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Abstract Objective What are the electrogustometer's (EGM) validity, reliability, and diagnostic accuracy in assessing taste sensation in adults compared to other taste tests? Data Sources PubMed Medline, Elseviers's Embase, and the six databases of Cochrane Library. Methods We conducted a systematic search on December 20, 2022, consisting of synonyms for EGM. We considered randomized controlled trials and observational studies with original data for inclusion if they included adults who underwent electrogustometry. Articles were excluded if no analysis regarding validity, reliability, or diagnostic accuracy had been performed or if these analyses could not be performed with the published data. Results Nineteen articles discussing 18 studies were included for data extraction. The included studies carry a high risk of bias. Overall, the association between a variety of reference taste tests and EGM was moderate or weak with correlation coefficients ranging from −0.51 to 0.40 with one outlier of −0.74 found in one study correlating EGM and taste solutions. Test–retest reliability was good with reported correlation coefficients between 0.78 and 1.0. The sensitivity, specificity, PPV, and NPV of EGM in identifying abnormal taste function varied widely between the four studies on diagnostic accuracy. Conclusion The included studies in this review lack the required standards regarding study design to draw firm conclusions about the validity, reliability, and diagnostic accuracy of the EGM. Future research is needed to assess these measurement properties. Based on the reported results, we would not recommend using the EGM as a screening test for taste disturbance in clinical practice. Level of Evidence NA.

Objective: What are the electrogustometer's (EGM) validity, reliability, and diagnostic accuracy in assessing taste sensation in adults compared to other taste tests? Data Sources: PubMed Medline, Elseviers's Embase, and the six databases of Cochrane Library. Methods: We conducted a systematic search on December 20, 2022, consisting of synonyms for EGM. We considered randomized controlled trials and observational studies with original data for inclusion if they included adults who underwent electrogustometry. Articles were excluded if no analysis regarding validity, reliability, or diagnostic accuracy had been performed or if these analyses could not be performed with the published data. Results: Nineteen articles discussing 18 studies were included for data extraction. The included studies carry a high risk of bias. Overall, the association between a variety of reference taste tests and EGM was moderate or weak with correlation coefficients ranging from −0.51 to 0.40 with one outlier of −0.74 found in one study correlating EGM and taste solutions. Test–retest reliability was good with reported correlation coefficients between 0.78 and 1.0. The sensitivity, specificity, PPV, and NPV of EGM in identifying abnormal taste function varied widely between the four studies on diagnostic accuracy. Conclusion: The included studies in this review lack the required standards regarding study design to draw firm conclusions about the validity, reliability, and diagnostic accuracy of the EGM. Future research is needed to assess these measurement properties. Based on the reported results, we would not recommend using the EGM as a screening test for taste disturbance in clinical practice. Level of Evidence: NA. [ABSTRACT FROM AUTHOR]

BACKGROUND: To evaluate chorda tympani nerve function as measured by unilateral increases of gustatory thresholds in the presence of ipsilateral acute otitis media. METHODS: Prospective clinical study comparing electrogustometric measurements was conducted to evaluate the taste thresholds of each side of the tongue in a patient during an acute episode of unilateral acute otitis media. Included were patients aged 12-40 who presented to the emergency department and outpatient ear, nose, and throat clinic of a university-affiliate tertiary medical center with unilateral acute otitis media between January 2019 and January 2020 and consented to the study. RESULTS: Eleven patients were initially recruited into the study, and 10 patients aged (mean ± standard deviation) 26.1 ± 11.2 years comprised the final study group. Taste thresholds were significantly elevated on the side ipsilateral to the ear affected by acute otitis media (P < .05). CONCLUSION: Chorda tympani nerve conductance is impaired during the acute stage of acute otitis media. This may have implications in the understanding of peripheral neural properties during acute middle ear inflammatory conditions and on the diagnosis of acute otitis media. [ABSTRACT FROM AUTHOR]

Electrogustometry (EGM) is a practical way to test taste. It is typically performed using unipolar electrodes, with the anode on the tongue and the cathode on the hand, forearm, or neck. This results in electric current passing through nontaste tissues and adds a level of impracticality to its clinical application. We compared, using a repeated measures counterbalanced design, anodal thresholds from a unipolar electrode to those of a unique bipolar electrode in which the anode and cathode are contiguously located. Both sides of the anterior tongue were assessed in 70 subjects, as were the effects of age and sex. Nonparametric analyses were performed. The median threshold of the bipolar electrode's central disk (2.49 µA) did not differ from that of the unipolar electrode (2.96 µA) (P = 0.84). On average, older persons exhibited higher thresholds. No significant sex or tongue side effects were evident. Interestingly, when the annular (donut-shaped) bipolar electrode served as the anode, the threshold was higher than that of the other electrodes (5.19 µA; P s < 0.001). This conceivably reflected lessened summation of activity among adjacent afferents and partial sampling of tongue regions with fewer taste buds. Correlations among all EGM thresholds were nominally higher for women than for men, ranging from 0.83 to 0.85 for women and 0.54 to 0.67 for men; all P s < 0.001. This study validates the use of a bipolar electrode for assessing taste function, averting movement of current through nontaste-related tissues and making such testing safer and more practical. [ABSTRACT FROM AUTHOR]

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Objective: To investigate changes in the clinical state of taste disorders between 1990, 2003, and 2019 using the same methodology as that in previous studies.Materials and Methods: In June 2019, we mailed a questionnaire to 1100 otolaryngologists belonging to the Japan Society of Stomato-pharyngology and investigated three question categories: "Institution", "Number of patients for 3 months", and "Treatment". In addition, we analyzed some results by the class of institution.Results: The rate of patients who complained of taste disorders in the 2019 survey (220/100,000 persons/year) was twice that of the 1990 survey (110/100,000 persons/year), and slightly higher than that of the 2003 survey (192/100,000 persons/year). The rate of female patients was higher than that of male patients in all age groups. The number of patients was correlated with age up to 70 years of age in both genders. The rates of performing taste tests to assess taste function in the 2019 survey were significantly decreased compared with a 2003 survey (electrogustometry: p<0.001, filter paper disk method: p<0.05 in university). The rate of examination of the serum zinc in the 2019 survey was increased compared with the 1990 survey (p<0.001). Zinc oral therapy was used for the treatment of taste disorders in 239/299 (79.9%) patients/institutes for 3 months. In addition, 213 institutions (69.6%) answered that zinc oral therapy was efficacious for taste disorders.Conclusion: The patients who complained of taste disorder have increased. The zinc administration is an appropriate clinical treatment for taste disorders in Japan. To enhance treatment for taste disorders, simpler methods for assessing taste function need to be developed, and the pathological mechanisms of taste disorders other than zinc deficiency need to be clarified. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract Background and Aim Approximately five percent of the general population are suffering from taste disorders. Usually, subjective loss of taste is caused by smell disorders; thus, isolated loss of the sense of taste is relatively rare. Despite the influence on quality of life, isolated taste disorders (ITD) are sparsely represented in literature and clinical research. In particular, there is need for sufficient diagnostic and treatment algorithms. Aim of study is to add further information to the sparse literature on ITD and suggest an appropriate diagnostic algorithm for ITD. Methods We present a retrospective study on patients with ITD diagnosed at the Flavour clinic, ENT department, Regional Hospital West Jutland, between 2017 and 2020. All patients underwent a thorough rhinolaryngological and otoneurologic examination, including olfactory and gustatory assessment, and a wide spectrum of biochemical, microbiological, and radiological examinations. Results In total, 522 patients referred due to smell and/or taste disorders, 423 (81%) complained of a subjective taste disorder, only 19 (3.4%) patients were diagnosed with ITD. According to etiology, the patients were categorized in following groups: medicine‐related (25%), mixed (21%), iatrogenic (21%), idiopathic (11%), radiotherapy‐related (11%), and autoimmune/inflammatory (11%). Based on etiology, individualized treatment was recommended with very discouraging results. Interpretation Diagnostics of taste disorders is a delicate and expertise demanding task. The mechanisms underlying isolated loss of taste are heterogeneous. ENT and otoneurologic examination, and specific olfactory and gustatory testing are required in all patients, whereas biochemical, microbiological, and radiological examinations are only necessary on an individual basis.

Background and Aim: Approximately five percent of the general population are suffering from taste disorders. Usually, subjective loss of taste is caused by smell disorders; thus, isolated loss of the sense of taste is relatively rare. Despite the influence on quality of life, isolated taste disorders (ITD) are sparsely represented in literature and clinical research. In particular, there is need for sufficient diagnostic and treatment algorithms. Aim of study is to add further information to the sparse literature on ITD and suggest an appropriate diagnostic algorithm for ITD. Methods: We present a retrospective study on patients with ITD diagnosed at the Flavour clinic, ENT department, Regional Hospital West Jutland, between 2017 and 2020. All patients underwent a thorough rhinolaryngological and otoneurologic examination, including olfactory and gustatory assessment, and a wide spectrum of biochemical, microbiological, and radiological examinations. Results: In total, 522 patients referred due to smell and/or taste disorders, 423 (81%) complained of a subjective taste disorder, only 19 (3.4%) patients were diagnosed with ITD. According to etiology, the patients were categorized in following groups: medicine‐related (25%), mixed (21%), iatrogenic (21%), idiopathic (11%), radiotherapy‐related (11%), and autoimmune/inflammatory (11%). Based on etiology, individualized treatment was recommended with very discouraging results. Interpretation: Diagnostics of taste disorders is a delicate and expertise demanding task. The mechanisms underlying isolated loss of taste are heterogeneous. ENT and otoneurologic examination, and specific olfactory and gustatory testing are required in all patients, whereas biochemical, microbiological, and radiological examinations are only necessary on an individual basis. [ABSTRACT FROM AUTHOR]

This study aimed to examine the relationships between subjective taste sensations and electrogustometry (EGM) findings in patients with taste disturbances according to the presence of burning mouth (BM) symptoms. Forty-six patients were included and asked to complete a questionnaire that contained questions on subjective taste sensations for the four basic taste qualities and the pattern of taste disorders such as ageusia, hypogeusia and dysgeusia. EGM was performed to measure detection thresholds. To examine the influence of BM symptoms, patients were divided into two groups: patients with and without BM symptoms. The patients consisted of 11 men and 35 women. The group without BM symptoms (n = 26) had significantly lower degrees of subjective taste sensations for all taste qualities and higher correlation levels between subjective taste sensations and EGM thresholds than the group with BM symptoms (n = 20). The patterns of taste disorders also showed more significant associations with the levels of subjective taste sensations in the patients without BM symptoms compared with those with BM symptoms. In conclusion, patients with taste disorders without BM symptoms had more severe taste disturbances than those with BM symptoms. The pathophysiology of taste disturbances differs according to the presence or absence of BM symptoms. [ABSTRACT FROM AUTHOR]

Objectives: We aimed to provide information on the effects of tonsillectomy, in particular, its effects on taste dysfunction; also known as dysgeusia, and provide direction for future research in this area. Methods: We independently searched five databases (PubMed, SCOPUS, Embase, the Web of Science, and the Cochrane database) for related studies published as recently as December 2019. From the included studies, we reviewed the findings on tonsillectomy and taste disturbance through the use of a questionnaire, chemogustometry, and electrogustometry. We analyzed other conditions that were measured in these studies that included; postoperative pain intensity and other morbidities (eg, postoperative bleeding, hemostasis, tongue numbness and zinc, copper, and iron hemoglobin levels measured). Results: Postoperative taste disturbance based on questionnaire (VAS) scores at 14 days (SMD = −0.31 [−0.50, −0.12], P value =.0012) tended to decrease significantly in the post-tonsillectomy group compared to the pre-tonsillectomy group. Patients showed significantly decreased taste sensation after tonsillectomy than in the preoperative test. Postoperative electrogusmetry at 7 days (SMD = 0.60 [0.27, 0.94], P =.0004) tended to increase significantly in the post-tonsillectomy group compared to the pre-tonsillectomy group. Conclusion: Tonsillectomy is a commonly performed surgery, and taste disturbance occurs frequently as a post operative effect. Taste dysfunction is important to patients with regard to their quality of life and the overall effects of taste on their day-to-day life. This study can be a useful meta-analysis of dysgeusia in tonsillectomy. [ABSTRACT FROM AUTHOR]

Age-related physiological and pathophysiological features of the masticatory apparatus were studied via electrodontometry, estesiometry, electrogustometry, and the determination of thresholds and functional mobility of taste receptors of the tongue. The study was based on an evaluation of the condition of organs and tissues of the masticatory apparatus in 275 (69 men and 206 women) individuals aged from 25 to 86 years, including 74 elderly and senile individuals suffering from diabetes mellitus type 2, chronic nonspecific inflammatory bowel diseases, alcoholism, and chronic kidney disease. It was found that the thresholds of pain sensitivity of teeth, oral mucosa, and the tongue and taste sensitivity increase with age, while the functional mobility of taste receptors becomes impaired. The presence in elderly and senile individuals of psychosomatic pathology, especially type-2 diabetes, chronic kidney disease, and chronic alcoholism in older age groups, exacerbates existing age-related changes in pain and taste sensitivity and leads to severe disorders in the directed response of taste receptors. The indicators presented in this paper, which characterize some age-related physiological and pathophysiological features of the masticatory apparatus in elderly and senile individuals, can be used as a starting point to study the degree of functional disorders of the masticatory apparatus and to take into account the degree of normalization of impaired functions in the treatment of individuals of older age groups. [ABSTRACT FROM AUTHOR]

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 [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Gustatory function is closely related to chewing and swallowing; however, there are currently no reports regarding gustatory function in persons with cerebral palsy (CP). The aim of this study was to compare the gustatory function between persons with CP and healthy controls. We investigated sweet, salty, sour and bitter tastes using the whole‐mouth method and measured the electrogustometric thresholds in the chorda tympani nerve area. Twelve participants with CP (6 women and 6 men) for whom gustatory testing was possible at our facilities, and 17 age‐matched controls (9 women and 8 men) were included. The mean age ± standard deviation was 58.6 ± 8.1 years and 58.5 ± 8.7 years in subjects with CP and controls, respectively. Taste detection and identification were significantly worse in persons with CP compared with the controls. Taste identification was more impaired than taste detection. At the highest concentration, taste identification was impossible 11 times out of 48 (12 persons × 4 kinds of tastes) in persons with CP but such a deficit was not observed in 68 attempts (17 persons × 4 kinds of tastes) involving controls. The electrogustometric thresholds were not significantly different between the groups. Gustatory function associated with chewing and swallowing is worse in persons with CP compared to the controls. [ABSTRACT FROM AUTHOR]

Purpose: We analyzed the prevalence of gustatory test abnormalities in breast cancer (BC) patients undergoing chemotherapy.Methods: We enrolled 43 BC patients undergoing chemotherapy and 38 BC patients who had never undergone chemotherapy (control group). Two gustatory tests were conducted: an instillation method examining the threshold for four basic taste stimuli and an electrogustometry method measuring the threshold for perception with electric stimulation at the front two-thirds of the tongue (cranial nerve VII) and at the back third of the tongue (cranial nerve IX). The results of the two gustatory tests and clinicopathological factors were compared between the chemotherapy and control groups and between patients with and without awareness of dysgeusia in the chemotherapy group.Results: In the chemotherapy group, 19 (44%) patients were aware of dysgeusia and 8 (19%) had hypogeusia using the instillation method. Although more patients had parageusia in the chemotherapy than control group, no significant differences in the results of the two gustatory tests were observed. Patients with dysgeusia awareness had a higher threshold at cranial nerve IX using the electrogustometry method than those without dysgeusia awareness; no significant differences in hypogeusia were observed using the instillation method. In fact, 74% (14/19) of patients with dysgeusia awareness could identify the four tastes accurately using the instillation method. Similar results were observed for the instillation and electrogustometry methods at cranial nerve VII.Conclusions: While approximately half of the chemotherapy patients were aware of dysgeusia, 81% (35/43) of them could accurately identify the four basic tastes using the instillation method. [ABSTRACT FROM AUTHOR]

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, 1904-1913, 2018. [ABSTRACT FROM AUTHOR]

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, 128:701-706, 2018. [ABSTRACT FROM AUTHOR]

Introduction Study results have shown that chronic exposure to cigarette smoke affects the taste function in humans. However, neither the quantitative impact on taste sensitivity nor the time-course of taste recovery on stopping smoking have been precisely examined. Material and Methods The experimental design included 2 phases, (i) a case–control phase comparing the taste sensitivity level measured by Electrogustometric (EGM) thresholds from various parts of the tongue (locus) between smokers (n = 83) and non-smokers (n = 48), (ii) a follow-up study looking at the taste sensitivity recovery in smokers after smoking cessation (n = 24) and compared with non-smokers. Results Smokers exhibited significantly lower taste sensitivity than non-smokers - the higher the nicotine dependence (Fagerström scores), the lower the taste sensitivity. After smoking cessation, EGM thresholds decreased progressively, and reached the taste sensitivity range of non-smokers depending on locus and time. After 2 weeks a recovery could be observed on the 3 Tip and the 2 edge loci; the recovery in the posterior loci was complete after 9 weeks, and in the dorsal loci recovery was observed only after 2 months or more. Conclusions Smoking cessation does lead to a rapid recovery of taste sensitivity among smokers, with recovery time found to differ based on the sensitivity of loci of the tongue. The use of EGM could potentially be explored as a motivational tool for smoking cessation.

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. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate differences in gustatory function and in shape, density, and vascularization of the fungiform papillae (fPap) of smokers' tongue before and after smoking cessation. In 24 smokers (19 males, 5 females; median age: 54.6 ± 2.9 years) 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 fungiform papillae (fPap) and blood vessels' density and morphology at the tip of the tongue were examined using contact endoscopy (CE). Followup exams (EGM and CE) were performed on average 3.2 months after smoking cessation. Findings were compared between the 2 conditions as well as to those of a group of 24 non-smokers (median age: 55.2 ± 3.4 years; 19 males, 5 females). After smoking cessation, EGM thresholds decreased significantly (P = 0.02 or P = 0.03 depending on the tested area) but nonetheless still were quite different from those of non-smokers (P = 0.05 or 0.04 depending on the site of EGM measurement). Under CE the fPap density was higher after quitting smoking (P = 0.05) and the shape and vascularization of fPap also exhibited a trend to improvement (P = 0.05) after smoking cessation. Chronic exposure to cigarette smoke infers long lasting, although to a large extent reversible, alterations in morphology of taste buds in fungiform papillae, but rather irreversible EGM-related functional gustatory compromise, suggesting a profound physiologic effect on human peripheral taste organs. [ABSTRACT FROM AUTHOR]

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 < 0.05. Results Mean EGMt were significantly increased with iBMS for right side of the dorsum of the tongue and right lateral side of the tongue ( P < 0.05). In the iBMS group, VAS scores were significantly correlated to EGMt at the tip of the tongue ( r = −0.59; P < 0.05) and at the right and left lateral sides of the tongue (respectively, r = −0.49 and r = −0.47; P < 0.05). Conclusion These data depicted impaired taste sensitivity in iBMS patients within fungiform and foliate taste bud fields and support potent gustatory/nociceptive interaction in iBMS. [ABSTRACT FROM AUTHOR]

Background: Study results have shown that chronic exposure to cigarette smoke affects the taste function in humans. However, neither the quantitative impact on taste sensitivity nor the time-course of taste recovery on stopping smoking have been precisely examined. Methods: The experimental design included 2 phases, (i) a case--control phase comparing the taste sensitivity level measured by Electrogustometric (EGM) thresholds from various parts of the tongue (locus) between smokers (n =8 3 ) and non-smokers (n = 48), (ii) a follow-up study looking at the taste sensitivity recovery in smokers after smoking cessation (n = 24) and compared with non-smokers. Results: Smokers exhibited significantly lower taste sensitivity than non-smokers - the higher the nicotine dependence (Fagerström scores), the lower the taste sensitivity. After smoking cessation, EGM thresholds decreased progressively, and reached the taste sensitivity range of non-smokers depending on locus and time. After 2 weeks a recovery could be observed on the 3 Tip and the 2 edge loci; the recovery in the posterior loci was complete after 9 weeks, and in the dorsal loci recovery was observed only after 2 months or more. Conclusions: Smoking cessation does lead to a rapid recovery of taste sensitivity among smokers, with recovery time found to differ based on the sensitivity of loci of the tongue. The use of EGM could potentially be explored as a motivational tool for smoking cessation. [ABSTRACT FROM AUTHOR]

The aim of this study was to elucidate the relationship between the gustatory function and average number of taste buds per fungiform papilla ( FP) in humans. Systemically healthy volunteers ( n = 211), pre-operative patients with chronic otitis media ( n = 79), and postoperative patients, with or without a chorda tympani nerve ( CTN) severed during middle ear surgery ( n = 63), were included. Confocal laser scanning microscopy was employed to observe fungiform taste buds because it allows many FP to be observed non-invasively in a short period of time. Taste buds in an average of 10 FP in the midlateral region of the tongue were counted. In total, 3,849 FP were observed in 353 subjects. The gustatory function was measured by electrogustometry ( EGM). An inverse relationship was found between the gustatory function and average number of fungiform taste buds per papilla. The healthy volunteers showed a lower EGM threshold (better gustatory function) and had more taste buds than did the patients with otitis media, and the patients with otitis media showed a lower EGM threshold and had more taste buds than did postoperative patients, reflecting the severity of damage to the CTN. It was concluded that the confocal laser scanning microscope is a very useful tool for using to observe a large number of taste buds non-invasively. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the distribution of taste buds in fungiform papillae ( FP) and gustatory function between young and elderly age groups. Confocal laser scanning microscopy was used because it allows many FP to be observed non-invasively in a short period of time. The age of participants ( n = 211) varied from 20 to 83 yr. The tip and midlateral region of the tongue were observed. Taste buds in an average of 10 FP in each area were counted. A total of 2,350 FP at the tongue tip and 2,592 FP in the midlateral region could be observed. The average number of taste buds was similar among all age groups both at the tongue tip and in the midlateral region. The taste function, measured by electrogustometry, among participants 20-29 yr of age was significantly lower than that in the other age groups; however, there was no difference among any other age groups in taste function. These results indicate that the peripheral gustatory system is well maintained anatomically and functionally in elderly people. [ABSTRACT FROM AUTHOR]

Introduction: The peripheral taste sensitivity is transmitted to the brain stem by the facial nerve, via the chorda tympani, and by the glossopharyngeal and vagus nerves. The trigeminal nerve is also involved in the sensory analysis of food. The objective of this study was to test the hypothesis of a modulation of taste perception by sensory afferents from the inferior alveolar nerve (IAN) in humans, by measuring electrogustometricdetection thresholds (EGM) before and after anesthesia of trigeminal afferents. Material and methods: A group A (n = 60) submitted to regional anesthesia of the inferior alveolar nerve (IAN) and a control group (n = 60) submitted to anesthesia of the maxillary nerve were compared before (stage 0) and after (stage 1) anesthesia. EGMrecordings were performed by an examiner single blinded to the anesthesia procedure, at 9 symmetrical lingual tongue loci: tip lateral (Tr, Tl) and central (T), median dorsal (Dr, Dl), posterior lateral edges (Er, El) and posterior dorsal (Pr, Pl). The correlation between the type of anesthesia and the EGM thresholds was calculated using the Spearman rho test and the intra- and intergroup comparisons, using Mann-Whitney tests and Wilcoxon, with a level of significance set at 0.05. Results: The average values of thresholds EGM group A were significantly increased after anesthesia of the NAI at all lingual loci (p <0.005). The highest thresholds (in μ0: Dr = 30.7 ± 9.4; Dl = 31 ± 9.5 vs Stage 1: 68.5 ± Dr = 44.6; dl = 63.3 ± 35.3) and at the posterior part of the tongue (stage 0: Pr = 20.9 ± 5.4; Pl = 21 ± 5.1 vs Stage 1: Pr = 37.3 ± 25, 4; Pl = 35.9 ± 16.6). No significant difference was observed in the control group for any of the nine loci before and after anesthesia. There was a significant correlation between EGM and regional anesthesia thresholds of the NAI at the 9 EGM recording tongue loci (p < 0.001). Conclusion: These results demonstrate that regional anesthesia of dental afferents of the NAI causes an increase of the electrogustometricdetection thresholds. [ABSTRACT FROM AUTHOR]

Introduction: The gustatory modality is provided by a branch of the facial nerve, the chorda tympani and the glossopharyngeal and vagus nerves. The trigeminal nerve is also involved in the sensory analysis of food. The objective of this study was to test the validity of the modulation of taste perception by sensory afferents of the Inferior Alveolar Nerve (IAN) in humans. Materials and methods: A group A (n = 100) submitted to regional anesthesia of the IAN and a control group (n = 100) submitted to maxillary nerve anesthesia were selected. The study was performed single-blind. Measurements of EGM detection thresholds were performed before and after anesthesia without the researcher knowing if the subject received anesthesia, or what type of anesthesia was administered. The thresholds were tested at 9 points of the tongue: first at the tip of the tongue and at the back, then at the lateral posterior edges, and finally, at the most posterior part of the back of the tongue. The correlation between the type of anesthesia and EGM thresholds was performed with Spearman's rho test, and intra- and intergroup comparisons with Mann-Whitney and Wilcoxon tests. The level of significance was set at p ≤ 0.05. Results: Group A showed an increase in the mean values of EGM thresholds after regional anesthesia of the NAI afferents at all lingual sites. The highest thresholds (in μA) were found at the back (stage 0: Dr = 31.3 ± 10.3; Dl = 31.5 ± 10.2 against stage 1: Dr = 71.5 ± 46.9; Dl = 56.4 ± 33) and the posterior part of the tongue (stage 0: Pr = 20.8 ± 6.2; Pl = 20.8±6.2 against stage 1: Pr = 38.7 ± 26.5; Pl = 32.1 ± 15.9). In this group the difference in thresholds before and after regional anesthesia of the IAN was statistically significant (p ≤ 0.005) for all measured sites. The control group showed no significant increase in the mean values of thresholds after anesthesia of afferents of the maxillary nerve at the 9 sites (p: NS). In the age group 18-29 years, regardless of age, all sites underwent a significant increase in EMG levels (p ≤ 0.05) after regional anesthesia of the IAN, in contrast to the group submitted to anesthesia of the maxillary nerve, where no increase was observed. There is a significant correlation between EMG thresholds and regional anesthesia of the afferents of the IAN for the 9 points of lingual stimulation (p < 0.001, Spearman's rho test). Conclusion: These results show that regional anesthesia of the dental afferents of the IAN causes a change in electrogustometry detection thresholds. [ABSTRACT FROM AUTHOR]

Although the ability to taste is critical for ingestion, nutrition, and quality of life, a clear understanding of the influences of age, sex, and chorda tympani (CT) resection on taste function in different regions of the anterior tongue is generally lacking. In this study we employed criterion-free signal detection analysis to assess electric and chemical taste function on multiple tongue regions in normal individuals varying in age and sex and in patients with unilateral CT resections. The subjects were 33 healthy volunteers, ranging from 18 to 87 years of age, and 9 persons, 27 to 77 years of age, with unilateral CT lesions. The influences of age, sex, tongue region, and chorda tympani resections on signal detection sensitivity (d′) and response bias (β) measures was assessed in 16 tongue regions to weak electric currents and solutions of sucrose, sodium chloride, and caffeine. Significant age-related decrements in d′ were found for sucrose (p = 0.012), sodium chloride (p = 0.002), caffeine (p = 0.006), and electric current (EC) (p = 0.0001). Significant posterior to anterior, and medial to lateral, gradients of increasing performance were present for most stimuli. β was larger on the anterior than the posterior tongue for the electrical stimulus in the youngest subjects, whereas the opposite was true for sucrose in the oldest subjects. No sex differences were apparent. d′ was depressed ipsilateral to the CT lesion side to varying degrees in all tongue regions, with the weakest influences occurring on the medial and anterior tongue. CT did not meaningfully influence β. This study is the first to employ signal detection analysis to assess the regional sensitivity of the tongue to chemical and electrical stimuli. It clearly demonstrates that tongue regions differ from one another in terms of their age-related sensitivity and their susceptibility to CT lesions. [ABSTRACT FROM AUTHOR]

Conclusion: 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. Objective: The aim of this study was to investigate the differences in taste detection thresholds between normal-weight and obese young adults. Methods: 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/m2 (normal-weight group) and 18 with BMI >25 kg/m2 (obese group). Results: BMI was significantly higher in the obese than in the normal-weight group ( p < 0.05). The obese group exhibited significantly higher EGM thresholds than the normal-weight group on the right ( p < 0.05) and left ( p < 0.05) 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 ( p < 0.05). 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 ( p < 0.05 each). [ABSTRACT FROM AUTHOR]

Objectives Increased consumption of carbohydrates and craving for sweets are considered core features of winter depression. Unfortunately, little is known about neural and behavioral correlates of these symptoms. The primary aim of the present study was to evaluate taste responses to sucrose solutions in depressed patients with seasonal affective disorder (SAD). Methods Intensity and pleasantness ratings of sucrose solutions, electrogustometric thresholds, and taste identification abilities were assessed in depressed patients with SAD and non-seasonal affective disorder (non-SAD), and in non-depressed controls. Results Electrogustometric thresholds and identification abilities did not differ between the study groups. There were no differences between the groups in intensity or pleasantness ratings of sucrose solutions (1–30%). The proportion of 'sweet likers', i.e. subjects rating the highest sucrose concentration as most pleasant, was similar in the controls, SAD, and non-SAD patients. Discussion The present results suggest that: (i) winter depression is not associated with major alterations in gustatory function; and (ii) sweet craving and increased consumption of carbohydrates in patients with winter depression is not secondary to altered responses to sweet tastants. More studies are needed to characterize hedonic responses of patients with SAD to other sweet and non-sweet foods. [ABSTRACT FROM AUTHOR]

This study aimed to investigate in parallel changes in gustatory function, changes in morphology of the fungiform papillae, as well as changes in the shape and density of the vessels of the tip of the tongue in patients treated with chemotherapy, radiotherapy, or radiochemotherapy. Twenty patients (7 females and 13 males; age range: 42–78 years) with head and neck malignancies (hypopharynx, larynx, oropharynx, and parotid) treated with radiochemotherapy (n = 8), chemotherapy (n = 8), or radiotherapy (n = 4) were prospectively studied. In all patients, electrogustometry and contact endoscopy were performed. Radiotherapy-treated patients exhibited higher electrogustometry thresholds and greater alterations in the morphology and vascularization of the fungiform papillae than the other two groups. Radiochemotherapy patients had less pronounced changes of the electrogustometry threshold and fungiform papillae structure compared with radiotherapy patients. Chemotherapy alone caused less severe change in both electrogustometry threshold and fungiform papillae structure than radiotherapy or radiochemotherapy. Radiotherapy alone caused greater disorders of taste-related anatomic parameters and electrogustometry thresholds compared with chemotherapy and combined radiochemotherapy. [ABSTRACT FROM AUTHOR]

Electrogustometry (EGM) is one of the most useful diagnostic tools widely used to evaluate the taste function by measuring the perception threshold to electrogustatory stimuli on the tongue. However, the effects of oral environments on electrogustometric threshold (EGMT) remain to be established despite its simple applicability. Thus, this study aims to determine the effect of mucosal dryness on EGMT in 68 healthy subjects. The experiment was conducted in two different conditions. First, the baseline EGMT was measured when the dryness of the tongue surface was normal. Second, the EGMT was remeasured after the tongue was intentionally desiccated. The current study showed that the mean of the EGMT was significantly increased when the tongue was desiccated, possibly indicating the reduced sensitivity to electrogustatory stimuli. Such an alteration may be related to the disturbed EGM electrical circuit through the dried mucosa with enhanced impedance. Thus, these findings suggested that mucosal dryness should be considered for better evaluation of gustatory function using EGM. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to test the prevalence and evolution of acute olfactory and gustatory functional impairment and their morphologic correlates in COVID-19 patients who require hospitalization due to COVID-19-related respiratory conditions., Methods: Included were 53 consecutive hospitalized patients (23 males, 30 females; age 42.54 ± 10.95 years) with an RT-PCR-confirmed COVID-19 diagnosis. Patients were examined twice: just after hospital discharge and 4-6 weeks later. Electrogustometric (EGM) thresholds at the tongue area supplied by the chorda tympani, at the soft palate, and in the region of the vallate papillae were recorded bilaterally. Olfaction was examined by Sniffin' sticks (Burghardt GmbH, Wedel, Germany). The patients' nasal and oral mucosa (fungiform papillae, fpap) were examined by contact endoscopy. Findings were compared to those of 53 healthy individuals matched for sex and age (23 males, 30 females; age 42.90 ± 10.64 years)., Results: EGM thresholds in patients were significantly higher than those of healthy subjects at both timepoints. EGM thresholds at the second measurement were significantly lower than those at the first measurement. Accordingly, patient-reported gustatory outcomes were improved at the second measurement. The same pattern was found using Sniffin' sticks. Significant alterations in form and vascularization of fPap were detected in patients, especially at the first instance. Interestingly we did not observe any significant changes in the morphology and vascularization of nasal mucosa., Conclusion: COVID-19 affects both gustatory and olfactory functions. In parallel, it also affects the structure and vascularization of both nasal and oral mucosa, albeit the nasal mucosa to a much lesser, non-significant extent. Our findings suggest that COVID-19 may cause a mild to profound neuropathy of multiple cranial nerves., (© 2022. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)