Objective Olfactory Function Research Articles

The relationship between survey-based subjective olfactory awareness and objective olfactory function.

Correlation between symptom-based surveys and objective olfactory testing is variable. For diagnosis and symptom monitoring, surveys should correlate with objective testing. The Odor Awareness Scale (OAS) and Affective Importance of Odor Scale (AIO) showed significant but moderate positive correlations with University of Pennsylvania Scent Identification Test (UPSIT) score.

Diagnostic accuracy of the screenings Sniffin' Sticks Test (SST-12) in COVID-19 induced olfactory disorders.

Objective olfactory function can be assessed using validated olfactory tests like the Sniffin' Sticks Test (SST). However, their extensive nature makes them less suitable for clinical practice. To address this, shorter olfactory tests like the screenings Sniffin' Sticks Test (SST-12) can be used for screening purposes and reduce testing time. The SST-12 serves as a diagnostic tool for screening olfaction in cases unrelated to COVID-19. However, these screening tests are uncertain regarding their accuracy in detecting olfactory dysfunction in patients with COVID-19 as the plausible cause. We aim to determine the diagnostic accuracy of the SST-12 in adults with post-COVID-19 olfactory dysfunction. We performed a diagnostic accuracy study with data from 113 consecutive COVID-19 diagnosed patients who experienced objectified smell loss ever since. At approximately 6 months after their diagnosis, all participants underwent the SST (reference standard), part of the SST was the SST-12 (index test). Diagnostic accuracy of the SST-12 is measured as negative predictive value (NPV), positive predictive value (PPV), sensitivity, and specificity. The SST-12 detected smell loss in 85 patients among 91 patients with smell loss and ruled out smell loss in 15 patients among the 22 patients without smell loss based on the reference standard. Making sensitivity 93.4% (CI 0.87-0.97), and specificity 68.2% (CI 0.48-0.85). Out of the 92 patients with a positive test result on SST-12, 85 patients had indeed smell loss (PPV 92.4% CI 0.86-0.97), and out of the 21 patients with a negative test result, 15 patients had no smell loss regarding the reference standard (NPV 71.4% CI 0.50-0.88). The findings suggest that the SST-12 holds promise as a useful tool for identifying individuals with smell loss, also in individuals with COVID-19 as cause, but it is important to have a good understanding of the interpretation of the results of the SST-12 when considering its implementation in clinical practice.

Factors influencing the recovery of anosmia in young medical students with COVID-19

Background: One of the most prevalent signs of COVID-19, accounting for 30–86% of cases, is olfactory impairment. Various researches have been carried out on anosmia due to COVID-19 based on self-reported questionnaires. To the best of our knowledge, very few studies have been done by conducting the olfactory function test to better understand and clarify the clinical outcomes. Aim and Objective: The present study aims to assess the recovery of anosmia and the factors affecting it among COVID-19-recovered individuals. Materials and Methods: An observational study was conducted from November 2021 to January 2022. RT-PCR-proven COVID-19 adult patients (17–25 years of age) with a positive history of anosmia were included in this study. Anosmia was assessed by performing an objective olfactory function test. The recovery of anosmia after 6 weeks was evaluated, and the relationship between the patient’s recovery and their clinical, demographic data, and medication use was assessed. A univariate cox proportional regression model was carried out for individual variables, variables with P < 0.10 in univariate cox proportional were considered for multivariate analysis, and P < 0.05 were considered statistically significant. Results: A total of 50 students were included in the study, out of which females were 40% and males were 60%. Their mean age was 20.18 ± 1.224 years. 30 (60%) out of 50 individuals reported complete recovery of anosmia, 17 (34%) reported partial recovery and 3 (6%) reported no recovery. The result of univariate and multivariate cox proportional hazard regression showed that those who consumed antihistamines had early recovery (2.475 [1.153–5.316], P = 0.020) and those who had associated cough showed a delay in the recovery of anosmia (0.408 [0.205–0.814] P = 0.011). Conclusion: The study concludes that the use of antihistamines is associated with early recovery from COVID-19-related anosmia. Cough associated with anosmia in COVID-19 decelerates the recovery from anosmia. Overall, there is an excellent prognosis in nearly complete recovery from anosmia in the population studied.

Olfactory Training Impacts Olfactory Dysfunction Induced by COVID-19: A Pilot Study

Introduction: Olfactory dysfunction is one of the main symptoms of COVID-19 and may last beyond resolution of the infection. The most promising intervention for post-viral olfactory dysfunction is olfactory training (OT), which involves exposing the olfactory system to a range of odors daily. This approach is thought of promoting the regeneration of olfactory receptor cells, but its effectiveness in patients with post-COVID-19 olfactory dysfunction has yet to be confirmed. Methods: This double-blind randomized pilot study compared the effectiveness of OT versus placebo in the treatment of post-COVID-19 olfactory dysfunction. Twenty-five participants were recruited in each group. OT protocol consisted of sniffing 4 scents (rose, orange, clove, and eucalyptus) for 5 min twice daily for 12 weeks. Olfactory function was assessed before and after the training using (1) a validated odor identification test (UPSIT-40) and (2) a 10-point visual analog scale; we further assessed the presence of (3) parosmia. Results: While we did not observe any effect of OT on olfactory test scores, we observed a significant improvement of subjective olfactory function in the intervention group, while no such effect was observed in the placebo group. Finally, the frequency of parosmia was significantly lower in the intervention group. Conclusions: This study highlights an increase in subjective but not objective olfactory function when performing OT for 12 weeks. Further, parosmia seems to be positively affected by OT. These results may serve as a starting point for larger scale studies to assess the efficacy of OT for treatment of post-COVID-19 olfactory dysfunction.

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.

Anosmia/hyposmia differences between severe acute respiratory syndrome coronavirus 2 variants; objective olfactory function evaluation

Objectives: This study aimed to investigate whether the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants cause more or less loss of smell than the wild type variant as a clinical finding that may guide physicians in addition to the increased mortality feature. Patients and Methods: In the prospective study, Connecticut Chemosensory Clinical Research Center (CCCRC) odor testing was performed on patients hospitalized for coronavirus disease 2019 (COVID-19) between May 2021 and December 2021, and variants of SARS-CoV-2 isolated from patients were analyzed. A total of 51 patients (30 males and 21 females; mean age 59.3±14.2 years; range, 29 to 88 years) were included in the study. Age, sex, and COVID-19 vaccine status of the patients were recorded. The patients were asked whether they had new-onset odor or taste complaints and whether they differently perceived smells they knew. Results: The delta variant was detected in 14 patients, the alpha variant was detected in 20 patients, and no variant of concern was detected in 17 patients. Odor disorders were present in 79.4% of all patients (13.73% anosmia, 15.69% severe hyposmia, 13.7% moderate hyposmia, and 37.2% mild hyposmia). There was no statistically significant difference between sex, age, smoking habits, presence of parosmia, degree of smell disorder, and Vicks definition results according to the variants (p>0.05). A statistically significant difference was found between alpha and delta variants in terms of patients' complaints of decreased smell and taste, mean olfactory threshold value, and mean olfactory score variables (p<0.05). There was no difference in terms of age and identification score. The complaints of smell and taste disorders, the mean threshold value of odor, and the mean odor score were found to be significantly lower in the delta variant than in the alpha variant. Conclusion: SARS-CoV-2 variants differ significantly in olfactory dysfunction. Future clinical and laboratory studies may show the diagnostic, clinical, and prognostic significance of olfactory nerve injury.

COCOS trial: COrticosteroids for COVID-19-induced loss of Smell–protocol for a single-centred, double-blind, randomised, placebo-controlled trial

IntroductionHyposmia and anosmia are common in COVID-19. Most patients regain normal smell within 4 weeks, but severe loss of smell persists roughly in 20% after 2 months and may last...

Associations of Prior Head Injury With Olfaction in Older Adults

Traumatic brain injury has been associated with short-term olfactory dysfunction, but the association of number of prior head injuries and head injury severity with both subjective and objective long-term olfactory function is less clear. To investigate the associations of prior head injury, number of prior head injuries, and head injury severity with subjective and psychophysical (objective) olfactory function in older adults and to examine concordance between subjective and objective olfactory function among individuals with and without head injury. This prospective cohort study included 5951 participants who attended Atherosclerosis Risk in Communities (ARIC) Study visit 5 (2011 through 2013). Data analysis was performed between November 2021 and May 2022. Head injury was defined by self-report and International Classification of Diseases codes. Self-reported subjective olfactory dysfunction was assessed by the question, "Do you suffer from smell loss or a significantly decreased sense of smell?" Objective olfactory performance was assessed using the 12-item Sniffin' Sticks odor identification test. Overall, the 5951 participants were a mean (SD) age of 75.6 (5.2) years, 3501 (58.8%) were female, 1356 (22.8%) were of Black race, and 1666 (28.0%) had a history of head injury. Participants with prior head injury were more likely than individuals without prior head injury to report subjective olfactory dysfunction (24% vs 20%; difference, 4%; 95% CI, 1% to 6%) and have objective anosmia (15% vs 13%; difference, 2%; 95% CI, 0.1% to 4%) but had lower concordance between subjective and objective assessment (72% vs 77%; difference, -5%; 95% CI, -8% to -3%). In logistic regression models adjusted for sociodemographics and medical comorbidities including cognitive status, participants with a history of prior head injury, particularly individuals with 2 or more prior head injuries and more severe head injuries, were more likely to self-report subjective olfactory dysfunction and were more likely to be found to have objective anosmia compared with participants with no history of head injury. Findings of this cohort study provide evidence supporting the association between head injury and olfactory dysfunction, particularly among individuals who experienced multiple prior head injuries and among individuals with more severe head injury. The findings also suggest that individuals with prior head injury were more likely to both under-self-report and over-self-report deficits compared with objective olfactory testing; therefore, it may be important to consider objective olfactory testing in this patient population.

Systematic review of olfactory outcomes after nasoseptal flap harvest for endoscopic skull base surgery: Does using cold steel or olfactory strip preservation matter?

Several studies have described techniques aimed at mitigating olfactory dysfunction after nasoseptal flap (NSF) harvest for endoscopic skull base surgery (ESBS). No consensus exists as to whether popular methods including using cold steel (CS) versus electrocautery (EC) or septal olfactory strip (SOS) preservation offer an advantage. This systematic review was performed to examine the impact of these two technical variations of NSF harvest on postoperative olfactory outcomes. Following PRISMA guidelines, PubMed, Scopus, and Web of Science were searched for articles reporting olfactory outcomes in ESBS cases employing an NSF. Original articles focusing on technique variations of the NSF and reporting at least one objective olfactory measure were included. Nine studies comprising 610 patients were included. Various, olfactory testing outcomes were reported, and postoperative follow-up ranged from 6weeks to 12 months. Three studies, including a randomized controlled trial, compared the use of CS and EC for the superior incision of the NSF. No significant difference was found in objective olfactory function (p>0.05) when comparing these techniques. Five studies comprising 504 patients reported results from SOS-sparing. SOS-sparing technique in NSF harvest demonstrated smell preservation in the postoperative setting when compared with preoperative measures (p>0.05); however, no direct comparison to non-SOS-sparing techniques was made. The use of CS as opposed to EC for the superior NSF incision does not appear to confer an advantage in preserving postoperative olfactory function (grade B evidence). SOS preservation may be associated with better olfactory outcomes in NSF harvest (grade C evidence).

Evaluation of chemosensory function in patients with upper respiratory tract post-viral olfactory dysfunction

Objective: To observe the changes of olfactory function, intranasal trigeminal nerve function and taste function in patients with upper respiratory tract post-viral olfactory dysfunction (PVOD), and to explore the correlation of chemosensory function. Methods: The clinical data of 42 patients with PVOD who visited to the Olfactory and Taste Center of Otorhinolaryngology Head and Neck Surgery Department of Beijing Anzhen Hospital from January to December of 2019 were analyzed retrospectively, including 20 males and 22 females, aging (48.86±11.47) years (x¯). Twenty subjects in normal control group were selected according to the sex ratio of PVOD patients. Sniffin' Sticks olfactory tests were performed on the subjects, including threshold test (T), discrimination test (D) and identification test (I), and the sum of the above three test scores was the TDI value. At the same time, olfactory event-related potentials (oERPs), trigeminal event-related potentials (tERPs) and taste function test were performed. According to the taste function test, the patients were divided into normal gustation (NG) group and gustatory dysfunction (GD) group. The results of olfaction, taste and intranasal trigeminal nerve function tests were compared among different groups, and the correlation analysis was carried out. SPSS statistical software was used for statistical analysis. Results: GD was present in 14 (33.3%) of 42 PVOD patients with a course of PVOD of 5 (3, 6) months (M (Q1, Q3)). The gustatory function of patients with PVOD was related to gender (r=0.565, P<0.001), smoking status (r=-0.512, P=0.001), duration (r=-0.357, P=0.020) and olfactory function (all P<0.05). The olfactory function of GD group was worse than that of NG group, and the differences of TDI value and T value between the two groups were statistically significant (10.25±4.58 vs 13.35±3.61, 1.54±0.66 vs 2.10±0.88, t value was 2.40 and 2.10 respectively, both P<0.05). The amplitudes of oERPs and tERPs were significantly lower in GD group than those in NG group (all P<0.05). Conclusion: In patients with PVOD, the subjective and objective olfactory function, intranasal trigeminal nerve function and taste function were decreased, and there was a correlation, suggesting that there was a synergistic effect between the chemosensory functions of PVOD patients.

Objective evaluation and predictive value of olfactory dysfunction among patients hospitalized with COVID-19

ObjectivesOlfactory dysfunction is a frequent feature of COVID-19. Despite the growing evidence, current knowledge on the subject remains insufficient, so that data obtained with different tools, from multiple centers and in distinct scenarios are welcome. Yet, the predictive value of olfactory dysfunction in terms of the overall prognosis of COVID-19 is unknown. This study aims to evaluate the olfactory function of hospitalized patients with COVID-19 and the impact of the results on their clinical outcomes. MethodsPatients with severe acute respiratory distress syndrome (ARDS) admitted to a university tertiary hospital were recruited and divided into those with ARDS due to COVID-19, and those with ARDS of any other cause. Sociodemographic and clinical data were collected at baseline and the patients had their objective olfactory function evaluated by the Alcohol Sniff Test on admission and during hospital stay. The participants were then followed up until reaching an endpoint: hospital discharge, endotracheal intubation, transfer to the intensive care unit, or death. Patients with COVID-19 were also subgrouped and compared according to their olfactory thresholds and to their overall clinical outcomes. The obtained data was analyzed using R software. Level of significance was set at 0.05. ResultsEighty-two patients were included (of which 58 had COVID-19). 87.93% of the patients with COVID-19 had diminished olfactory dysfunction on admission. The mean length of hospital stay among patients with olfactory dysfunction was greater (7.84 vs 6.14 days) and nine individuals in this subgroup had poor overall outcomes. None of those with normal olfactory function developed critical COVID-19. The mean olfactory function was significantly worse among patients with COVID-19 and poor outcomes (3.97 vs 7.90 cm, P = .023). ConclusionObjective olfactory dysfunction is frequent in ARDS caused by SARS-CoV-2 infection. Patients with longitudinal poorer outcomes present worse olfactory thresholds on admission.

Clinical Features of Olfactory Dysfunction in COVID-19 Patients.

BackgroundThe aim of this study was to evaluate the subjective and objective olfactory function in coronavirus disease 2019 (COVID-19) patients and the effect of olfactory training.MethodsA prospective cohort study was performed in 53 patients who recovered from COVID-19 and visited our tertiary hospital. Subjective olfactory function was evaluated using the 11-point Likert scale (0–10) and the Korean version of the Questionnaire of Olfactory Disorders (QOD). Objective olfactory function was evaluated using Cross-Cultural Smell Identification Test (CC-SIT). Confirmed patients were followed up after 2 months of olfactory training.ResultsThe median, interquartile range (Q1–Q3) score of subjective olfactory function significantly deteriorated in patients with olfactory dysfunction (OD) than in those without OD, even after 3 months of onset (11-point Likert scale, 8, 6–9 vs. 10, 10–10; short version of QOD-negative statements, 19, 16–21 vs. 21, 21–21; QOD-visual analogue scale, 7, 1–13 vs. 0, 0–0; all P < 0.001). However, the objective olfactory function was not significantly different between the two groups (median, interquartile range; 11, 9–11 vs. 11, 9–11, P = 0.887). The percentage of patients with objective hyposmia (CC-SIT ≤ 10) was also not significantly different (47.4% vs. 40%, P = 0.762). OD in COVID-19 was normalized after 2 months of olfactory training in 70% of patients even after 3 months of olfactory impairment.ConclusionAlthough subjective olfactory function is significantly decreased in the OD group, the objective olfactory function was not significantly different. Moreover, olfactory training is effective in COVID-19 patients with OD.

Chemosensory perception and food preferences in colorectal cancer patients undergoing adjuvant chemotherapy

Cancer is one of the major public health problems, with colorectal cancer being one of the most occurring types of cancer. During treatment, patients may experience changes in their dietary intake due to side-effects of treatment, like changes in chemosensory perception, i.e. smell and taste function. This study investigated alterations in chemosensory perception and food preferences in colorectal cancer patients during and after adjuvant chemotherapy. Objective olfactory and gustatory function were measured by the Sniffin' Sticks and the Taste Strips test. Subjective smell and taste perception were determined with a questionnaire, while food preferences were assessed with a computer-based ranking task. To investigate changes during chemotherapy, patients undergoing adjuvant chemotherapy were measured before the start, halfway through (approximately 3 months after the start of adjuvant chemotherapy), and within one month after finishing chemotherapy (longitudinal measurements, n=15 patients). As a comparison group, colorectal cancer patients not undergoing chemotherapy (n=20), underwent the same measurements at similar time points. To measure changes after treatment, chemosensory perception and food preferences of patients who had undergone chemotherapy treatment were measured once, either at 6, 12 or 24 months after diagnosis (cross-sectional measurements; n=20 for all time points). Changes during treatment were assessed using linear mixed model analyses, and changes after treatment were assessed with a one-way ANOVA or a Kruskal Wallis test. Objective olfactory and gustatory function did not differ statistically significantly between any of the groups and at any time point during or after treatment (all p>0.05). In contrast, subjective smell (F(1,84)=8.17, p=0.005) and taste (F(1,99)=4.08, p=0.046) perception were rated statistically significantly lower by patients undergoing chemotherapy than the comparison group during treatment. At 6 months after diagnosis, patients who underwent chemotherapy rated their subjective taste perception significantly lower than patients at 12 and 24 months after treatment (F(2,57)=12.05, p=0.002). Food preferences did not change during treatment, or thereafter (all p>0.05). Preference for protein-rich foods was positively correlated with objective gustatory function (r=0.36, p<0.001), while the preference for low-energy foods showed a negative correlation with objective gustatory function (r=-0.28, p=0.004). Similar to other cancer patient populations, mainly subjective smell and taste perception are affected in colorectal cancer patients undergoing adjuvant chemotherapy. Changes in objective olfactory and gustatory function in relation to chemotherapy were not detected by the tests used in our study nor did food preferences change. However, it should be noted that subjective changes in smell and taste perception can affect subsequent flavor perception and food enjoyment, which might negatively impact eating behavior and nutritional intake.

A Comparison of Olfactory and Sinonasal Outcomes in Endoscopic Pituitary Surgery Performed by a Single Neurosurgeon or a Collaborative Team of Surgeons.

ObjectivesEndoscopic pituitary surgery usually requires a collaboration between neurosurgeons and ENT surgeons to achieve optimal outcomes. However, neurosurgeons occasionally perform these procedures alone without an ENT surgeon. In this study, postoperative sinonasal quality of life and olfactory function were compared in patients who underwent endoscopic pituitary surgery performed by a single neurosurgeon or by a collaborative team of a neurosurgeon and an ENT surgeon.MethodsA retrospective review of prospectively collected data was performed. Patients who underwent endoscopic pituitary surgery for pituitary adenoma from January 2015 to April 2018 were included. The study patients were divided into two groups; patients in group 1 underwent surgery performed by a single neurosurgeon, while patients in group 2 received surgery performed by a collaborative team of surgeons. Olfaction was assessed using a subjective Likert scale, the Cross-Cultural Smell Identification Test (CC-SIT), and the butanol threshold test (BTT). In addition, patients answered the Sino-nasal Outcome Test (SNOT-22) questionnaire regarding sinonasal quality of life before and 3 months after surgery.ResultsThis study included 152 patients (46 patients in group 1 and 106 patients in group 2). Significant differences were not observed between the two groups regarding age, sex, tumor size, or operation time. Although subjective olfaction was not significantly different before and after surgery, group 2 showed significantly better objective olfactory function based on the CC-SIT (8.44±3.00 vs. 9.84±1.40; P=0.012) and BTT (4.67±0.84 vs. 5.02±0.33; P=0.022) scores at 3 months after surgery. The SNOT-22 scores were not statistically significantly different between the two groups (P>0.05).ConclusionIn the present study, better olfactory outcomes were observed in patients who underwent surgery performed by a collaborative team of a neurosurgeon and an ENT surgeon. This result shows the need for collaboration between neurosurgeons and ENT surgeons in endoscopic pituitary surgery.

Post-traumatic brain injury olfactory dysfunction: factors influencing quality of life.

To evaluate if and how post-traumatic brain injury (TBI) olfactory dysfunction affects the quality of life (QoL). In this case-control observational study, 32 adults with post-TBI olfactory dysfunction (cases) were matched with 32 TBI patients with intact olfactory function (controls). All subjects self-rated their olfactory function using the Visual Analogue Scale (VAS). Cases also underwent objective olfactory function assessment with the Sniffin' Sticks test, which generated a Threshold, Discrimination, and Identification (TDI) score. QoL was assessed with the Questionnaire for Olfactory Disorders (QOD). Factors evaluated included age, gender, smoking, TBI severity and duration, lesion localisation, and Disability Rating Scale (DRS) score. Cases had a higher mean QOD score than controls at 26.31 ± 14.37 and 9.44 ± 8.30, respectively (F = 16.426, p < 0.001, η2 = 0.224). The effect size was large (d = 1.07) with an odds ratio of 7.02. The features of QoL most affected were perception of smell changes, adapting to smell changes, and fear of hazardous substance exposure. DRS score and severity of olfactory dysfunction significantly affected QoL (p < 0.05). Post-TBI olfactory dysfunction significantly lowered QoL and increased the likelihood of having a low QoL relative to TBI alone.

Post-traumatic brain injury olfactory dysfunction: Factors influencing quality of life

Introduction/Background Previous studies have explored the quality of life (QoL) in people with olfactory dysfunction from various aetiologies. However, knowledge on QoL in people with post-traumatic brain injury (TBI) olfactory dysfunction is still limited. This study evaluates the impact of post-TBI olfactory dysfunction on QoL and determine factors influencing resultant QoL. Material and method A case-control study conducted in a single centre on 30 TBI adults with olfactory dysfunction; matched by age and gender with 32 TBI controls having intact olfactory function. All 64 adults self-rated their olfactory function using a Visual Analogue Scale (VAS). Sniffin’ Sticks test was used as an objective olfactory function assessment and results measured as TDI (Threshold, Discrimination and Identification) score. QoL was determined by a self-rated questionnaire; Questionnaire for Olfactory Disorders (QOD). Influential factors evaluated include age, gender, employment, level of education, marital status, smoking habit, TBI-related clinical information and Disability Rating Scale (DRS) score. A correlation test between the VAS and natural log TDI was also conducted. Results Mean QOD score of case group was significantly higher than control group (26.31 ± 14.37 vs 9.44 ± 8.30 respectively; P Conclusion Individuals with post-TBI olfactory dysfunction are at higher risk of developing a lower QoL. One of the factors influencing this is the severity of olfactory dysfunction itself.

Olfactory dysfunctions in drug-naïve Parkinson's disease with mild cognitive impairment

BackgroundEvaluation of olfactory function is valuable for the detection of pre-motor state of Parkinson's disease (PD). PD patients have an increased risk of associated dementia and one-third of PD patients have mild cognitive impairment (MCI) at the time of diagnosis. However, the characteristics of olfactory dysfunction in PD-MCI patients are unclear. This study examined the relationship between olfactory dysfunction and cognitive function in drug-naïve PD at the time of diagnosis with the patterns of olfactory function in PD-MCI patients using the Korean version of the Sniffin’ stick test II (KVSS II). MethodsA total of 66 drug-naïve PD patients were enrolled. A neuropsychiatric assessment battery and KVSS II were performed. For the statistical analyses, univariate, multivariable linear regression and Student's t-test were used to determine the relationship between the variables and olfactory function. ResultsOlfactory dysfunction was more prevalent in the PD-MCI group than in the PD-normal cognition (PD-CN) group. Each domains of odor threshold, discrimination, identification and total olfactory score were more impaired in the PD-MCI group than the PD-CN group. Whether cognitive impairment was single or multiple domain was not affected. ConclusionPD-MCI is more likely to be associated with severe olfactory impairment than PD-CN. There may be more extensive neurodegenerative processes affecting olfaction in PD-MCI patients. With further investigation and validation using neuropathological data, an objective olfactory function test could be used as a tool to evaluate disease progression. Further studies with prospective design investigating the prognostic value of olfactory dysfunction in PD-MCI patients are essential.

Understanding the relationship between olfactory-specific quality of life, objective olfactory loss, and patient factors in chronic rhinosinusitis.

Chronic rhinosinusitis (CRS) significantly impacts olfaction. However, the relationship between objective olfaction and patient-reported olfactory-specific quality of life (QOL) is not well understood. Furthermore, objective olfactory testing can be time consuming, so we sought to determine if patient-reported olfactory QOL can be used as screening tool for olfactory dysfunction. Olfactory dysfunction was evaluated in 109 patients with CRS using the Questionnaire of Olfactory Disorders-Negative Statements (QOD-NS) and the Sniffin' Sticks Test, assessing for olfactory threshold, discrimination, identification, and overall composite scores (TDI; composite score of threshold, discrimination, and identification). Regression analysis was performed to correlate olfactory metrics and patient and disease-specific factors with QOD-NS scores. Optimal QOD-NS scores to classify patients based upon objective olfactory function were established. Bivariate and multivariate regression analyses of QOD-NS and CRS-associated comorbidities, objective measures of disease, demographics, and CRS-specific QOL were performed. Non-white race, depression, and worse 22-item Sino-Nasal Outcome Test (SNOT-22) scores correlated with worse QOD-NS scores (p < 0.005). Worse TDI scores correlated with worse QOD-NS scores, and discrimination had the strongest correlation (p < 0.001). Mean ± standard deviation (SD) QOD-NS scores for normosmia, hyposmia, and anosmia were 44 ± 7.2, 35.7 ± 12.8, and 31.6 ± 10.7, respectively. Receiver operating characteristic curve analysis revealed an area under the curve of 0.770 (p < 0.001), and a QOD-NS cutoff of 38.5 to have maximal Youden's index to define normal vs abnormal TDI score. In CRS, QOD-NS correlates with non-white race, depression, SNOT-22, and TDI score, with discrimination having the strongest correlation. The QOD-NS also appears to be a feasible tool for olfaction screening.

Mucous Cytokine Levels in Chronic Rhinosinusitis-Associated Olfactory Loss.

Olfactory loss is a frequent symptom of patients with chronic rhinosinusitis (CRS), but our understanding of how inflammatory cytokines affect olfaction is limited. To examine whether inflammatory cytokines are present in the olfactory cleft and whether they correlate with objective olfaction. In this cross-sectional study, patients with CRS underwent quantitative olfactory testing using the Sniffin Sticks test to calculate a composite threshold discrimination identification (TDI) score from October 21, 2013, to November 12, 2015. Nasal mucus was collected using a sponge placed in the olfactory cleft for 5 minutes, and Cytometric Bead Array was used to measure secreted immunomodulatory products. Correlations between TDI score and secreted mediators were then calculated. Data analysis was performed from October 15, 2015, to December 17, 2015. Composite TDI scores and mean secreted mediator levels in mucus from the olfactory cleft. Thirty-four patients were enrolled (mean [SD] age, 57.3 [15.7] years; female, 21 [61.8%]; white, 26 [76.5]). The TDI scores were lower in patients with CRS with nasal polyps (CRSwNP) than in patients with CRS without nasal polyps (CRSsNP) (difference, 8.7; 95% CI, 2.5-15.0; P = .007). Interleukin (IL) 5 levels were inversely correlated with TDI scores in patients with CRSwNP and those with CRSsNP (mean [SE] β estimate, -46.56 [15.11]; P = .005), whereas IL-6, IL-7, and vascular endothelial growth factor A were positively correlated with TDI scores only in the CRSwNP cohort. Subscale olfactory TDI scores followed similar correlations to composite TDI scores. In this study, inflammatory cytokines were found in mucus collected from the olfactory cleft. Levels of IL-5, in addition to other cytokines, were associated with objective olfactory function. Further inquiry is needed to establish the source of mucous cytokines and establish whether they play a causal role in olfactory loss.

Twice-daily application of topical corticosteroids with a squirt system for patients with steroid-responsive olfactory impairment

Conclusion: Twice-daily topical corticosteroid treatment using a squirt system was beneficial in maintaining improvements in olfactory dysfunction which had been achieved by oral steroid treatment.Objectives: Some patients suffering from olfactory dysfunction respond well to corticosteroids. However, maintaining these improvements is challenging. The aim of this study was to evaluate the maintenance effect of twice-daily topical steroid treatment using a squirt system.Methods: Twenty-two anosmic patients with an increase in odor threshold, discrimination, and identification (TDI) scores in Sniffin’ Sticks tests by more than six points after 1-week of oral steroid treatment were enrolled. All the patients used a squirt system to apply topical corticosteroids and were followed up at 1, 3, and 6 months.Results: Nineteen, 16, and 10 patients were followed-up at 1, 3, and 6 months after treatment, respectively. All the patients had significant visual analog scale scores improvements compared to pre-treatment. The mean improvements in TDI scores were 9.80 (p < 0.001), 11.58 (p = 0.001), and 13.87 (p = 0.005) after 1, 3, and 6 months of treatment, respectively. The self-rated and objective olfactory function scores were maintained with steroid squirt therapy without significant decline, even in the patients who were followed up for 6 months.