Clinical assessment of gustatory function before and after middle ear surgery: a prospective study with a two-year follow-up period.

OBJECTIVES: Middle ear surgery can affect gustatory function because of the course of the chorda tympani nerve (CTN) close to the tympanic membrane. The aim of the study was to evaluate the sense of taste before and after middle ear surgery with a test suitable for clinical routine. Moreover, subjective complaints were assessed over a relatively long period of time. METHODS: Forty-seven patients (26 female, 21 male; mean age, 42 years) were investigated before and 4 days after surgery on both sides of the anterior part of the tongue. Self-assessment of taste function was performed by visual analog scales. RESULTS: The mean (+/- SD) taste scores significantly decreased on the side ipsilateral to the operated ear in patients with major manipulation of the CTN (12.0 +/- 4.5 before surgery and 6.9 +/- 4.5 after surgery; p < 0.001), whereas no significant changes were measured in patients with minor manipulation of the CTN (12.5 +/- 3.1 before surgery and 11.2 +/- 3.9 after surgery; p = 0.14). Self-assessed ratings of taste function significantly decreased after surgery in all patients (p < 0.001). Reassessment of subjective taste function after 2 years indicated no persisting complaints. CONCLUSIONS: Depending on the amount of manipulation of the CTN, taste function is decreased after surgery. However, long-lasting changes of gustatory function seem to be rare.

Effects of cochlear implantation on gustatory function.

OBJECTIVES: Because of the anatomic position of the chorda tympani in the tympanic cavity, the nerve is at risk during cochlear implantation. The aim of this study was to assess changes in taste sensitivity and in self-ratings of gustatory function after surgery. METHODS: Twenty-four patients (mean age, 54 years) who underwent cochlear implantation were investigated. Taste function was tested with a validated test for regional quantitative assessment of sweet, sour, salty, and bitter tastes on each side of the tongue before and 4 days after surgery. RESULTS: The mean taste score was 10.0 (SD, 4.0) before and 8.0 (SD, 4.1) after surgery on the side of the tongue ipsilateral to the operated ear (p = .004). However, only 1 patient reported subjective taste loss due to surgery. Taste testing of the side of the tongue contralateral to the operated ear yielded a score of 10.0 (SD, 4.1) before and 10.9 (SD, 4.5) after surgery (p = .037). Self-ratings of gustatory function did not change significantly as a consequence of the procedure. CONCLUSIONS: Our results indicate that cochlear implantation is a relatively safe procedure regarding taste function. Preoperative testing of gustatory function is recommended, at least in those patients who already have undergone operation on the contralateral ear.

Gustatory function after tonsillectomy.

OBJECTIVE: To assess taste function before and after tonsillectomy (TE). DESIGN: Prospective study. SETTING: University hospital. PATIENTS: Sixty-five patients (42 females, 23 males; mean age, 28 years). MAIN OUTCOME MEASURES: Taste function was investigated before TE with 4 concentrations each of sweet, sour, salty, and bitter quality, respectively, on both sides of the anterior and posterior areas of the tongue. Self-assessment of gustatory function was performed by visual analogue scales. Thirty-two patients were retested 64 to 173 days after TE. Thirty-three patients could not be retested after TE but were interviewed by telephone. RESULTS: Self-assessed taste function significantly decreased (P=.001). Yet, none of the subjects reported taste dysfunction. Tonsillectomy had no major effect on taste test scores (P>.27). CONCLUSION: Persisting taste dysfunction seems to be rare after TE.

A self-administered odor identification test procedure using the "Sniffin' Sticks".

Assessment of smell function in clinical routine is often limited due to a lack of time and/or costs of the personnel administering the test. The aim of the present study was to validate a procedure allowing for self-administered olfactory testing in a clinical setting. Seventy-four healthy subjects (13 male, 61 female) from 18 to 30 years of age (mean 20.3 years) were tested on 2 days (interval 7-21 days, mean 8.7 days) with 16 odors of the "Sniffin' Sticks" identification test kit. On one occasion, the test was administered by an examiner. On another occasion, subjects administered the test to themselves, with the odors being identified after they had been "painted" on a sheet of paper. No significant differences were obtained between the results from both test procedures. With a maximum score of 16, assisted testing yielded a mean score of 13.7 [standard deviation (SD) 1.3] while the self-administered procedure yielded an average score of 13.8 (SD = 1.5) (P = 0.72). The mean difference between the assisted and the self-administered smell test procedures was 0.05 (SD = 1.28). The 95% confidence interval of differences ranged from -2.51 to 2.61. These results suggest that odor identification with the Sniffin' Sticks can also be administered by the subjects themselves.

Computed tomography scans in the evaluation of patients with olfactory dysfunction.

BACKGROUND: The necessity of computed tomography (CT) scans of the olfactory cleft and the sinuses in patients presenting with olfactory dysfunction is a matter of debate. This study aimed to investigate the significance of CT scans for the diagnosis of olfactory loss and for therapeutic decisions. METHODS: This retrospective study included 137 consecutive patients presenting with the main complaint of olfactory loss. Standardized history; ear, nose, and throat examination; and olfactory tests were administered. In addition, a CT scan of the nasal sinuses was obtained. The assumed diagnosis (sinonasal disease [SND] or non-SND) was compared with the diagnosis when additionally considering results from the CT scan. RESULTS: CT scans suggested SND in 7/101 patients, without clinical evidence of its presence. In 12/36 patients with suspected SND-related olfactory loss, no signs of SND were detected in CT scans. CONCLUSION: CT scans are useful to diagnose conductive/inflammatory olfactory loss in patients suspected of non-SND, which may then justify a course with systemic steroids. Alternatively, considering low costs and rare side effects of a short course with steroids in selected patients, CT scans appear to be of clinical significance only when surgical treatment is contemplated or where the use of systemic corticosteroids is not possible.

Taste function in xerostomia before and after treatment with a saliva substitute containing carboxymethylcellulose.

BACKGROUND AND AIM: The feeling of a dry mouth may affect individual dietary habits, nutritional status, oral hygiene, speech, and gustatory sensitivity. The present study aimed to specifically investigate gustatory function before and after saliva replacement therapy. MATERIAL AND METHODS: Whole-mouth gustatory function was assessed in 25 patients suffering from xerostomia (6 male, 19 female; age range 42-82 years) before and after 4 to 6 weeks of saliva replacement therapy using a preparation containing carboxymethylcellulose. The results were compared with those from healthy controls matched for age and sex (6 male, 19 female; age range 42-82 years). Using a whole-mouth test, gustatory function was assessed for sucrose, citric acid, sodium chloride, and caffeine. RESULTS: All subjects detected the four taste qualities at the highest concentration. However, the patients with xerostomia had lower scores in the gustatory test compared with the healthy controls (p < .001). No correlation was found between gustatory scores and the duration or severity of the disorder. Therapy had no effect on measured gustatory function (p = .33); however, saliva replacement led to a significant improvement in other xerostomia-related symptoms (p < .001). CONCLUSIONS: This study confirms previous work indicating that xerostomia is accompanied by decreased gustatory sensitivity. Lubricants based on carboxymethylcellulose may have a positive effect on some of the symptoms of xerostomia. However, these "simple" lubricants based on carboxymethylcellulose have little or no effect on whole-mouth gustatory function.

Dysfunction of the liver affects the sense of smell.

BACKGROUND: Cirrhosis of the liver (CL) has been reported to be accompanied by olfactory loss. The aim of the present study was to re-investigate previous work with a special focus on differential olfactory function, the relation between CL etiology and olfactory function, and the correlations between laboratory/psychological parameters and olfactory function. MATERIALS AND METHODS: A total of 45 CL patients participated. Olfactory function was tested using the "Sniffin' Sticks" technique, which provides measures for butanol odor thresholds, odor discrimination and odor identification. Serum levels of zinc and bilirubin were obtained. Psychometric measurements included the trailmaking test. RESULTS: The study provided the following major results: (1) Olfactory function was compromised in 76% of CL patients; in addition, the patient's ability to identify odors, but not odor thresholds or odor discrimination, was related to the degree of CL. This pattern may be an expression of a stronger effect of CL on the central- nervous processing of odors than on the periphery of the system. (2) Neither etiology of the CL (e.g., alcoholism) nor serum levels of bilirubin and zinc were correlated with olfactory function. However, (3) there was a relation between the results from psychometric function tests and the ability to identify odors. CONCLUSION: Although the reason for olfactory dysfunction in CL is far from clear, future investigations should focus on the hypothesis that endogenous intoxication may lead to a stronger deficit in the central-nervous processing of olfactory information than to peripheral lesions in the olfactory system. In addition, while more specific research is needed, olfactory dysfunction may serve as a subclinical indicator of hepatic encephalopathy.

Characteristics of olfactory disorders in relation to major causes of olfactory loss.

OBJECTIVE: To investigate the consequences of olfactory loss and explore specific questions related to the effect of duration of olfactory loss, degree of olfactory sensitivity, and cause of the olfactory loss. PATIENTS: A total of 278 consecutive patients with hyposmia or anosmia were examined. RESULTS: Causes of olfactory loss were categorized as follows: trauma (17%), upper respiratory tract infection (URI) (39%), sinonasal disease (21%), congenital anosmia (3%), idiopathic causes (18%), or other causes (3%). Our data suggest that (1) recovery rate was higher in URI olfactory loss than in olfactory loss from other causes; (2) likelihood of recovery seemed to decrease with increased duration of olfactory loss; and (3) the elderly are more prone to URI olfactory loss than younger patients. Regarding changes in quality of life (QoL), we found that (1) in most patients olfactory loss caused food-related problems; (2) loss in QoL did not change with duration of olfactory loss; (3) younger patients had more complaints than older ones, and women had more complaints than men; (4) complaint scores were higher in hyposmic patients than in anosmic patients; and (5) self-rated depression did not relate to measured olfactory function. CONCLUSIONS: Among many complaints of olfactory loss, the predominant ones were food related. This loss in QoL seemed to be of greater importance in younger than in older people, and women seem to be affected more strongly than men.

The quinoxaline derivative caroverine in the treatment of sensorineural smell disorders: a proof-of-concept study.

The treatment of non-conductive olfactory disorders is to a large extent an unsolved problem. This proof-of-concept study focused on possible effects of the N-methyl-D-aspartate (NMDA) antagonist caroverine. Potential mechanisms for the hypothesized effect included reduced feedback inhibition in the olfactory bulb as a consequence of NMDA antagonistic actions and antagonism of an excitotoxic action of glutamate. A total of 77 consecutive patients with non-conductive olfactory disorders were included in the study. Fifty-one patients received caroverine for 4 weeks (120 mg/day); 26 controls matched for age, gender and duration of olfactory loss were treated with zinc sulfate for the same length of time (400 mg/day). Olfactory sensitivity was evaluated before and after treatment. Testing included assessment of n-butanol odor threshold and odor identification. When compared to baseline, treatment with caroverine improved both odor thresholds (p = 0.005) and odor identification (p = 0.042) in anosmic patients. In hyposmic patients it significantly improved odor identification ability (p = 0.041). In contrast, zinc sulfate had no significant effect on olfactory function. These results indicate that caroverine appears to be effective for the treatment of non-conductive smell disorders.