Olfactory function following late repair of choanal atresia

Results of olfactory function tests (threshold determination and odor identification) in three cases of bilateral and one case of unilateral choanal atresia are reported. All four patients underwent successful repair of choanal atresia at relatively advanced ages (8 to 31 years). Test results showed that patients who had suffered from bilateral atresia had permanent olfactory deficits, while the patient who had suffered from unilateral atresia appeared to have normal olfactory acuity. Although these results should be interpreted with caution due to the small number of cases examined, they suggest the possibility that early sensory exposure might be needed for the normal development of central olfactory functions in analogy to the visual system.     

Study on difference in olfactory response in dysosmia patients

Using 1952 dysosmia patients, we studied the difference in olfactory response to 5 types of odorous substances used in the standard olfactory acuity test in Japan--beta-phenyl ethyl alcohol, methyl cyclopentenolone, isovaleric acid, gamma-undecalactone, and scatol. Olfactory dysfunctions included 887 patients with chronic paranasal sinusitis, 255 with allergic rhinitis, 326 with common cold sequela, 77 with complications from head injuries, 28 with drug-induced dysosmia, 39 with congenital dysosmia, 257 with dysosmia of unknown etiology, and 83 miscellaneous. The standard olfactory acuity test before treatment indicated that 82 patients detected only one odor within the detection threshold and 157 within the recognition threshold; 40 responded only to isovaleric acid at the detection threshold and 101 at the recognition threshold. Both figures were significantly greater than those who responded to other odors (p < 0.01). No specific trends were noted in etiologies of dysosmia that allowed smelling of isovaleric acid only either at the detection or recognition threshold. Among those whose olfactory thresholds were judged to be scaled out against all 5 odorous substances, 552 were rated as scaled out at the detection threshold and 630 at the recognition threshold. During post treatment, 33 scaled out at the detection threshold and 32 scaled out at the recognition threshold improved enough to smell 1 type of odor. Of these, 15 scaled out at the detection threshold and 13 scaled out at the recognition threshold became able to smell only isovaleric acid. Those becoming able to smell only isovaleric acid either at the detection or recognition threshold, significantly outnumbered those becoming able to smell other odors (p < 0.01). No outstanding cause of dysosmia was seen in those able to smell isovaleric acid. This data indicates that olfactory function for detecting isovaleric acid is relatively resistant to disease and is most likely to be restored. The difference in olfactory response of patients with olfactory dysfunction such as those above may be due to variations in the number of olfactory receptor proteins for specific odors within olfactory cells or different responses to the type of molecules of odor-emitting substances.     

Unilateral examination of olfactory threshold using the Jet Stream Olfactometer

Objective: The Jet Stream Olfactometer, a modification by the T&T olfactometer, has been recently developed and is now commercially available. This Jet Stream Olfactometer can routinely measure the unilateral sense of smell. Clinical usefulness of the Jet Stream Olfactometer was evaluated. Methods: Twenty-three patients with sinus-related symptoms were examined. Unilateral olfactory acuity was examined using the Jet Stream Olfactometer and compared it with the anatomy of the olfactory cleft by computed tomographic (CT) scans. Results: In 13 of the 23 patients examined the right olfactory threshold was similar to that of the left. Of these 13, in seven patients there was transport damage of the odorants and in the other six there was sensorineural damage. Ten patients showed an apparent difference between the right and left smell thresholds. Anosmia in seven of these ten patients was due to a conductive olfactory disturbance resulting from rhinosinusitis, whereas sensorineural damage was recognized in the other three patients. The difference in the detection threshold between the right and left nasal cavities was well correlated to that of the opacity between the right and left olfactory clefts. Conclusion: Jet Stream Olfactometer provides a convenient and reliable means for assessing the ability of unilateral smell.     

Sense of smell in long-standing nasal polyposis.

An impaired sense of smell is a common complaint in patients with nasal polyposis, and hyposmia is usually attributed to obstruction of the nasal airways. The duration of nasal polyposis and nasal surgery may also affect olfaction. It has been shown that aging and chronic rhinitis both impair olfaction. The aim of our study was to evaluate the sense of smell in patients who had had nasal polyposisfor at least 20 years. The olfactory threshold was assessed with a commercially available odor detection threshold test. The threshold of 19 (46%) of 41 patients was greater than the age-related upper 95% reference limit. In a forward stepwise multiple regression analysis of all the polyposis patients, the degree of opacity of ethmoidal sinuses seen in computed tomography (CT), polyposis visible in anterior rhinoscopy, total nasal resistance, and gender had a significant association with olfactory threshold.     

Clinical study of flavor disturbance

OBJECTIVE: We have observed that, in cases of smell loss, patients often complain of taste loss as well even though they actually have normal gustatory acuity according to gustatory tests; we have defined such symptoms as "flavor disturbance". The clinical features of flavor disturbance are reported in this paper. MATERIAL AND METHODS: A total of 297 patients (99 males, 198 females; mean age 55.5 years) were treated for olfactory disturbance at the hospital of Hyogo College of Medicine between July 1995 and August 2001. Sixty-six out of 297 patients (22.5%) also experienced taste disturbance, and 49 of these 66 cases were evaluated by means of smell and taste tests. These 49 patients who complained of taste and smell loss were classified into two groups according to the results of their smell and taste tests. Patients who only complained of olfactory disturbance were also reviewed. RESULTS: There was no relationship between the severity of olfactory disturbance and the degree of flavor disturbance. The incidence of flavor disturbance was high in patients with sudden olfactory disturbance after upper respiratory tract infection or head trauma and low in those with slowly progressive olfactory disturbance. The symptoms of flavor disturbance improved regardless of whether smell was improved or not. CONCLUSIONS: The patients with flavor disturbance tended to misrecognize that they had taste loss because of sudden smell loss, and there were more of these cases than we expected. When patients with smell and taste loss are treated, flavor disturbance should also be considered.     

Validation of the combined olfactory test

A new test of olfactory function, the combined olfactory test, has been designed to assess odours easily recognizable by the test population. The test consists of an odour recognition test of nine odours, where an odour in a bottle is chosen from a list of four possible odours in a forced choice manner. This is followed by a threshold test using a series of three-fold dilutions of l-butanol. The mean of the two scores is the combined olfactory score. The test was subjected to a validation study. It was performed on 133 participants with a normal sense of smell and a normal rhinological examination and on 94 participants who said that they did not have a sense of smell. There was a highly significant difference between the combined olfactory score in the normal and ‘anosmic’ groups (P < 0.001). This significant difference was the same between the two groups for the threshold and odour recognition arms of the test. There was a highly significant differece (P < 0.001) between the two subgroups of ‘completely anosmic’ and ‘almost anosmic’ participants, indicating that the test could grade the degree of olfactory dysfunction.     

Olfactory changes at threshold and suprathreshold levels following septoplasty with partial inferior turbinectomy

Partial inferior turbinectomy with septoplasty is routinely carried out for airway obstruction. However, its effects on the sense of smell have not been systematically evaluated. The aim of this prospective study was to evaluate the influence of septoplasty with partial inferior turbinectomy on threshold and suprathreshold olfactory acuity. The subjects were 30 patients undergoing septoplasty including partial inferior turbinectomy. Olfactory function was determined by the "Sniffin' Sticks," which allow the assessment of odor thresholds, odor discrimination, and odor identification. The patients rated both olfactory function and nasal airflow using visual analog scales. Nasal airflow was measured by anterior rhinomanometry. Multivariate analyses of variance for repeated measures were used to analyze the results before and after surgery (mean interval, 9.1 weeks). After operation, 87% of the patients had increased airflow, 80% had improved olfactory function in terms of odor identification, and in 70% odor discrimination was found to be improved - but only 54% had improved olfactory function in terms of odor thresholds. Surgery increased ratings of nasal airflow in 93%, and those of olfactory function in 77% (p < .001). Similarly, bilateral inspiratory nasal flow increased (p < .001) and olfactory function was improved (p < .001) after surgical treatment. However, this increase was most pronounced for suprathreshold tests, while it was moderate for odor thresholds (interaction "surgery" x "olfactory test," p = .001). The present investigation suggests that septoplasty in combination with inferior turbinectomy has a beneficial effect on olfaction, mainly on suprathreshold olfactory functions. This effect may be partly due to interactions between the increased perception of nasal airflow and cognitive factors involved in olfactory sensitivity. According to the present results and data from the literature, a moderate decrease of olfactory function appears to occur in as many as 20% of patients. However, anosmia seems to be an extremely rare complication of septoplasty and partial turbinectomy.     

Chemosensory function assessed with psychophysical testing and event-related potentials in patients with atrophic rhinitis

Atrophic rhinitis (AR) is a chronic inflammation of the nose characterized by an atrophy of the nasal mucosa. This is typically associated with an impaired sense of smell and a subjective sensation of poor nasal breathing. The aim of this study is to assess chemosensory function in patients suffering from AR using psychophysical testings and event-related potentials (ERP) responses. A cohort of nine patients was extensively studied. Eight out of nine had secondary AR sequela of a bilateral total inferior turbinectomy whereas one patient had a primary AR. All the patients had a clinical evaluation using Sniffin’ Sticks test and a retro-olfaction test and an electrophysiological evaluation based upon ERPs obtained after both olfactory and trigeminal stimuli. All the patients complained of a poor nasal breathing and presented a distortion of the chemosensory function. Actually, the orthonasal psychophysical testing showed that four patients out of nine had anosmia, three out of nine had hyposmia and two out of nine were normosmic. All the patients demonstrated retro-olfaction scores inferior to the normal values. The chemosensory ERP showed that seven patients had no olfactory response whereas six had no trigeminal response. Four patients had neither olfactory nor trigeminal ERP response. In conclusion, this study demonstrates that most patients with AR secondary to a total bilateral inferior turbinectomy have a reduction of the chemosensory function measured objectively by psychophysical testings and ERP. Moreover, the trigeminal responses were absent in all the cases.     

Changes in smell acuity induced by radiation exposure of the olfactory mucosa

The effects of ionizing radiation on smell acuity were assessed in 12 patients in whom the olfactory mucosa was exposed to radiation in the course of treatment for nasopharyngeal carcinoma or pituitary adenoma. Olfactory detection thresholds for two odorants (amyl acetate and eugenol) were determined before the start of radiation therapy, within a week of termination of therapy, and 1, 3, and 6 months later. The results show clearly that smell acuity is profoundly affected by therapeutic irradiation. Thresholds had increased in all 12 patients by the end of treatment and were still high one month later. Varying degrees of recovery were noted in most patients three to six months after cessation of treatment. The fate of the sense of smell deserves more attention when considering the disability caused by irradiation to certain head and neck tumors.     

Validation study of the "Sniffin' Sticks" olfactory test in a British population: a preliminary communication

Clin. Otolaryngol. 2012, 37 , 23–27 Objective: The ‘Sniffin’ Sticks’ olfactory test contains pen‐like odour dispensing devices which are used to assess olfactory threshold, discrimination and identification. Odour identification is strongly dependent on familiarity with the odours and has an important cultural component which has limited the usefulness of other validated tests. The ‘Sniffin’ Sticks’ test was developed in Germany and is validated in other countries but not in the UK. This study aims to validate the applicability of ‘Sniffin’ Sticks’ in a local population. Design: Prospective controlled study. Setting: Rhinology or olfactory disorder clinic. Participants: About 82 subjects, 33 healthy volunteers with a reported normal sense of smell, and 49 patients with an impaired sense of smell presenting either at a rhinology or an olfactory disorder clinic. Each subject’s olfactory function was assessed using the ‘Sniffin’ Sticks’ test with a maximum score of 48. Main outcome measures: Threshold, discrimination and identification scores along with the combined olfactory score. Results: The mean age of the subjects tested was 46.7 years; 46 female and 36 male. In the patient group 36 were hyposmic and 13 anosmic. In the healthy volunteers group all subjects were normosmic. In the control group the mean combined olfactory score was 34.5 (±2.5). The mean combined score in the patients group was 20.8 (±7.4). Odour threshold scores were 3.7(±2.8) for patients (hyposmics and anomics) and 8.3(±1.8) for controls. In the identification test the controls mean score was 13.6 (±1.2) for while the patients’ mean score was 8.6 (±3.5). Conclusions: In our sample of the local population the combined olfactory and odour identification scores for healthy volunteers and patients with olfactory disorders are comparable with the normative data published on large samples of European populations. However, modification of a few of the distracters is recommended for British patients based on our findings.     

Magnetic resonance imaging for diagnosis of congenital anosmia

Magnetic Resonance Imaging (MRI) was performed on 9 patients who lacked a sense of smell since birth. Seven of them, including two patients with Kallmann syndrome, exhibited abnormality of the olfactory bulb, olfactory tract, olfactory sulcus, or rectus gyrus, with some variation among patients in type and degree of abnormality. The other two patients exhibited normal olfactory pathway morphology, and for them the possibility of acquired sensorineural anosmia could not be ruled out. MRI is useful for determining whether patients with congenital anosmia have olfactory pathway anomalies. Many patients with congenital anosmia and hypoplasty or aplasty of the olfactory pathway nevertheless had no gonadal or endocrinological disorders.     

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.     

Olfaction in rhinology--methods of assessing the sense of smell

Olfactory disorders frequently occur in rhinological disease. Different subjective and objective test methods are available to assess the sense of olfaction. Among the subjective methods, screening tests and threshold measurements are commonly used to quantify hyposmia or anosmia. Qualitative methods are available using discrimination and identification tests. Objective methods are used in research and in some medicolegal situations. Objective tests include olfactory evoked potentials, functional Magnetic Resonance Imaging and functional Positron Emission Tomography. The measurement of the sense of smell helps to assess the whole spectrum of the effects of nasal disease. This is especially important before rhinological surgery, because a non-detected smell disorder in patients with rhinological disease is common. The assessment of a pre-existing hyposmia or anosmia helps to avoid a postoperative claim that this was caused by surgery. A variety of validated screening tests for olfaction is available and they are a useful tool to document whether a patient is able to smell.     

Smell and taste in drug addicts

The main objective of this study was to establish the degree of influence of various illicit drugs, taken into the body in different ways, on the senses of smell and taste. Other possible factors, that might have caused disturbances in normal functioning of both senses, were outlined. The studied group consisted of 48 drug addicts, between the age of 16 and 48 years, addicted to various illicit drugs for several years. Olfactory testing included two methods. First quantitative method described by Elsberg and Levy, modified by Pruszewicz, was used to establish the smell detection threshold. Then the University of Pennsylvania Smell Identification Test was used as a method for odor identification. The sense of taste was tested with the use of method described by Krarup and modified by Pruszewicz. The results showed disturbances in olfactory performance (combined in both method) in 52.1% of all drug abusers, and 16.7% of them were diagnosed with ageusia when the sense of taste was tested. The route of administration of illicit drugs proved to be a statistically significant factor that might have caused disturbances of smell perception and identification in the study group. Drug abusers who were taking drugs intravenously and those who smoked and inhaled various drugs had the most significant olfactory problems. Both means for assessing smell function were statistically compared and the results showed that approximately 75% of drug users with olfactory disturbances had olfactory problems in both tests.     

Olfaction after endoscopic sinus surgery: long-term results

Loss of olfactory function is one of the main symptoms in patients with chronic rhinosinusitis. This prospective, non-randomized interventional study reports five years results of olfaction of patients with chronic rhinosinusitis who underwent endoscopic sinus surgery in conjunction with topical medical treatment. Forty-five patients with chronic rhinosinusitis who underwent endoscopic sinus surgery were evaluated preoperatively, after three months and 34 (76%) of them after five years. Olfactory function was assessed by a subjective visual analogue scale, by a screening test of olfaction with Smell Diskettes and by measuring the N-Butanol threshold. Patient`s subjective sense of olfaction using a visual analogue scale was improved in 79% at 5 years. Objective measurements by Smell Diskettes improved in 53% at 5 years whilst the quantitative measurement by the N-Butanol threshold improved in 85% at 5 years. The high percentage of patients with improvement of olfaction five years after surgery indicates that endoscopic sinus surgery in conjunction with continued topical treatment leads to a long term improvement of the sense of smell. However, it was found that - measured by the sensitive N-Butanol threshold - up to 9% had no improvement and 6% had deterioration in their olfaction at 5 years after endoscopic sinus surgery. This fact has to be considered in the preoperative counselling of patients.     

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.     

放疗对鼻咽癌患者嗅觉的影响

目的 :探讨放疗对鼻咽癌 (NPC)患者嗅觉的影响。方法 :对 10 0例 NPC患者于放疗前、后 3和 6个月 ,1、2、3年 ,分别进行嗅觉检测 ,比较其变化。结果 :与放疗前比较 ,放疗后 3个月患者嗅觉锐度明显减退 ;0 .5～1年 ,嗅觉有所改善 ,但未能达到放疗前水平 ,且感觉阈与识别阈出现分离 ;此后 ,再次出现嗅觉锐度减退现象。结论 :放疗可影响 NPC患者嗅觉 ,放疗后患者嗅觉呈波浪式、永久性减退。     

The effect of human olfactory biopsy on olfaction: A preliminary report

Normal human olfactory function is subject to a wide variety of factors. Although biopsy of human olfactory neuroepithelium has been reported by several researchers, there are no studies which have evaluated the effect of this procedure on olfactory function. In this retrospective study, we sought to determine if tissue removal from the olfactory cleft has an adverse influence on the sense of smell. Nineteen subjects underwent bilateral olfactory testing and subsequent endoscopic olfactory mucosal biopsy. All subjects were retested 6 weeks to 1 year after olfactory neuroepithelial biopsy. No statistical difference was found between olfactory tests performed before or after biopsy. These data suggest that biopsy of human olfactory neuroepithelium has no discernible adverse effect on the ability to smell.     

A study on the mechanism of phleboid olfactory function

Phleboid olfactory test has wide clinical application for olfactory disturbance. Many unclarified aspects still remain concerning the mechanism of smell after an intravenous infusion of Alinamin. It is believed that when Alinamin is infused intravenously and byproducts are discharged from the blood into the alveoli, odorous substances reach the nasal cavity through exhalation. In order to clarify the mechanism of smell in more detail, we conducted the following experiments: 1) Cases of laryngectomy were examined to determine if intravenous infusion of Alinamin affected the olfactory organ. 2) Saliva specimens in healthy subjects were collected before and after intravenous infusion of Alinamin and examined for the presence of a secreted odorous substance using a functional test. 3) Healthy subjects who were inhibited in their sense of smell were examined for the presence of garlic odor after intravenous infusion of Alinamin. The results were as follows: 1) 80% of subjects of laryngectomy without cotton in the nares and 20% of subjects of laryngectomy with cotton in the nares perceived the garlic odor. 2) Garlic odorous substance was not recognized in saliva specimens collected before and after intravenous infusion of Alinamin. 3) The healthy subjects inhibited in their sense of smell and intravenously infused with Alinamin perceived the odor at the same time as exhalation. The above results indicated that the mechanism of smell after intravenous infusion of Alinamin occurred via exhalation, but not through the other routes.     

Decreasing nasal mucus Ca++ improves hyposmia

It is well documented that cytoplasmic Ca++ regulates sensitivity to cyclic adenosine monophosphate (cAMP). There is also evidence that Ca++ in the mucus may also modulate sensitivity to cAMP in vivo. Assuming that mucosal Ca++ could significantly change the excitability of the receptor neurons, we examined the alterations in the olfactory sensitivity by creating small changes in mucosal Ca++. Thirty one patients complaining of olfactory loss were examined and their olfactory acuity was measured before and after the administration of a sodium citrate buffer solution in the nasal cleft. Thirty patients (96.8%) improved their scores in less than an hour period of time. Furthermore, 23 of them (74.2%) realized an improvement in their own sense of smell.