Threshold Discrimination Identification Research Articles

내시경적 경접형동 접근법에서의 중비갑개 부분 절제가 후각 기능에 미치는 영향

Background: There are controversies on whether endoscopic transsphenoidal approach (TSA) affects postoperative olfaction. This study aimed to compare olfactory function in regard of partial resection status of middle turbinate (MT) and analyze the amount of resection in images.
 Materials and Methods: This study retrospectively reviewed 46 patients who had undergone endoscopic TSA due to pituitary adenoma or Rathke’s cleft cyst from 2015 to 2019. MT preserva-tion (MTP) group was defined as the group of patients whose MTs were preserved. MT resection (MTR) group was defined as the group of patients whose MTs were partially resected unilaterally or bilaterally. Olfactory function was compared with pre- and postoperative 3-month Korean version of sniffing sticks test-II which was composed of threshold, discrimination, identification (TDI) scores each making 16 with correct answers. Pre- and postoperative images including paranasal computed tomography and sellar magnetic resonance imaging were analyzed using Picture Archiving and Communication System.
 Results: There were 41 pituitary adenomas and 5 Rathke’s cleft cysts. Male patients were 39.1% (n = 18) and mean age was 42.6. About 1/3 (31%) of MT was resected in MTR group (n = 13), which had the effect of increasing the cross-sectional area of the nasal cavity by 19%. Post-septectomy area was 6% of total septum. Preoperative TDI score was 27.34 and postoperative TDI score was 25.42. There were no significant differences of olfactory score in total, MTR and MTP groups 3 months after endoscopic TSA.
 Conclusions: Resection of lower third of MT may produce low morbidity in respect of olfactory function after endoscopic TSA.

Long-term Recovery Patterns of Olfactory Function after Trans-sphenoidal Approach with Nasoseptal Flap Elevation.

Introduction Nasoseptal flap is widely used in reconstruction of the skull base to prevent cerebrospinal fluid leakage after surgery for skull base lesions. There has been a debate on whether more severe olfactory dysfunction occurs after nasoseptal flap elevation than the conventional trans-sphenoidal approach. Objective To compare the long-term recovery patterns associated with nasoseptal flap and the conventional trans-sphenoidal approach. Methods The subjects were divided into the conventional trans-sphenoidal approach group and the nasoseptal flap elevation group. We followed up self-reported olfactory score using the visual analogue scale and threshold discrimination identification (TDI) score of the Korean Version of the Sniffin Stick test II for 12 months, with olfactory training. Results The study included 31 patients who underwent the trans-sphenoidal approach. Compared with preoperative status, the mean visual analogue scale and TDI scores in the conventional trans-sphenoidal approach group recovered 2 months postoperatively, while in the nasoseptal flap elevation group the visual analogue scale and TDI scores recovered 6 months and 3 months after surgery, respectively. Twelve months after surgery, the visual analogue scale and TDI scores in the conventional trans-sphenoidal approach group were 9.3 ± 0.5 and 28.5 ± 4.3, while those from the nasoseptal flap elevation group were 8.9 ± 1.5 and 27.2 ± 4.7 ( p = 0.326; 0.473). Only one of the patients in the nasoseptal flap elevation group had permanent olfactory dysfunction. Conclusion The olfactory function recovered more gradually in the nasoseptal flap elevation group than in the conventional trans-sphenoidal approach group, but there was no difference between the two groups after 6 months.

Short-Term Efficacy and Safety of the Direct Triamcinolone Application Using Absorbable Nasal Packing in Anosmic Patients

Background and Objectives The most common treatment for olfactory dysfunction is the use of glucocorticoids. However, using systemic glucocorticoids is limited due to systemic side effects, and topical glucocorticoids are less effective than systemic glucocorticoids. The aim of this study is to evaluate short-term therapeutic effects of direct triamcinolone (TA) application using absorbable nasal packing material on anosmia patients.Subjects and Method This was a retrospective study that evaluated patients who were diagnosed with anosmia and treated with oral prednisolone (PD) pulse therapy or 2 times of a 20 mg dose of TA impregnated absorbable nasal packing in both olfactory clefts. Information of the demographic features, the self-reporting olfaction scores (visual analogue scale [VAS], 0-10), and the threshold, discrimination, identification (TDI) scores of Korean version of the Sniffin’ stick test II were collected and analyzed.Results The data of 72 patients were analyzed in this study: 30 patients were treated with TA nasal packing, and 42 patients with oral PD. In both group, VAS and TDI scores were significantly improved 2 weeks after treatment. The rate of significant olfactory improvement of TA nasal packing group was higher than oral PD group (60.0% vs. 47.6%), but there was no statistically significant difference (<i>p</i>=0.300). There was no significant systemic adverse effect after TA nasal packing treatments.Conclusion Direct TA application using absorbable nasal packing is a possible treatment option in anosmic patients.

Olfactory dysfunction in patients with Wilson's Disease.

Many neurodegenerative disorders are associated with olfactory dysfunction (OD), but little is known about OD in Wilson's Disease (WD). We evaluated olfactory function in patients with WD. OD was examined in 68 patients with WD and 70 sex- and age-matched healthy controls using subjective testing with 'Sniffin Sticks'. Threshold discrimination identification (TDI) score and its three components (odour detection threshold, discrimination, and identification) were assessed. Compared to controls, patients with WD had a significantly weaker sense of smell in terms of TDI (p < 0.01), odour discrimination (p < 0.01), and identification (p < 0.01), but not in terms of odour detection threshold (p = 0.27). Patients with predominantly neurological symptoms were characterised by greater OD by TDI (p < 0.01), odour detection threshold (p = 0.01), and discrimination (p = 0.03). The presence of pathological lesions (p = 0.04) in brain magnetic resonance imaging and generalised brain atrophy (p = 0.02) predisposed to worse TDI. In the WD group, weak inverse correlations between age and TDI score (r = -0.27), odour detection threshold (r = -0.3), and discrimination (r = -0.3) were found. Male gender was a risk factor for abnormal TDI in both WD and controls (both p = 0.02). Patients with WD, particularly older individuals, more frequently had OD than healthy volunteers. Predominantly neurological symptoms, and the presence of typical brain MRI changes, predisposed patients with WD to smell disorders.

Olfactory training reduces pain sensitivity in children and adolescents with primary headaches.

Headache prevalence among children and adolescents has increased over the last few years. Evidence-based treatment options for pediatric headaches remain limited. Research suggests a positive influence of odors on pain and mood. We investigated the effect of repeated exposure to odors on pain perception, headache-related disability, and olfactory function in children and adolescents with primary headaches. Eighty patients with migraine or tension-type headache (mean 13.1 ± 3.29 years) participated, of whom 40 underwent daily olfactory training with individually selected pleasant odors for 3 months and 40 received state-of-the-art outpatient therapy as a control group. At baseline and after a 3-month follow-up, olfactory function [odor threshold; odor discrimination; odor identification; comprehensive Threshold, Discrimination, Identification (TDI) score], mechanical detection and pain threshold (quantitative sensory testing), electrical pain threshold, patient-reported outcomes on headache-related disability [Pediatric Migraine Disability Assessment (PedMIDAS)], pain disability [Pediatric Pain Disability Index (P-PDI)], and headache frequency were assessed. Training with odors significantly increased the electrical pain threshold compared to the control group (U = 470.000; z = -3.177; p = 0.001). Additionally, olfactory training significantly increased the olfactory function (TDI score [t(39) = -2.851; p = 0.007], in particular, olfactory threshold, compared to controls (U = 530.500; z = -2.647; p = 0.008). Headache frequency, PedMIDAS, and P-PDI decreased significantly in both groups without a group difference. Exposure to odors has a positive effect on olfactory function and pain threshold in children and adolescents with primary headaches. Increased electrical pain thresholds might reduce sensitization for pain in patients with frequent headaches. The additional favorable effect on headache disability without relevant side effects underlines the potential of olfactory training as valuable nonpharmacological therapy in pediatric headaches.

A multicenter real-life study to determine the efficacy of corticosteroids and olfactory training in improving persistent COVID-19-related olfactory dysfunction.

No definitive treatment exists to effectively restore function in patients with persistent post-infectious olfactory dysfunction (OD). Corticosteroids have been considered as a therapeutic option in post-infectious OD but their benefit in COVID-19-related OD remains unexplored. We aim to determine the role of the combination of corticosteroids plus olfactory training (OT) in improving persistent COVID-19-related OD. A multicenter real-life cohort study was conducted between December 2020 and April 2022 on patients with reported COVID-19-related OD. Only patients with confirmed OD at Sniffin' Sticks (S'S) and those who attended their 6-month follow-up were included. Patients were started on a combined treatment of corticosteroids and OT. Patients refusing corticosteroids or not doing any treatment formed the control groups. Visual analogue scale (VAS) for sense of smell and SNOT-22 were used to assess patients reported symptoms. Sixty-seven subjects with reported COVID-19-related OD were initially seen. Normosmic patients at S'S (n=14) and those not attending their follow-up (n=9) were excluded. Of the 44 patients included in the analysis, 19 patients had the combined treatment (group A), 16 patients refused to take corticosteroids and did the OT alone (group B) whereas 9 patients did not do any treatment (group C). An improvement of threshold + discrimination + identification (TDI) score (p=.01) and VAS for smell (p=.01) was found in group A whereas only the TDI score improved in group B (p=.04). Presence of comorbidities, age, sex (male), and length of OD negatively influenced olfactory recovery. Our study confirms the importance of OT in long-term OD suggesting that the addition of corticosteroids may give a benefit in terms of patient's perceived olfaction. 2b.

Prednisolone does not improve olfactory function after COVID-19: a randomized, double-blind, placebo-controlled trial

BackgroundPrednisolone has been suggested as a treatment for olfactory disorders after COVID-19, but evidence is scarce. Hence, we aimed to determine the efficacy of a short oral prednisolone treatment on patients with persistent olfactory disorders after COVID-19.MethodsWe performed a randomized, double-blind, placebo-controlled, single-centered trial in the Netherlands. Patients were included if they were > 18 years old and if they had persistent (> 4 weeks) olfactory disorders within 12 weeks after a confirmed COVID-19 test. The treatment group received oral prednisolone 40 mg once daily for 10 days and the placebo group received matching placebo. In addition, all patients performed olfactory training. The primary outcome was the objective olfactory function on Sniffin’ Sticks Test (SST) 12 weeks after the start of treatment, measured in Threshold-Discrimination-Identification (TDI) score. Secondary outcomes were objective gustatory function assessed by the Taste Strip Test (TST) and subjective self-reported outcomes on questionnaires about olfactory, gustatory and trigeminal function, quality of life, and nasal symptoms. The CONSORT 2010 guideline was performed.ResultsBetween November 2021 and February 2022, we included 115 eligible patients, randomly assigned to the treatment (n = 58) or placebo group (n = 57). No difference in olfactory function between groups was obtained after 12 weeks. Median TDI score on SST was 26.8 (IQR 23.6-29.3) in the placebo group and 28.8 (IQR 24.0-30.9) in the prednisolone group, with a median difference of - 1.5 (-3.0 to 0.25). There was similar improvement on olfactory function in both groups after 12 weeks. Furthermore, on secondary outcomes, we obtained no differences between groups.ConclusionsThis trial shows that prednisolone does not improve olfactory function after COVID-19. Therefore, we recommend not prescribing prednisolone for patients with persistent olfactory disorders after COVID-19.Trial registrationThis trial is registered on the ISRCTN registry with trial ID ISRCTN70794078.

Subjective Gustatory Dysfunction Is Correlated With Subjective Olfactory Dysfunction in Geriatric Patients Regardless of Cognitive Function

Background and Objectives Fewer studies are available on geriatric patients’ gustatory dysfunction than on their olfactory dysfunction. Here we aimed to evaluate the relationship between subjective gustatory dysfunction and subjective or objective olfactory dysfunction according to cognitive function in geriatric patients.Subjects and Method We prospectively enrolled patients who underwent both cognitive function test and olfactory function test between August 2018 and May 2019. The correlation between subjective gustatory dysfunction and subjective olfactory dysfunction or conventional olfactory function scores was evaluated for geriatric patients with or withhout cognitive dysfunction. Participants with a threshold-discrimination-identification (TDI) score (&lt;21) on the YSK olfactory function test were diagnosed with olfactory dysfunction. Subjective gustatory function and olfactory function were evaluated using the visual analog scale. The Korean version of the Consortium to Establish a Registry for Alzheimer’s Disease Assessment Packet and Mini-Mental State Examination were administered to all participants. Overall, 120 patients (27 male, 93 female; mean age, 73.00±7.50 years) were enrolled.Results We found that the subjective gustatory function score did not correlate with the threshold, discrimination, identification, or the summation of TDI scores of the olfactory function test but was significantly associated with the subjective olfactory function score (p&lt;0.001). Further, there was no significant correlation between the subjective gustatory function score and cognitive function.Conclusion The subjective olfactory function score was the only factor significantly correlated with the subjective gustatory function score. Based on these results, we suggest evaluating gustatory function in geriatric patients with olfactory dysfunction.

Evaluation of the complete Sniffin Sticks Test versus its subtests in differentiating Parkinson's disease patients from healthy controls.

Hyposmia is one of the most common, as well as the first nonmotor condition in Parkinson disease (PD). The sniffin sticks test (SST) evaluates three different aspects of olfactory function: threshold (T), discrimination (D), and identification (I). The sum of the scores of these three subtests produce a global score of olfaction, the Threshold-Discrimination-Identification (TDI) score. The aim of this study was to investigate if the TDI score or one of its subtests is better to discriminate PD patients from controls. We recruited 27 PD patients and 17 healthy age-matched controls (HC) who were evaluated through a clinical interview, the Montreal Cognitive Assessment and Movement Disorders Society - Unified Parkinson Disease Rating Scale. The olfaction was assessed using the complete SST. The performance of PD patients on the olfactory test was significantly worse when compared with the HC (T: 3.0 vs. 6.5, p < 0.001; D: 8.1 vs. 11.2, p < 0.001; I: 7.3 vs. 11.7, p < 0.001; TDI: 18.8 vs. 29.9, p < 0.001). The prevalence of olfaction impairment in our study (PD: 100%, and HC: 56%) was greater than that found in the literature. Cognition influenced the performance on TDI. The olfactory subtests were impaired proportionally between patients and controls. Furthermore, D and I were correlated, but only in PD patients. The TDI showed a tendency to better discriminate PD patients from HC, when compared with its subtests. Although the complete olfactory evaluation is time consuming, it seems to be a superior tool to identify olfaction impairment in PD patients, when compared with the isolated subtests.

The YSK Olfactory Function Test: Development of a New Korean Olfactory Test

Olfaction is an important aspect of quality of life, beyond simply smelling food and recognizing danger. Recently, research has focused on its association with various diseases, such as neurodegenerative diseases or viral infections. The evaluation of olfactory function must take into consideration the cultural experience of the target group. A new Korean culturefriendly olfactory function test, the YSK olfactory function test (YOF test, Kimex Co.), uses safe odorants, such as phenyl-ethyl alcohol (PEA) (not n-butanol), for the threshold test. Furthermore, odorants in the YOF identification test reflect each of eight major chemical functional groups. The diagnostic cut-off for anosmia was a Threshold Discrimination Identification (TDI) score of ≤14.5 and that for hyposmia was 14.5&lt;TDI≤21.0. The YOF test showed relevant diagnostic validity for olfactory dysfunction when compared with the Korean version of the Sniffin’ Stick-II test. In this review, we share our experiences developing a new Korean-friendly olfactory function test.

Parosmia assessment with structured questions and its functional impact in patients with long-term COVID-19-related olfactory dysfunction.

Parosmia assessment with structured questions and its functional impact in patients with long-term COVID-19-related olfactory dysfunction.

Smell Sensitivity in Primary Open-angle Glaucoma and Pseudoexfoliation Glaucoma.

This cross-sectional study of 20 patients with primary open-angle glaucoma (POAG), 20 with exfoliative glaucoma (XFG), 20 with exfoliation syndrome (XS) showed that exfoliative group had a significantly lower smell identification level as compared with the control groups. To investigate smell sensitivity in POAG, XFG, and XFS in comparison with healthy controls. This prospective, cross-sectional study included 20 patients with POAG, 20 with XFG, and 20 with XFS. The control group consisted of 20 age-matched and sex-matched healthy subjects with no evidence of ocular disease. The Sniffin' Sticks smell test was used to determine the, threshold values, and to assess the ability of smell identification, and differentiation in all patients One eye per patient was included for statistical purposes. One-way analysis of variance was used to compare the differences between the groups. Tukey honestly significant difference was used as a post hoc test when significant differences were detected among the 3 groups. The XFG, POAG, and control groups showed a significant difference in the odor discrimination, odor identification, and threshold discrimination identification scores. The median (minimum-maximum) smell threshold levels for the POAG, XFG, and XFS groups and healthy controls were 4.5 (0 to 7.5), 4 (0 to 7.5), 5 (4.5 to 6), and 5.5 (4 to 7.5), respectively. The smell differentiation values for the POAG, XFG, and XFS groups and healthy controls were 12 (2 to 14), 8 (0 to 13), 11 (10 to 13), and 12 (9 to 14), respectively. Smell sensitivity for the POAG, XFG, and XFS groups and healthy controls were 26 (4 to 30.5), 19 (0 to 29.5), 28.3 (22.8 to 30.5), and 29 (26.5 to 32), respectively. The smell sensitivity and differentiation were significantly different among the groups (P<0.001). The XFG group had a significantly lower smell identification level than the POAG, XFS, and control groups. Patients with XFS and XFG revealed reduced smell sensitivity and identification compared with patients with POAG and those without glaucoma. These findings provide new insights into neural degeneration and pseudoexfoliation.

Prognostic value of olfactory bulb volume in patients with post-viral olfactory dysfunction

Objective:The purpose of this study was to compare the olfactory function examination results of patients with post-viral olfactory dysfunction（PVOD） in different prognostic groups and analyze prognostic factors, especially the influence of olfactory bulb volume（OBV） on prognosis, so as to provide objective basis for clinical diagnosis and treatment. Methods:After approval by the hospital ethics committee, the patients with PVOD admitted to Beijing Anzhen Hospital's outpatient department from January 2019 to December 2019 were followed up for at least 1 year. These patients completed the Sniffin' Sticks test and MRI examination of the olfactory pathway before treatment. According to the results of the Sniffin' Sticks test after 1 year follow-up（threshold-discrimination-identification（TDI） score of the patients was increased at least 6 points）, the patients were divided into two groups as the improvement group and the non-improvement group. The prognostic factors of PVOD patients were preliminarily determined by comparing the differences of various factors and the results of olfactory function examination between the two groups. Results:In this study, 47 patients with PVOD were included, with the smell improvement rate was 53.2%. Compared with the improvement group, the patients in the non-improvement group had longer duration, poorer initial olfactory function, higher olfactory threshold, and poorer olfactory discrimination and recognition ability（All P<0.01）. There was no statistical difference in terms of gender, age, allergic rhinitis and smoking between the two groups（All P>0.05）.The OBV of the non-improvement group was （59.48±23.92） mm³, which was significantly lower than that in the improvement group（[92.77±14.35]mm³, P<0.001）. Multiple logistic regression analysis showed that prognostic factors included course of disease（OR 0.677, 95%CI 0.461-0.993, P=0.046）, initial T value（OR 263.806, 95%CI 1.028-67 675.884, P=0.049） and OBV（OR 1.160, 95%CI 1.002-1.343, P=0.047）. The area under the receiver operating characteristic curve（ROC curve） of OBV was 0.888（0.797-0.979, P<0.001）. The correct diagnostic index of OBV≥78.50 mm³was used to determine the prognosis of olfactory function, with a specificity of 0.818 and a sensitivity of 0.840. The ROC curve analysis showed that the area under the ROC curve of duration was 0.822（0.703-0.940, P<0.001）. The correct diagnostic index of the duration ≤6 months was used to determine the prognosis of olfactory function, with a specificity of 0.727 and a sensitivity of 0.800. The area of T score was 0.793（0.662-0.924, P=0.001）. T score ≥1.25 was used as the correct diagnostic index to determine the prognosis of olfactory function. The specificity and sensitivity were 0.818 and 0.680, respectively. Conclusion:The prognosis of olfactory function in PVOD patients is related to the course of disease, the degree of olfactory loss and OBV. Those with no improvement in olfactory function have a longer disease course, aggravated olfactory damage and reduced OBV than those with improved olfactory function. The factors of Duration ≤6 months, T value ≥1.25 and OBV≥78.50 mm³suggested better prognosis, and the results of objective olfactory examination have greater value in evaluating the prognosis of olfactory function.

Normative data of olfactory abilities using cultural adaption Sniffin' sticks smell test in different age groups.

Objectives:To assess olfactory abilities using a culturally adapted Sniffin’ Sticks smell test in different age groups.Methods:This was a cross-sectional study, conducted at Otorhinolaryngology outpatient clinic of Universiti Kebangsaan Malaysia Medical Centre, Secondary Science School, and Children Learning Centre in Kuala Lumpur, Malaysia, from August 2019 until December 2021.Results:In 450 healthy participants, the cut-off points of the threshold discrimination identification (TDI) scores at the 10th percentile for olfactory abilities were 19 in children, 30.1 in adolescents, 32.1 in young adults, 31.1 in middle-aged adults, and 28.6 in older adults. The children had significantly lower olfactory abilities, with the Bonferroni post-hoc tests of p<0.001. The young adults had higher olfactory abilities than older adults (p<0.05). The results showed that the identification score was highest in middle-aged adults (p<0.001). The discrimination score was the highest in young adults (p<0.001). The best odor threshold performance was observed in adolescents (p<0.001). The TDI score showed a significant difference in olfactory abilities between men and women (p=0.001).Conclusion:Using a culturally adapted smell test, our population was able to identify, discriminate, and perceive odorants better than the European population. This data will help clinicians and researchers with a tool to reliably establish the correct results of olfactory function in our population. Women had better olfactory abilities than men.

Olfactory function in patients with obstructive sleep apnea and the effect of positive airway pressure treatment: a systematic review and meta-analysis.

ObjectivesTo investigate olfactory function (OF) in patients with obstructive sleep apnea (OSA) and evaluate whether or not the use of positive airway pressure (PAP) treatment has an impact on olfactory performance.MethodsAll studies published in English that gave satisfactory data regarding the assessment of OF in patients with OSA were included in this review. First, a baseline assessment of OF in patients with OSA who had not received any treatment was examined. Second, the effect of PAP therapy on OF was assessed to be able to make before and after comparisons. The primary outcome of this study was the threshold-discrimination identification (TDI) scores, obtained from the Sniffin’ Sticks test.ResultsThe database search identified 552 articles. According to the exclusion criteria, 11 studies involving 557 patients diagnosed with OSA were included in this meta-analysis. The general rate of olfactory dysfunction was 73% (95% CI: 56.481–87.057) among the patients with OSA. The patients with OSA had lower TDI scores compared to the control group and the difference was statistically significant (p < 0.001). PAP treatment significantly improved the TDI scores in patients with OSA (p < 0.001). There was a significant negative correlation between the severity of apnea-hypopnea index and TDI scores (p = 0.001, z = −3.377, r = −0.438) and between age and TDI scores (p = 0.007, z = −2.695, r = −0.236).ConclusionThis meta-analysis demonstrates that OSA impairs OF, while PAP treatment can reverse the olfactory performance of patients with OSA.

Prognostic value of olfactory evoked potentials in patients with post-infectious olfactory dysfunction

Prognostic assessment of patients with post-infectious olfactory dysfunction (PIOD) poses a challenge for clinicians. While there have been some studies on the prognostic factors of PIOD focusing on demographic factors, the aim of this study was to investigate whether event-related potentials (ERPs) could be used as a new predictor of olfactory recovery in PIOD. This was a retrospective study involving patients who underwent olfactory examinations using Sniffin' Sticks test before treatment and after 1year of follow-up. The responder group was defined by an increase of threshold-discrimination-identification (TDI) score of ≥ 6 points. All patients underwent ERP examination and the amplitude and latency of each wave of ERPs were recorded before treatment. A total of 61 patients (age 47.50 ± 11.04years, 27 males) were analyzed. The presence of olfactory ERPs (oERPs) was greater in the responder group than in the non-responder group (P = 0.007), while that of trigeminal ERPs (tERPs) did not differ between the two groups (P = 0.346). Logistic-regression analyses showed that factors associated with improvement of subjective olfactory function were duration (OR, 1.604; 95% CI, 1.062-2.423; P = 0.025), initial threshold (odds ratio [OR], 0.043; 95% confidence interval [CI], 0.004-0.439; P = 0.008), and latency of N1 in oERPs (OR, 1.007; 95% CI, 1.001-1.013; P = 0.021). Our study shows that duration of OD, initial threshold, and latency of N1 in oERPs were associated with olfactory improvement in PIOD patients, which may provide guidance for clinicians.

Determination of Retronasal Olfactory Threshold Values.

The aim of this study was to generate normative data of retronasal olfactory threshold values for normosmic and hyposmic individuals and to test the validity of that data by determining the discriminative power for normosmic/hyposmic differentiation. Prospective, descriptive and methodological study. The orthonasal olfactory function of 20 normosmic and 20 hyposmic cases was evaluated using the Sniffin' Sticks Olfactory test. Sniffin' Sticks odor threshold, odor discrimination, and odor identification values and threshold discrimination identification (TDI) scores were recorded. A 13-item test battery previously prepared in our Rhinology Laboratory for retronasal olfactory threshold test that consisted of concentrated solutions prepared from 2:1 diluted 99% phenylethyl alcohol (PEA) and water was used. Each concentration was evaluated with water control, and if not answered correctly, the same process was continued by moving to a higher concentration series. Four consecutive correct answers were determined as the patient's retronasal olfactory threshold. A strong correlation was found between Sniffin' Sticks TDI scores and retronasal odor threshold values in the normosmic group (P < .001, r:0.67). A very strong correlation was found between Sniffin' Sticks TDI scores and retronasal olfactory threshold values in the hyposmic group (P < .001, r:0.81). Furthermore, receiver operating characteristic (ROC) analysis revealed that the sensitivity and the specificity of normosmic/hyposmic differentiation of retronasal olfactory threshold test was 95% and 100%, respectively. The diagnostic cutoff value was 8.5. This study shows that the retronasal olfactory test, a psychophysical odor test performed using an orally presented stimulus, can be used to differentiate normosmic and hyposmic cases. 3 Laryngoscope, 131:1608-1614, 2021.

Imaging Features to Predict Response to Olfactory Training in Post-Traumatic Olfactory Dysfunction.

Prognosis of post-traumatic olfactory dysfunction is poor, with medical treatment options showing limited success rates. Olfactory training (OT) has been introduced as a potential therapeutic option in olfactory dysfunction. We aimed to identify the imaging features that would predict a better response to OT and create an imaging-based prognostic scale. We retrospectively reviewed 52 patients that underwent OT at our center for post-traumatic olfactory dysfunction. Olfactory functions at the time of initial presentation and at completion of OT were evaluated using Sniffin' Sticks test and threshold discrimination identification (TDI) scores were calculated. Patients were divided into responders (ROT group: 16 cases) and non-responders (n-ROT group: 36 cases) to OT based on TDI score change (cut-off 5.5 point). Morphological measurements of olfactory fossa, olfactory bulb volume and signal abnormalities, olfactory nerve filia integrity, siderosis, encephalomalacic changes in olfactory cortex, and other cortical regions were reviewed. There was no significant difference between the two groups in terms of age, gender distribution, olfactory dysfunction duration, head-trauma severity, and initial TDI scores. A model incorporating five variables: cribriform plate fracture, olfactory fossa depth (cut-off: 4.9 mm), olfactory bulb encephalomalacia, olfactory bulb volume (cut-off: 27.1 mm3 ), and siderosis was developed. This model had an area under the curve (AUC) of 0.950, and a cut-off value of 1 had 76.5% sensitivity and 97.1% specificity in prediction of response to OT. We developed an imaging-based scoring system with good specificity that can be used as an adjunctive tool for patient counseling, and optimal selection of management options. 4 Laryngoscope, 131:E2243-E2250, 2021.

Data Science-Based Analysis of Patient Subgroup Structures Suggest Effects of Rhinitis on All Chemosensory Perceptions in the Upper Airways

Viral rhinitis contributes significantly to olfactory dysfunction, but it is unclear how many patients have other chemosensory symptoms in addition to olfactory loss. This was addressed in the present reanalysis of data previously published in Pellegrino R, Walliczek-Dworschak U, Winter G, Hull D, Hummel T. 2017. Investigation of chemosensitivity during and after an acute cold. Int Forum Allergy Rhinol. 7(2):185-191, using unsupervised and supervised machine-learning methods. Fifty-eight patients with acute rhinitis and 59 healthy controls were assessed for orthonasal and retronasal olfactory function, taste, and intranasal trigeminal sensitivity. Unsupervised analysis showed that during rhinitis, clinical scores of olfactory function, expressed as threshold, discrimination, identification (TDI) values, were trimodally distributed. Two minor modes were separated from the main mode at TDI = 30.5, which corresponds to the established limit of hyposmia. This trimodal distribution was not observed after the rhinitis subsided. Olfactory function was not significantly impaired in 40% of all rhinitis patients, whereas it was transiently impaired in 59%. For this group, supervised machine-learning algorithms could be trained with information on retronasal olfactory function, gustatory function, and trigeminal sensitivity to assign patients to subgroups based on orthonasal olfactory function with a balanced classification accuracy of 64-65%. The ability to recognize patients with olfactory loss based on retronasal olfactory function as well as gustatory function and trigeminal sensitivity suggests in turn that these modalities are affected by rhinitis. However, the only modest accuracy at which this information allowed to reproduce the olfactory diagnosis indicated they are involved in the symptomatology of rhinitis to a lesser extent compared with the orthonasal olfactory function.

Evaluation of Olfactory Function With Objective Tests in COVID-19-Positive Patients: A Cross-Sectional Study.

Objective:Olfactory dysfunction is relatively high in coronavirus disease 2019 (COVID-19) patients. The aim of this study is to investigate the incidence of olfactory disorder objectively in patients with laboratory-confirmed COVID-19 infection.Material and Method:The study included 31 healthy controls and 59 COVID-19 patients who were diagnosed and treated in the COVID departments in a tertiary hospital. The patients with corona virus infection were screened by a questionnaire and were classified into 2 groups as either group 2 (patients without self-reported smell loss) or group 3 (patients with self-reported smell loss). Age and gender matched healthy controls who do not have chronic nasal condition or nasal surgery history comprised the control group (group 1). All of the patients and subjects in the control group were tested by the Sniffin’ Sticks test. All of the answers and scores were recorded, and the comparisons were made.Results:The rate of self-reported smell and taste loss in all COVID-19 patients in this study was 52.5% and 42%, respectively. There was a significant difference in threshold, discrimination, identification, and Threshold, Discrimination, Identification (TDI) scores between groups 1 and 2. When the comparisons between group 1 and 3 were made, again threshold, discrimination, identification, and TDI scores were significantly different. The comparison between groups 2 and 3 demonstrated a significant difference in discrimination, identification, and TDI scores, but threshold score was not different statistically. With questionnaire, the rate of olfactory dysfunction in COVID-19 patients was 52.5%, but with objective test, the rate was calculated as 83%.Conclusion:Olfactory and gustatory dysfunctions are common in COVID-19 patients. According to findings with the objective test method in this study, smell disorder in COVID-19 patients was much higher than those detected by questionnaires.