Postoperative dysgeusia following microsurgical resection for acoustic neuroma: a systematic review and meta-analysis.

OBJECTIVE: To determine the collated rate of postoperative dysgeusia after microsurgical intervention in acoustic neuroma patients. METHODS: The systematic review with meta-analysis was undertaken following PRISMA guidelines. A thorough search of PubMed/Medline, the Cochrane Database of Systematic Reviews, and Epistemonikos was undertaken for studies published up until May 16, 2024 reporting postoperative taste disturbance rates after microsurgical intervention for acoustic neuroma. The methodological quality of the included studies was assessed via the Methodological Index for Non-Randomized research (MINORS) tool. Using MedCalc (v. 20.215) software, the random-effects model was developed for proportional meta-analysis. RESULTS: Eight studies, encompassing 2,402 patients (mean age = 49.06 years; 48.54% female population), were included in the analysis. The overall pooled rate of postoperative dysgeusia following microsurgical management of acoustic neuroma was 23.7% (95% CI: 9.266-42.359, p < 0.0001). When stratified by surgical approach, the rate of postoperative dysgeusia for the retrosigmoid approach was 18.8% (95% CI: 2.821-44.461, p < 0.0001). Postoperative dysgeusia data stratified for other major microsurgical approaches (subtemporal and translabirynthine approaches) was not reported by any of the included studies. CONCLUSION: Our systematic review and meta-analysis calculated a collated rate of almost 25% and recognized postoperative dysgeusia as a common complication following microsurgical management of acoustic neuromas. These results highlight the significance of preoperative counselling and the development of strategies that minimize the likelihood of harm to the chorda tympani nerve during microsurgical intervention for acoustic neuroma.

The nutritional impact of metallic taste in head and neck cancer patients: explorations and clinical implications.

PURPOSE: Metallic taste (MT) is frequently observed during head and neck cancer treatments, but very little is known about its impact on nutritional status. The aim of this study was to explore the impact of MT on the quality of life and nutritional status in patients with head and neck cancer expressing MT. METHODS: Questionnaires on quality of life, MT, weight, and food intake were filled out by 44 patients with head and neck cancer before, during, and up to 1 year after their treatment. Patients were divided into two groups based on their reported experience of MT. RESULTS: MT was commonly observed (n = 12, 27.2%), always during the treatment phase, and mostly linked with radiotherapy or radiochemotherapy. Reported MT intensity was moderate (n = 6, 40%) to high (n = 4, 26.7%). MT had a significant negative impact on quality of life linked to dysgeusia (p = 0.025). The negative impacts of MT on food intake and on weight were not significant, possibly due to a combination of sample size, dropouts, and duration of observation. Further research in this area could provide additional insights into how to better address the issue related to MT and enhance the quality of care provided to this patient population. CONCLUSION: Metallic taste, experienced by 27.2% of the 44 patients with head and neck cancer, contributes to dysgeusia and results in a significant decline in quality of life associated with dysgeusia. TRIAL REGISTRATION: ClinicalTrials.gov trial registration number: NCT03558789.

Taste alterations after hematopoietic cell transplantation: a scoping review.

PURPOSE: This review aimed to evaluate the prevalence and characteristics of dysgeusia after hematopoietic cell transplantation (HCT). METHODS: A literature search (in PubMed, Embase.com and Web of Science) for clinical studies evaluating taste before and after HCT was performed up to June 22, 2023, in collaboration with a medical information specialist. After title and abstract review (N = 807) followed by full-text review (N = 61), articles that met the inclusion criteria were summarized in a table and synthesized narratively. RESULTS: 11 articles were analyzed in this review. All studies had a prospective design and patient populations included children (N = 3) and adults (N = 8) undergoing allogeneic or autologous HCT. Taste was assessed objectively (N = 6) and/or subjectively (N = 8) between baseline and 12 months after HCT. Before HCT, the self-reported (0-31%) and objective (2.4-10%) prevalence of dysgeusia was low. During the neutropenic phase, self-reported (20-100%) and objective (21.4%) dysgeusia was highest. In the post-engraftment period, the self-reported (18%) and objective (0-33%) prevalence of dysgeusia decreased. Different taste qualities were assessed in six studies including salt, sour, bitter, sweet, and umami. CONCLUSIONS: Some patients undergoing HCT experience dysgeusia prior to treatment. During the neutropenic phase, they had highest complaints, with recovery occurring in the post-engraftment period. All basic tastes, except bitter, were affected. Umami and salt were most affected during treatment. These findings have implications for patient management.

Transient Ageusia and Dysgeusia Following Thalamic Cyst Drainage.

Taste consists of sensation and perception. Specific neural structures transmit a stimulus from the taste buds to the gustatory cortex to generate taste sensation. Any disruption of this pathway, whether it affects sensation or perception, can result in taste disorders. Stereotactic procedures involving the thalamus may result in gustatory complications. A 41-year-old female patient who underwent stereotactic drainage of a thalamic cyst suffered transient ageusia. Subsequently, she developed metallic taste perception. When her stereotactic plan was re-evaluated, it was noted that the posteromedial ventral thalamus nucleus was in the path of the needle tract and the needle had passed through it. Follow-up was recommended and her symptoms completely resolved within 2 months following surgery. Modern imaging techniques allow for the visualization of neural structures related to the sense of taste. Additionally, care must be taken when planning stereotactic procedures for such lesions.

Mucocutaneous Manifestations in Patients with Dengue Fever: From the EPIDENGUE Cohort on Reunion Island.

Nearly 4 billion people live in a dengue risk area worldwide. The prevalence of dengue-related mucocutaneous manifestations and their association with severe dengue differ across studies. The aim of the study was to describe the characteristics of patients with dengue-related mucocutaneous manifestations and to investigate those were associated with severe dengue. A retrospective study was conducted in 2019 among patients with a positive RT-PCR for dengue at the University Hospital of Reunion, which has been experiencing a re-emergence of dengue since 2018. Of 847 patients with confirmed dengue, 283 (33.4%) developed mucocutaneous manifestations. Only manifestations of dehydration such as glossitis, dysgeusia, or conjunctivitis were associated with severe dengue, unlike pruritus and rash, in bivariate analysis but not in multivariate analysis. The rash and pruritus of dengue appear to be accompanied by a pronounced flu-like syndrome in younger people without comorbidity or severity, although careful examination of mucous membranes would better identify signs of dehydration and thus cases likely to worsen.

Systematic Review of Dysgeusia Frequency Following Hematopoietic Stem Cell Transplant.

OBJECTIVES: In this systematic review, we aimed to shed light on the frequency of dysgeusia among patients who had received hematopoietic stem cell transplantation and to determine factors that may be conducive to this buccal symptom. MATERIALS AND METHODS: We conducted a systematic review of the literature on frequency of dysgeusia in patients who received hematopoietic stem cell transplant. We searched PubMed, PMC-PubMed, and Web of Science and followed the Preferred Reporting Items for Systematic reviews and Meta-analyses statement. RESULTS: We identified 15 studies. The global frequency of dysgeusia varied greatly, ranging from 16.7% to 95%. Allogeneic stem cell transplant, including cells from other individuals, had more secondary effects than autologous transplant. Rate of dysgeusia was higher at the beginning of treatment. We found some differences according to populations, with dysgeusia increasing with age. Pediatric patients recovered more quickly, perhaps as a result of their faster cell division and development of taste receptors. CONCLUSIONS: Dysgeusia can greatly affect quality of life during graft treatment. The frequency can vary according to a number of factors, which are different targets in treatment. Symptom management during transplant seems to contribute to overall improvement in treatment.

Dysgeusia and Chronic Kidney Disease: A Scoping Review.

Dysgeusia is a common altered taste perception in chronic kidney disease patients. The study aims to identify available treatments for educating, screening, and clinically managing dysgeusia in this population. A scoping review was conducted following the protocol of Arksey and O'Malley, incorporating the Joanna Briggs Institute methodology, and adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews guidelines. Among the 424 identified records, 13 studies were included. Screening methodologies, educational strategies, particularly a hospital-based program focusing on salt reduction, showed a significant improvement in dysgeusia (P < .001). The identified clinical treatments exclusively included oral zinc supplementation, with dosages ranging from 50 to 220 mg, reporting heterogeneous results not consistent across different studies. The personalized management of dysgeusia associated with chronic kidney disease is crucial, requiring targeted education and treatment protocols to prevent and address nutritional complications such as malnutrition.

Taste dysfunction after endoscopic endonasal resection of olfactory groove meningioma: Case series and review of the literature.

PURPOSE: The incidence of ageusia and dysgeusia after endoscopic endonasal (EEA) resection of olfactory groove meningioma (OGM) is not well established despite recognized impairment in olfactory function. METHODS: We retrospectively administered a validated taste and smell survey to patients undergoing EEA for resection of OGM at two institutions. Demographics and clinical characteristics were collected and survey responses were analyzed. RESULTS: Twelve patients completed the survey. The median time from surgery was 24 months. The average total complaint score was 5.5 out of 16 [0-13]. All patients reported a change in sense of smell while only 42 % reported a change in sense of taste. Taste changes did not consistently associate with laterality or size of the neoplasm. Significant heterogeneity existed when rating severity of symptoms. CONCLUSIONS: To our knowledge this is the first case series examining taste changes after EEA resection of OGM. Despite universal olfactory dysfunction, only a minority of patients reported a change in their sense of taste. Our findings may improve patient counseling and expectations after surgery.

Common Oral Conditions: A Review.

Importance: Dry mouth, oral candidiasis, and recurrent aphthous ulcers are 3 of the most common oral conditions that may be associated with patient discomfort, decreased quality of life, and morbidity. Observations: In a meta-analysis of 26 population-based cohort and cross-sectional studies, the global prevalence of dry mouth symptoms was 23% (95% CI, 18% to 28%), placing individuals at risk of oral candidiasis, dental caries, dysgeusia, masticatory/speech impairment, and oropharyngeal dysphagia. Dry mouth is associated with using more than 3 oral medications per day (odds ratio [OR], 2.9 [95% CI, 1.4 to 6.2]), head and neck radiation, and Sjögren disease. Symptoms may include difficulty swallowing and speaking, thirst, and halitosis. Dry mouth is associated with an 11.5% (95% CI, 3.6% to 27%) higher risk of oral candidiasis, based on a meta-analysis of 6 observational cohorts. Management of dry mouth includes mechanical salivary stimulants, oral moisturizers, and/or systemic sialagogues. Oral candidiasis is an opportunistic fungal infection caused by overgrowth of the Candida genus with C albicans, which accounts for 76.8% of infections. The prevalence of oral candidiasis is higher in patients who are immunosuppressed, for example, those with HIV (35% [95% CI, 28% to 42%]) and those with salivary gland hypofunction (OR, 3.02 [95% CI, 1.73 to 5.28]). Common risk factors associated with oral candidiasis include use of antibiotics (P = .04) and oral mucosal disorders such as lichen planus. Oral burning and dysgeusia are common symptoms of oral candidiasis. Treatment includes addressing risk factors and use of topical and/or systemic antifungal medications. Recurrent aphthous stomatitis is characterized by symptomatic round or oval oral ulcers, which are covered by a gray-white fibrin layer and encircled by an erythematous ring. A meta-analysis of 10 case-controlled studies revealed an increased risk of recurrent aphthous stomatitis associated with polymorphism of IL-1ß (+3954C/T) (OR, 1.52 [95% CI, 1.07 to 2.17]) and IL-1ß (-511C/T) (OR, 1.35 [95% CI, 1.09 to 1.67]). Another meta-analysis of 9 case-control studies reported that patients with recurrent aphthous stomatitis had a higher frequency of nutritional deficiencies, including vitamin B12 (OR, 3.75 [95% CI, 2.38 to 5.94]), folic acid (OR, 7.55 [95% CI, 3.91 to 14.60]), and ferritin (OR, 2.62 [95% CI, 1.69 to 4.06]). Recurrent aphthous stomatitis can be associated with systemic diseases. A meta-analysis of 21 case-control studies revealed that celiac disease is associated with a higher incidence of recurrent aphthous stomatitis (25% vs 11%; OR, 3.79 [95% CI, 2.67 to 5.39]; P <.001). Topical corticosteroids are first-line agents to manage recurrent aphthous stomatitis; however, systemic medications may be necessary in more severe cases. Conclusions and Relevance: Dry mouth, oral candidiasis, and recurrent aphthous ulcers are common oral conditions that may be associated with patient discomfort, decreased quality of life, and morbidity. First-line treatment includes over-the-counter sialagogues for dry mouth, topical antifungals for oral candidiasis, and topical corticosteroids for aphthous ulcers. Oral conditions that do not improve with first-line treatment may require treatment with systemic medications.

[Questionnaire Survey on Oral Care and Oral Troubles for Patients with Gastric Cancer Received Chemotherapy].

BACKGROUND: The actual situation of oral care and oral troubles for patients with gastric cancer received chemotherapy is not clear. METHODS: Questionnaire survey in the form of oral questions was performed for patients with gastric cancer who received chemotherapy from December 2021 to February 2022. The relevance between the survey results and background factors was examined using the χ2 test. RESULTS: We performed the questionnaire survey for 36 patients. Of the 36 patients, 29 patients received dental check-up before starting chemotherapy. Fourteen of the 29 patients(48%)continued the dental check-up. Of 14 patients who continued the dental check-up, 9 patients were 65 years or older, while 14 of 15 patients who discontinued the dental check-up were 65 years or older. Continuity of dental check-up was low among the elderly patients. The rate of dysgeusia were 78 vs 30% in the patients who adopted and who did not adopt oral care other than toothbrushing(p=0.01). The frequency of oral troubles was dysgeusia(47%), stomatitis(42%), and dry mouth(36%). The severity of the oral troubles was, in order, dysgeusia, dry mouth, and pain. The most common side effect due to chemotherapy causing decreased food intake was dysgeusia. CONCLUSIONS: Dysgeusia was the most frequent and severe oral trouble.

Photobiomodulation in the Treatment of Dysgeusia in Patients with Long COVID: A Single-Blind, Randomized Controlled Trial.

Objective: The aim of this study is to evaluate local and systemic photobiomodulation (PBM) in patients with COVID-19-related dysgeusia, with the expectation of improving taste dysfunction. Background: PBM has garnered attention as a potential therapy in long COVID, a condition characterized by many persistent symptoms following the acute phase of COVID-19. Among these symptoms, dysgeusia, or altered taste perception, can significantly affect patients' quality of life. Emerging research suggests that PBM may hold promise in ameliorating dysgeusia by modulating cellular processes and reducing inflammation. Further clinical studies and randomized controlled trials are essential to establish the efficacy and safety of PBM for the treatment of dysgeusia in long COVID, but initial evidence suggests that this noninvasive modality may offer a novel avenue for symptom management. Methods: Seventy patients experiencing dysgeusia were randomly assigned to receive active local and systemic PBM (n = 34) or simulated PBM (n = 36). Low-power laser (red wavelength) was used at 18 spots on the lateral borders of the tongue (3 J per spot), salivary glands (parotid, sublingual, and submandibular glands-3 J per spot), and over the carotid artery for 10 min (60 J). Alongside laser therapy, all patients in both groups received weekly olfactory therapy for up to 8 weeks. Results: Dysgeusia improved in both groups. At weeks 7 and 8, improvement scores were significantly higher in the PBM group than in the sham group (p = 0.048). Conclusions: Combined local and systemic PBM, as applied in this study, proved effective and could serve as a viable treatment option for alleviating dysgeusia in long-COVID patients. Clinical Trial Registration: RBR-2mfbkkk.

Post-COVID-19 patients suffer from chemosensory, trigeminal, and salivary dysfunctions.

Recent literature indicates that post-COVID-19 patients suffer from a plethora of complications, including chemosensory dysfunction. However, little attention has been given to understand the interactions between chemosensory, trigeminal, and salivary dysfunctions in these patients. The aims of this study were (1) to investigate the prevalence and combinations of chemosensory, trigeminal, and salivary dysfunctions, (2) to identify the odorants/tastants that are compromised, and (3) to explore possible associations between the four dysfunctions in post-COVID-19 patients. One hundred post-COVID-19 patients and 76 healthy controls (pre-COVID-19) were included in this cross-sectional, case-controlled study. Participants' smell, taste, trigeminal, and salivary functions were assessed. The patients had a significantly higher prevalence of parosmia (80.0%), hyposmia (42.0%), anosmia (53.0%), dysgeusia (34.0%), complete ageusia (3.0%), specific ageusia (27.0%), dysesthesia (11.0%) and dry mouth (18.0%) compared to controls (0.0% for all parameters, except 27.6% for hyposmia). Complete loss of bitter taste was the most prevalent specific ageusia (66.7%) and coffee was the most common distorted smell (56.4%). Seven different combinations of dysfunction were observed in the patients, the most common being a combination of olfactory and gustatory dysfunction (48.0%). These findings indicate that post-COVID-19 patients experience a range of chemosensory, trigeminal, and salivary disturbances, occurring in various combinations.

Effectiveness of intraoral stents in reducing oral adverse events during radiotherapy for maxillary or nasal cavity malignant tumors.

PURPOSE: Many patients experience oral adverse events during head and neck cancer radiotherapy (RT). The methods of management of such events are under debate. One such technique is the intraoral stent (IOS) technique, which removes normal tissue from the irradiation field. This retrospective study examined the factors associated with the occurrence of oral mucositis (OM) and dysgeusia and the efficacy of IOSs in preventing them. METHODS: Twenty-nine patients who underwent RT in the maxilla or nasal cavity between 2016 and 2022 were included. They were investigated for background characteristics, treatment factors (IOS and dose-volume histogram), and oral adverse events (OM and dysgeusia). RESULTS: Significant risk factors for the incidence of grade ≥ 2 (Common Terminology Criteria for Adverse Events v5.0) OM were the non-use of IOSs (p = 0.004) and diabetes (p = 0.025). A significant risk factor for the incidence of grade ≥ 1 dysgeusia was concomitant chemotherapy (p = 0.019). The radiation dose to the tongue was significantly lower in the IOS group than in the non-IOS group. CONCLUSION: Our findings suggest that the use of an IOS during RT reduces the severity of OM by reducing irradiation to the tongue. Therefore, the use of an IOS is recommended during RT performed in the maxilla or nasal cavity.

Long-Term Dysfunction of Taste Papillae in SARS-CoV-2.

BACKGROUND: We sought to determine whether ongoing taste disturbance in the postacute sequelae of coronavirus disease 2019 period is associated with persistent virus in primary taste tissue. METHODS: We performed fungiform papillae biopsies on 16 patients who reported taste disturbance lasting more than 6 weeks after molecularly determined severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Then, on multiple occasions, we rebiopsied 10 of those patients who still had taste complaints for at least 6 months postinfection. Fungiform papillae obtained from other patients before March 2020 served as negative controls. We performed hematoxylin and eosin staining to examine fungiform papillae morphology and immunofluorescence and fluorescence in situ hybridization to look for evidence of persistent viral infection and immune response. RESULTS: In all patients, we found evidence of SARS-CoV-2, accompanying immune response and misshapen or absent taste buds with loss of intergemmal neurite fibers. Six patients reported normal taste perception by 6 months postinfection and were not further biopsied. In the remaining 10, the virus was eliminated in a seemingly random fashion from their fungiform papillae, but four patients still, by history, reported incomplete return to preinfection taste perception by the time we wrote this report. CONCLUSIONS: Our data show a temporal association in patients between functional taste, taste papillae morphology, and the presence of SARS-CoV-2 and its associated immunological changes. (Funded by Intramural Research Program/National Institute on Aging/National Institute of Allergy and Infectious Diseases/National Institutes of Health; ClinicalTrials.gov numbers NCT03366168 and NCT04565067.).

Oral manifestations of COVID-19 in unvaccinated patients: a cross-sectional study.

BACKGROUND: Early studies have highlighted the possible development of dysgeusia and anosmia in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and these manifestations should be considered a potential indication of coronavirus disease 19 (COVID-19). As potential contributors to these symptoms, dentists should perform careful oral and oropharyngeal examinations and document suspicious oral lesions in patients with COVID-19, especially in those who complain of loss of taste and smell. The study's objective was to assess the prevalence of oral manifestations among ambulatory unvaccinated symptomatic patients with suspected COVID-19 during the acute phase of the disease. METHODS: This cross-sectional study evaluated oral manifestations in adults (aged ≥ 18 years) with suspected and confirmed SARS-CoV-2 infection. Chi-square and Fisher's exact tests were used to compare data between the groups (rRT-PCR-positive and rRT-PCR-negative patients). RESULTS: One hundred thirty-six participants were included. Most were female (n = 79; 58.1%), with a mean age of 39.53 (± 14.17) years. Of these, 54 (39.7%) had a positive rRT-PCR test, and 82 (60.3%) had negative rRT-PCR results. Oral manifestations were observed in 40 participants (74.1%) in the rRT-PCR-positive group and 67 participants (81.7%) in the rRT-PCR-negative group. The most common oral manifestations were xerostomia (n = 85; 62.5%) and dysgeusia/ageusia (n = 57; 41.9%). Different rates of gingivitis (n = 12; 22.2% vs. n = 5; 6.1%; p = 0.005) and halitosis (n = 7; 13.0% vs. n = 1; 1.2%; p = 0.007) were observed between the rRT-PCR-positive and -negative groups, respectively. Mouth ulcers, glossitis, tongue coating, and petechiae were reported in both groups without significant differences. CONCLUSIONS: A high prevalence of oral manifestations was observed in symptomatic patients with suspected or confirmed COVID-19. CLINICAL RELEVANCE: This study highlights the importance of routine oral examinations by dentists as part of the multidisciplinary care of COVID-19 patients.

Subjective and Objective Taste Change After Cochlear Implantation Systematic Review and Meta-Analysis.

INTRODUCTION: There is a paucity of data reporting the rate of chorda tympani nerve injury during cochlear implantation (CI) surgery. To better provide clarity to patients and surgeons regarding the risk of taste change, we performed a systematic review and meta-analysis of prospective studies examining taste change after CI. DATA SOURCES: PubMed, Embase, and Cochrane Library databases were queried. METHODS: Databases were queried according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Search terms included "(chorda tympani OR gustatory OR taste OR chemosensory OR dysgeusia OR nervus intermedius) AND (cochlea OR cochlear implant OR cochlear implantation)." Prospective studies were included and further divided into "objective" and "subjective" assessments of taste dysfunction. A systematic review was performed for all studies. A random-effects model was used to compare studies with similar methods and patient demographics. RESULTS: The initial database query yielded 2,437 articles, which were screened according to inclusion and exclusion criteria. Nine appropriate studies were identified, including 442 total patients-254 with subjective assessment and 271 with objective assessment of gustation. Seventeen of 144 patients (11.8%) reported short-term taste change (incidence = 0.09 [0.02-0.16], 95% confidence interval with pooled data). Twenty-six of 265 patients (9.8%) reported long-term taste change (incidence = 0.07 [0.01-0.13]). Objective results were heterogenous and therefore not amenable to pooled meta-analysis. CONCLUSIONS: Taste change from chorda tympani nerve injury is a likely underrecognized complication of CI and may be the most common adverse consequence of CI surgery. Surgeons should counsel prospective patients on this potential complication and that the risk of taste change may persist longer than the immediate postoperative period.

Virus SARS-CoV-2 y su impacto en el bruxismo / SARS-CoV-2 virus and its impact on bruxism

La cavidad oral se puede ver alterada a causa del virus SARS-CoV-2 de manera transitoria o permanente, lo que afecta a distintas partes de la cavidad oral incluyendo las glándulas salivales, esto causa xerostomía. La disgeusia es uno de los síntomas principales a lo largo de la enfermedad, nos enfocaremos en aquellas manifestaciones psicológicas como la ansiedad y el estrés en su interacción con la aparición del trastorno llamado bruxismo (AU)

The oral cavity can be altered by the SARS-CoV-2 virus in a transient or permanent manner, affecting different parts of the oral cavity including salivary glands causing xerostomia. Dysgeusia is one of the main symptoms throughout the disease, we will focus on those psychological manifestations such as anxiety and stress in their interaction with the appearance of the disorder called bruxism (AU)

The impact of injury of the chorda tympani nerve during primary stapes surgery or cochlear implantation on taste function, quality of life and food preferences: A study protocol for a double-blind prospective prognostic association study.

BACKGROUND: The chorda tympani nerve (CTN) is a mixed nerve, which carries sensory and parasympathetic fibres. The sensory component supplies the taste sensation of the anterior two-thirds of the ipsilateral side of the tongue. During middle ear surgery the CTN is exposed and frequently stretched or sacrificed, because it lacks a bony covering as it passes through the middle ear. Injury may cause hypogeusia, ageusia or altered taste sensation of the ipsilateral side of the tongue. To date, there is no consensus regarding which type of CTN injury (sacrificing or stretching), during middle ear surgery, leads to the least burden for the patient. METHODS: A double-blind prospective prognostic association study was designed in a single medical centre in the Netherlands to determine the effect of CTN injury on postoperative taste disturbance and quality of life. 154 patients, who will undergo primary stapes surgery or cochlear implantation will be included. The taste sensation, food preferences and quality of life of these patients will be evaluated preoperatively and at one week, six weeks and six months postoperatively using the Taste Strip Test, Electrogustometry, supplementary questionnaire on taste disturbance, Macronutrient and Taste Preference Ranking Task, Appetite, Hunger and Sensory Perception questionnaire and Questionnaire of Olfactory Disorders to assess the association of these outcomes with CTN injury. Evaluation of olfactory function will only take place preoperatively and at one week postoperatively using the Sniffin' Sticks. The patient and outcome assessor are blinded to the presence or absence of CTN injury. DISCUSSION: This study is the first to validate and quantify the effect of chorda tympani nerve injury on taste function. The findings of this study may lead to evidence-based proof of the effect of chorda tympani injury on taste function with consequences for surgical strategies. TRIAL REGISTRATION: Netherlands Trial Register NL9791. Registered on 10 October 2021.