An observational study of olfactory functions in total laryngectomees.

OBJECTIVE: To evaluate the olfactory acuity and quality of life in patients who have undergone total laryngectomy. The study also aims to identify any specific patient-related risk factors linked to worse olfactory outcomes. METHODS: This is a prospective cross-sectional study conducted at the University Malaya Medical Centre. A total of 30 patients who have undergone total laryngectomy were assessed objectively using the Sniffin' Sticks test and compared against normal age-matched Malaysians. Subsequently, they also filled out the modified Questionnaire on Olfactory Disorders. Correlations of patient demographics, disease and treatment variables against olfactory outcomes were conducted. RESULTS: All subjects suffered olfactory impairment, with 66.7% of them being anosmic after total laryngectomy. The Sniffin' Sticks test demonstrated a statistically significant difference between laryngectomees and the normal age-matched Malaysian population in all three subtests for odor threshold, discrimination and identification. 37% of patients developed olfactory adaptive methods, which resulted in higher olfactory scores and a better quality of life. There were no patient demographics, disease or treatment variables associated with a poorer olfactory outcome identified. CONCLUSION: Olfactory impairment should not be overlooked among patients after total laryngectomy. Although as many as a third of patients developed some sort of olfactory adaptive behavior, early rehabilitation should be integrated into the multidisciplinary rehabilitation program after total laryngectomy.

Poor olfaction prior to cardiac surgery: Association with cognition, plasma neurofilament light, and post-operative delirium.

OBJECTIVES: Post-operative delirium (POD) affects up to 50% of cardiac surgery patients, with higher incidence in older adults. There is increasing need for screening tools that identify individuals most vulnerable to POD. Here, we examined the relationship between pre-operative olfaction and both incident POD and POD severity in patients undergoing cardiac surgery. We also examined cross-sectional relationships between baseline olfaction, cognition, and plasma neurofilament light (NfL). METHODS: Individuals undergoing cardiac surgery (n = 189; mean age = 70 years; 75% men) were enrolled in a clinical trial of cerebral autoregulation monitoring. At baseline, odor identification performance (Brief Smell Identification Test), cognitive performance, and plasma concentrations of NfL levels (Simoa™ NF-Light Assay) were measured. Delirium was assessed with the Confusion Assessment Method (CAM) or CAM-ICU, and delirium severity was assessed using the Delirium Rating Scale-Revised-98. The association of baseline olfaction, delirium incidence, and delirium severity was examined in regression models adjusting for age, duration of cardiopulmonary bypass, logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE), and baseline cognition. RESULTS: Olfactory dysfunction was present in 30% of patients, and POD incidence was 44%. Pre-operative olfactory dysfunction was associated with both incident POD (OR = 3.17, p = 0.001) and greater severity of POD after cardiac surgery (OR = 3.94 p < 0.001) in models adjusted for age, duration of bypass, and a surgical risk score. The addition of baseline cognition attenuated the strength of the association, but it remained significant for incident POD (OR = 2.25, p = 0.04) and POD severity (OR 2.10, p = 0.04). Poor baseline olfaction was associated with greater baseline cognitive dysfunction (p < 0.001) and increased baseline plasma NfL concentrations (p = 0.04). Neither age, cognition, nor baseline NFL concentration modified the association of impaired olfaction and delirium outcomes. CONCLUSIONS: Olfactory assessment may be a useful pre-surgical screening tool for the identification of patients undergoing cardiac surgery at increased risk of POD. Identifying those at highest risk for severe delirium and poor cognitive outcomes following surgery would allow for earlier intervention and pre-operative rehabilitation strategies, which could ultimately impact the functional disability and morbidity associated with POD.

Factors associated with impaired psychophysical gustatory function.

OBJECTIVE: To investigate the clinical characteristics associated with measured gustatory dysfunction in patients with chemosensory (smell and taste) discomfort. STUDY DESIGN: Retrospective study. DESIGN: Hospital-based cohort. SETTING: The clinical characteristics associated with the measured diagnosis of gustatory dysfunction were statistically analysed. PARTICIPANTS: Patients who underwent all the psychophysical olfactory and chemical gustatory function tests (YSK olfactory function test and chemical gustometry exam) and the subjective questionnaires between October 2021 and February 2023. MAIN OUTCOME MEASURES: YSK olfactory function test and chemical gustometry results, subjective questionnaire score about chemosensory (smell and taste) functions. The Medical records of patients who visited the smell and taste centre in a tertiary. RESULTS: A total of 219 patients were enrolled; 180 were diagnosed as having normal gustatory function, and 39 were diagnosed as having gustatory dysfunction. Subjective recognition of gustatory function was not associated with the measured gustatory function. Age, sex, measured olfactory function and the threshold and discrimination scores for the olfactory function test were significant factors in the multivariate analysis. When the patients were further divided according to age, the threshold test scores rather than other subsets in the olfactory function test were significantly associated with measured gustatory dysfunction in patients 60 and older. CONCLUSION: In older adult male patients with olfactory dysfunction, gustatory function should be considered regardless of subjective gustatory dysfunction.

Olfactory and Gustatory Function 3 Years After Mild COVID-19-A Cohort Psychophysical Study.

This case-control study estimates the 3-year prevalence of measured olfactory dysfunction and gustatory dysfunction associated with SARS-CoV-2 infection.

Effectiveness of Platelet-Rich Plasma for COVID-19-Related Olfactory Dysfunction: A Controlled Study.

OBJECTIVE: To investigate the effectiveness of platelet-rich plasma (PRP) injection into the olfactory clefts of coronavirus disease 2019 (COVID-19) patients with persistent olfactory dysfunction (OD). STUDY DESIGN: Controlled study. SETTING: Multicenter study. METHODS: From March 2022 to November 2022, COVID-19 patients with persistent OD were recruited from three European hospitals to undergo PRP injections into the olfactory clefts. Olfactory function was evaluated at baseline and 10 weeks postinjection with the Olfactory Disorder Questionnaire (ODQ) and threshold, discrimination, and identification (TDI) test. Data were compared with a control group of untreated patients. RESULTS: Eighty-one patients who underwent PRP injection and 78 controls were included. Sixty-five PRP patients (80.3%) experienced subjective smell improvement after a mean duration of 3.4 ± 1.9 weeks. The parosmia, life quality statement, and ODQ sub- and total scores significantly decreased from pre- to 10-week postinjection in the PRP group. The TDI sub- and total scores significantly increased 10 weeks postinjection. In controls, the ODQ score did not change over time, while the discrimination, identification, and total TDI scores significantly increase after 10 weeks of follow-up. The 10-week TDI and ODQ scores were significantly better in the PRP group compared with the controls. CONCLUSION: Patients who underwent PRP injection reported better 10-week subjective and objective smell outcomes than controls. Future randomized-controlled studies using saline injection into the olfactory cleft of controls are needed to determine the superiority of PRP over placebo.

Stellate Ganglion Block for the Treatment of COVID-19-Induced Olfactory Dysfunction: A Prospective Pilot Study.

OBJECTIVE: The objective of this study was to explore the safety and feasibility of stellate ganglion blocks (SGBs) to treat persistent COVID-19-induced olfactory dysfunction (OD). Secondarily, the goal was to determine effect sizes to plan a future randomized clinical trial. STUDY DESIGN: Prospective case series. SETTING: Quaternary Care Academic Medical Center. METHODS: In this single-arm pilot trial, adult participants with a COVID-19 diagnosis ≥ 12 months prior to enrollment with OD underwent bilateral SGBs. Subjects were followed for 1 month after completion of SGB. The primary outcome measure was the change in the Clinical Global Impression-Improvement Scale for smell loss. Secondary outcome measures included changes in the University of Pennsylvania Smell Identification Test (UPSIT) and Olfactory Dysfunction Outcomes Rating (ODOR). RESULTS: Twenty participants were enrolled with a mean (SD) age of 46 (11) years and a mean (SD) duration of OD of 21 (5) months. At 1 month, 10 (50%) participants experienced at least slight subjective improvement in their OD, 11 (55%) attained a clinically meaningful improvement in smell identification using the UPSIT, and 7 (35%) achieved a clinically meaningful improvement in olfactory-specific quality of life (QoL) measured by the ODOR. The median difference between UPSIT scores at baseline and 1 month was 6 (95% confidence interval: 3-11), exceeding the minimal clinically important difference of 4. There were no serious adverse events. CONCLUSION: Sequential SGBs for COVID-19-associated OD were safe and associated with modest improvements in subjective olfaction, odor identification, and olfactory-specific QoL. A placebo-controlled trial is warranted to determine the efficacy of SGBs for COVID-19-associated OD.

Olfactory status in neurodegeneration with brain iron accumulation disorders.

BACKGROUND: Olfactory dysfunction has been suggested as a diagnostic and discriminative biomarker in some neurodegenerative disorders. However, there are few studies regarding the olfactory status in rare diseases including neurodegeneration with brain iron accumulation (NBIA) disorders. METHODS: Genetically-confirmed NBIA patients were enrolled. Neurological and cognitive examinations were conducted according to the Pantothenate Kinase-Associated Neurodegeneration-Disease Rating Scale (PKAN-DRS) and the Mini-Mental State Examination (MMSE) questionnaire, respectively. Olfaction was assessed in three domains of odor threshold (OT), odor discrimination (OD), odor identification (OI), and total sum (TDI) score by the Sniffin' Sticks test. The olfactory scores were compared to a control group and a normative data set. RESULTS: Thirty-seven patients, including 22 PKAN, 6 Kufor Rakeb syndrome, 4 Mitochondrial membrane Protein-Associated Neurodegeneration (MPAN), 5 cases of other 4 subtypes, and 37 controls were enrolled. The mean PKAN-DRS score was 51.83±24.93. Sixteen patients (55.2%) had normal cognition based on MMSE. NBIA patients had significantly lower olfactory scores compared to the controls in TDI and all three subtests, and 60% of them were hyposmic according to the normative data. Including only the cognitively-normal patients, still, OI and TDI scores were significantly lower compared to the controls. The phospholipase A2-Associated Neurodegeneration (PLAN) and MPAN patients had a significantly lower OI score compared to the cognitively-matched PKAN patients. CONCLUSION: Olfactory impairment as a common finding in various subtypes of NBIA disorder can potentially be considered a discriminative biomarker. Better OI in PKAN compared to PLAN and MPAN patients may be related to the different underlying pathologies.

Neuroimaging the Development of Olfactory Function in a Woman With No Olfactory Bulbs.

This case report describes a woman with lifelong anosmia in her 20s who presented with the acquisition of unpleasant olfactory phantoms.

Evaluation of peripheral and central olfactory pathways in HIV-infected patients by MRI.

AIM: To investigate peripheral and central olfactory pathways using cranial magnetic resonance imaging (MRI) in human immunodeficiency virus (HIV)-infected patients. MATERIALS AND METHODS: The cranial MRI images of 37 HIV-infected adult patients and 37 adults without HIV infection having normal cranial MRI results were included in the study. In both groups, olfactory bulb (OB) volume and olfactory sulcus (OS) depth; and insular gyrus and corpus amygdala areas were measured using cranial MRI. In the HIV group, disease duration, HIV RNA, and CD4 lymphocyte count and levels as a percentage were also recorded. RESULTS: The HIV group had significantly lower bilateral OB volumes, insular gyrus and corpus amygdala areas compared to the control group. The HIV group showed positive correlations between OB volumes, OS depths, insular gyrus, and corpus amygdala areas bilaterally. Increases in OB volumes and OS depths were associated with an increase in the insular gyrus area. The corpus amygdala and insular gyrus areas increased similarly. There was no significant correlation between age, gender, disease duration, CD4 lymphocyte count and per cent, HIV RNA values, and the measurement values of the central and peripheral olfactory regions. CONCLUSION: A decrease in olfactory regions of OB, insular gyrus, and corpus amygdala in HIV-infected patients shows that HIV infection may cause olfactory impairment. There is no correlation between disease duration and olfactory impairment. It may be related to neuroinflammation, HIV-related brain atrophy, acquired immunodeficiency syndrome (AIDS) dementia complex, or neurocognitive impairment, which are the other explanations for the olfactory impairment in HIV. The possible toxicity from antiretroviral therapy (ART) may be another cause that should be investigated further.

Do Children with Previous COVID Infection Have Hyposmia?

OBJECTIVE: Our goal was to see if children with a history of COVID infection had subclinical hyposmia. METHODS: Consecutive patients at a pediatric otolaryngology clinic aged 5-17 years were recruited. Demographics including gender, race, use of nasal topical medications (NTM), previous nasal surgery including adenoidectomy (NSA), and previous COVID-19 infection were collected. Each child performed a test of their sense of smell using the Pediatric Smell Wheel (PSW, Sensonics Intl, USA) under the direct supervision and scores were compared. RESULTS: 260 children were included; mean age 10.1 years (95% CI 9.7-10.5), 128 (49.2%) female and 132 (50.8%) male. 65 (25%) used steroid nasal sprays, 100 (38.5%) had undergone adenoidectomy, and 36 (13.8%) had other nasal surgery. 120 (46.2%) had a previous COVID-19 infection. The COVID+ and COVID- groups were the same for age, gender, race, use of NTMs, and previous NSA (p > 0.05). Mean PSW score was 7.8 (95% CI 7.6-8.0), median of 8, ranging from 2 to 11. The mean PSW score was 8.0 for the COVID- group and 7.6 for the COVID+ group (p = 0.005). There was no significant difference in total PSW scores based on gender, race, use of NTMs, previous NSA. Linear regression showed previous COVID infection was significantly negatively associated with total PSW score (Beta -0.636, p = 0.006) with age significantly positively associated (Beta 0.122, p < 0.001). CONCLUSION: Children with a history of COVID infection performed slightly worse when identifying odors than children without a COVID history. More study into the rates of pediatric anosmia related to COVID infection is needed. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:901-906, 2024.

Olfactory training with four and eight odors: comparison with clinical testing and olfactory bulb volumetrics.

PURPOSE: Post-infectious olfactory dysfunction (PIOD) is one of the most common causes of olfactory impairment but has limited treatment options. Recently, olfactory training (OT) has been considered an effective treatment method; however, several questions have arisen regarding its optimal scheme. The aim of this study was to assess whether an OT scheme with 8 odors is more effective than the classic OT scheme with 4 odors by comparing psychophysical test results and olfactory bulb (OB) volumetrics. METHODS: In this prospective cohort study, 72 patients with PIOD were included. The patients followed either the classic 4-odor OT scheme (COT; n = 34 patients) or an extended 8-odor scheme (EOT; n = 38 patients) for 16 weeks. All patients underwent olfactory testing with a Sniffin'Sticks battery test at 0, 8, and 16 weeks. Of the patients, 38 underwent brain magnetic resonance imaging for OB volumetric assessment before and after treatment. RESULTS: The comparison of the olfactory test results did not show any significant difference between the two study groups, in agreement with the OB volumetrics. The convex OB showed better test results than the non-convex OB, with significantly better improvement after treatment regardless of OT type. The EOT group presented significantly better adherence than the COT group. CONCLUSION: The number of odors did not appear to play a significant role in the effect of the OT. However, the training scheme with more than four odors showed better adherence among the patients in a long-term treatment plan. The shape of the OB may have prognostic value in clinical assessment and warrants further investigation.

Therapeutic Efficacy of Nasal Corticosteroids in COVID-19-Related Olfactory Dysfunction: A Comprehensive Systematic Review and Meta-analysis.

OBJECTIVE: Olfactory disturbance is one of the main symptoms of coronavirus disease-2019 (COVID-19). Various olfactory disorders caused by viral infections are treated with nasal corticosteroids. This study aimed to evaluate the safety and efficacy of nasal corticosteroids in the treatment of olfactory disorders caused by the severe acute respiratory syndrome coronavirus 2. DATA SOURCES: We searched the Web of Science, Embase, PubMed, and Cochrane Library databases for clinical trials of nasal corticosteroids for treating COVID-19 olfactory dysfunction. REVIEW METHODS: We assessed the effect of nasal corticosteroids on olfactory function in COVID-19-affected individuals using a Meta-analysis of published studies, considering the number of patients who fully recovered from olfactory dysfunction, olfactory scores following treatment, and olfactory recovery time. RESULTS: Seven studies involving 930 patients were analyzed. The Meta-analysis results revealed that the olfactory score of the experimental group was 1.40 points higher than that of the control group (standardized mean difference [MD]: 1.40, 95% confidence interval [95% CI]: 0.34-2.47, P < .00001). However, the differences in the outcomes of cure rate (risk ratio: 1.18, 95% CI: 0.89-1.69, P = .21) and recovery time (MD: -1.78, 95% CI: -7.36 to 3.81, P = .53) were not statistically significant. Only 1 study reported adverse effects of nasal steroid treatment, namely tension, anger, and stomach irritation. CONCLUSION: Although nasal steroid therapy does not result in significant adverse effects, it proves ineffective in the treatment of COVID-19 olfactory dysfunction.

Trigeminal function in patients with COVID-associated olfactory loss.

PURPOSE: Olfactory dysfunction (OD) can be a long-term consequence of various viral infections, including COVID-19. Dysfunction includes hyposmia/anosmia and parosmia (odor distortions). Interactions of the virus with the olfactory nerve have been extensively researched, but little is known about the interactions of the intranasal trigeminal nerve system in modulating this sensory loss. METHODS: We investigated intranasal trigeminal function across COVID-19 OD patients with and without parosmia compared to normosmic controls, to determine whether (1) post-viral hyposmia and/or (2) post-viral hyposmia with parosmia is associated with altered trigeminal function. OD patients (n = 27) were tested for olfactory function using the extended Sniffin' Sticks olfactory test and for trigeminal function through three methods-odor lateralization, subjective ratings of nasal patency, and ammonium vapor pain intensity ratings. This group was subsequently compared to controls, normosmic subjects (n = 15). RESULTS: Our findings revealed that post-COVID OD patients without parosmia experienced decreased sensitivity in ammonium vapor pain intensity ratings and odor lateralization scores-but similar nasal patency ratings-compared to normosmic controls. There were no significant differences in trigeminal function between OD patients with and without parosmia. CONCLUSIONS: Based on our results, we conclude that the trigeminal nerve dysfunction may partially explain post-viral OD, but does not seem to be a major factor in the generation of parosmia pathophysiology.

Chronic rhinosinusitis and olfaction after highly effective modulator therapy: The role of individual sinus inflammation.

KEY POINTS: Individual sinus opacification (ISO) is measurable via a convolutional neural network approach. ISO decreased through 2 years after highly effective modulator therapy was initiated. In adults with cystic fibrosis, ISO did not correlate with quality of life or olfaction.

[Artificial intelligence-assisted prediction of olfactory disorders in patients with chronic rhinosinusitis].

Objective:To analyze the influencing factors and perform the prediction of olfactory disorders in patients with chronic rhinosinusitis（CRS） based on artificial intelligence. Methods:The data of 75 patients with CRS who underwent nasal endoscopic surgery from October 2021 to February 2023 in the Department of Otorhinolaryngology Head and Neck Surgery, the Third Affiliated Hospital of Sun Yat-sen University were analyzed retrospectively. There were 53 males and 22 females enrolled in the study, with a median age of 42.0 years old. The CRS intelligent microscope interpretation system was used to calculate the proportion of area glands and blood vessels occupy in the pathological sections of each patient, and the absolute value and proportion of eosinophils, lymphocytes, plasma cells and neutrophils. The patients were grouped according to the results of the Sniffin' Sticks smell test, and the clinical baseline data, differences in nasal mucosal histopathological characteristics, laboratory test indicators and sinus CT were compared between the groups. Determine the independent influencing factors of olfactory disorders and receiver operating characteristic curves（ROC） were used to evaluate the performance of the prediction model. Statistical analysis was performed using SPSS 25.0 software. Results:Among the 75 CRS patients, 25 cases（33.3%） had normal olfaction and 50 cases（66.7%） had olfactory disorders. Multivariate Logistic regression analysis showed that tissue eosinophils percentage（OR=1.032, 95%CI 1.002-1.064, P=0.036）, Questionnaire of olfactory disorders-Negative statement（QOD-NS）（OR=1.079, 95%CI 1.004-1.160, P=0.040） and Anterior olfactory cleft score（AOCS）（OR=2.672, 95%CI 1.480-4.827, P=0.001） were independent risk factors for olfactory disorders in CRS patients. Further research found that the area under the ROC curve（AUC） of the combined prediction model established by the tissue eosinophil percentage, QOD-NS and AOCS was 0.836（95%CI 0.748-0.924, P<0.001）, which is better than the above single factor prediction model in predicting olfactory disorders in CRS. Conclusion:Based on pathological artificial intelligence, tissue eosinophil percentage, QOD-NS and AOCS are independent risk factors for olfactory disorders in CRS patients, and the combination of the three factors has a good predictive effect on CRS olfactory disorders.

Intra Nasal Use of Ethylene Diamine Tetra Acetic Acid for Improving Olfactory Dysfunction Post COVID-19.

BACKGROUND: COVID-19 has been associated with olfactory dysfunction in many infected patients. The rise of calcium levels in the nasal secretions plays an essential role in the olfaction process with a desensitization effect on the olfactory receptor neurons and a negative impact on the olfaction transmission. Ethylene diamine tetra acetic acid (EDTA) is a chelating agent that can bind free calcium in the nasal secretions, thereby reducing the adverse effects of calcium on olfactory function. OBJECTIVES: The objective of this work is to demonstrate the effect of intranasal EDTA on improving olfactory dysfunction following COVID-19. METHODS: Fifty patients with a history of COVID-19 and olfactory dysfunction that persisted for more than 6 months were enrolled in the current prospective randomized clinical trial. Participants were randomized into 2 equal groups. Twenty-five patients were treated with olfactory training only, while the remaining 25 patients received treatment with olfactory training and a topical nasal spray of ethylene diamine tetra acetic acid. The olfactory function was assessed before treatment and 3 months later using the Sniffin' Sticks test. Additionally, the determination of calcium level in the nasal secretions was performed using an ion-selective electrode before treatment and 3 months later. RESULTS: Eighty-eight percent of the patients treated with olfactory training in addition to EDTA exhibited clinical improvement, while 60% showed improvement in patients treated with olfactory training only. Furthermore, a significant decrease in the measured calcium level in the nasal secretions was demonstrated after the use of ethylene diamine tetra compared to patients treated with olfactory training only. CONCLUSION: Ethylene diamine tetra acetic acid may be associated with an improvement of the olfactory function post-COVID-19.

[Persistent olfactory impairment after COVID-19-recommendations of the Working Group on Olfactology and Gustology of the German Society of Oto-rhino-laryngology, Head and Neck Surgery]. / Persistierende Riechminderung nach COVID-19 ­ Empfehlungen der Arbeitsgemeinschaft Olfaktologie und Gustologie der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e. V.

This article does not intend to comprehensively review the existing literature on coronavirus disease 2019 (COVID-19)-associated smell disorders, but aims to summarize scientific evidence for otorhinolaryngological practice and provide recommendations for diagnosis and treatment of persistent smell disorders following COVID-19.

Olfactory disorders in childhood: A comparative study of olfaction in children with adenoid hyperplasia versus a control group and the postoperative effects of adenoidectomy with respect to olfactory ability.

PURPOSE: Hyposmia in childhood is poorly characterized. The "U-Sniff Test", validated for children with anosmia, can be used to objectify olfactory impairment but has not been used to distinguish between hyposmia and normosmia. Therefore, we investigated children with enlarged adenoids with respect to hyposmia, its correlation with adenoid size, and the sensitivity of questionnaires to predict olfactory impairment. METHODS: In a prospective comparison, olfaction was assessed by "U-Sniff Test" (score 0-12; <8 hyposmia) in 41 children (5-18 years) with adenoid hyperplasia and compared with 196 children without any respiratory affection (control) after exclusion of previous SARS-Cov2-infection from December 2020 to December 2021. ENT-related complaints were collected using a self-designed questionnaire. We were able to include 13 children in a follow-up examination to compare preoperative performance in the "U-Sniff Test" with postoperative outcome after adenoidectomy. STATISTICS: chi-square-test (p < 0.05), odds-ratio, Spearman's rho, ROC-, cluster analysis. RESULTS: Severe hyposmia was present in 36.6% of children with adenoid-hyperplasia compared to 3.1% of the control-group. Adenoid-children scored significantly more often between 8 and 10 points (58.5%) than the control (31.6%; p < 0.01). Adenoid size and olfactory performance correlate significantly (r: 0.83; CI -0.89 … -0.72). Hyposmia in the adenoid group is characterized predominately by loss of the odors banana, butter and rose. None of children with hyposmia or parents reported impaired olfactory performance. Postoperatively, olfactory function improved significantly in 85% of cases (p 0.01, SD ± 1.71, Δ3.54points). CONCLUSION: Questionnaires are insufficient to detect hyposmia in this cohort. In contrast, the "U-Sniff Test" detects even reduced olfactory performance without reaching the cut-off value, which represents the majority of test results in the adenoid group. Therefore, we recommend the classification of moderate hyposmia (8-10 points) to be included for our study population.

Distinct smell and taste disorder phenotype of post-acute COVID-19 sequelae.

PURPOSE: Olfactory dysfunction (OD) commonly accompanies coronavirus disease 2019 (COVID-19). We investigated the kinetics of OD resolution following SARS-CoV-2 infection (wild-type and alpha variant) and its impact on quality of life, physical and mental health. METHODS: OD prevalence was assessed in an ambulatory COVID-19 survey (n = 906, ≥ 90 days follow-up) and an observational cohort of ambulatory and hospitalized individuals (n = 108, 360 days follow-up). Co-occurrence of OD with other symptoms and effects on quality of life, physical and mental health were analyzed by multi-dimensional scaling, association rule mining and semi-supervised clustering. RESULTS: Both in the ambulatory COVID-19 survey study (72%) and the observational ambulatory and hospitalized cohort (41%) self-reported OD was frequent during acute COVID-19. Recovery from self-reported OD was slow (survey: median 28 days, observational cohort: 90 days). By clustering of the survey data, we identified a predominantly young, female, comorbidity-free group of convalescents with persistent OD and taste disorders (median recovery: 90 days) but low frequency of post-acute fatigue, respiratory or neurocognitive symptoms. This smell and taste disorder cluster was characterized by a high rating of physical performance, mental health, and quality of life as compared with convalescents affected by prolonged fatigue or neurocognitive complaints. CONCLUSION: Our results underline the heterogeneity of post-acute COVID-19 sequelae calling for tailored management strategies. The persistent smell and taste disorder phenotype is characterized by good clinical, physical, and mental recovery and may pose a minor challenge for public health. STUDY REGISTRATION: ClinicalTrials.gov: NCT04661462 (survey study), NCT04416100 (observational cohort).