Olfactory function assessed with orthonasal and retronasal testing, olfactory bulb volume, and chemosensory event-related potentials

OBJECTIVE: To investigate whether differences in olfactory function between healthy individuals and patients with olfactory loss could be detected by various diagnostic tests. DESIGN: Psychophysical testing of orthonasal and retronasal olfactory functions, magnetic resonance imaging of olfactory bulb (OB) volume, and chemosensory event-related potential (ERP) measurement performed between January 1, 2005, and October 31, 2005. SETTING: Academic tertiary referral medical center. PATIENTS: Eleven healthy individuals with normal olfactory function (NL) and 11 patients with nasal polyposis (NP), 11 with posttraumatic olfactory loss (PT), and 11 with postinfectious olfactory loss (PI) were included in this study. MAIN OUTCOME MEASURES: Orthonasal and retronasal olfactory test results, magnetic resonance imaging-based OB volume, and ERPs to both olfactory and intranasal trigeminal stimulation. RESULTS: Orthonasal and retronasal testing revealed that NL individuals had higher scores than patients with NP, PT, or PI. Retronasal scores were higher in NP patients compared with PT and PI patients. The OB volumes were higher in NL individuals compared with NP, PT, and PI patients. The OB volumes in PT patients were significantly lower than those from NP and PI patients. Olfactory ERPs were different between NL individuals and NP, PT, and PI patients, and trigeminal ERPs were significantly different when comparing NL individuals with NP patients. For the entire cohort, a significant correlation was found between orthonasal testing and OB volume, between retronasal testing and OB volume, and between both orthonasal and retronasal testing and olfactory ERP amplitudes. Olfactory ERPs were recorded in the 11 NL individuals and in 3 NP, 3 PT, and 4 PI patients, defined as responders. Orthonasal and retronasal test scores, OB volume, and olfactory ERPs were significantly larger in responders compared with nonresponders. CONCLUSIONS: Significant differences in various tests that evaluate olfactory function were detectable in a cohort of NL individuals and NP, PT, and PI patients. This finding suggests that these diagnostic tools provide information in terms of the clinical assessment of olfactory function. Future studies will investigate their combined use in terms of the prognosis of olfactory function in patients with olfactory loss.     

Retronasal and orthonasal olfactory function in relation to olfactory bulb volume in patients with posttraumatic loss of smell

OBJECTIVE: The aims of this study were to evaluate olfactory function with orthonasal and retronasal testing in patients with posttraumatic olfactory loss and to investigate the relation between residual olfactory function and olfactory bulb (OB) volume. METHOD: A retrospective study of 25 patients with posttraumatic olfactory loss was performed. Orthonasal olfactory function was assessed with the Sniffin' Sticks test kit; retronasal olfactory function was assessed with intraorally applied odors. Magnetic resonance imaging was used to determine OB volume and cortical damage in the frontal and temporal areas. RESULTS: The main outcomes of the present study were the demonstration of a correlation between olfactory function and OB volume, which was more pronounced for retronasal than for orthonasal olfactory function; retronasal olfactory function was most affected in the patients with the most extensive cerebral damage and was least compromised in patients without such damage; OB volumes were smaller in patients with parosmia compared with those without; and the presence of parosmia was clearly associated with the presence of cerebral damage. CONCLUSION: The data confirm that OB volume is an indicator of olfactory function but, interestingly, in this study, it is largely determined by retronasal olfactory sensitivity. In addition, these results emphasize the role of higher cortical centers in olfactory function, and especially in parosmia, which may, at least in some cases, be related to lesions in the fronto-orbital and anterior temporal cortices. It would be of interest to investigate OB volume further in relation to the prognosis of the disorder.     

Retro- and orthonasal olfactory function in relation to olfactory bulb volume in patients with hypogonadotrophic hypogonadism

Introduction

Idiopathic hypogonadotrophic hypogonadism with an olfactory deficit is defined as Kallmann syndrome and is distinct from normosmic idiopathic hypogonadotrophic hypogonadism.

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.     

Changes in olfactory identification function in total laryngectomy patients - A retrospective study focusing on nasal airflow-inducing maneuver usage,Open Essence misreactions,and odor cluster

PurposeWe aimed to examine how the olfactory identification function of laryngectomy patients is altered by nasal airflow-inducing maneuver (NAIM), a method of olfactory rehabilitation, by analyzing incorrect and correct responses to olfactory identification tests to achieve odor classification.MethodsOlfactory identification test (Open Essence [OE]) was administered to 46 patients who had undergone a total laryngectomy [Start group (NAIM was initiated from this study) = 17; (already) Using group = 19; and Nonuse group = 10]. The tests were immediately performed after the NAIM and after a mean duration of 8 months.ResultsIn the Start group, changes in OE correct and incorrect responses showed a significant increase and decrease in the number of correct (p < 0.01) and “detectable but not recognizable” responses (p < 0.05), respectively. In the Using group, errors related to “same cluster” and “detectable but not recognizable” increased and decreased significantly (p < 0.05), respectively. The Nonuse group showed a trend of demonstrating a relatively lower number of correct responses (p < 0.1). Results of odor classification showed that only “putrefaction and sulfur” did not have any significant positive responses in the Start group.DiscussionEvidently, the possibility of capturing changes in olfactory identification function by performing a false response analysis was observed, even if recovery appears to have stalled after long-term use of NAIM. Furthermore, including the “putrefaction and sulfur” cluster in the olfactory rehabilitation of laryngectomy patients and teaching them to consciously sniff “putrefaction and sulfur” in their daily lives is necessary.     

Development of a clinical instrument improving rehabilitation of olfaction with the Nasal Airflow-Inducing Maneuver in Swedish laryngectomized patients

Conclusion: The protocol is a useful and reliable tool for evaluating the use of the Nasal Airflow-Inducing Maneuver (NAIM) in patients who have undergone total laryngectomy. It facilitates the optimization and improvement of olfactory treatment with NAIM and is sensitive to changes over time. However, further modification of the protocol is needed before a broad implementation into routine clinical practice can be recommended. Objectives: To develop and assess whether a protocol evaluating NAIM variables is sensitive and reliable to study olfactory function after total laryngectomy. Subjects and methods: Video documentation from 21 laryngectomized patients receiving olfactory rehabilitation during the study period 2002–2005 was used. The patients’ execution of NAIM was evaluated using a protocol with identified NAIM variables. Olfactory acuity was tested with the Scandinavian Olfactory Identification Test (SOIT). Data from the first (baseline) and third (after treatment) intervention sessions and from follow-up at 6 and 12 months are reported. Results: According to the NAIM evaluation protocol patients significantly improved their execution of the NAIM technique over time and these improvements were associated with improvements in olfactory acuity (SOIT). Using the protocol important key variables for improvement of the NAIM technique were identified. The inter- and intra-rater reliability for the NAIM evaluation protocol was moderate to good.     

Olfactory ensheathing cells in facial nerve regeneration

IntroductionOlfactory ensheathing cell is a unique kind of glia cells, which can promote axon growth. Little is known about the differences between olfactory mucosa olfactory ensheathing cells and olfactory bulb olfactory ensheathing cells in the capability to promote nerve regeneration.ObjectiveTo study the recovery of the rat facial nerve after olfactory ensheathing cells transplantation, and to compare the differences between the facial nerve regeneration of olfactory mucosa-olfactory ensheathing cells and olfactory bulb olfactory bulb olfactory ensheathing cells transplantation.MethodsInstitutional ethical guideline was followed (201510129A). Olfactory mucosa-olfactory ensheathing cells and olfactory bulb olfactory ensheathing cells were cultured and harvested after 7 days in vitro. 36 Sprague Dawley male rats were randomly divided into three different groups depending on the transplanting cells: Group A: olfactory mucosa-olfactory ensheathing cells; Group B: olfactory bulb olfactory ensheathing cells; Group C: DF-12 medium/fetal bovine serum. The main trunk of the facial nerve was transected and both stumps were inserted into a polylactic acid/chitosan conduit, then the transplanted cells were injected into the collagen in the conduits. After 4 and 8 weeks after the transplant, the rats of the three groups were scarified and the facial function score, facial nerve evoked potentials, histology analysis, and fluorescent retrograde tracing were tested and recorded, respectively, to evaluate the facial nerve regeneration and to analysis the differences among the three groups.ResultsOlfactory ensheathing cells can promote the facial nerve regeneration. Compared with olfactory bulb olfactory ensheathing cells, olfactory mucosa olfactory ensheathing cells were more effective in promoting facial nerve regeneration, and this difference was more significant 8 weeks after the transplantation than 4 weeks.ConclusionWe discovered that olfactory ensheathing cells with nerve conduit could improve the facial nerve recovery, and the olfactory mucosa olfactory ensheathing cells are more effective for facial nerve regeneration compared with olfactory bulb olfactory ensheathing cells 8 weeks after the transplantation. These results could cast new light in the therapy of facial nerve defect, and furnish the foundation of auto-transplantation of olfactory mucosa olfactory ensheathing cells in periphery nerve injury.     

Olfactory bulb volume and depth of olfactory sulcus in patients with idiopathic olfactory loss

Olfactory loss is considered as idiopathic (IOL) when no cause can be found, neither on the basis of a standardized history nor a thorough clinical evaluation. Olfactory bulb volume (OB) has been shown to be decreased in patients with olfactory loss due to trauma, infections, or sinonasal disease. However, OB volume has not yet been investigated in IOL patients. Twenty-two patients with IOL were compared with 22 controls in terms of olfactory performance and of OB volume assessed with magnetic resonance imaging (MRI). Psychophysical testing confirmed that patients had lower scores than controls: P < 0.001 for threshold (T), discrimination (D), identification (I) and global TDI score. Mean right, left and total OB volumes were significantly smaller for IOL patients as compared to controls. Both for IOL and controls, there was a significant correlation between odor thresholds and total OB volume, respectively. In conclusion, patients with IOL have decreased olfactory function and decreased OB volume when compared with controls. This was previously demonstrated for patients with postinfectious or posttraumatic olfactory dysfunction, but not for patients with uneventful conditions possibly damaging their olfactory apparatus.     

Olfactory acuity based on Brief Smell Identification Test (BSITⓇ) in migraine patients with and without aura: A cross-sectional,controlled study

ObjectiveThe aim of this study was to evaluate olfactory acuity in migraine patients with and without aura (MwA and MwoA)Material and methodsThe study included 30 MwA patients, 30 MwoA patients, and 30 age- and gender-matched controls. Demographic features and odor-related symptoms (osmophobia, odor offensiveness, and odor-triggered attack status) were noted. Olfactory acuity was measured using the Brief Smell Identification Test (BSIT®), a 12-item derivative of the University of Pennsylvania Smell Identification Test (UPSIT®). BSIT® scores were compared between the migraine patients and controls.ResultsThe mean BSIT® score did not differ significantly between the MwA patients (8.7 ± 0.9) and MwoA (9.17 ± 0.9) patients (P = 0.094); however, the mean score in the control group was higher (10.4 ± 0.6) than in the MwA and MwoA patients (P < 0.001). The mean BSIT® score did not differ significantly between patients with and without odor-triggered migraine attacks (9 ± 0.9 and 8.8 ± 0.8, respectively) (P = 0.4). Osmophobia and odor-triggered attacks were more common in the MwA patients than in the MwoA patients (odor-triggered attacks: 66% vs. 40% [P = 0.04]; osmophobia: 76.6% vs. 60% [P = 0.16])ConclusionOlfactory acuity is lower during attack-free periods in migraine patients, as compared to controls. Migraine aura status does not affect olfactory acuity. Odor-triggered attacks, osmophobia, and offensive odors between attacks were more common in the MwA patients than in the MwoA patients.     

上呼吸道感染后嗅觉障碍患者脑形态学与嗅觉功能相关性分析

目的 通过探究上呼吸道感染后嗅觉障碍脑灰质形态变化,得出上呼吸道感染后嗅觉障碍患者嗅觉中枢结构的影像学特点。方法 选取上呼吸道感染后嗅觉障碍的患者24例与嗅觉功能正常的健康对照受试者20例,通过基于体素的大脑皮质形态学体积测量(VBM)比较患者的大脑灰质和白质体积与对照组的差异。结果 上呼吸道感染后嗅觉障碍组患者TDI[气味察觉阈(T)、气味辨别能力(D)、气味识别能力(I)]总分(16.45±5.62)分,T为(2.33±0.93)分,D为(6.54±2.60)分,I为(7.58±3.22)分;嗅觉障碍平均时长为(19.00±6.33)个月;视觉模拟量表评分(VAS)为(7.79±2.41)分,与对照组比较均存在统计学差异(P<0.05)。上呼吸道感染后嗅觉障碍患者的大脑灰质总体积和嗅皮质体积明显小于对照组(P<0.05),大脑灰质总体积占全脑体积的比例和皮质厚度与嗅觉功能评分TDI值呈正相关(r=0.71,P<0.000 1;r=0.69,P=0.000 9)。结论 上呼吸道感染后嗅觉障碍患者大脑灰质总体积和嗅皮质体积减少,且嗅觉功能与大脑灰质体积比例及皮质厚度呈...     

Die Untersuchung des Riechvermögens

Olfactory disorders are common. Functional anosmia is present in about 5–6% of the general population, while from the age of about 55 years the olfactory sense is restricted in about 25% of cases. A precise examination is necessary to describe the patient’s symptoms and ascertain possible reasons for them. As far as diagnosis and possible treatment of olfactory or gustatory disorders are concerned, the main advantage allowing progress is the availability of standardised methods of testing the chemical senses. In this article procedures for orthonasal and retronasal psychophysical examination of the olfactory sense and the derivation of potentials evoked by olfactory stimuli are described. In addition, possible ways of examining the intranasal sensitivity of the trigeminal nerve and measuring the volume of the olfactory bulb, and also for immunochemical investigation of biopsies from the olfactory region, are discussed as possible means of reaching a diagnosis.     

Gustatory and olfactory dysfunction in laryngectomized patients

After total laryngectomy surgery, nasal airflow is moved permanently to the tracheostomy opening, compromising the contact of odorant molecules with the nasal cavity, which may reflect changes in the olfactory and gustatory perception in these individuals.ObjectiveTo evaluate the functions of smell and taste in total laryngectomized patients. Study design: a study of series.MethodThe sample included a group of 25 patients submitted to total laryngectomy and another group of 25 patients who did not underwent the procedure. The taste function was evaluated by gustatory strips of filter paper. To assess the olfactory function we employed the Brief Smell Identification Test.ResultsAmong the laryngectomized patients there was more hypogeusia (80%, p < 0.05), as well as hyposmia (88%, p < 0.001), alone and concomitant (72%, p < 0.001). Concerning flavor discrimination, the bitter taste did not differ between the groups - which was different from the other flavors. In the olfactory aspect, laryngectomized patients performed worse in detecting warning and food-related odors. We found that a history of smoking and alcohol consumption were significantly more frequent among laryngectomized patients.ConclusionWe found a decrease of gustatory and olfactory functions in total laryngectomized patients in this study.     

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.

Total laryngectomy negatively impacts sinonasal and olfactory-specific quality of life

PurposeThe purpose of this study is to characterize deficits in olfactory-specific and sinonasal-specific QoL after total laryngectomy (TL) with validated patient reported outcome measures.MethodsThirty patients who had a TL were prospectively enrolled. Patient demographics, as well as scores from the Questionnaire of Olfactory Disorders Negative Statements (QOD-NS) and the Sino-nasal Outcome Test-22 (SNOT-22) were collected. Univariate analysis was performed to assess associations between patient characteristics and QoL scores.ResultsThe average QOD-NS score was 37.9 ± 11.4 (<38.5 is considered abnormal) and average SNOT-22 score was 32.0 ± 3.8 (>20 indicates a moderate/severe impact on QoL). The abnormal QOD-NS group had a greater percentage of former smokers compared to the normal group (77.8% vs. 58.1%; P = 0.56) and more median days from surgery compared to the normal group (904 vs. 477 days; P = 0.24).ConclusionsOlfactory dysfunction associated with TL results in blunting of olfactory-specific QoL.     

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.     

Examination of the sense of smell

Olfactory disorders are common. Functional anosmia is present in about 5-6% of the general population, while from the age of about 55 years the olfactory sense is restricted in about 25% of cases. A precise examination is necessary to describe the patient's symptoms and ascertain possible reasons for them. As far as diagnosis and possible treatment of olfactory or gustatory disorders are concerned, the main advantage allowing progress is the availability of standardised methods of testing the chemical senses. In this article procedures for orthonasal and retronasal psychophysical examination of the olfactory sense and the derivation of potentials evoked by olfactory stimuli are described. In addition, possible ways of examining the intranasal sensitivity of the trigeminal nerve and measuring the volume of the olfactory bulb, and also for immunochemical investigation of biopsies from the olfactory region, are discussed as possible means of reaching a diagnosis.     

Olfactory training for patients with olfactory loss after upper respiratory tract infections

Olfactory training consisting of daily suprathreshold odor exposure over 12 weeks seems to improve olfactory function. It is unknown if a longer period of training might be more effective. A prospective non-randomized clinical study was performed including 39 patients with olfactory loss after an upper respiratory tract infection (URTI) of less than 24 months duration. Patients exposed themselves with suprathreshold concentrations of four odors (rose, eucalyptus, lemon, cloves) applied in ‘‘Sniffin’ Sticks’’ felt-tip pens over 32 weeks. Olfactory function was performed before (T1), after 16 weeks (T2), and 32 weeks of training (T3) using the ‘the Sniffin’ Sticks test kit calculating the TDI score (Threshold, Discrimination, Identification). The mean TDI score showed a non-significant trend of improvement at T2, and was significantly increased at T3 (p = 0.021). Overall, 31 patients (79 %) showed an increased TDI score at T3. The increase of TDI from T1 to T3 was 4.6 ± 5.1. Age, gender, duration and initial severity of olfactory loss had no influence on the improvement (all p > 0.05). Only patients with a D score lower than the median value of 8 showed a significantly higher increase of the D score at T3 (p = 0.004). The present study confirmed that olfactory training improves olfactory function in patients with olfactory loss after URTI. A longer duration of training over 32 weeks seems to increase the effectiveness in comparison to a 12-week period. This was tested in a completed German multicenter trial to be published soon containing a control group to include the effect of a spontaneous recovery after URTI.     

精粹摘选

（一项前瞻性纵向研究：全喉切除术后患者嗅球体积缩小嗅觉功能减退）这项纵向前瞻性研究首次通过研究发现因全喉切除后嗅觉刺激中断可导致嗅球体积的缩小和嗅觉功能的减退。     

Effectiveness of olfactory rehabilitation with the nasal airflow-inducing maneuver after total laryngectomy: one-year follow-up study

OBJECTIVE: To assess the long-term results of the nasal airflow-inducing maneuver in olfaction rehabilitation in patients who had undergone laryngectomy. DESIGN: Prospective interventional study. SETTING: University hospital. PATIENTS: Twenty-four patients who had undergone laryngectomy (21 men and 3 women; mean age, 68 years) who received olfactory rehabilitation with the nasal airflow-inducing maneuver were reevaluated 6 and 12 months after primary treatment. MAIN OUTCOME MEASURE: Olfactory function was tested by means of a semistructured interview; the Questionnaire on Olfaction, Taste and Appetite; and the Scandinavian Odor-Identification Test. Quality of life was measured with the European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-H&N35 questionnaires. Patients were categorized as smellers or nonsmellers based on results of the Scandinavian Odor-Identification Test. RESULTS: Before treatment, 10 of 24 patients (42%) were smellers and 14 (58%) were nonsmellers. At 6-month follow-up, 20 of 23 patients (87%) were smellers, whereas after 12 months, 21 of 24 patients (88%) were smellers. Long-term olfaction rehabilitation was achieved in 11 of 14 patients (79%) with anosmia, and 15 of all 24 patients (63%) could be classified as having normal olfactory capacity at the end of the study. CONCLUSION: The nasal airflow-inducing maneuver is a patient-friendly, inexpensive, and effective method for restoring the sense of smell in patients after laryngectomy, and the results persist in the long term.     

Analysis of the clinical effect of olfactory training on olfactory dysfunction after upper respiratory tract infection

Background: Olfactory dysfunction is a common symptom during otolaryngology outpatient service.

Objective: To explore the clinical effect of olfactory training on olfactory dysfunction after upper respiratory tract infection (URTI), and its influence factors.

Material and methods: A total of 60 confirmed cases of URTI-induced olfactory dysfunction were enrolled into the present study. The olfactory training lasted for 24 weeks. These patients were tested using Sniffin’ Sticks and threshold-discrimination-identification (TDI) composite scoring before treatment, and at 1, 3 and 6 months after treatment.

Results: It was found that URTI-induced olfactory dysfunction patients had more evident deterioration in odor identification ability. The effective rates of olfactory training on olfactory dysfunction at 1, 3 and 6 months after treatment were 1.67%, 26.67% and 41.67%, respectively. The TDI scores at the 3rd and 6th months, but not at the 1st month, were significantly higher, when compared to those before treatment. The course of diseases was a significant influence factor on the therapeutic effect of olfactory training (OR = 0.805, 95% CI: 0.696–0.931).

Conclusions: Olfactory training can efficiently cure URTI-induced olfactory dysfunction, and in particular, significantly improve the odor discrimination ability and odor identification ability.

Significance: Providing useful data for further research regarding olfactory dysfunction.