Taste and Smell Functions in Long-term Survivors after Childhood Medulloblastoma/CNS-PNET

Purpose Our aim was to investigate taste and smell functions in survivors, with a minimum of 2 years follow-up time, after treatment of childhood medulloblastoma/CNS-PNET. Methods This cross-sectional study included 40 survivors treated ≤ 20 years of age. Taste strips with four concentrations of sweet, sour, salt, and bitter were used to assess taste function in all participants. Score from 0-16; ≥ 9 normogeusia, < 9 hypogeusia, and complete ageusia which equals no sensation. No sensation of a specific taste quality equals ageusia of that quality. Thirty-two participants conducted smell testing using three subtests of Sniffin’ sticks; threshold, discrimination, and identification. Together they yield a TDI-score from 1-48; functional anosmia ≤ 16.00, hyposmia >16.00 - < 30.75, normosmia ≥ 30.75 - < 41.50, and ≥ 41.50 super smeller. Results were compared with normative data. Survivors subjectively rated their taste and smell functions using a numerical rating scale (NRS) score 0-10. Results Forty survivors with a mean follow-up of 20.5 years, 13 (32.5 %) were diagnosed with hypogeusia, nine (22.5 %) of these being ageusic of one or more taste qualities. Seventeen (53 %) of 32 participants were diagnosed with hyposmia. Comparing survivors with hyposmia to those with normosmia, a significant difference (p<0.05) was found in TDI-score and in all the subtests. The mean NRS score of subjective ratings of functions were high.Conclusion Our study showed impaired taste and smell functions in long-term survivors of childhood MB/CNS-PNET using objective measurements. However, subjective ratings did not reflect objective findings.

Prevalence of Persistent Olfactory Disorders in Patients With COVID-19: A Psychophysical Case-Control Study With 1-Year Follow-up

The purpose of this multicenter case-control study was to evaluate a group of patients at least 1 year after coronavirus disease 2019 (COVID-19) with Sniffin’ Sticks tests and to compare the results with a control population to quantify the potential bias introduced by the underlying prevalence of olfactory dysfunction (OD) in the general population. The study included 170 cases and 170 controls. In the COVID-19 group, 26.5% of cases had OD (anosmia in 4.7%, hyposmia in 21.8%) versus 3.5% in the control group (6 cases of hyposmia). The TDI score (threshold, discrimination, and identification) in the COVID-19 group was significantly lower than in the control group (32.5 [interquartile range, 29-36.5] vs 36.75 [34-39.5], P < .001). The prevalence of OD was significantly higher in the COVID-19 group, confirming that this result is not due to the underlying prevalence of OD in the general population.

Olfaction in COPD

Background: Olfaction is poorly characterized in COPD. To test the hypothesis that olfaction is reduced in COPD, we assessed olfaction with the “Sniffin’ Sticks” test and a questionnaire addressing olfaction in COPD and a corresponding control group in respect to age and sex. We also explored whether there is an association between COPD, chronic rhinosinusitis without nasal polyps (CRSsNP), and other predefined covariates with olfactory function. Methodology: Olfactory function was assessed by the score for threshold (T), discrimination (D) and identification (I), and the composite TDI score in the “Sniffin’ Sticks” test and by self-reported evaluation of impaired olfaction and of “decreased sense of smell and taste” in the 22-item Sino-Nasal Outcome Test (SNOT-22) in 90 COPD patients and 93 controls. A clinical interview and ENT-examination with nasal endoscopy, skin prick test and spirometry with reversibility were performed. Results: The TDI, D and I scores were significantly lower in the COPD group than in the control group. The T score was not significantly different between the two groups. Hyposmia and anosmia were present in up to 79% of patients with COPD. The prevalence of self-reported impaired olfactory function and for 'decreased sense of smell and taste'; - was more than two-fold greater in the COPD than in the control group. COPD, higher age, male sex and allergy were associated with a lower TDI score, while CRSsNP was not associated with the TDI score. Conclusions: COPD is associated with olfactory dysfunction and the underlying mechanisms for this dysfunction should be elucidated.

Comparison of Olfactory Cleft Width and Volumes in Patients with COVID-19 Anosmia and COVID-19 Cases Without Anosmia

<b><i>Introduction:</i></b> The aim of this study was to assess the relationship between olfactory cleft width/volume and COVID-19-related anosmia. <b><i>Methods:</i></b> This study consisted of PCR-proven COVID-19 patients. Cases with COVID-19-related anosmia constituted Group 1 and cases without any olfactory dysfunction (OD) throughout COVID-19 infection or after recovery constituted Group 2. A total of 50 patients were included in the study, comprising 24 cases in Group 1 and 26 cases in Group 2. Group 1 patients underwent a 4-item-odor identification test during active symptoms and a Sniffin’ Sticks test after reconversion of PCR results to negative. All patients in Group 2 also underwent the Sniffin’ Stick test to document normosmia. All cases had paranasal sinus CT performed. Olfactory cleft widths and olfactory volumes were measured. The differences in width and volume between groups and the correlation with odor test scores (threshold-discrimination-identification [TDI]) were calculated. In addition, regression analyzes analysis was performed for cleft widths, volumes, and TDI scores according to age. <b><i>Results:</i></b> Olfactory cleft widths and olfactory volumes were significantly higher in Group 1 than those in Group 2 (<i>p</i> = 0.001; <i>p</i> &#x3c; 0.01). There was a significant negative correlation between total TDI scores and olfactory cleft widths and total olfactory volumes (<i>r</i> = −0.665; <i>r</i> = −0.731, respectively). Patients younger than 40 years of age had significantly higher right olfactory cleft width, left olfactory cleft width, and olfactory cleft volume than those in patients older than 40 years of age (<i>p</i> = 0.004, <i>p</i> = 0.005, <i>p</i> = 0.003; <i>p</i> &#x3c; 0,01, respectively). However, patients younger than 40 years of age had a significantly lower total TDI score and in all other values individually (t-d-i) than those in patients older than 40 years of age (<i>p</i> = 0.004; <i>p</i> &#x3c; 0.01). <b><i>Conclusion:</i></b> Patients with COVID-19-related OD had larger olfactory cleft width and volumes than those without OD in this study. Total TDI score was found to be inversely correlated with cleft width and volume.

Cultural Adaptation and Validity of the Sniffin’ Sticks Psychophysical Test for the UK Setting

Introduction Olfactory testing must be culturally adapted to be relevant to the target population. This study aimed to validate the Sniffin’ Sticks test for the UK setting. Methods A cohort study was conducted at a tertiary olfactory dysfunction clinic. Phase 1—healthy volunteers underwent the original German identification test followed by a UK adapted version. Phase 2—patients with olfactory dysfunction underwent the extended smell test (TDI) including the new descriptors. Outcome measures included differences in identification test (phase 1), retest reliability and differences in scores before and after treatment. Results A total of 31 healthy volunteers and 87 patients were recruited (6 and 31 males, respectively). Phase 1—mean identification scores showed a small improvement after descriptor adaptations (13.77 and 14.57, p = 0.0029). Phase 2—41 untreated participants had a mean identification score of 7.31 at both intervals (95% CI: − 1.15 to 1.15, p > 0.999). The mean change in treated participants was 1.88 (0.70 to 3.06, p = 0.0224). TDI score difference between treated and untreated groups was 6.63 (2.48 to 10.79, p = 0.0023). The intraclass correlation coefficient for untreated patients was high for both TDI score (ICC = 0.82, 95% CI 0.57 to 0.93) and identification score (ICC = 0.80, 0.52 to 0.93); CIs suggest the reliability is moderate to excellent. Conclusions This study confirms the validity of the descriptor adaptations of the identification component of the Sniffin’ Sticks test to distinguish between health and disease. Implications The Sniffin’ Sticks test can now reliably be used for clinical assessment of British patients, modifying only the descriptors.

Impact of renal replacement therapies on olfactory ability: results of a cross-sectional case control study

Introduction Several studies have suggested that chronic kidney disease (CKD) may be associated with olfactory impairment. However, to date, the impact of renal replacement therapies has only been partly defined. Methods We tested the olfactory function of 235 participants [50 kidney transplant recipients (KT), 49 hemodialyzed patients (HD), 30 peritoneal dialysis patients (PD), 51 patients with CKD not on dialysis (ND-CKD) and 55 healthy subjects (HS)] by the Sniffin’ Sticks test (Burghardt®, Wedel, Germany), including the sub-tests for the determination of odor threshold (T), odor discrimination (D), odor identification (I). Each subtest result was then summed up to a composite score, known as the TDI score. The Sino-Nasal Outcome Test-22 (SNOT22), Montreal Cognitive Assessment (MoCA) test and olfactory function Visual Analogue Scale (ofVAS) were also performed. Results The mean TDI score was significantly lower (and consistent with hyposmia), in HD, PD and ND-CKD compared to HS and KT (ANOVA p < 0.001). Similar results were observed in the I and D tests, and with the T score, though with regard to the latter, only in PD and ND-CKD patients. Multiple comparisons among groups demonstrated no significant differences between KT and HS. After adjustments for confounding factors, a significant linear association was found between both urea (β − 0.03, p < 0.003) and eGFR (β 0.08, p < 0.001) with TDI score. No significant association was observed between the TDI score and the ofVAS score (p = 0.293). Conclusions Olfactory impairment affects a large number of CKD patients in the pre-dialysis phase as well as those on dialysis. Kidney transplantation may reverse this condition with a possible positive impact on the quality of life and social behaviors/relationships. Graphic abstract

Gaining Back What Is Lost: Recovering the Sense of Smell in Mild to Moderate Patients After COVID-19

The purpose of our cohort study was to quantify olfactory deficits in Coronavirus disease 2019 (COVID-19) patients using Sniffin’ Sticks and a pre-post design to evaluate olfactory recovery. Thirty adult patients with laboratory-confirmed mild to moderate forms of COVID-19 underwent a quantitative olfactory test performed with the Sniffin’ Sticks test (SST; Burghardt, Wedel, Germany), considering olfactory threshold (T), odor discrimination (D), and odor identification (I). Results were presented as a composite TDI score (range 1–48) that used to define functional anosmia (TDI ≤ 16.5), hyposmia (16.5 &lt; TDI &lt; 30.5), or functionally normal ability to smell (TDI ≥ 30.5). Patients also self-evaluated their olfactory function by rating their ability to smell on a visual analogue scale (Visual Analog Scale rating) and answering a validated Italian questionnaire (Hyposmia Rating Scale). Patients were tested during hospitalization and about 2 months after symptoms onset. During the hospitalization, the overall TDI score indicated that our cohort had impairments in their olfactory ability (10% was diagnosed with anosmia and more than 50% were hyposmic). Almost all patients showed a significant improvement at around 1 month following the first test and for all the parts of the SST except for odor identification. None of the subjects at 1 month was still diagnosed with anosmia. We also quantified the improvement in the TDI score based on initial diagnosis. Anosmic subjects showed a greater improvement than hyposmic and normosmic subjects. In conclusion, within a month time window and 2 months after symptoms’ onset, in our cohort of patients we observed a substantial improvement in the olfactory abilities.

Development of a Korean Culture-Friendly Olfactory Function Test and Optimization of a Diagnostic Cutoff Value

Objectives. Cultural familiarity and safety must be considered when assessing olfactory ability. The YSK olfactory function (YOF) test is a new olfactory function test using culturally familiar odorants to Koreans.Methods. The YOF test comprises three subtests for threshold (T), discrimination (D), and identification (I). The identification test included eight universal and four Korean culture-friendly odorants, which were selected considering eight major functional groups. Data were obtained from 1,127 subjects over 19 years old. Subjects were classified as having normosmia (n=542), hyposmia (n=472), and anosmia (n=113) by self-reported olfactory function. The YOF test and the Korean version of the Sniffin’ stick test (KVSS-II) were performed on the same day in random order. Diagnostic cutoffs for anosmia and hyposmia were calculated using the Youden index (J).Results. The mean values for each T/D/I subtest and the total TDI score were as follows: normosmia (T, 4.6±2.3; D, 8.6±2.1; I, 11.1±1.7; TDI score, 24.2±4.5); hyposmia (T, 3.3±2.2; D, 7.1±2.5; I, 9.2±3.1; TDI score, 19.5±6.4); and anosmia (T, 1.7±1.2; D, 5.1±2.5; I, 5.0±3.2; TDI score, 11.8±5.6). The correlation coefficients between the YOF test and KVSS-II were 0.57, 0.65, 0.80, and 0.86 for T, D, I, and the TDI score, respectively (P<0.001). The diagnostic cutoffs were a TDI score ≤14.5 (J=0.67) for anosmia and 14.5(TDI score ≤21.0 (J=0.38) for hyposmia. The diagnostic efficacy of the YOF test (area under the curve [AUC], 0.88) was equivalent to that of the KVSS-II (AUC, 0.88; P=0.843; DeLong method).Conclusion. The YOF test is a new olfactory test using safe and Korean culture-friendly odorants. It showed equivalent validity with the conventional olfactory function test. Furthermore, the YOF test provides information on the major functional groups of odorants, potentially enabling a more comprehensive interpretation for patients with olfactory disorders.

A Community-Based Study on the Prevalence of Olfactory Dysfunction

Background Olfactory dysfunction (OD) is common, affecting an estimated 13 million adults in the United States. Prior studies may underestimate OD prevalence due to use of brief smell identification tests or age-adjusted cutoff values, which concede that it is acceptable for older people to have a decreased sense of smell. Objective To determine OD prevalence in the healthy community when the goal and expectation is ideal olfactory function, rather than age-based population norms. Secondary goals were to explore factors associated with OD. Methods Subjects without otolaryngic complaints were recruited from the community surrounding the Medical University of South Carolina. Olfactory-specific information was collected, and olfactory function was assessed using the Sniffin’ Sticks test (Burghardt, Wedel, Germany) to measure threshold, discrimination, and identification (TDI). OD was defined as a TDI score < 31. Bivariate analysis and linear regression were used to determine factors associated with OD. Results In total, 176 subjects were included with mean age of 52 years (range: 20–93), 111 (63%) female, and 127 (72%) white. Mean TDI score was 28.8 (6.9) and OD was present in 94 (53%) subjects. Multivariate linear regression revealed that TDI decreased an average of 1 point every 5 years. TDI was also associated with Mini-Mental Status Examination (MMSE) score, asthma, and gastroesophageal reflux disease. Threshold was associated with age, heart problems, and gastroesophageal reflux disease. Discrimination was associated with age and MMSE scores. Identification was associated with age, heart problems, and anxiety. Conclusions In a community-based sample, OD affects greater than 50% of subjects. Aging impacts all aspects of olfaction, while the effects of factors such as asthma, MMSE scores, gastroesophageal reflux disease, heart problems, and anxiety may only be evident in specific olfactory subtests.

Short-Course Pentoxifylline Is Not Effective in Post-Traumatic Smell Loss: A Pilot Study

It has been suggested that systemic pentoxifylline may be beneficial in the treatment of olfactory dysfunction. The postulated mechanism of action involves nonselective competitive phosphodiesterase inhibition, leading to increased intracellular cyclic adenosine monophosphate and consequent increased olfactory neuron activity. This should in theory lead to improved olfactory function. We describe a pilot case series from our tertiary referral center of patients treated with oral pentoxifylline for olfactory dysfunction. Six patients with post-traumatic impairment who were treated with systemic pentoxifylline were included. Patients were treated with 200 mg of oral prolonged release pentoxifylline, 3 times a day for 21 days. Olfactory function was tested pre and post-treatment for odor threshold (T), discrimination (D), identification (I) and composite 'TDI' score using a psychophysical test battery, the “Sniffin’ Sticks.” Oral pentoxifylline was well tolerated and all patients completed the treatment period. There was a small improvement in odor threshold and identification scores, but these did not reach statistical or clinical significance. There were deteriorations in discrimination and composite TDI score, which did not reach significance. While our case series was small, systemic pentoxifylline did not appear to be beneficial in the treatment of hyposmia in this patient group.