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Objective To evaluate the gustatory function before and after vestibular schwannoma (VS) surgery. Methods In this retrospective study, we evaluated the gustatory function of 12 patients who underwent VS surgery at Tsukuba University Hospital between 2012 and 2018. Gustatory function was examined using electrogustometry before VS surgery and 3 months, 6 months and 1 year after surgery. Electrogustometry was tested at the area mapped to the chorda tympani nerve, glossopharyngeal nerve and greater superficial petrosal nerve (GSPN). Intergroup mean comparisons of the threshold were performed using a one-way analysis of variance (ANOVA) followed by the Bonferroni post-hoc test. Results The gustatory function mapped to the chorda tympani nerve was significantly disturbed 6 months after the surgery as compared with the preoperative function (p = 0.033) and that the dysfunction recovered at 1 year. However, gustatory function mapped to the glossopharyngeal nerve and greater superficial petrosal nerve (GSPN) was not impaired. Conclusion The gustatory function mapped to the chorda tympani nerve is impaired after surgery for VS. The dysfunction peaked at 6 months after surgery, and recovered within 1 year.

Objectives Our primary goal was to evaluate the effect of stimulus duration on electrogustometry (EGM) thresholds. Additionally, we sought to evaluate any sex-related influences and compare the above results to those of taste strips. Design Electrogustometry thresholds of various stimulus durations (0.5, 1.0, 1.5 and 2.0 seconds) were measured in 212 non-smokers (age range: 10-80 years, divided into eight age-groups) without self-reported gustatory impairment. Furthermore, taste strips chemogustometry measurements in 132 participants were performed. Setting Tertiary referral medical centre. Participants 212 non-smokers, divided into eight age-groups participated in the study. Main outcome measures Electrogustometry thresholds and taste strips, duration of EGM stimuli. Results Electrogustometry thresholds increased progressively with age and with stimulus duration from 0.5 to 2 seconds. This pattern was consistent in all six anatomic areas, irrespective of sex. In contrast, when using chemogustometry, no age- or sex-related differences were observed. Conclusions Electrogustometry-threshold values increase progressively with age and with stimulus duration. Therefore, we recommend documenting stimulus duration in the future EGM recordings as it may significantly affect EGM amplitude threshold values.

Objectives It is generally thought that the recovery of damaged chorda tympani nerve (CTN) function after middle ear surgery is different in pediatric patients from that in adult patients. The purpose of this study was to investigate the changes and the progress of taste and somatosensory functions of the tongue after middle ear surgery in pediatric patients compared with those of adult patients. Study design Prospective study. Methods Fifty-nine pediatric patients and 106 adult patients underwent middle ear surgery. Taste and somatosensory functions of the anterior tongue, the so-called CTN functions, were assessed using electrogustometry (EGM), a 2-point discriminator, an electrostimulator, and a questionnaire before and 2 weeks and 6 months after surgery. Results Two weeks after surgery, there was no significant difference in the incidence of dysgeusia and abnormal EGM thresholds between the patient groups. The incidence of tongue numbness was significantly lower in pediatric patients than in adult patients regardless of CTN manipulation. Although the lingual somatosensory thresholds of adult patients were significantly increased, those of pediatric patients were not increased. Six months after surgery, the incidences of dysgeusia and an abnormal EGM threshold were lower in pediatric patients than in adult patients. Tongue numbness disappeared, and the thresholds of lingual somatosensory tests returned to normal in most pediatric patients. Conclusion Not only taste function but also lingual somatosensory function was damaged after middle ear surgery even in pediatric patients. Pediatric patients complained of tongue numbness less frequently and showed earlier recovery than adult patients. Level of evidence 2 Laryngoscope, 130:1016-1022, 2020.

Objectives To investigate the relationships among four different gustatory function tests in healthy young adults: electrogustometry (EGM), filter paper disk (FPD), whole-mouth, and taste strip methods. The relationships of the results of gustatory function tests with salivary flow rate were also investigated. Methods Sixty healthy young adults (30 men, 26.9 ± 4.7 years; 30 women, 25.7 ± 4.6 years) who did not have disorders or conditions related with gustatory function were included. Four different gustatory function tests using the EGM, FPD, whole-mouth, and taste strip methods were performed in each participant with 2- to 3-day intervals between tests. The flow rates of unstimulated and stimulated whole saliva were measured. Results There were no significant differences between sexes in all the examined gustatory function tests. The levels of correlations between the gustatory function tests were low. The EGM threshold correlated with the taste score of the FPD method in the chorda tympani nerve area. Different chemical gustatory function tests did not correlate significantly in any of the four taste qualities. Salivary flow rates did not correlate with taste perception. Conclusions The correlations between gustatory function tests were weak. A significant correlation was found between the results of EGM and FPD methods in the chorda tympani nerve area.

Objective/Hypothesis: Taste disturbances are often seen in patients after middle ear surgery due to the stress received by an unprotected chorda tympani. It has also been reported that loss in tactile sensitivity may accompany this issue. The current study was designed to measure electrical, chemical, and tactile sensitives of several senses involved in oral processing, smell, taste and touch, over time. Study Design: Prospective cohort study. Methods: For three time points, one before middle ear surgery and two after operation (about 5 and 23 days), sensitivity thresholds were obtained using electrogustometry (electrical taste), taste strips (chemical taste), Sniffin’ Sticks (smell) and Von Frey Hairs (point-pressure tactile sensitivity). Results: The results show a decline in both chemical and electrical taste responses. Additionally, the electrical taste response showed more sensitivity to deviations and no sign of recovery unlike the chemical taste response. Mechanosensory function of the anterior tongue and olfactory function was not strongly affected by middle ear surgery. Conclusion: Taste responses, but not mechanosensory or olfaction function, are altered after middle ear surgery. Due to the effects that taste loss has on quality of life, gustometry is recommended for this group of patients. Levels of Evidence: 4

Background Cross-modal chemosensory dysfunction between olfaction and gustation is not well known. Methodology 180 participants were classified into three groups (60 with olfactory dysfunction, 60 with gustatory dysfunction and 60 healthy controls without chemosensory dysfunction). Olfactory functions were obtained with Sniffin Sticks; gustatory function was measured by suprathreshold gustatory stimuli (taste sprays) and a quasi-threshold measure of taste function (taste strips) for five taste qualities (sweet, salty, sour, bitter and umami). Electric taste threshold was measured using electrogustometry (EGM). In addition, group differences in dietary behaviors were investigated with a specifically designed questionnaire. Results Patients with olfactory dysfunction had increased electric taste thresholds and decreased scores for the umami taste strip test as compared to healthy controls. Overall there was no major difference between patients with chemosensory dysfunction and healthy controls regarding dietary behaviors, although some patients certainly exhibited dietary problems. Importantly, patients with taste loss, but not patients with smell loss, exhibited a higher degree of depression than controls. Conclusion Patients with olfactory dysfunction showed decreased taste sensitivity which suggested an interaction between the chemical senses taste, trigeminal function, and olfaction. This provides the basis for including both smell and taste psychophysical assessment in clinical practices. In addition, patients with taste loss appeared to suffer most from chemosensory dysfunction.

Lingual branches of the glossopharyngeal nerve (CN Ⅸ) are at risk of injury during tonsillectomy due to their proximity to the muscle layer of the palatine tonsillar bed. However, it is unclear how often this common surgery leads to taste disturbances. We conducted a literature search using PubMed, Embase, Cochrane Library, Google Scholar, PsychInfo, and Ovid Medline to evaluate the available literature on post-tonsillectomy taste disorders. Studies denoting self-reported dysfunction, as well as those employing quantitative testing, i.e., chemogustometry and electrogustometry, were identified. Case reports were excluded. Of the 8 original articles that met our inclusion criteria, only 5 employed quantitative taste tests. The highest prevalence of self-reported taste disturbances occurred two weeks after surgery (32%). Two studies reported post-operative chemical gustometry scores consistent with hypogeusia. However, in the two studies that compared pre- and post-tonsillectomy test scores, one found no difference and the other found a significant difference only for the left rear of the tongue 14 days post-op. In the two studies that employed electrogustometry, elevated post-operative thresholds were noted, although only one compared pre- and post-operative thresholds. This study found no significant differences. No study employed a normal control group to assess the influences of repeated testing on the sensory measures. Overall, this review indicates that studies on post-tonsillectomy taste disorders are limited and ambiguous. Future research employing appropriate control groups and taste testing procedures are needed to define the prevalence, duration, and nature of post-tonsillectomy taste disorders. Keywords: Tonsillectomy, Taste, Ageusia, Hypogeusia, Taste disturbances

Objective The objective of our systematic review is to investigate the postoperative gustatory function of the chorda tympani nerve following noninflammatory ear surgery for which the chorda tympani is at risk for iatrogenic injury (stretching, handling, or sacrificing). Data Sources PubMed and EMBASE. Review Methods A PubMed and EMBASE databases search was conducted on November 15, 2016. Study inclusion criteria included: 1) ear surgery performed for noninflammatory ear diseases, and 2) gustatory function of the chorda tympani reported as an outcome. The quality of eligible studies was assessed using the risk of bias assessment tool for nonrandomized studies. Study characteristics and outcome data of the included studies were extracted. Results In total 1,094 articles were retrieved. Fourteen studies encompassing 1,062 operated ears were included after quality assessment. Stapedectomy was the most frequent surgical procedure performed in 398 ears. The follow-up time varied between 6 weeks and 99 months. Patients with a preserved chorda tympani were less symptomatic (24% was symptomatic) compared to patients with a stretched (53% was symptomatic) or sacrificed chorda tympani (47% was symptomatic). The recovery rate varied from 61% to 79%. The results of the electrogustometry and strip test showed a discrepancy with the subjective complaints of the patients. Conclusion Patients with a stretched chorda tympani were slightly more symptomatic compared to patients with a sacrificed chorda tympani. Therefore, in cases for which the chorda tympani greatly hinders a proper view of the surgical field, sacrificing the nerve could be considered to maximize surgical performance and have a satisfactory postoperative result. Laryngoscope, 2017

Objectives Patients after middle ear surgery often complain of taste disturbance and a lingual numbness. The purpose of this study was to objectively assess changes in the somatosensation of the tongue and taste function in patients undergoing stapes surgery. Study Design Prospective study. Methods Symptoms of taste disturbance and tongue numbness after surgery were investigated before and after surgery in 41 patients (13 males, 28 females; mean age 41.8 years) who underwent stapes surgery. Twenty-eight patients (9 males, 19 females; mean age 43.1 years) underwent sensory and taste function tests before and after surgery. Sensory function of the tongue was measured at the operated side and the nonoperated side using the 2-point discrimination test and an electrostimulator test. Taste function was assessed with electrogustometry (EGM). Results The chorda tympani nerve (CTN) was gently touched or stretched in all patients. Postoperative thresholds on the operated side were significantly higher than preoperative thresholds in all tests in the patients who underwent all three kinds of tests. Tongue somatosensory symptoms improved significantly earlier than the taste disturbance postoperatively, and the sensory thresholds returned to the baseline along with recovery of symptoms. Conclusion These findings suggest that dysfunction of the CTN occurred following surgery even when the CTN was preserved, and that the sensory nerve threshold of the tongue correlated with the symptom of lingual numbness. The CTN may play a role not only in taste function but also in the somatosensory function of the tongue. Level of Evidence 4. Laryngoscope, 2017

Background Cochlear implantation (CI), the standard therapy for rehabilitation of severe to profound sensorineural hearing loss, exhibits taste dysfunction as a possible postoperative complication. This study aimed to investigate possible postoperative changes in taste and in addition baseline taste function in CI candidates. Methodology We included 61 patients (32 male, 29 female) planned to undergo CI surgery and 23 healthy controls (8 male, 15 female). Gustatory function was measured using a chemosensory quasi-threshold test (taste strips) and electrogustometry (EGM). To exclude possible effects of olfaction on taste, olfactory function was tested by means of the Sniffin Sticks odor identification test. Furthermore, the density of fungiform papillae (fPAP) was analyzed. Measurements were taken pre- and 2-4 weeks postoperative. Results Preoperative taste function and fPAP density was reduced in CI patients compared to controls. The fPAP density correlated significantly with the total taste score, EGM scores and age. Postoperative taste function decreased significantly, whereas EGM scores and fPAP density did not significantly change. Also baseline olfactory function in CI candidates was decreased, whereas no significant change of olfactory function was found post-surgery. Conclusion CI candidates exhibited taste and olfactory dysfunction already preoperatively. Furthermore, a significant decrease in taste scores after CI surgery was detected.

Compared with normal-weight individuals, obese young adults exhibited a significantly higher taste threshold for salty taste. Smoking also affected taste functions in this population.The aim of this study was to investigate the differences in taste detection thresholds between normal-weight and obese young adults.Taste threshold was measured using electrogustometry (EGM) and chemically with sucrose, NaCl, citric acid, and quinine hydrochloride in 41 volunteers in their twenties, 23 with body mass index (BMI)23 kg/m(2) (normal-weight group) and 18 with BMI25 kg/m(2) (obese group).BMI was significantly higher in the obese than in the normal-weight group (p0.05). The obese group exhibited significantly higher EGM thresholds than the normal-weight group on the right (p0.05) and left (p0.05) posterior tongue. In chemical taste tests, the obese group had higher thresholds for sweet, salty, sour, and bitter tastes than the normal-weight group, although the difference in threshold was significant only for salty taste (p0.05). Smoking had an impact on taste threshold, with smokers having higher thresholds than non-smokers, with significantly higher EGM thresholds on the right anterior and posterior and the left anterior tongue (p0.05 each).

The senses of smell and taste can be adversely affected by both tumour- and treatment-related factors amongst head and neck cancer patients. The consequences may negatively impact nutritional status as well as quality of life in this patient population. This prospective longitudinal follow-up study is consisted of 44 patients treated for oral cavity, oropharyngeal or hypopharyngeal cancer with tumour resection and microvascular free tissue transfer reconstruction at the Helsinki University Hospital, Helsinki, Finland. Thirty-nine (89%) of them also received radiotherapy. The senses of smell (odour detection, identification and threshold test) and taste (electrogustometry) and quality of life (UW-QOL) were evaluated preoperatively, and at 6 weeks, 3 months, 6 months and 12 months, postoperatively. There were higher scores in the odour detection values in the 6-week and 3-month tests compared with preoperative values for the tumour side. Other detection scores did not differ statistically from the preoperative values neither in the tumour nor the contralateral side. However, in the odour identification test, all posttreatment values were statistically significantly higher than pretreatment ones. In the olfactory threshold test, no statistically significant differences were found between pre- and posttreatment values. Electrogustometry values for the taste on the tumour side were statistically significantly impaired at 6 weeks (p

CONCLUSION This is the first report to investigate the correlation between ear anomalies related to the development of specific ear structures and chorda tympani dysfunction (CTD) in congenital microtia. CTD is not always consistent with the severity of the ear anomaly or the presence of facial nerve paralysis (FNP). OBJECTIVES To investigate the relationship between the severity of ear anomalies and CTD as well as FNP in congenital microtia. METHODS A retrospective assessment was performed for all patients with microtia over the period 2010-2016. All ears were graded based on the severity of ear deformity using the Jahrsdoerfer system, based on findings on computed tomography of the temporal bone. Electrogustometry (EGM) was performed to evaluate CTD. RESULTS The group included 110 male and 62 female patients. The right ear was the most commonly affected (right 106, left 47). Eighteen patients (10.5%) had abnormal EGM thresholds. The mean (± SD) Jahrsdoerfer scores in the without CTD and positive for CTD groups were 6.53 ± 0.32 and 7.06 ± 0.37, respectively. In terms of sub-total points, there was no significant correlation between anatomic structure and CTD. There was no significant correlation between CTD and the presence of FNP.

The objective of this study was to evaluate differences in gustatory function in smokers of both sexes and identify any differences in the shape, density and vascularisation of the fungiform papillae (fPap) of smokers' tongue. Additional aim was to investigate any relation between the age, pack years and differences in shape, density, vascularization of fPap and sex. In 166 smokers (81 males, 85 females, age range 20-80 years), divided in age groups, electrogustometry (EGM) thresholds at the chorda tympani area, at the soft palate area and at the area of the vallate papillae were recorded bilaterally. Morphology and density of the fPap and blood vessels' density and morphology at the tip of the tongue were examined using contact endoscopy (CE). EGM thresholds of all smoking subjects tended to increase compared to the non-smoking participants. Morphology, vascularization and density of fPap were found to be worse in smokers than in non-smokers. Interestingly, some participants, despite having increased number of pack years, tended to have almost similar EGM thresholds with non-smoking subjects of the same age group. Smoking tends to affect density, morphology and vascularization of the fPap. There is a correlation between the duration of smoking (pack years) and the afore-mentioned parameters. The use of τ-Kendall criterion provided useful information about the different correlation between the EGM thresholds and vascularization, the EGM thresholds and morphology of fPap and EGM thresholds and density of fPap. The majority of smokers had elevated EGM thresholds compared to non-smokers. Smoking is an important factor which can lead to decreased taste acuity. The combination of methods, such as EGM and CE, can provide useful information about the morphology and function of taste buds. Of interest, women are less affected than men, irrespective of the age group.

Objective To establish clinical tests for measurement of trigeminal sensitivity on the human tongue and objectively assess changes in oral trigeminal sensitivity and taste ability after chorda tympani nerve (CTN) injury. Study design Prospective study. Setting University hospital. Patients One-hundred and twenty-six patients with unilateral middle ear diseases who underwent primary middle ear surgery. Main outcomes and measures Trigeminal sensation was measured each operated side as well as nonoperated side both before and 14 days after surgery using 3 kinds of tests: Semmes-Weinstein sensory test (SW test), 2-point discrimination test, and the electrostimulator test. Taste function was assessed with electrogustometry (EGM) similarly. Results The patients which the CTN was not touched (n = 6) showed no differences between preoperative and postoperative thresholds in any tests. In the patients with sectioned CTN (n=30), postoperative thresholds on the operated side were significantly higher than preoperative thresholds on the electrostimulator test, 2-point discrimination test, and EGM. In the patients with manipulated but not sectioned CTN (n = 90), postoperative thresholds were significantly higher than preoperative thresholds on the electrostimulator test and EGM. The patients with manipulated but not sectioned CTN and abnormal EGM postoperative thresholds (n = 48) showed that postoperative thresholds were significantly higher than preoperative thresholds in all tests. Conclusion These findings suggest that the electrostimulator test was most useful to objectively assess small changes of trigeminal sensation among the 3 tests. The finding that trigeminal sensitivity of the tongue deteriorated on the operated side after CTN injury suggests that CTN function affected both taste sensation and trigeminal sensation of the tongue.

Objective Idiopathic burning mouth syndrome (iBMS) is characterized by oral persistent pain without any clinical or biological abnormality. The aim of this study was to evaluate taste function in iBMS subjects and healthy controls. Material and Methods Electrogustometric thresholds (EGMt) were recorded in 21 iBMS patients and 21 paired-matched controls at nine loci of the tongue assessing fungiform and foliate gustatory papillae function. Comparison of EGMt was performed using the nonparametric Wilcoxon signed-rank test. A correlation between EGMt and self-perceived pain intensity assessed using a visual analogic scale (VAS) was analyzed with the Spearman coefficient. The level of significance was fixed at P

Objective: To compare the number of fungiform taste buds among patients with chronic otitis media (COM), those with pars flaccida retraction type cholesteatoma, and those with pars tensa retraction type cholesteatoma in combination with gustatory function. Methods: Thirty-seven patients with COM, 22 patients with pars flaccida retraction type cholesteatoma, and 17 patients with pars tensa retraction type cholesteatoma were included. An average of 10 fungiform papillae (FP) per patient in the midlateral region of the tongue were observed by confocal laser scanning microscopy in vivo, and the average number of taste buds were counted. Just before the observation of FP, electrogustometry (EGM) was performed to evaluate gustatory function. Results: A significant decrease of the average number of fungiform taste buds and significant elevation of EGM thresholds were clarified in the pars tensa retraction type cholesteatoma group but not in the COM or pars flaccida type cholesteatoma group. Conclusion: It was suggested that some neurotoxic cytokines produced by cholesteatoma tissue might affect the CTN morphology, resulting in a decreased number of fungiform taste buds and elevation of EGM threshold in patients with pars tensa retraction type cholesteatoma.

OBJECTIVE To compare the incidence of regeneration of the chorda tympani nerve (CTN) and taste function recovery between pediatric and adult patients after severing the CTN. STUDY DESIGN Retrospective study. SETTING University hospital. PATIENTS Consecutive 31 pediatric patients and 61 adult patients who underwent staged tympanoplasty (86 patients) or reoperation (6 patients) because of chronic otitis media with (89 patients) or without cholesteatoma (3 patients) and whose CTN was severed during primary surgery were included. INTERVENTION Therapeutic. MAIN OUTCOME MEASURES The severed nerves were readapted or approximated on the temporalis muscle fascia used to reconstruct the eardrum. During secondary surgery, we tried to detect regenerated CTN. Preoperative and postoperative gustatory function was assessed using electrogustometry. RESULTS Regenerated CTN was detected during secondary surgery in 58.1% (18/31) of pediatric patients and 31.1% (19/61) of adults (p < 0.05). However, the number of patients with preoperatively elevated electrogustometry threshold was greater in adult patients. When the subjects were limited to those with preoperatively normal taste function, there was no significant difference between the 2 groups. Among patients with CTN regeneration, the incidence of taste function recovery was higher (12/18; 66.7%) in children than that (6/19; 31.6%) in adults (p < 0.05). However, there was no significant difference when the subjects were limited to those with preoperatively normal taste function. CONCLUSION Chronic inflammation may not severely affect the CTN in pediatric patients, resulting in higher incidences of CTN regeneration and gustatory function recovery after severing the nerve, compared with those in adult patients.

Objective A manipulation of chorda tympani nerve (CTN) is frequently necessary during the surgical therapy of stapedial ankylosis. The aim of this study was to re-assess the taste function before and after stapes surgery in patients with unilateral stapes ankylosis. Methods Eighteen patients (14 female and 4 male) with unilateral stapedial ankylosis were included. Taste and olfactory function were measured preoperatively, 3 days and 3 months after surgery by questionnaire, chemical taste test, electrogustometry, and Sniffin'Sticks. The patients who reported deterioration in taste and revealed pathological taste test results were re-investigated 8–12 months after surgery. Postoperatively 11 patients were treated intravenously for 3 days for inner ear protection with 1 g of cortisone. The gustatory and olfactory results were compared with age and sex specific normative data. Results A significant transient decrease of gustatory measurement values was found on the ipsilateral two thirds of the anterior tongue. 12 out of 17 patients whose CTN was slightly manipulated during stapes surgery reported tongue sensations, such as numbness or gustatory blindness of the ipsilateral tongue side. The measures of chemical taste test significantly decrease in lateralized taste test on the ipsilateral side and in whole mouth testing. There was no significant increase of the EGM measures at the ipslateral tongue. In 11 of 12 patients with symptoms, complaints recovered within one year after surgery completely. The factor “cortisone” did not have a significant effect on the taste test results after surgery. Conclusion In conclusion, even after minor CTN manipulation the rate of postoperative taste disorders or tongue symptoms after stapes surgery is high. The symptoms appear to be transient. Therefore CTN should be preserved in stapes surgery after mild trauma of the CTN. Transient taste alteration should be mentioned prior to stapes surgery.

Objectives: The aim of this study was to evaluate the mean number of regenerated fungiform taste buds per papilla and perform light and electron microscopic observation of taste buds in patients with recovered taste function after severing the chorda tympani nerve during middle ear surgery. Methods: We performed a biopsy on the fungiform papillae (FP) in the midlateral region of the dorsal surface of the tongue from 5 control volunteers (33 total FP) and from 7 and 5 patients with and without taste recovery (34 and 29 FP, respectively) 3 years 6 months to 18 years after surgery. The specimens were observed by light and transmission electron microscopy. The taste function was evaluated by electrogustometry. Results: The mean number of taste buds in the FP of patients with completely recovered taste function was significantly smaller (1.9 ± 1.4 per papilla; p < 0.01) than that of the control subjects (3.8 ± 2.2 per papilla). By transmission electron microscopy, 4 distinct types of cell (type I, II, III, and basal cells) were identified in the regenerated taste buds. Nerve fibers and nerve terminals were also found in the taste buds. Conclusions: It was clarified that taste buds containing taste cells and nerve endings do regenerate in the FP of patients with recovered taste function.

Objectives. To investigate the changes in gustatory function as a complication after radiofrequency tongue base reduction (RTBR) in patients with obstructive sleep apnea (OSA). Study Design. Before-and-after study. Setting. Academic tertiary medical center. Subjects and Methods. Thirty-four patients with suspected velopharyngeal collapse only underwent uvulopalatopharyngo- plasty (UPPP group). Twenty-five patients with velopharyngeal and retrolingual collapse underwent concurrent UPPP with RTBR (RTBR group). All patients were evaluated before surgery and at 1 and 4 weeks after surgical treatment. A questionnaire was given to assess symptoms of hypogeusia, dysgeusia, hypos- mia, and sensation of the tongue. Electrogustometry (EGM) in 4 areas was used to determine gustatory function. Results. Postoperative values for subjective symptoms did not significantly change following surgical treatment in either group. EGM thresholds of all tested in both groups did not significantly change 1 week and 4 weeks after surgery. Conclusions. Gustatory function remained unchanged after RTBR in patients with OSA. The authors suggest that RTBR is a safe procedure in terms of taste sensation in OSA patients.

The results indicate that electrogustometry and the filter paper disc method are reliable methods to measure taste with a high degree of reproducibility.To thoroughly evaluate the reliability of electrogustometry and the filter paper disc method for taste assessments.Thirty-nine healthy test persons without any history of chronic middle ear disease, aged between 27 and 62 years, were recruited. In all, 772 electrogustometry and 30 filter paper disc assessments were made. A nerve decay test was performed, with measures taken before and after eating sweet, sour, bitter, salt, a mild or spicy meal, after smoking, and after taking Swedish tobacco snuff ('snus'), as well as before and after local anesthesia of the tongue. Measurements were performed on 5 consecutive days and repeatedly during 1 day. The correlation between electrogustometry and the filter paper disc method was also studied.The results indicate that electrogustometry and the filter paper disc method are reliable methods to measure taste with a high degree of reproducibility. The only actions causing significant changes in the electrogustometry readings were eating a bitter substance and having local anesthesia of the tongue. The correlation between the methods was statistically significant except for the bitter flavor, where the correlation was just below the level of significance.

Objective/hypothesis A relationship between acute otitis media and elevated body mass index has recently been reported. Intriguingly, it was postulated that this relationship may result from altered chorda tympani nerve function impacting taste sensation and eating habits. We sought to test this directly by measuring chorda tympani nerve function in children with and without a previous history of acute otitis media and to determine the relationship to body mass index. Study design Retrospective cohort study. Methods Institutional research ethics board approval was obtained. Study participants included 142 children (5–18 years of age) who were recruited from an otolaryngology outpatient clinic at a tertiary academic pediatric hospital between May and August 2009. Children were excluded if they were not able to communicate effectively, younger than age 5, or had developmental disabilities. Body mass index was calculated and the history of previous otologic disease carefully elicited from the caregivers. Electrogustometric threshold, a validated measure of chorda tympani function, was obtained bilaterally in each child. Children were divided into cohorts based on the number of acute otitis media episodes, and electrogustometry thresholds were compared between cohorts. Results Electrogustometric thresholds were successfully obtained in all children. There was no significant relationship between chorda tympani nerve function and history of acute otitis media. Similarly, there was no significant association between the history of otitis media and body mass index. Conclusion This study did not demonstrate any effect of previous acute otitis media history on chorda tympani nerve function. Furthermore, it did not demonstrate a relationship between acute otitis media and elevated body mass index. This is counter-evidence to the previous hypothesis that increasing acute otitis media is responsible for increasing childhood obesity through alteration in chorda tympani nerve function.

Summary Background Chronic rhinosinusitis with nasal polyps is observed in 1–4% persons during rhinoscopy. While the occurrence of their problems is connected with smell sense, still not enough attention is paid to the malfunctioning of their taste sense. Aim The purpose of this study was estimation of taste sense functioning in patients with chronic rhinosinusitis with nasal polyps, treated with oral glucocorticosteroid. Material and methods The study included 82 persons. The 31 of them were patients of Otolaryngology Department of Warsaw Military Institute with chronic rhinosinusitis with nasal polyps’ diagnosis, who were treated with systemic – oral glucocorticosteroid for three weeks. There were 51 healthy people as a control group. Both prior to the treatment and one month after it was finished, all patients had the taste examination. The taste functioning was examined with two methods: the gustometry by Bornstein and impulse bipolar electrogustometry method. Subjective nasal patency was noted based on analogical scale. The smell function was assessed with the Elsberg–Levy olfactometry in Pruszewicz's modification. Results Before treatment the taste disturbances were observed, depending on kind of taste, in 6–16 cases (19,4–51,6%) in gustometry and for 10 patients (32,26%) in electrogustometry. Before treatment the taste examination results in chronic rhinosinusitis with nasal polyps’ cases were statistically significantly different than in the control group. After treatment with glucocorticosteroid the taste disturbances were observed, depending on kind of taste, in 0–9 cases (0–29%) in gustometry and for 4 patients (12,9%). in electrogustometry. Statistically, glucocorticosteroid therapy also decreased the smell threshold and was effective in restoration of the nose patency. Conclusions Statistically, therapy with glucocorticosteroid significantly improved both the taste and smell perception in patients with chronic rhinosinusitis with nasal polyps

Most of the clinical cases experienced taste disturbance after stapes surgery, and in a few cases this disturbance persisted for a long time. The animal experiment suggested the role of geniculate ganglion (GG) cells in nerve generation.To clinically examine taste disorder and its recovery after stapes surgery and experimentally demonstrate a role of GG.Taste function after preservation of chorda tympani nerve (CTN) in stapes surgery was prospectively investigated with a questionnaire and electrogustometry (EGM). Further, expression of neurotrophic factors in GG after injury of CTN was examined by in situ hybridization histochemistry (ISSH) and RT-PCR.Among the cases, 15/18 (83.3%) were associated with taste disturbance and 6/18 (33.3%) were associated with tongue numbness 2 weeks after surgery; however, the symptoms ceased in 14/18 cases (77.8%). Two weeks after surgery, the EGM threshold was found to be elevated in 15/18 cases (83.3%), while in 10/18 cases (55.6%), it did not decrease until 1 year after surgery. Expression of ISSH and amplified bands of BDNF and GFR increased at 7 and 14 days after nerve injury in ipsilateral GGs and also increased at 7 days on the contralateral side.

Background:Electrogustometry is an accurate and increasingly popular method used to examine taste. However, its usefulness as a screening test is unknown.Methods:We asked 114 subjects, some healthy but most with medical conditions possibly affecting taste, to rate their overall taste ability, on a scale of zero to 10. Those who had current symptoms related to taste– and who rated their taste as five or worse – were defined as ‘aberrant tasters’. We recorded automated electrogustometry thresholds, and visual analogue scale intensity ratings, for solutions of the four basic tastes (sweet, sour, salty and bitter). A visual analogue scale score of 50 was used as a cut-off point to identify ‘poor tasters’.Results:The sensitivity and specificity of electrogustometry in identifying abnormal taste function were low.Conclusions:We conclude that automated electrogustometry is not a useful clinical screening method for taste disturbance in a population such as ours.

Summary Aim The purpose of this study was estimation of taste and smell senses functioning in patients with nasal polyps and the analysis of correlation between taste and smell perception threshold and polyps size. Material and method The study included 86 persons. The 35 of them were patients of Otolaryngology Department of Warsaw Military Institute with nasal polyps diagnosis. There were 51 healthy people as a control group. The smell perception examination was performed using Elsberg-Levy method in Pruszewicz modification. The gustatory function was investigated using gustatory method by Borstein and electrogustometry. The Borstein method based on four substances (each of them in three increasing concentrations) related to four basic tastes: sweet (glucose), bitter (chininum hydrochloride), sour (citric acid) and salty (sodium chloride). The taste feeling threshold (POS), that meant the lowest concentration of each solution being correctly recognized by a person, was noticed for each taste. For quantitative estimation of taste perception threshold we included impulse electrogustometry with bipolar electrode. Results In our study the taste disturbances were observed, depending on kind of taste, in 20–70% cases in gustometry and for 13 patients in electrogustometry. Abnormal olfactory results we diagnosed in more then 57% patients. We did not confirm correlation between taste perception threshold and polyps size but polyps size influenced olfactory results. Conclusions Smell and taste disturbances are very often symptoms of nasal polyposis. The taste and olfactory estimation ought to be integral part of routine patient examination in otolaryngology department.

The chorda tympani nerve is often severed during middle ear surgery. After being severed, regeneration of the nerve was observed in 46% (33/71 ears) of patients who underwent second surgery or reoperation. Since it is unclear whether these regenerated nerves have gustatory function, the threshold of electrogustometry (EGM) was measured periodically over a one-year period after surgery. In 20 (61%) of 33 cases demonstrating regenerated nerves, EGM threshold recovered completely or incompletely compared with pre-operative values. Furthermore, the morphological examination of fungiform papillae of the tongue using a digital microscope was performed. In 35 patients with recovery of gustatory function, 11 (31%) showed a similar size and distribution of fungiform papillae compared with that on the non-severed side. Based on these findings, it was concluded that the severed chorda tympani nerve can regenerate and regain gustatory function. Furthermore, it was suggested that the regenerated chorda tympani nerve fibers distribute to fungiform taste buds, although morphological study of the taste buds using a transmission electron microscope is needed.

Objective: To investigate the incidence of taste disturbance after tonsillectomy and laryngomicrosurgery. Study design: A prospective study. Methods: Thirty-five consecutive patients underwent tonsillectomy with electric coagulator at Kanebo Memorial Hospital from September 2002 to May 2004. Another 35 consecutive patients underwent laryngomicrosurgery in a routine way during the same period. Both procedures were performed by two experienced doctors. The postoperative taste function was evaluated with questionnaire, electrogustometry (EGM), and serum levels of Zn, Cu and Fe. Results: After tonsillectomy, 3/35 patients (8.6%) complained of taste disturbance, due to the pressure on the tongue in two, and Zn deficiency after lack of intake in one. All three patients recovered taste within 1.5 months. None of our patients had taste disturbance due to surgical insult of the lingual branch of the glossopharyngeal nerve. After laryngomicrosurgery, only one patient (2.9%) complained of taste disturbance with elevation of the EGM threshold that resulted from the pressure on the tongue. In addition, abnormal sensation in the tongue occurred in 9 cases (25.7%) after tonsillectomy and in 2 cases (5.7%) after laryngomicrosurgery, and feeling of thirst occurred in 12 cases (34.3%) and in 8 cases (22.9%), respectively. Conclusion: Taste disturbance occurs in few cases when experienced surgeons perform tonsillectomy or laryngomicrosurgery. However, it is recommended to inform the patients of the potential postoperative complications such as taste disturbance and abnormal sensation of the tongue.

It is generally said that taste function deteriorates naturally with age. Taste function after middle ear surgery in elderly patients has not been clarified.The taste function of the chorda tympani nerve on the normal and diseased sides was examined before and after middle ear surgery using electrogustometry in 79 patients aged60 years, and the findings were compared with those in 228 young and middle-aged patients.The threshold of electrogustometry on the normal side increased significantly with increasing age (p0.0001). The rate of thresholds that were off the scale was highest in the70 years age group. The preoperative threshold on the diseased side increased significantly with increasing age in patients with chronic otitis media (p=0.0029) and cholesteatoma (p0.0001). In patients with chronic otitis media, the postoperative threshold of the60 years age group tended to be higher than that of the60 years age group.These findings suggest that the taste function of the chorda tympani nerve deteriorated on the diseased side as much as on the normal side in elderly patients. Therefore, in most cases, we do not have to pay as much attention to the chorda tymapani nerve when performing surgery in elderly patients compared to young and middle-aged patients.

Objective/Hypothesis: Tonsillectomy is among the most commonly performed procedures. As with any surgery, head and neck surgeons must be aware of possible complications and their potential affects. At our smell and taste center, we have been referred several patients in a 6-month period with the complaint of taste distortion after tonsillectomy. We report in this article a patient that complains of taste distortion after a right tonsillectomy for unilateral tonsillar hypertrophy. Study Design: A prospective study documenting taste distortion after tonsillectomy using clinical, subjective, and objective evaluation. Methods: The clinical course of a patient with taste distortion after a tonsillectomy is described. The gustatory function was investigated by conducting electrogustometry and spatial taste testing. Threshold measurements were determined at three left- and three right-side tongue regions: 1) the tongue tip region (innervated by the chorda tympani branch of the facial nerve), 2) the lateral margin of the tongue (anterior to the foliate papillae), and 3) the posterior tongue region (innervated by the lingual branch of the glossopharyngeal nerve). Results: After a complete clinical evaluation and taste testing, it was found that the patient suffered an injury to the right lingual branch of the glossopharyngeal nerve. The close anatomic relationship between the palatine tonsil and lingual branch of the glossopharyngeal nerve makes the nerve vulnerable during tonsillectomy. This injury has caused the patient to suffer ageusia to the right posterior one third of the tongue, compensated by a contralateral phantogeusia (phantom taste) with clinical dysgeusia. The phantogeusia was abolished by application of anesthetic to the area where the phantom was perceived. We propose that the phantogeusia is the result of release-of-inhibition in the contralateral glossopharyngeal nerve. Conclusion: Taste distortion (including, phantogeusia and dysgeusia) after tonsillectomy is rarely reported as a complication but has a significant impact on quality of life. This article examines the taste distortion presence as a complication after tonsillectomy to make head and neck surgeons aware of this serious complication and the pathophysiology of taste distortion.

Electrogustometry is well established as a clinical tool for the estimation of taste detection thresholds. Nevertheless, the user is sometimes unaware of the impact of superficially minor procedural and psychophysical factors upon the reliability and comparability of threshold estimates. The inherent strengths and limitations of the procedure are outlined, and aspects of the control and specification of the stimulus that moderate threshold measures are discussed. In addition, threshold estimates from two individuals with severe unilateral taste loss are used to illustrate the level at which anodal dc current may elicit common, rather than taste, sensation. Where chorda tympani section is complete and historical (older than 7-14 days), very high stimulus levels, conservatively over 5 micro A/mm2 (100 micro A linear current with a 5-mm diameter electrode), are required to activate trigeminal responses.

Background The incidence and the scale of recovery of the taste function after middle ear surgery is usually determined by the use of anamnestic data and electrogustometry. Methods Taste tests (regional chemical taste test, electrogustometry and subjective evaluation) were performed preoperatively, 2 to 3 weeks and 6 to 9 months after middle ear surgery. These results were evaluated by taking the scale of chorda tympani nerve (CTN) manipulation into consideration. Three groups were chosen: group 1: no or small CTN manipulation, n = 54; group 2: strong CTN manipulation, n = 14; group 3: severed CTN, n = 50. Patients In a prospective study 118 patients were examined after middle ear surgery in the ENT-Department of the University of Rostock between 2001 and 2002. 61 females and 57 males, age from 7 - 81 years, were included. Results Complaints were observed in all three groups, mainly in groups 2 and 3. These included taste disorders, taste phenomenon and numbness of the tongue. Using regional chemical taste tests, the taste loss of group 3 could be proven for those patients with complaints in 64 % and for those patients without complaints in 27 %. The electrogustometry is more sensitive than chemical taste test. All patients had pathological thresholds after chorda cutting (78 % no thresholds; 22 % elevated thresholds). 68 out of 118 patients (58 %) had a second follow-up after 6 to 9 months after middle ear surgery. The complaints are declining in all groups. In groups 2 and 3 a recovery of taste function could be observed. Even if the number of patients with severed chorda, who suffer from taste disorders, diminishes, a recovery of the taste function could only be observed in 30 %. Conclusions The scale of chorda manipulation is important for the recovery of the taste function after middle ear surgery. The CTN should be preserved intraoperatively, especially when an operation of the contralateral ear is planned as well.

Background: Besides anamnestic data and taste test, the clarification of epithelial taste disorders makes macroscopic evaluation of the surface of the tongue necessary. Methods: In this article the contact endoscopy is evaluated for examination of the tongue epithelium and for quantification of the fungiforme papillae. These results are related to the results of the spatial taste test (1. chemical taste test with sodium chloride in 2 different suprathreshold concentrations and sucrose in also 2 different suprathreshold concentrations; 2. electrogustometry with a bipolar electrode). Patients: In a prospective study we performed contact endoscopy in 16 healthy volunteers from ages 7 to 68 years. The subjects were divided into 2 age groups (≤ 45 years and > 45 years) and 2 papillae density groups. In 34 patients with either taste disorders of unknown cause or in patients with macroscopic changes at the tongue surface the spatial and whole mouth taste tests and contact endoscopy were used to clarify the cause of the complaints. Results: Density and shape of the fungiform papillae as well as the shape of the subepithelial vessels of the papillae vary among the investigated human subjects in the different age groups. No correlation between intensity ratings, papillae density und age was found after stimulation with 40% sucrose at the tongue tip in the younger age group. Stimulation of the tongue edge with 15% sodium chloride, however, showed a relationship between the two different density groups and the different age groups. Conclusions: The contact endoscopy allows the evaluation of the epithelium in the oral cavity. It is a nondestructive method and is additionally easy to handle, but the evaluation of the observed epithelia needs interdisciplinary co-operation with pathologists. No relevant informations are supplied in diagnostics of taste disorders.

To study the recovery of function of the chorda tympani nerve, we examined by electrogustometry 79 patients (83 ears) with both preoperative normal function of the nerve and operative preservation of the nerve, every 2 days during hospitalization and at 6 months after surgery. For symptoms such as tongue numbness and taste disturbance, patients with noninflammmatory (NI) diseases (13/20 or 65.0%) showed a significantly higher rate of symptoms than did patients with chronic otitis media (COM; 13/35 or 37.1%) at 2 weeks after surgery (p = .032). The patients with NI diseases (5/20 or 25.0%) tended to show a higher rate of symptoms than did the COM patients (2/35 or 5.7%) or cholesteatoma patients (2/28 or 7.1%) at 6 months after surgery. The rate of recovery of the EGM threshold to normal at 2 weeks after surgery was significantly lower in NI disease patients (6/20 or 30.0%) than in COM patients (23/ 35 or 62.9%) or cholesteatoma patients (19/28 or 67.9%; p = .015 and .008, respectively). Thus, the patients with NI diseases had postoperative symptoms and elevation of EGM threshold more frequently than did the patients with inflammatory diseases.

We retrospectively reviewed 52 patients who underwent middle ear surgery during which the chorda tympani nerves were severed and who then underwent secondary surgery 1 to 5 years later. In 22 patients (42.3%), regenerated chorda tympani nerves (entire length of the tympanic segment) were detected in the submucosal layer of the reconstructed eardrum during the secondary surgery. Before the secondary surgery, 16 patients (30.8%) showed threshold recovery on electrogustometry. When 5 regenerated nerves were observed by transmission electron microscopy, myelinated nerve fibers were detected in a small fascicle or connective tissue, but the number of myelinated axons was significantly decreased (7.4% to 84.6%; p = .01) compared with that in normal subjects (1,911 ± 324; n = 4). There was a significant difference in the incidence of regeneration between the group with end-to-end anastomosis (5/5 or 100%) and that with nerve gap defects (17/47 or 36.2%; p < .05); this finding suggests that repair of the sectioned nerve produces a better incidence of regeneration than leaving the nerve unrepaired.

We report two cases of temporary taste disturbance after inferior alveolar nerve block. The first patient to present with this rare complication of anesthesia for dental surgery was a 41-year-old woman. She lost the sense of taste on the left side of her tongue after local anesthesia for treatment of a left mandibular molar and first visited our outpatient clinic complaining of taste disorder 3 months later. Electrogustometry (EGM) and filter paper disk (FPD) testing revealed a taste disturbance in the innervation area of the left chorda tympani nerve and atrophy of the fungiform papillae on the left side of the tongue was observed. Eleven months after the dental treatment, the fungiform papillae and the results of EGM were normal. The second patient, a 22-year-old woman, received local anesthetic for extraction of a right mandibular molar and subsequently developed loss of taste on the right side of the tongue. When she visited our outpatient clinic 3 months later, atrophy of the fungiform papillae on the right side was observed. Her gustatory sense began to improve 4 months after the dental surgery and was normal at 13 months. From these findings we conclude that taste disturbance on the same side as the inferior alveolar nerve block in each case was due to direct injury to the chorda tympani and lingual nerves during administration of the local anesthetic. The results of EGM and FPD testing were diagnostic: atrophy of the fungiform papillae on the same side and disappearance of taste on the same side in the intravenous taste test provided complementary diagnostic information. The outcome was satisfactory in both cases.

Changes in gustatory sense were investigated in 97 pregnant women and in 30 healthy, non-pregnant women who served as controls. All 97 pregnant women completed a questionnaire regarding taste changes and 32 of them underwent serial tests of gustatory function, including electrogustometry and testing with filter paper disks placed over the areas of the chorda tympani nerve and glossopharyngeal nerve. All gustatory testing was performed by the same person. In addition, serum levels of trace elements were measured in 72 of the pregnant women. Of the 97 pregnant women, 90 (92.8%) reported in the questionnaire that they had experienced some type of change in taste during pregnancy, usually a change in sour taste (59 women; 65.6%). Pregnant women had higher gustatory thresholds than non-pregnant women, with an especially marked decrease in gustatory function being noticed in the first trimester. Although serum zinc levels decreased in pregnant women between the second and third trimesters, zinc levels were in the normal range in the early stage of pregnancy. Thus, it is difficult to explain dysgeusia in the early stage of pregnancy as being associated with a deficiency of zinc. The decrease in gustatory function during the first trimester is considered to be due to the notable changes in secretion of hormones that occur during this stage.

Of the 3583 outpatients treated at our taste disorder clinic over a period of 15 years, 11 (0.31%) complained of taste disorder after tonsillectomy. The cause of taste disorder was identified in 8 of the 11 cases: in 3 cases it was caused by direct or indirect damage to the lingual branch of the glossopharyngeal nerve; in 2 cases it was attributable to medication taken by the patient after tonsillectomy; and in 3 cases taste disturbance was caused by a lack of dietary zinc, even though this was identified at the time of tonsillectomy. These findings indicate the importance of (i) informing patients when consent for tonsillectomy is obtained that there is a risk of postoperative taste disorder; (ii) measuring the patient's taste threshold and serum zinc level preoperatively; and (iii) obtaining a thorough drug history, including details of non-prescription medications habitually taken by the patient.

The course of recovery from taste receptor disturbance was studied in 119 patients with moderate-to-severe taste receptor disturbance that was cured or improved with zinc therapy. Taste receptor disturbance was idiopathic in 45 patients, drug-induced in 38 and due to zinc deficiency in 36. Recovery of taste, evaluated by filter paper disk testing and electrogustometry, followed 1 of 3 patterns: (i) in 54 (45.4%) of the 119 cases, taste improved simultaneously in the anterior (innervated by the chorda tympani nerve) and posterior (innervated by the glossopharyngeal nerve) portions of the tongue; (ii) in 53 (44.5%) of the cases, taste improved in the posterior portion first; and (iii) in 12 (10.1%) of the cases, taste improved in the anterior portion first. Zinc therapy was more effective in patients with the "posterior" pattern of recovery, and these patients also recovered the ability to sense sweet and bitter tastes earlier than other tastes. These results indicate that recovery of taste begins on the posterior portion of the tongue, which has an abundance of taste buds. The results of electrogustometry were not helpful in assessing recovery from taste disturbance, but testing for taste using the filter paper disk method on the posterior portion of the tongue was useful for identifying the onset of recovery.

Objective To elucidate the degeneration process of fungiform taste buds after severing the chorda tympani nerve (CTN) by confocal laser scanning microscopy in vivo. Study design Prospective study. Setting University hospital. Patients Seven consecutive patients whose CTN was severed during tympanoplasty for middle ear cholesteatoma. Intervention Diagnostic. Main outcome measures Preoperative and postoperative gustatory functions were assessed by electrogustometry (EGM). An average of 10 fungiform papillae (FP) in the midlateral region of the tongue were periodically observed, and the number of taste buds was counted using a confocal laser microscope. Among them, 2 to 3 reference FPs were selected based on the typical form of the FP or characteristic arrangements of taste pores. Observation was performed before surgery, 1 or 2 days after surgery, 2 or 3 times a week until 2 weeks after surgery, once a week between 2 and 4 weeks, and every 2 to 4 weeks thereafter until all taste buds had disappeared. Results EGM thresholds showed no response within 1 month after surgery in all patients. The initial change in the degeneration process was the disappearance of taste pores. The surface of taste buds became covered with epithelium. Finally, taste buds themselves atrofied and disappeared. The time course of degeneration differed depending upon individuals, each FP, and each taste bud. By employing the generalized linear mixed model under the Poisson distribution, it was calculated that all taste buds would disappear at around 50 days after surgery. Conclusion Confocal laser scanning microscopy was useful for clarifying the degeneration process of fungiform taste buds.

OBJECTIVE To evaluate whether regenerated fungiform taste buds after severing the chorda tympani nerve can be detected by confocal laser scanning microscopy in vivo. STUDY DESIGN Retrospective study. SETTING University hospital. PATIENTS Six patients with a normal gustatory function (Group 1), 9 patients with taste function recovery after severing the CTN (Group 2), and 5 patients without taste function recovery (Group 3) were included. In Groups 2 and 3, canal wall up (closed) tympanoplasty or canal wall down with canal reconstruction tympanoplasty was performed in all patients. INTERVENTION Diagnostic. MAIN OUTCOME MEASURES The severed nerves were readapted or approximated on the temporalis muscle fascia used to reconstruct the eardrum during surgery. Preoperative and postoperative gustatory functions were assessed using electrogustometry. Twelve to 260 months after severing the CTN, the surface of the midlateral region of the tongue was observed with a confocal laser microscope. RESULTS EGM thresholds showed no response 1 month after surgery in all patients of Groups 2 and 3. In Group 2, EGM thresholds showed recovery 1 to 2 years after surgery and before confocal microscopy (-1.3 ± 6.5 dB). There was a significant difference between Group 1 (-5.7 ± 2.0 dB; p < 0.01) and Group 2. In Group 3, EGM thresholds showed no response for more than 2 years. In the control group (Group 1), 0 to 16 taste buds were observed in each FP, and 55 (79.7%) of 69 FP contained at least 1 taste bud. The mean number of taste bud per papilla was 3.7 ± 3.6. In patients with a recovered taste function (Group 2), 0 to 8 taste buds were observed in each FP. In this group, 54 (56.2%) of 94 FP contained at least 1 taste bud. The mean number of taste bud per papilla was 2.0 ± 2.2 (p < 0.01). In Group 3, without recovery, the FP was atrophied, and no taste bud was observed. CONCLUSION Regenerated fungiform taste bud could be observed in vivo using confocal laser scanning microscopy, indicating that regenerated taste bud can be detected without biopsy.

Objectives The present study compares the long-term follow-up results of electrogustometry with patient reports of taste dysfunction after middle ear surgery. Study Design Retrospective review of 371 patients who underwent middle ear surgery. Methods Patients were divided into the following groups depending on the degree of manipulation or surgical damage to the chorda tympani nerves: the no-touch group (group 1 [n = 109]); the touch group (group 2 [n = 149]); and the severed nerve group (group 3 [n = 113]). Electrogustometry was periodically performed over the course of several years. Results The incidences of postoperative subjective taste disorder in groups 1, 2, and 3 were 2.8%, 25.5%, and 38.9%, respectively. Although the subjective taste disorder usually recovered within 1 to 2 years after surgery in all groups, it persisted for more than 2 years in 2.7% of the touch group and 5.3% of the severed nerve group. Concerning postoperative electrogustometric results, in the no-touch group, 8.3% of patients showed threshold elevation on electrogustometry, but the elevated thresholds completely recovered in all cases. In the touch group, 45% of patients exhibited elevated electrogustometric thresholds on their first postoperative test, including 32.9% who subsequently had complete electrogustometric recovery, 10.1% who subsequently had incomplete recovery, and 2% who failed to recover during the follow-up period. In the severed nerve group, none of the patients was responsive to the electrical stimulus on the first postoperative test, including 8.8% of patients who subsequently exhibited complete electrogustometric recovery, 32.7% who later had incomplete electrogustometric recovery, and 58.4% who never recovered any electrogustometric responsiveness. Nerve repair in the severed nerve group produced better recovery, as measured electrically. Conclusions The incidence of postoperative subjective taste disorder was low, although inconsistent with the high incidence of threshold elevation on electrogustometry, especially in the severed nerve group. Preservation or repair of the chorda tympani nerve is recommended in order to maintain or recover gustatory function.

Electrogustometry has been used as a clinical tool for diagnosis and assessment of a variety of conditions. Several studies which have estimated electrogustometric taste threshold have reported good test-retest reliability but there is some evidence that thresholds measured this way may decrease with practice. In this study, repeated testing of the right and left sides of the tongue of two subjects over 80 sessions resulted in considerable session-to-session variability for both subjects, and three of the four sets of threshold estimates decreased systematically with continued testing. Two of the four data sets continued to show systematic decreases when the first 10 sessions were omitted from analysis to allow for any initial unfamiliarity with the testing procedure. This suggests that estimates based on few tests should be interpreted with caution, particularly when used for evaluation or monitoring of interventions.

Electrogustometery, first introduced in the 1950s for the clinical assessment of taste function, has returned to favour in recent years. This is due, in part, to the credence given to the procedure by an increased understanding of the mechanisms of taste transduction. The reliability and validity of electrogustometric assessments of taste function should increase with the use of automated testing. An automated computer-controlled testing paradigm was used to obtain threshold estimates simultaneously from the left and right sides of the tongue in 97 volunteers aged between 17 and 63 years. A small but statistically significant advantage was found for thresholds from the right side of the tongue (P < 0.01). The range of thresholds, and of interside differences obtained with this procedure, are reported, and practical issues related to testing are discussed.

We examined the senses of smell and taste in 240 patients with verified hypersensitivity reactions of the respiratory tract. Olfactometry was performed according to Elsberg and Levy's method and followed by electrogustometry. The examinations revealed that the incidence of smell and taste disorders in patients with allergic rhinitis is 21.4% and 31.2%, respectively. No significant relationships between smell and taste dysfunction were found. We evaluated statistically positive correlations between the olfactory and gustatory thresholds compared with 78 qualitative and quantitative factors assessed in the study. There was a statistically significant relationship between the olfactory thresholds and levels of eosinophils in blood and in nasal discharge. acid reaction of the nasal mucosa, coexisting nasal polyps and X-ray changes in the ethmoid sinuses. There was a positive influence of pharmacotherapy as well as specific desensitization and surgery on the impairment of the sense of smell in allergic rhinitis.

Summary Electrogustometry has been used as a clinical tool for diagnosis and assessment of a variety of conditions. Since the lack of versatile electrogustometer for research and diagnosis, the new electrogustometer EG-1 was developed in 2006. It was done in cooperation between Warsaw University of Technology and Military Institute of Medicine in Warsaw. EG-1 allows quantitative estimation of taste perception threshold using both static and impulse electrogustometry with bipolar electrode. It is a fully autonomous, battery powered and portable instrument. Because of small size and weight, it can be easily placed in any environment. Microprocessor controlled measurement system and user-friendly interface (LCD display with simple keyboard) make EG-1 electrogustometer very handy and flexible in operation. Data obtained during measurements is stored in the internal device memory. After taste examinations measurement data can be transferd to a personal computer via inbuilt USB port for further analysis and storage. EG-1 can generate three predefined variously shaped current impulses: sinus-, saw- and rectangleshaped. There is an optional possibility of creating own shapes of stimulus puls by the user. The electrical parameters of generated pulses are as follow: current amplitude 1–2000 μ A regulated with 1 μ A step, stimulus frequency 0(DC)-500 Hz regulated with 5 Hz step, controlable fulfillment factor and signal rise time (optional for automatic measurements). The operator can trigger the stimuli via a hand switch on the bipolar electrode (with goldplated endings), via keyboard or via additional independent hand switch. Three years of experience collected during EG-1 exploitation allowed to design a new version of electrogustometer EG-2 with a touch panel and color graphical display.

We report the case of a 16-year-old female patient with taste impairment of the soft palate. After receiving a skull fracture due to a traffic accident, she experienced the taste of bitter chocolate. CT showed the fracture around the right temporal bone. Electrogustometry showed that the decreased sensation of taste was restricted to the right soft palate. Shirmer test showed that lacrimal secretion of the right eye was decreased. These findings indicated that the selective injury of the major petrosus nerve on the right side due to the fracture caused taste impairment of the soft palate. It has been reported that the sensation of a sweet taste is more sensitive in the soft palate of young women. Therefore, it is suggested that the taste impairment of the soft palate caused the dissociated impairment of a sweet taste, resulting in the taste of bitter chocolate in the present case.

Objectives/Hypothesis: The present study determined whether a 125 mm2 electrode would produce lower and more reliable electrical taste thresholds than a 25 mm2 electrode when measurement occurred in a medial tongue region relatively sparse in taste bud numbers. We hypothesized this would be the case and that the obtained threshold values would be higher than those previously reported for anterior and lateral tongue regions. Study Design And Methods: Sixteen college-age subjects were tested twice, once using the 25 mm2 electrode and once using the 125 mm2 electrode on each of two sessions separated by 2 to 16 days. The order of presentation of the sessions was counterbalanced across subjects. Measurement was confined to the medial tongue, 0.7 cm lateral to the median furrow. Results: As hypothesized, the larger electrode resulted in lower and more reliable threshold values than the smaller electrode (respective median threshold values = 20.06 μA & 33.59 μA, P = .001; respective test-retest rs = 0.78 [P < .001] and 0.46 [P < .05]). Also as hypothesized, the threshold values were higher (i.e., sensitivity lower) than previously reported for anterior and lateral tongue regions. Conclusions: The magnitude and reliability of electrical taste thresholds depends on the tongue region examined and the size of the electrodes used. These results suggest that relatively large electrodes should be considered for electrogustometric threshold testing, particularly when lingual regions not highly populated with taste buds are evaluated.