Olfactory Test Research Articles

Dual blockade of IL-4 and IL-13 with dupilumab ameliorates sensorineural olfactory dysfunction in mice with eosinophilic sinonasal inflammation.

Dupilumab, an antibody that binds IL-4Rα and inhibits IL-4 and IL-13 signals, has demonstrated efficacy in chronic rhinosinusitis with nasal polyps (CRSwNP) primarily characterized by type 2 inflammation. Current evidence suggests that the rate of improvement in olfactory dysfunction with dupilumab exceeds that of nasal polyp reduction, yet the underlying mechanism remains undisclosed. We hypothesize that dupilumab may initially ameliorate sensorineural olfactory dysfunction. Male BALB/c mice were intranasally administered ovalbumin and Aspergillus protease for 12 weeks to induce eosinophilic sinonasal inflammation. Dupilumab treatment was also administered. The mice underwent histological assessment, olfactory behavioural test, and gene expression profiling to identify neuroinflammatory markers within the olfactory bulb. Dupilumab treatment resulted in a reduction in the number of mucosal protruding lesions, as well as decreased infiltration of eosinophils and neutrophils, along with a decrease in olfactory sensory neuron injury. Furthermore, there was a downregulation in the mRNA expression related to microglia activation and neuroinflammation in the olfactory bulb. Dupilumab improves the sensorineural pattern of olfactory dysfunction in mice, potentially explaining why olfaction improves more rapidly than polyp reduction in patients with CRSwNP.

Intracerebroventricular injection of α-synuclein preformed fibrils do not induce motor and olfactory impairment in C57BL/6 mice

IntroductionAlpha-synuclein (αSyn) is believed to play a central role in the pathogenesis of Parkinson’s disease (PD). Cerebrospinal fluid (CSF) total αSyn were significantly lower in PD patients, whereas the aggregates were higher, and this phenomenon was further exacerbated with longer disease duration. However, whether CSF αSyn can be the cause and/or a consequence in PD is not fully elucidated. MethodWe administered 2 ng or 200 ng αSyn preformed fibrils (PFFs) by intracerebroventricular injection for consecutive 7 days in C57BL/6 mice. The olfactory function was assessed by the olfactory discrimination test and buried food-seeking test. The locomotor function was assessed by the rotarod test, pole test, open field test and CatWalk gait analysis. Phosphorylated αSyn at serine 129 was detected by the immunohistochemistry staining. Iron levels was determined by Perl’s-diaminobenzidine iron staining and synchrotron-based X-ray fluorescence. ResultsThe mice did not exhibit any diffuse synucleinopathy in the brain for up to 30 weeks, although αSyn PFFs induced aggregation in SH-SY5Y cells and in the substantia nigra and striatum of mice with stereotactic injection. No impairment of motor behaviors or olfactory functions were observed, although there was a temporary motor enhancement at 1 week. We then demonstrated iron levels were comparable in certain brain regions, suggesting there was no iron deposition/redistribution occurred. ConclusionThe intraventricular injection of αSyn PFFs does not induce synucleinopathy or behavioral symptoms. These findings have implications that CSF αSyn aggregates may not necessarily contribute to the onset or progression in PD.

Subjective methods for olfactory testing – a review of selected diagnostic tools

Subjective methods for olfactory testing – a review of selected diagnostic tools

Olfactory event-related potentials (OERPs) and trigeminal event-related potentials (TERPs) in subjects after Covid-19 infection: single-center prospective study.

Olfactory dysfunction (OD) is a common symptom associated with Covid-19. During the Covid-19 pandemic, the importance of psychophysical olfactory tests and electrophysiological olfactory assessment increased. The purpose of the study was to analyze the psychophysical olfactory tests and the post-covid curves of olfactory event-related potentials (OERPs) and trigeminal event-related potentials (TERPs). The prospective study included 98 subjects (62 females / 36 males). The average age was 42 years (range 21-84 years). Group I (n = 77) contained participants who had been infected with Covid-19. They were enrolled in the study at least 1 year after Covid-19. Group II (n = 21) was the healthy normosmic control group. In Group I, the OERPs of 18% participants were absent. Patients in Group I were statistically more likely to have an absence of OERPs (p = 0.036) than subjects in Group II. We did not detect a statistical difference in amplitudes and latencies of the OERPs between Group I and Group II. In Group I, N1 latency of the TERPs was significantly longer (p = 0.002) than in Group II. The amplitude of the N1-P2 interval of the TERPs was significantly lower (p = 0.025) in Group I than in Group II. According to the psychophysical Sniffin stick identification test, hyposmia was detected in 39% in Group I versus 0% in the control Group II. OD is a common post-covid symptom. The presence of OERPs is a significant prognostic factor for olfactory function after Covid 19. We detected a lower percentage of absence of OERPs after Covid-19 compared to the previously published studies of post-viral OD and post-infectious OD. For TERPs, we detected a longer N1 latency and a lower amplitude for the N1-P2 interval after Covid-19. OERPs and TERPs can be considered valid biomarkers to evaluate the progress of post-covid OD.

The digital scent device 20: an automated, self-administered odor identification test.

Assessing olfactory function is highly significant in clinical practice, particularly in the context of the recent COVID-19 pandemic. Recent approaches in this field emphasize the importance of reducing the time and cost devoted to olfactory testing procedures. Hence, the aim of the present study was to examine the reliability and basic characteristics of Digital Scent Device 20 (DSD-20), an innovative olfactory test consisting of 20 "universal odors", in a European population. A total of 88 participants (mean age = 45.1, SD = 20.3) volunteered for the study. The sample consisted of 37 normosmic controls and 51 dysosmic patients. The correlation between DSD-20 and the total score in Sniffin' Sticks was high (TDI; R = .80, p < .001), and the test correlated with the individual components of the Sniffin' Sticks test. Furthermore, the correlation coefficient between DSD-20 test and retest was very high (R = .88, p < .001), which was additionally confirmed by a Bland-Altman plot. Essential characteristics of the DSD-20 are its simplicity in self-administration, speed of application, portability, and the fact that it can be reused. Overall, the present study confirms previous notions on DSD-20 by demonstrating its high reliability and usefulness in separating patients with hyposmia/anosmia and normosmic controls.

Kallmann Syndrome - causes, symptoms, treatment - review of literature

Background: Kallmann syndrome is a rare congenital disorder characterized by hypogonadotropic hypogonadism and anosmia or hyposmia. KS results from abnormalities in the migration of GnRH neurons from the nasal placode to the hypothalamus. The prevalence of KS is estimated to be approximately 1:30,000 in males and 1:125,000 in females. KS manifests at various stages of life, ranging from the neonatal period through adolescence to adulthood. In the neonatal period, boys may present with cryptorchidism and micropenis, while symptoms in girls may be less apparent. During adolescence, patients often experience the absence or incomplete development of secondary sexual characteristics. In adulthood, KS often leads to infertility, cardiovascular issues, and neurological symptoms. Diagnostic methods include olfactory tests and hormonal analysis, assessing levels of gonadotropins, testosterone, LH and FSH. MRI can reveal structural abnormalities in the olfactory system. Aim of study: The goal of this article was to gather information about the Kallmann syndrome, focusing on its epidemiology, etiology, characteristic features, and treatment strategies. Materials and Methods: A review of the literature available in the “PubMed”, Google Scholar and Medline databases. The search was performed by using following keywords: “kallmann syndrome”, “anosmia”, hypogonadotropic hypogonadism”. Results and conclusions: Kallmann syndrome is a complex condition that necessitates a multifaceted approach to diagnosis and treatment. Early identification of the disorder is crucial, allowing for the timely initiation of appropriate hormonal therapy and psychological support, which significantly improves the quality of life for patients. Further research into the genetic and neurobiological mechanisms of KS is essential for the development of more effective therapeutic and diagnostic methods.

COGMED: a database for Chinese olfactory and gustatory metaphor

In recent years, metaphors have been used to understand how abstract concepts are processed, and developing metaphorical database can aid this research agenda. Accordingly, the present study aimed to produce a broad Chinese olfactory and gustatory database of metaphors. Expressions for two sensory types (olfaction/gustation) were compiled and classified according to two conditions (metaphorical/literal) and three parts of speech (adjective/noun/verb). To test the validity of this database, we enrolled 199 participants, of whom 97 completed the olfactory test (319 items) and 102 completed the gustatory test (352 items). Each item was rated on seven dimensions: familiarity, meaningfulness, figurativeness, valence, difficulty, imageability, and naturalness. Descriptive statistics and reliability and correlation analyses were conducted for the items under the two sensory types, two conditions, three parts of speech, and seven dimensions mentioned above. The results showed high internal consistency and split-half reliability for the participants’ scores; the correlations between the seven dimensions resembled those of previous studies. We concluded by suggesting several ways the database might be applied to aid future research efforts.

Effects of Mucuna pruriens (L.) DC. and Levodopa in Improving Parkinson's Disease in Rotenone Intoxicated Mice.

Parkinson's disease (PD) is the second leading neurodegenerative disease after Alzheimer's disease. Mucuna pruriens (L.) DC. (MP) is a plant that contains Levodopa (L-DOPA) and has been known to improve the symptoms of PD. In this preliminary study, we investigated the anti-parkinsonian potential of MP to compare the effects of L-DOPA. We first developed an in vivo model of the PD in C57BL/6 male mice using rotenone. A total of twelve mice were used for this experiment. Nine mice were injected with rotenone (28 mg/kg) daily for 28 days. The mice experiments were performed to validate the effectiveness of MP to treat PD. Synthetic L-DOPA in a ratio of 1:20 with MP was used as MP contains 5% L-DOPA by weight in it. MP and L-DOPA were injected for 19 days on a daily basis. Cognitive function was evaluated using beam balance and olfactory tests. Serum analysis was performed using serum enzyme-linked immunosorbent assay (ELISA) analysis test. IL-12, IL-6, and TGF-β 1 were evaluated to validate the PD inducement and treatment. The levels of IL-12, IL-6, and TGF-β1 (p < 0.0001) in the PD mice group were significantly higher than those in the control group. The PD mice also showed higher latencies in beam balance and olfactory tests (p < 0.0001) compared to the control group. Both MP and L-DOPA-treated groups showed alleviation in latencies in beam balance and olfactory tests and decreased neuroinflammation in ELISA analysis (p < 0.001). The results treated by MP and L-DOPA showed insignificant differences in their values (p > 0.05). This proved that the MP and L-DOPA had similar effects in improving the symptoms of PD when used in the ratio of 1:20. Furthermore, both MP and L-DOPA reduced the level of IL-6 and TGF-β1 in this study. It may be inferred that a reduction in the level of IL-6 and TGF-β1 eventually leads to a reduction in the Th17 cells. The pathogenic Th17 is thought to be present in virtually all chronic inflammatory disorders. This can be an interesting area of research in further understanding the immunological effect of MP in ameliorating PD symptoms.

Neurological soft signs and olfactory dysfunction in patients with borderline personality disorder

BackgroundBorderline personality disorder (BPD) is a serious disorder with a lifetime prevalence of 2.7–5.9% and is thought to correlate with altered neuroplasticity. The aim of the present study is to investigate possible associations of BPD (−severity) and alterations in neurological soft signs (NSS) and olfactory function. MethodsFor the monocentric observational study, 39 female subjects with a BPD diagnosis and 19 female healthy control subjects were recruited. The groups were matched by age. Olfactory functions were examined using Sniffin’ Sticks. NSS were assessed by a standardized test with 50 items. ResultsBPD subjects have higher NSS scores in group comparison. By contrast, there are no alterations in the total score of olfactory function, while the BPD subjects scored higher in smell identification. Within the BPD group, the total NSS score was discovered to have a negative correlation with olfactory function. BPD subjects taking antipsychotics show more NSS than those without. We found no significant influence of posttraumatic stress disorder on the NSS or olfactory function. The BPD-severity correlates with NSS. LimitationsDue to the cross-sectional design, we did not have a follow up examination. The sample size was small, and all patients had psychiatric comorbidities. Additionally, we did not perform MRI to connect our findings with possible structural abnormalities. ConclusionsOur study confirmed altered NSS in BPD patients, whereas no impairment in the olfactory function was found. Further research is required to establish NSS and smell tests as clinical screening tools in BPD patients and to uncover the disorder's impact on neuroplasticity.

Association of olfactory and cognitive function test scores with hippocampal and amygdalar grey matter volume: a cross-sectional study

Few population-based studies including younger adults have examined the potential of olfactory function tests to capture the degree of atrophy in memory-associated brain regions, which cannot be adequately explained by cognitive function tests screening for cognitive impairment. This population-based study investigated associations between high-resolution olfactory test data with few odours and grey matter volumes (GMVs) of the left and right hippocampi, amygdala, parahippocampi, and olfactory cortex, while accounting for differences in cognitive decline, in 1444 participants (aged 31–91 years). Regression analyses included intracranial volume (ICV)-normalised GMVs of eight memory-related regions as objective variables and age, sex, education duration, smoking history, olfaction test score, and the Montreal Cognitive Assessment-Japanese version (MoCA-J) score as explanatory variables. Significant relationships were found between olfactory test scores and ICV-normalised GMVs of the left and right hippocampi and left amygdala (p = 0.020, 0.024, and 0.028, respectively), adjusting for the MoCA-J score. The olfactory test score was significantly related to the right amygdalar GMV (p = 0.020) in older adults (age ≥ 65 years). These associations remained significant after applying Benjamini–Hochberg multiple testing correction (false discovery rate < 0.1). Therefore, olfactory and cognitive function tests may efficiently capture the degree of atrophy in the hippocampi and amygdala, especially in older adults.

Altered functional connectivity of primary olfactory cortex-hippocampus-frontal cortex in subjective cognitive decline during odor stimulation.

Subjective cognitive decline (SCD) is a high-risk population in the preclinical stage of Alzheimer's disease (AD), and olfactory dysfunction is a risk factor for dementia progression. The present study aimed to explore the patterns of functional connectivity (FC) changes in the olfactory neural circuits during olfactory stimulation in SCD subjects. A total of 56 SCD subjects and 56 normal controls (NCs) were included. All subjects were assessed with a cognitive scale, an olfactory behavior test, and olfactory task-based functional magnetic resonance imaging scanning. The FC differences in olfactory neural circuits between the two groups were analyzed by the generalized psychophysiological interaction. Additionally, we calculated and compared the activation of brain regions within the olfactory neural circuits during odor stimulation, the volumetric differences in brain regions showing FC differences between groups, and the correlations between neuroimaging indicators and olfactory behavioral and cognitive scale scores. During odor stimulation, the FC between the bilateral primary olfactory cortex (bPOC) and the right hippocampus in the SCD group was significantly reduced; while the FC between the right hippocampus and the right frontal cortex was significantly increased in the SCD group. The bPOC of all subjects showed significant activation, but no significant difference in activation between groups was found. No significant differences were observed in the volume of the brain regions within the olfactory neural circuits or in olfactory behavior between groups. The volume of the bPOC and right frontal cortex was significantly positively correlated with olfactory identification, and the volume of the right frontal cortex and right hippocampus was significantly correlated with cognitive functions. Furthermore, a significant correlation between the activation of bPOC and the olfactory threshold was found in the whole cohort. These results suggested that while the structure of the olfactory neural circuits and olfactory behavior in SCD subjects remained stable, there were significant changes observed in the FC of the olfactory neural circuits (specifically, the POC-hippocampus-frontal cortex neural circuits) during odor stimulation. These findings highlight the potential of FC alterations as sensitive imaging markers for identifying high-risk individuals in the early stage of AD.

Subjective and objective effects of radioiodine therapy on the sense of smell.

Evaluating the impact of radioiodine therapy (RIT) on olfactory function in thyroid cancer patients through quantitative and qualitative olfactory tests. In this cohort study, patients with thyroid cancer were included. Demographic, clinical, and laboratory data were collected. To subjectively evaluate the olfactory changes aftter RIT, the Visual Analog Scale (VAS), Self-Reported Mini-Olfactory Questionnaire (self-MOQ), and the University of Washington Quality of Life Questionnaire (UW-QOL) were assessed. Out of UW-QOL questions those related to saliva, taste, and overall health condition were analysed. For objective assessment, patients underwent both the Butanol Threshold Test (BTT) and the a version of Smell Identification Test (SIT). Patients were assessed before, one month, and six months after RIT. Ninety eight patients were included (Male = 17). A statistically significant decrement was observed in olfaction based on the VAS, between the baseline and one (pvalue = 0.015) and six months (pvalue = 0.031) of follow-up. Additionally, saliva (pvalue = 0.001), taste (pvalue = 0.000), and overall health condition (pvalue = 0.010) significantly decreased one-month after RIT. The measures were not different between the baseline and 6-month follow up and the improvement of index of taste was significant from 1-month to 6-months follow ups (pvalue = 0.000). However, none of the objective tests (the BTT and the SIT) indicated a significant decline in olfaction during the follow up. A subjective RIT related decrease in smell function, taste, and saliva production was documented without any objective olfactory dysfunction.

Assessing parosmia patients: a study on the evaluation method using a self-administered odor questionnaire for parosmia.

Parosmia symptoms are difficult to quantify due to their heterogeneity among patients, and thus a clinical challenge. This study aimed to assess parosmia with Self-Administered Odor Questionnaire for Parosmia (SAOQ-P), a modification of the widely used SAOQ in Japan. The primary objective was to assess the effectiveness of SAOQ-P in identifying parosmia symptoms and its potential integration into the clinical assessment process. The study also explored traditional olfactory test differences between patients with and without parosmia. Patients at Jikei Smell Clinic that presented between May 2022 and November 2022 were recruited and administered the SAOQ-P, which had an added question about changes in the perception of 20 daily odors compared to the original SAOQ. Traditional olfactory tests utilized T&T olfactometry and Open Essence. Of 279 patients, 81 had parosmia, while 198 did not exhibit parosmic symptoms. Parosmia prevalence was influenced by the cause of olfactory dysfunction, with post-infectious and post-COVID-19 patients showing higher parosmia rates. Among parosmia patients, 87% reported changes in their perception of at least one odor assessed by SAOQ-P, with coffee, stool, and perfume most commonly affected. Traditional olfactory tests showed no significant differences between parosmia and non-parosmia groups. The number of odors causing parosmia was negatively correlated with age. SAOQ-P offers a promising approach to assess and quantify parosmia symptoms, seamlessly integrating into clinical assessments. SAOQ-P identified parosmia in 87% of patients and revealed insights into triggering factors. Traditional olfactory tests' limitations underscore the need for more accurate, patient-centric diagnostic approaches for parosmia.

Insufficient Diagnostic Value of Serum Galactomannan and (1,3)-β-D-Glucan in Paranasal Sinus Fungus Balls

Background and Objectives: The serum galactomannan test (GM test) and the (1,3)-β-D-glucan test (G test) are utilized in diagnosing invasive fungal sinusitis. However, their effectiveness in detecting paranasal sinus fungus balls (FBs) has not been established. This study aimed to explore their diagnostic value in patients with FBs.Methods: We retrospectively reviewed the medical records of 105 patients (42 with FBs and 63 with chronic rhinosinusitis [CRS]) who underwent serum GM and G tests between June 2020 and May 2021. Olfactory test results and demographics were also analyzed.Results: There were 42 FB patients (10 men, 32 women) and 63 CRS patients (27 men, 36 women). The positivity rates for serum GM (7.1% in the FB group vs. 3.2% in the CRS group, p=0.640) and G test (9.5% in the FB group vs. 11.1% in the CRS group, p=0.482) did not differ significantly between groups. The sensitivities of the GM and G tests were 7.1% and 9.5%, respectively, and their specificities were 96.8% and 88.9%, respectively. The positive predictive values were 60.0% for the GM test and 36.3% for the G test, and the negative predictive values were 61.0% for the GM test and 59.6% for the G test.Conclusion: Serum GM and G tests demonstrated low sensitivity and high specificity, indicating limited effectiveness in differentiating between patients with FBs and those with CRS. Histological examination remains the gold standard for the definitive diagnosis of FBs.

Smell and Taste Alterations in Patients Receiving Curative or Palliative Chemotherapy-The CONKO 021-ChemTox Trial.

Previous data regarding chemotherapy-induced olfactory and gustatory dysfunction (CIOGD) are heterogeneous due to inconsistent study designs and small numbers of patients. To provide consistent, reliable data, we conducted a cohort study using standardized testing. Patients diagnosed with lymphoma, leukemia, or gastrointestinal malignancies were examined up to five times (T1 to T5), beginning prior to chemotherapy. We examined patients receiving temporary treatment up to 12 months post-therapy. Clinical assessment included extensive questionnaires, psychophysical tests of olfactory and gustatory function, and measurement of peripheral neuropathy. Statistical analysis included non-parametric tests to evaluate the longitudinal development of CIOGD. Our data (n = 108) showed a significant decline in olfactory and gustatory testing during chemotherapy (p-values < 0.001). CIOGD appeared stronger among patients above 60 years, while sex did not matter significantly. However, we identified distinct associations between CIOGD and reported anorexia as well as with higher neuropathy scores. Self-assessment appeared less sensitive to chemosensory dysfunction than psychophysical testing. Post-therapy, olfactory and gustatory function regenerated, though baseline levels were not attained within 6 to 12 months. In conclusion, our data highlight the wide prevalence and slow recovery of CIOGD. Understanding CIOGD as a potential neurotoxic effect may disclose new therapeutic prospects.

Self-Reported Hypersensitivity to Smells: Objective Evidence for Hyposmia, not Hyperosmia.

To compare, using state-of-the-art psychophysical tests, the olfactory function of patients complaining and not complaining of olfactory hypersensitivity. Retrospective cross-sectional. The Smell and Taste Center at the University of Pennsylvania. University of Pennsylvania Smell Identification Test (UPSIT) scores were obtained from 148 patients complaining of hyperosmia and 494 patients with no such complaints; detection threshold test scores were obtained from 77 and 483 patients of these respective groups. The effects of subject group, age, and sex on the test scores were assessed using analyses of variance. Categorical variables were evaluated by χ2. Responses to items within a detailed intake questionnaire, for example, the Beck Depression Inventory (BDI-II), were also evaluated. Unexpectedly, those complaining of hyperosmia had lower olfactory test scores than those with no such complaints (respective UPSIT means [95% confidence interval [CIs]] = 27.86 (26.85, 28.87) and 32.19 (31.67, 32.71); P < .001; respective threshold means (log vol/vol) = -4.49 (-4.89, -4.09) and -5.22 (-5.36, -5.06); P < .001). Remarkably, 70.95% of the self-identified hyperosmics exhibited mild to severe microsmia. The hyposmia complainers also exhibited elevated BDI scores (11.02 [9.53, 12.51] vs7.58[6.80, 8.34]). When objectively tested, many patients who complain of hypersensitivity to odors are actually less sensitive to them. The basis of this phenomenon is unclear. It could reflect the presence of emotionally disturbing altered smell sensations, or one or more comorbidities, such as hypochondria or osmophobia. These findings point to the importance of objective testing of persons with complaints of chemosensory dysfunction and reiterate the inaccuracy of self-reports.

Pregnant women exhibit decreased trigeminal sensitivity.

Chemosensory function in pregnant women is far from being fully understood due to the lack of data and inconsistencies between the results of self-reports and objective studies. In the present study in pregnant and non-pregnant women (npregnant=14, nnon-pregnant=13), we measured EEG-derived electrophysiological response measures supported by psychophysical olfactory and trigeminal tests. Results indicate that the olfactory event-related potential amplitudes or latencies of the P1, N1, and P2 components remain unchanged in pregnant women. In accordance with these findings, no difference was observed between pregnant and non-pregnant women in psychophysical olfactory tests. However, pregnant women displayed a lower degree of sensitivity to trigeminal stimuli compared to non-pregnant controls, which was also reflected in the electrophysiological responses to trigeminal stimuli. Counterintuitive as they may seem, our findings demonstrate a "flattening" of chemosomatosensory responses. Psychological processes occurring during pregnancy, such as changes in socioemotional perception of odors resulting from the diminished stress response, may provide a background to these results. Overall, the present results indicate the absence of major differences between non-pregnant and pregnant women in terms of measured olfactory function though chemosomatosensory function of the pregnant women appears to be decreased.

Olfactory dysfunction in patients with type 2 diabetes mellitus.

diabetic complications and olfactory dysfunction (OD) in patients with type 2 diabetes mellitus (T2DM) seem related. This study aims to evaluate the prevalence of OD in T2DM patients and to analyze its relationship with diabetic complications. 130 T2DM patients and 100 comparable controls were enrolled. Olfaction was evaluated using the Extended Smell Test (TDI) and the Italian brief Questionnaire of Olfactory Disorders â€" Brief-IT-QOD. T2DM patients were divided into: "Group 1" patients with no complications, and "Group 2" patients with at least one diabetic complication. Non-parametric tests were used. Machine learning algorithms were applied to explore which variables were most important in predicting the presence of OD in T2DM. The prevalence of OD was significantly higher in Group 2 than in controls (71.4% vs 30%) and in Group 1 (71.4% vs 43.3%). However, when comparing the TDI scores between Group 1 and 2 the only significant difference was found for the discrimination scale and not for the identification and threshold scales. Brief-IT-QOD scores were significantly higher in Group 2 than in controls. The Random Forest and variable importance algorithms highlighted the relevance of LDL, glycated hemoglobin, type of complication (macrovascular) and age in determining OD in T2DM. The last three variables were included in a nomogram for the prediction of OD risk in T2DM. T2DM patients with diabetic complications are more frequently affected by OD. Poor glycemic control, LDL values, age and presence of macrovascular complications are the more important factors in determining OD in T2DM patients.

Neurofilament light chain is associated with olfactory dysfunction in US adults: findings from National Health and Nutrition Examination Survey.

Many individuals who have olfactory dysfunction are not aware of their impairment, which results in delayed detection of potentially hazardous situations. Simple and accurate methods for objectively assessing olfactory function are needed. In this study, we aim to investigate the utility of serum neurofilament light chain (NfL) levels as an indicator of olfactory dysfunction. We analysed data on 1290 participants aged 40 years and older, who had valid data on olfaction and NfL level from the National Health and Nutrition Examination Survey 2013â€"2014. Multivariable modeling was used to investigate the relationship between olfactory dysfunction and NfL. Among 1290 participants, 174 participants had olfactory dysfunction based on the results of the NHANES Pocket Smell Test. In ordinal regression models, objective olfactory dysfunction was associated with NfL. After adjusting for age, sex, race/ethnicity, diabetes, smoking, olfaction-related medical history, Parkinson's disease and Alzheimer’s disease, the association remained significant. In logistic regression models, compared to participants with lower levels of NfL in the first tertile, those in the second and third tertiles had higher odds of objective olfactory dysfunction. There was no association between self-reported olfactory dysfunction and NfL tertiles. A strong association between objective olfactory dysfunction and serum NfL level was observed. NfL, independent of age, is a reliable marker indicating the development of olfactory dysfunction. The measurement of serum NfL level provides valuable support for assessment of olfactory dysfunction in clinical practice.

COVID-19 olfactory dysfunction: associations between coping, quality of life, and mental health.

Persistent olfactory dysfunction (OD) is a common symptom following SARS-CoV-2 infection that can greatly impact quality of life (QoL). Because coping strategies have been shown to moderate the effect of disease symptoms on functional and affective outcomes, this study aims to determine whether specific coping strategies are associated with and moderate QoL outcomes. Participants with prior SARS-CoV-2 infection underwent psychophysical olfactory testing with Sniffin’ Sticks and completed questionnaires to elicit subjective olfactory function, coping strategies, olfactory-specific QoL, general QoL, and mental health. There were 93 participants included in the study. Olfactory specific QoL scores were significantly worse among individuals with subjective and psychophysically measured OD compared to those with subjective and psychophysically confirmed normosmia. Olfactory-specific QoL, general QoL, and anxiety symptom scores were positively correlated with avoidant and disengagement coping among individuals with subjective and psychophysically measured OD. Depression symptom scores were positively correlated with avoidant and disengagement coping and negatively correlated with approach and engagement coping. There were no significant moderating effects on the association between olfactory performance and QoL or mental health screening assessment. Approach and engagement coping mechanisms are associated with improved depression, whereas avoidant and disengagement coping tracks with worse QoL and mental health screening assessment, offering an opportunity to counsel patients accordingly.