERPs were recorded in the anosmic group. Prevalence of OERPs in a cohort of patients with olfactory dysfunction was 33.8% (22 of 65). Median score (expressed as the percentage of the maximal score that could be obtained theoretically) in which OERPs were recorded was 50% (24 of 48) with orthonasal testing and 80% (16 of 20) with retronasal testing. CONCLUSIONS: Patients with olfactory dysfunction usually demonstrate OERPs in one third of the cases. When olfactory dysfunction is in the range that separates normosmic subjects from anosmic patients, patients may have identifiable OERPs. Interpretation of both orthonasal and retronasal psychophysical olfactory testing should be supported by the recording of OERPs in a clinical setting.     

Clinical assessment of olfactory functions in children who underwent adenotonsillectomy during pre- and post-operative period

Objective

The aim of this study was to investigate the changes of both ortho- and retronasal olfactory function in children who underwent adenotonsillectomy (AT) operation due to infectious and/or obstructive adenotonsillar disease.

Material and methods

A total of 25 children with adenotonsillar disease are included in the study; the children were followed for 6 months in the conducted clinics and underwent AT operation. An age- and sex-matched control group was constituted with 25 healthy children free of adenotonsillar disease. Adenoid and tonsillar hypertrophy was graded according to the subjective size scales. Each subject’s orthonasal and retronasal olfactory functions were assessed using odor identification test and retronasal olfactory testing. These tests were performed once, at the beginning of the study, for the control group and performed twice, at the beginning of the study and the third month follow-up, for the disease group. Parents of children in the adenotonsillar disease group filled out a visual analog scale to evaluate the children’s appetite at the same time with olfactory testing.

Results

The current investigation produced four major findings: (1) both ortho- and retronasal olfactory abilities of participants were improving following AT operation, (2) adenoid hypertrophy had a significant negative effect on both ortho- and retronasal olfaction, whereas tonsil hypertrophy had significant negative effect only on the retronasal olfactory score, (3) retronasal olfaction was found to be more affected by the adenoid size than the orthonasal, as shown with correlation analysis, and (4) the increase in appetite of children after AT operation had been specified by parents.

Conclusions

Children with adenotonsillar disease have increased olfaction abilities, namely ortho- and retronasal olfactory function following AT operation. In addition, retronasal olfactory function, an important component of flavor, seems to be more affected than orthonasal function. These results also explain the increased appetite of operated children.     

A questionnaire to assess olfactory rehabilitation for laryngectomized patients (Provox voice prosthesis users) in Japan

Objective

We used a questionnaire to investigate olfactory function and the present state of olfactory rehabilitation for laryngectomized patients in Japan.

Clinical assessment of retronasal olfactory function

OBJECTIVES: To develop a test kit for the simple assessment of retronasal olfactory function and to compare orthonasal and retronasal olfactory function in healthy subjects and patients with olfactory disorders. DESIGN AND PATIENTS: We tested 230 individuals with normosmia, hyposmia, and anosmia using grocery-available powders. Initially, 30 different substances were investigated. Subjects identified each substance using a list with 4 verbal items (forced choice). After preliminary experiments, 20 items were selected according to the degree to which they were identified by normosmic and anosmic subjects. Orthonasal olfactory function was assessed psychophysically using "sniffin' sticks," which includes tests for odor identification, discrimination, and butanol odor thresholds. In addition, anosmia was confirmed electrophysiologically by means of olfactory-evoked potentials. RESULTS: In healthy subjects, there was a test-retest reliability correlation of r(27) = 0.76 for retronasal olfactory function, which is similar to other odor identification tests. Retronasal testing in normosmic subjects allowed for the discrimination of sex-related differences, with women scoring higher than men (P =.007), and the identification of a slight decrease with age (r(120) = -0.20; P =.03). Orthonasal and retronasal identification of odors was found to correlate (r(86) = 0.78; P<.001). Retronasal testing allowed for the discrimination between normosmia, hyposmia, and anosmia (P<.001). In addition, retronasal performance of anosmic patients appeared to improve with duration of anosmia (P =.03). No difference was found between patients with anosmia of different origin. CONCLUSION: Results of the present investigation indicate that the assessment of retronasal olfactory function is possible using oral stimulus presentation.     

Differences between orthonasal and retronasal olfactory functions in patients with loss of the sense of smell

OBJECTIVE: To investigate differences between orthonasal and retronasal olfaction in patients with loss of the sense of smell without taste complaints. DESIGN: Electrophysiological and psychophysical testing of orthonasal and retronasal olfactory functions. SETTING: Outpatient clinics. PATIENTS: A series of 18 patients who had olfactory loss due to various reasons but no "taste" complaints. MAIN OUTCOME MEASURES: Orthonasal and retronasal olfactory functions assessed by olfactory event-related potentials and psychophysical smell tests. RESULTS: Psychophysical testing revealed retronasal olfaction to be normal or slightly altered, whereas orthonasal olfaction was either absent or severely compromised. Findings from nasal endoscopic examinations and computed tomographic scans were within the reference range in all subjects. In response to orthonasal stimulation there were neither detectable olfactory event-related potentials nor any with small amplitudes, whereas olfactory event-related potentials in response to retronasal stimulation were clearly present in some patients. CONCLUSION: These clinical observations, together with the psychophysical and electrophysiological findings, suggest that orthonasal and retronasal olfaction might be processed differently.     

The effect of non-diabetic chronic renal failure on olfactory function

Objectives

In chronic renal failure (CRF), deterioration of glomerular filtration results in accumulation of metabolites in the body which affect all organs. This study was performed to investigate the olfactory functions, and determine if hemodialysis or peritoneal dialysis improves olfactory function in non-diabetic CRF patients.

Retronasal and orthonasal olfactory ability after laryngectomy

OBJECTIVE: To characterize orthonasal and retronasal olfactory ability in patients who have had a total laryngectomy (TL). DESIGN: Prospective psychophysical evaluation of orthonasal and retronasal olfactory function. SETTING: Academic center outpatient clinic. PATIENTS: Volunteer sample of 36 subjects who underwent laryngectomy 0.5 to 25.0 years after TL (median, 3.5 years) and 36 age-, sex-, and smoking history-matched controls. MAIN OUTCOME MEASURES: Scores on established psychophysical tests of orthonasal and retronasal olfaction and self-rating scores of smell assessed with a visual analog scale. RESULTS: Assessment of orthonasal olfactory ability yielded a mean composite score of 4.3 (maximum score, 7) for the TL group and 5.3 for the control group (P = .002). Evaluation of retronasal olfactory ability resulted in a mean score of 11.0 (maximum score, 20) for the TL group vs 14.3 for the control group (P<.001). The mean self-rating scores of smell were 2.9 and 6.6 (maximum score, 10) for the TL and control groups, respectively (P<.001). Self-ratings of smell positively correlated with orthonasal (r(S) = 0.42; P<.001) and retronasal (r(S) = 0.50; P<.001) olfactory ability. CONCLUSIONS: Laryngectomy is associated with measurable decreases in olfactory function that are also subjectively perceived. Quantification of decrements in orthonasal and retronasal olfactory function can be used to characterize the severity of hyposmia and to assess the potential for, and efficacy of, olfactory rehabilitation. Although self-assessment with a simple visual analog scale successfully identifies many laryngectomy patients who have objective evidence of olfactory dysfunction, further investigation is necessary to evaluate and compare its validity and reliability with other available survey instruments that purport to measure olfaction.     

Reduction of olfactory sensitivity during normobaric hypoxia

Objective

Acute mountain sickness (AMS) is caused by a low partial pressure of oxygen and may occur above 2500 m. The aim of this research was to evaluate olfactory and gustatory abilities of healthy subjects during baseline conditions and after seven hours of normobaric hypoxia.

Application of the European Test of Olfactory Capabilities in patients with olfactory impairment

A central issue in olfaction concerns the characterization of loss of olfactory function: partial (hyposmia) or total (anosmia). This paper reports the application in a clinical setting of the European Test of Olfactory Capabilities (ETOC), combining odor detection and identification. The study included three phases. In phase 1, anosmics, hyposmics and controls were tested with the 16-items version of the ETOC. In phase 2, a short version of the ETOC was developed: patients with and controls without olfactory impairment were tested on a 6-items ETOC. In phase 3, to predict olfactory impairments in new individuals, the 16-items ETOC was administered on samples of young and older adults, and the 6-items version was applied in samples of young, elderly participants and Alzheimer patients. In phase 1, linear discriminant analysis (LDA) of ETOC scores classified patients and controls with 87.5 % accuracy. In phase 2, LDA provided 84 % correct classification. Results of phase 3 revealed: (1) 16-items ETOC: whereas in young adults, 10 % were classified as hyposmic and 90 % as normosmic, in elderly, 1 % were classified as anosmic, 39 % hyposmic and 60 % normosmic; (2) 6-items ETOC: 15 % of the young adults were classified as having olfactory impairment, compared to 28 % in the older group and 83 % in Alzheimer patients. In conclusion, the ETOC enables characterizing the prevalence of olfactory impairment in young subjects and in normal and pathological aging. Whereas the 16-items ETOC is more discriminant, the short ETOC may provide a fast (5–10 min) tool to assess olfaction in clinical settings.     

Retronasal olfactory function in nasal polyposis

OBJECTIVE: To investigate the question of whether there is a difference in retronasal olfactory function between patients suffering from chronic rhinosinusitis with nasal polyposis (NP) and healthy controls. This question was based on the clinical observation that many of these patients present with smell loss without complaining about loss of the appreciation of foods. STUDY DESIGN: Open prospective study comparing symptomatic patients with healthy controls. METHODS: A total of 56 healthy volunteers and 42 NP patients were tested for orthonasal and retronasal odor identification. All subjects received detailed nasal endoscopy; NP was staged according to the Malm classification. Patients rated their olfactory function on visual analogue scales. Orthonasal testing was performed using the "Sniffin' Sticks" test kit. Retronasal testing was evaluated with odorized powders applied to the oral cavity. In both tests, subjects were asked to identify 10 items using a forced choice paradigm. RESULTS: Overall, odor identification was better in controls compared with NP patients (P <.001). Although controls exhibited no difference between orthonasal and retronasal smelling (P =.26), in NP patients, olfactory function was significantly better when odors were applied through the retronasal route (P <.001). Ratings of general olfactory abilities correlated with retronasal and orthonasal olfactory function in NP patients (P <.001) but not in healthy controls (P =.34). CONCLUSION: Better retronasal than orthonasal olfactory function seems to be associated with the presence of mechanical obstruction in the anterior portion of the olfactory cleft. In turn, these data indicate that olfactory loss in NP seems to be caused by regional mechanical or inflammatory factors.     

Comparison of the effects of nasal steroids and montelukast on olfactory functions in patients with allergic rhinitis

Objective

Olfactory dysfunction is one of the comorbidities associated with allergic rhinitis (AR) and AR is one of the common causes of olfactory problems. We aimed to evaluate by the Sniffin’ Sticks test the effects on olfactory functions of nasal steroids and leukotriene antagonists used for allergic rhinitis.

Importance of neoadjuvant chemotherapy in olfactory neuroblastoma treatment: Series report and literature review

Introduction and objectives

Olfactory neuroblastoma (ONB) is a rare entity that constitutes less than 5% of nasosinusal malignancies. Mainstream treatment consists in surgical resection +/? adjuvant radiotherapy. By exposing results observed with apparition of new therapeutic options as neoadjuvant chemotherapy, the objective is to evaluate a series and a review of the current literature.

Newly developed method for mouse olfactory behavior tests using an automatic video tracking system

Objective

The mouse is the most popular animal model in olfactory research. Behavior tests with odorants are essential for determining olfactory phenotype. To the best of our knowledge, the mouse olfactory behavior test has not been standardized, making the results vulnerable to inter-observer variation. We sought to develop a new mouse olfactory behavior test assessed by an automatic video tracking system with minimal inter-observer variation.

Correspondence between three olfactory tests and suprathreshold odor intensity ratings

OBJECTIVES: The capability of three olfactory tests (European Test of Olfactory Capabilities, Sniffin' Sticks and Cross-Cultural Smell Identification Test) to similarly classify subjects as normosmics, hyposmics and anosmics as well as the relation between test performance and suprathreshold ortho- and retronasal odor intensity ratings were examined. MATERIAL AND METHODS: A total of 48 subjects (age range 15-84 years; mean age 49.5 years) completed the 3 olfactory tests, rated aqueous solutions of vanilla (0-0.31%) and lemon aroma (0-0.17%) for odor and flavor intensity and filled in a background questionnaire. Ten subjects had case histories indicating anosmia, with the remainder having subjectively normal olfaction. RESULTS: The test results were highly correlated and differentiated anosmic, hyposmic and normosmic subjects. At an individual level, some discrepancy was seen in the olfactory diagnoses given by the three tests. In principal component analysis, olfactory measurements were loaded on three components: (i) odor detection, discrimination and identification; (ii) suprathreshold intensity ratings; and (iii) threshold for n-butanol. Advanced age was related to impaired olfactory performance. CONCLUSIONS: Although the three olfactory tests diagnosed the individuals slightly differently, all were considered to be valid for clinical evaluation of olfactory capabilities. The tests separated anosmics and normosmics highly significantly, and permitted an assessment of hyposmia. The suprathreshold odor intensity ratings reflected a different dimension of olfaction than the three olfactory tests.     

Evaluation of the efficacy of the ‘nasal airflow‐inducing manoeuvre’ for smell rehabilitation in laryngectomees by means of the Sniffin′ Sticks test

Clin. Otolaryngol. 2011, 36 , 17–23 Objective: To determine the efficacy of the nasal airflow‐inducing manoeuvre (NAIM) as a method for olfactory rehabilitation in laryngectomees by the means of the Sniffin′ Sticks test. Study design: Prospective open interventional trial. Setting: Tertiary academic hospital. Participants: Thirty‐seven patients after laryngectomy have been screened and 25 patients have been included into the study. The participant’s sense of smell was tested with the Sniffin′ Sticks test before and after learning the nasal airflow inducing manoeuvre. The individual level of threshold, discrimination and identification (TDI) was determined and the individual threshold, discrimination and identification score was used to classify the patients as being anosmic, hyposmic or normosmic. Main outcome measures: The primary endpoint was the change of the threshold, discrimination and identification score before and after learning the nasal airflow inducing manoeuvre. The secondary endpoint was a change in the diagnostic group (normosmic, hyposmic and anosmic) after learning of the nasal airflow inducing manoeuvre. Results: There was a statistically significant increase in the total threshold, discrimination and identification score (P < 0.001) and the three sub‐scores (P ≤ 0.02) before and after the learning of the nasal airflow inducing manoeuvre. Patients gained seven points on average in the threshold, discrimination and identification score. Twenty of 25 patients showed an increase of five or more point in the threshold, discrimination and identification score. In the classification of the smell ability, 15 of 25 patients showed a change to a higher class (hyposmic to normosmic or from anosmic to hyposmic or normosmic). Conclusion: The nasal airflow inducing manoeuvre is a method for the successful rehabilitation of the sense of smell in laryngectomees. The evaluation with the Sniffin′ Sticks tests showed a clinically relevant increase of olfaction in 80% of patients. The teaching of the nasal airflow inducing manoeuvre should be included in post‐laryngectomy rehabilitation programmes.     

Clinicopathologic factors associated with recurrence in parotid carcinoma

Introduction

Parotid carcinomas have varying histological types and diverse biologic behaviors. Establishing an adequate treatment plan and predicting recurrence is important.

Esclerosis múltiple: ventaja izquierda para la lateralidad auditiva en pruebas dicóticas de procesamiento auditivo central y relación de pruebas psicoacústicas con examen de discapacidad-EDEM

Objective

To evaluate the central auditory processing disorders in patients with multiple sclerosis, emphasizing auditory laterality by applying psychoacoustic tests and to identify their relationship with the Multiple Sclerosis Disability Scale (EDSS) functions.

Prognostic significance of soft tissue deposits in laryngeal carcinoma

Introduction

Soft tissue deposits is tumorous islands apart from lymph nodes and occasionally diagnosed in neck dissection specimens. Their importance has begun to be recognized, however, their value has not been investigated in laryngeal cancer as a single tumor site.

The combined olfactory test in a Chinese population

OBJECTIVE: To establish an olfactory test in the Hong Kong Chinese population. STUDY DESIGN: Prospective analysis of the results of a combined olfactory test (COT) for patients with olfactory dysfunction and for normal subjects attending a secondary and tertiary ear, nose and throat centre. METHOD: Our COT was based on and modified from the Connecticut Chemosensory Research Centre test. It consisted of an odour identification test involving nine substances and a threshold test using a series of threefold dilutions of 1-butanol. From September 1998 to June 2002, 188 Hong Kong Chinese patients with olfactory dysfunction and subjects with normal olfaction were prospectively recruited. The subjects were categorized into normal, hyposmic and anosmic groups. The olfactory function of the main group of subjects (n = 153) was assessed with the COT by a blinded observer and also quantified with a visual analogue scale; the results were analysed to validate the discriminative ability of the COT. Another subgroup of subjects (n = 35) was tested with the COT twice with a two-week interval to evaluate test-retest reliability. RESULTS: There were 42 normal, 68 hyposmic and 43 anosmic subjects within the main group (total n = 153). The identification scores, threshold scores and combined olfactory scores were statistically significantly different between the anosmic, hyposmic and normal groups of subjects (p < 0.001). The combined olfactory score correlated with the visual analogue score and the correlation coefficient was 0.56 (p < 0.01). The mean time spent on each COT was 8.6 minutes (standard deviation = 3.4 minutes). The test-retest reliability of the COT was satisfactory, with a one-way model intraclass correlation coefficient of 0.87 (n = 35). CONCLUSION: The satisfactory discriminative ability and test-retest reliability of the COT have been demonstrated in this study. The COT is a feasible method for assessing sense of smell in the Hong Kong Chinese population.