Brief Smell Identification Test Research Articles

Topical platelet-rich plasma as a possible treatment for olfactory dysfunction-A randomized controlled trial.

Olfactory dysfunction (OD) affects many survivors of COVID-19. Prior studies have investigated the use of platelet-rich plasma (PRP) injections for OD. We describe the first randomized controlled trial investigating topical PRP for OD treatment and contribute to existing literature illustrating PRP as an emerging therapeutic. This is a single-blinded, randomized controlled trial conducted from July 2022 to December 2023. Adult patients with OD ≥6 months secondary to COVID-19 with Brief Smell Identification Test (BSIT) scores of ≤8/12 or SCENTinel odor intensity of ≤40/100 were included. Patients were randomized to three, monthly PRP or placebo-impregnated Surgifoam treatments into bilateral olfactory clefts. The BSIT, SCENTinel, and Questionnaire of Olfactory Disorders-Negative Statements (QOD-NS) were completed monthly through month 12. Of 104 patients screened, 83 participated. No significant differences in age, OD duration, BSIT, SCENTinel, or QOD-NS scores were found between PRP (n=42) and placebo (n=41) patients at baseline. PRP patients experienced a statistically significant increase in BSIT scores from baseline at months 5‒9, 11, and 12, while placebo patients did not (p<0.05). However, total BSIT scores were similar between the two groups throughout the study. Neither the SCENTinel odor intensity scores nor the change from baseline were significantly different between the treatment groups. At month 12, PRP patients experienced minor improvement in OD-related quality-of-life compared with placebo. This study is the first to describe topical PRP as a safe, experimental treatment for OD in humans. PRP may impact odor identification in post-COVID-19 OD patients, although the lack of difference in total BSIT scores highlights the need for further study.

Diagnostic value of vietnamese smell identification test in Parkinson's disease

IntroductionThe Vietnamese Smell Identification Test (VSIT) has been validated in determining olfactory dysfunction in the Vietnamese population; however, its value in diagnosing Parkinson's disease (PD) has not been established. MethodsThis case-control study was conducted at University Medical Center HCMC, Ho Chi Minh City, Vietnam. The study sample included non-demented PD patients and healthy controls (HC) who were gender- and age-matched. All participants were evaluated for odor identification ability using the VSIT and the Brief Smell Identification Test (BSIT). ResultsA total of 218 HCs and 218 PD patients participated in the study. The median VSIT and BSIT scores were significantly different between PD and HC groups (VSIT, 5 (3) vs. 9 (2), P < 0.0001; BSIT, 6 (3) vs 8 (2), P < 0.0001). Using the cut-off of <8 for correct answers out of 12 odorants, the VSIT had higher sensitivity (84.4%) and specificity (86.2%) than those of the BSIT (sensitivity of 81.7% and specificity of 69.3%) for the diagnosis of PD. The area under the curve (AUC) value was greater for the VSIT than for the BSIT (0.909 vs 0.818). The smell identification scores were not significantly correlated with disease duration, disease severity, or LEDD (all p > 0.05). ConclusionThe VSIT can be a valuable ancillary tool for supporting the diagnosis of PD in Vietnam. Olfactory dysfunction in PD was unrelated to the disease duration and severity. The VSIT can be applied to improve the accuracy of clinical PD diagnosis.

Deep Sleep, Olfactory Loss, and Cognition in Early-stage Parkinson's Disease: Pilot Study Results.

Individuals with Parkinson's disease (PD) have a higher risk of developing dementia compared to age-matched controls. Rapid eye movement sleep behavior disorder (RBD) and hyposmia can influence symptoms severity. We report associations between polysomnography-assessed sleep architecture, olfactory identification, and cognition. Twenty adults with early-stage PD (mean age 69 ± 7.9; 25% female) completed cognitive assessments, the Brief Smell Identification Test (BSIT), and overnight in-clinic polysomnography. A global cognitive score was derived from principal component analysis. Linear regression models examined associations between sleep variables, BSIT performance, and cognition. Cognitive performance was compared between participants with and without RBD. Deep sleep attainment (β ± SE: 1.18 ± 0.45, p = .02) and olfactory identification (0.37 ± 0.12, p = .01) were associated with better cognition. Light sleep, REM sleep, arousal index, and sleep efficiency were not (all p > .05). Participants with RBD had significantly worse cognition (t-test = -1.06 ± 0.44, p = .03) compared to those without RBD; none entered deep sleep. Deep sleep attainment was associated with better memory (1.20 ± 0.41, p = .01) and executive function (2.94 ± 1.13, p = .02); sleep efficiency was associated with executive function (0.05 ± 0.02, p = .02). These findings suggest interrelationships between lack of deep sleep, hyposmia, and poorer cognition in PD, particularly among individuals with RBD. Assessing these markers together may improve early identification of high-risk individuals and access to interventions.

Covid‐19 may have a detrimental impact on sensorimotor function

AbstractBackgroundThe long‐term impact of COVID‐19 on global health is still unknown. Sensorimotor biomarkers may be promising indicators of lasting effects of COVID‐19. Although normal aging may cause changes in sensorimotor function, more severe changes may indicate the subsequent impacts of COVID‐19 on brain health. The objective of this study was to investigate the association between COVID‐19 and sensorimotor markers (grip strength, gait, and smell) in the 7T neuroCOVID consortium, which is comprised of 5 sites: The University of Texas Health Science Center at San Antonio, Houston Methodist Research Institute, The University of Pittsburgh, Massachusetts General Hospital, and Nottingham University (UK).MethodsWe studied 101 adult participants (mean age 60.9 ± 8.5 years, range 45‐80 years, 51% women) without prior cognitive impairment or cerebrovascular disease from the 7T consortium across 3 US and 1 UK sites. The sample included 77 COVID‐19 survivors and 24 healthy controls. Sensorimotor markers were measured for olfaction (n = 59; 12‐item Brief Smell Identification Test (B‐SIT)), grip strength (n = 97; measured using a hand dynamometer), and Gait (n = 101; 4‐meter normal walk time and n = 99; 4‐meter fast‐paced walk time). To assess the association between COVID‐19 and sensorimotor outcomes, we performed a series of linear regression models adjusting for age, sex, site, and handedness (grip strength only). Statistical significance was set at a 5% level.ResultsAs compared to healthy controls, COVID‐19 survivors, on average had a significantly reduced hand grip in the right hand (β ± standard error: ‐0.18 ± 0.07, p = 0.006). We also observed associations with reduced gait speed. COVID‐19 survivors, on average, had a slower walk time in both normal (0.17 ± 0.06, p = 0.004) and fast‐paced (0.04 ± 0.02, p = 0.022) as compared to healthy controls. We did not observe any statistical associations between COVID‐19 survivors and left‐hand grip strength or B‐SIT.ConclusionsThese results highlight that Covid‐19 infection may have a detrimental impact on sensorimotor function. Additional analysis with a larger sample size are ongoing, which will allow us to further assess the effect of infection severity. Future studies will look to evaluate the association between sensorimotor markers, cognition, and ultra‐high field 7T MRI‐based imaging markers. Funding:R56AG074467P30AG066546

Co‐morbidity of sensory loss (hearing, vision, olfaction) in persons with or at risk for dementia: Implications for brain structure and function

AbstractBackgroundHearing, vision, and olfactory loss have each independently been associated with cognitive decline and increased risk for dementia. Research has examined their individual relationships with brain structure and function, but these predictors have not been examined together in older adults who vary along a spectrum of risk for dementia. We examined groups who range from relatively low risk (those with normal cognition and no cognitive complaints (NC)), to those with higher risk, namely individuals with subjective reports of cognitive decline (SCD) but normal cognition and those with mild cognitive impairment (MCI).MethodWe used data from the Comprehensive Assessment of Neurodegeneration and Dementia (COMPASS‐ND) study. Hearing loss was assessed with a pure‐tone screening protocol and a speech‐in‐noise test, vision was assessed with the MNRead for visual acuity and the MARS test for contrast sensitivity, and olfaction was assessed with the Brief Smell Identification Test (BSIT). We examined the frequency of sensory deficits in 60 NC (mean age = 69 years; mean education = 16 years), 55 participants with SCD (age = 70; education = 17), 102 with MCI (age = 72; education = 16), and 47 with Alzheimer’s disease (AD, age = 75; education = 15). Participants were matched on age and education, except for AD participants who were older.ResultsThe frequency of having at least one impairment in at least one sensory domain increased across groups (55% NC, 62% SCD, 75% MCI, 96% AD). A deficit in olfaction was the most common single deficit. Sensory deficits became increasing more co‐morbid across the risk spectrum. Hearing loss and olfaction loss were each associated with lower hippocampal volume and hearing loss was associated with alterations in functional brain connectivity in the default mode network.ConclusionThese analyses indicate that sensory loss is highly frequent and co‐morbid in persons with or at risk for dementia. These findings have implications for cognition, brain function, functional activities, and care delivery for persons with or at risk for dementia.

B - 92 Poor Olfaction Prior to Cardiac Surgery: Associations with Cognition, Plasma Neurofilament Light and Postoperative Delirium in a Prospective Nested Cohort Study.

This study examined the association between pre-operative olfactory performance and delirium after cardiac surgery. As a secondary aim, we examined the relationship between baseline olfaction, cognitive functioning, and plasma neurofilament light (NfL). Individuals undergoing cardiac surgery were recruited as part of a clinical trial in which blood pressure during bypass was targeted using cerebral autoregulation monitoring. There were 189 participants (mean age = 70years; 75% men). At baseline, olfaction, cognition, and plasma concentrations of NfL were assessed using the 12-item Brief Smell Identification Test (BSIT), a battery of neuropsychological tests, and the Simoa™ NF-Light Assay, respectively. Impaired olfaction was defined as a score of ≤8 for men and ≤ 9 for women. Delirium was assessed using the Confusion Assessment Method (CAM) and CAM-ICU, and delirium severity was assessed using the Delirium Rating Scale-Revised-1998 (DRS-R-98). The association of baseline olfaction and delirium and delirium severity was examined in regression models adjusting for age, duration of bypass, a surgery risk score, and baseline cognitive performance. In adjusted models, impaired olfaction at baseline was associated with both incident delirium (OR = 2.25, p = 0.04) and greater delirium severity (OR = 2.10, p = 0.04) after cardiac surgery. Furthermore, worse baseline olfaction was associated with impaired cognition (p < 0.001) and increased perioperative concentrations of plasma NfL (p = 0.04). Pre-operative olfactory testing may provide insight into brain vulnerability, cognitive dysfunction, and delirium risk in individuals undergoing cardiac surgery. Psychophysical olfactory assessment may inform strategies for patient risk stratification and early identification of individuals at risk for post-operative delirium, allowing for delirium-prevention strategies.

Olfactory Dysfunction Is Associated with Cerebral Amyloid Deposition and Cognitive Function in the Trajectory of Alzheimer's Disease.

Olfactory dysfunction is consistently observed in individuals with Alzheimer's disease (AD), but its association with beta-amyloid (Aβ) deposition remains unclear. This study aimed to investigate the relationship among olfactory function, cerebral Aβ deposition, and neuropsychological profiles in individuals with no cognitive impairment (NCI), mild cognitive impairment (MCI), and AD dementia. A total of 164 participants were included, and olfactory function was assessed using the brief smell identification test (B-SIT). Cerebral Aβ deposition was measured using [18F]-flutemetamol PET imaging (A-PET). The results show a significant group difference in olfactory function, with the highest impairment observed in the Aβ-positive MCI and AD dementia groups, and the impairment was the lowest in Aβ-negative NCI. Olfactory dysfunction was positively associated with cognitive impairments across multiple domains. Furthermore, individuals with Aβ deposition had lower olfactory function compared to those without Aβ, even within the same neuropsychological stage. The association between olfactory dysfunction and Aβ deposition was observed globally and in specific cortical regions. These findings suggest that olfactory dysfunction is associated with both cognitive function and cerebral Aβ pathology in the trajectory of AD. Olfactory deficits may serve as an additional marker for disease progression and contribute to understanding the underlying mechanisms of AD.

Polygenic risk score for Parkinson's disease and olfaction among middle-aged to older women

IntroductionOlfactory impairment and Parkinson's disease (PD) may share common genetic and environmental risk factors. This study investigates the association of a PD polygenic risk score (PRS) with olfaction, and whether the associations are modified by environmental exposures of PM2.5, NO2, or smoking. MethodsThis analysis included 3358 women (aged 50–80) from the Sister Study with genetic data and results from the Brief Smell Identification Test (B-SIT) administered in 2018–2019. PD PRS was calculated using 90 single nucleotide polymorphisms. Olfactory impairment was defined with different B-SIT cutoffs, and PD diagnosis was adjudicated via expert review. We report odds ratios (ORs) and 95% confidence intervals (CIs) from multivariable logistic regression. ResultsAs expected, PD PRS was strongly associated with the odds of having PD (OR highest vs. lowest quartile = 3.79 (1.64, 8.73)). The highest PRS quartile was also associated with olfactory impairment, with OR ranging from 1.24 (0.98, 1.56) for a B-SIT cutoff of 9 to 1.42 (1.04, 1.92) for a cutoff of 6. For individual B-SIT items, the highest PRS quartile was generally associated with lower odds of correctly identifying the odorant, albeit only statistically significant for pineapple (0.72 (0.56, 0.94), soap (0.76 (0.58, 0.99)) and rose (0.70 (0.54, 0.92)). The association of PD PRS with olfactory impairment was not modified by airborne environmental exposures or smoking. ConclusionThese preliminary data suggest that high PD genetic susceptibility is associated with olfactory impairment in middle-aged and older women.

Ambient Air Pollutants and Olfaction among Women 50-79 Years of Age from the Sister Study.

Poor olfaction is common in older adults and may have profound adverse implications on their health. However, little is known about the potential environmental contributors to poor olfaction. We investigated ambient fine particulate matter [PM in aerodynamic diameter ()] and nitrogen dioxide () in relation to poor olfaction in middle-aged to older women. The Sister Study is a nationwide cohort of 50,884 women in the United States with annual average air pollutant exposures estimated based on participants' residences from enrollment (2003-2009) through 2017. This analysis was limited to 3,345 women, 50-79 years of age as of January 2018, who completed the Brief Smell Identification Test (B-SIT) in 2018-2019. Poor olfaction was defined as a B-SIT score of in the primary analysis. We conducted multivariable logistic regressions, accounting for covariates and study sampling design. Overall, we found little evidence for associations of air pollutants with poor olfaction. The odds ratio (OR) and 95% confidence interval (CI) of poor olfaction for each interquartile range (IQR) increment of air pollutants in 2006 were 1.03 (95% CI: 0.91, 1.17) for (per ) and 1.08 (95% CI: 0.96, 1.22) for (per ). Results were similar in the analyses using the most recent (2017) or the cumulative average (2006-2017) air pollutant exposure data. Secondary analyses suggested potential association in certain subgroups. The OR per IQR was 1.35 (95% CI: 1.11, 1.65) for among younger participants ( years of age) and 1.87 (95% CI: 1.29, 2.71) for among current smokers. This study did not find convincing evidence that air pollutants have lasting detrimental effects on the sense of smell of women 50-79 years of age. The subgroup analyses are exploratory, and the findings need independent confirmation. https://doi.org/10.1289/EHP12066.

Association of Performance on Olfactory and Cognitive Screening Tests With Conversion to Dementia in a Biracial Cohort of Older Adults.

Odor identification deficits are associated with transition to dementia, whereas intact odor identification and global cognition test performance may identify lack of transition. The purpose of this study was to examine intact odor identification and global cognition as prognostic indicators of lack of transition to dementia in a biracial (Black and White) cohort. In a community-dwelling sample of older adults from the Health, Aging, and Body Composition study, odor identification was measured using the Brief Smell Identification Test (BSIT), and global cognition was measured using the Teng Modified Mini-Mental State Examination (3MS). Survival analyses for dementia transition over 4 and 8 years of follow-up used Cox proportional hazards models. A total of 2,240 participants had an average age of 75.5 years (SD 2.8). Approximately 52.7% were female individuals. Approximately 36.7% were Black and 63.3% were White individuals. Impaired odor identification (hazard ratio [HR] 2.29, 95% CI 1.79-2.94, p < 0.001) and global cognition (HR 3.31, 95% CI 2.26-4.84, p < 0.001) were each independently associated with transition to dementia (n = 281). Odor identification remained robustly associated with transition to dementia for Black (HR 2.02, 95% CI 1.36-3.00, p < 0.001, n = 821) and White participants (HR 2.45, 95% CI 1.77-3.38, p < 0.001, n = 1,419), whereas global cognition was associated with transition among Black participants only (HR 5.06, 95% CI 3.18-8.07, p < 0.001). ApoE genotype was consistently associated with transition among White participants only (HR 1.75, 95% CI 1.20-2.54, p < 0.01). Among participants with intact performance on both odor identification (BSIT ≥9/12 correct) and global cognition (3MS ≥ 78/100 correct), 8.8% transitioned to dementia over 8 years. Intact performance on both measures had high positive predictive value for identifying individuals who did not transition to dementia over 4 years (0.98 for ages 70-75 years with only 2.3% transitioning, 0.94 for ages 76-82 years with only 5.8% transitioning). Odor identification testing paired with a global cognitive screening test identified individuals at low risk of transition to dementia in a biracial community cohort with a pronounced effect in the eighth decade of life. Identification of such individuals can reduce the need for extensive investigation to establish a diagnosis. Odor identification deficits showed utility in both Black and White participants, unlike the race-dependent utility of a global cognitive test and ApoE genotype.

Development and validation of the Vietnamese smell identification test

BackgroundCorrect olfactory identification requires familiarity with the odor stimuli and is culturally dependent. Existing smell identification tests (SIT) are not culturally specific and may not be reliable in detecting hyposmia in all populations. This study aimed to develop a smell identification test suitable for Vietnamese patients (VSIT). MethodsThe study included 4 phases: 1) survey-based evaluation of the familiarity of 68 odors to identify 18 odors for subsequent testing (N = 1050); 2) smell identification test of 18 odors in healthy patients (N = 50) to determine which 12 should be included in the VSIT; 3) comparison of VSIT scores on 12 odors in patients with hyposmia (N = 60; Brief smell identification test (BSIT) score <8 and those with normosmia (N = 120; BSIT score ≥8) to establish the validity of the newly developed test; and 4) retest of the VSIT in 60 normosmic patients from phase 3 (N = 60) to determine test-retest reliability. ResultsAs expected, the mean (SD) VSIT score was significantly higher in the healthy participants than in the hyposmic patients [10.28 (1.34) vs 4.57 (1.76); P < 0.001]. Using a cut-off score at 8, the sensitivity and specificity of the instrument in detecting hyposmia were 93.3% and 97.5% respectively. The test-retest reliability using the intra-class correlation coefficient was at 0.72 (P < 0.001). ConclusionThe Vietnamese Smell Identification Test (VSIT) demonstrated favorable validity and reliability and will allow for assessment of olfactory function in Vietnamese patients.

Evaluation of Clinical Features and Olfactory Functions in COVID-19: A Multicentre Study.

Introduction Coronavirus Disease-2019 (COVID-19) causes olfactory loss one of the initial diagnostic criteria. The brief smell identification test (BSIT) is an objective test frequently used in olfactory dysfunction. This study aimed to observe the changes in olfactory functions and clinical features in a short time in COVID-19. Methods In this prospective study involving 64 patients, the BSIT was performed at two different times; at the time of first application and on the 14th day. Demographic features, laboratory findings, body mass index (BMI), blood oxygen saturation values (SpO2), complaints at first admission, fever, follow-up place, and treatment schemes were noted. Results There was a significant difference between the BSIT scores at the first admission and when the polymerase chain reaction (PCR) became negative on the 14th day (p<0.001). Low oxygen saturation values at first admission were associated with low BSIT scores. No relationship was found between olfactory functions and complaints at admission, fever, follow-up place, and treatment schemes. Conclusion As a result, negative effects of COVID-19 on olfactory functions have been demonstrated even in the short follow-up period. In addition, low saturation values at first admission were associated with low BSIT scores.

The combination of olfactory dysfunction and depression increases the risk of incident dementia in older adults.

Olfactory dysfunction and depression are common in later life, and both have been presented as risk factors for dementia. Our purpose was to investigate the associations between these two risk factors and determine if they had an additive effect on dementia risk. Olfactory function was assessed using the Brief Smell Identification Test (BSIT), and depression was classified using a combination of the 15-item Geriatric Depression Scale (GDS) score and current antidepressant use. Cross-sectional associations between depression and olfactory function were examined using correlations. Cox regression analyses were conducted to examine the longitudinal relationship between olfaction and depression and incident dementia across 12-years of follow-up. Participants were 780 older adults (aged 70-90 years; 56.5% female) from the Sydney Memory and Ageing Study (MAS) without a diagnosis of dementia at baseline. Partial correlation revealed a nonsignificant association between baseline depression and olfactory function after accounting for covariates (r = -.051, p = .173). Cox regression showed that depression at baseline (hazard ratio = 1.706, 95% CI 1.185-2.456, p = .004) and lower BSIT scores (HR = .845, 95%CI .789-.905, p < .001) were independently associated with a higher risk of incident dementia across 12 years. Entering both predictors together improved the overall predictive power of the model. Lower olfactory identification scores and depressive symptoms predict incident dementia over 12 years. The use of BSIT scores and depression in conjunction provides a greater ability to predict dementia than either used alone. Assessment of olfactory function and depression screening may provide clinical utility in the early detection of dementia.

Olfaction and anxiety differently associated in men and women in cognitive physiological and pathological aging

AbstractBackgroundOlfactory and affective factors are associated in a complex way, likely due to partial overlap in brain regions involved. Although the role of olfaction in disorders such as Parkinson Disease (PD) is documented, less clear is the association between olfaction and psychological symptoms, such as anxiety, in Mild Cognitive Impairment (MCI) and elderly cognitively healthy controls (HCs). Also, the role of sex differences in olfaction and psychological symptoms in healthy and pathological aging is poorly understood.MethodsWe included 117 subjects: 29 HCs (62.1% women), 43 MCI (34.9% women) and 45 PD (40% women), from the Center for Neurodegeneration and Translational Neuroscience. We assessed olfactory function with the Brief Smell Identification Test (BSIT) and anxiety with the State Trait Anxiety Inventory (STAI). We used a regression model for BSIT predicting STAI_Traits. We also used an interaction regression model to determine interaction between sex and olfaction predicting anxiety traits, in our three different groups.ResultsLoss of olfaction is related to greater anxiety traits in all our groups. Our regression model for BSIT predicting STAI_Traits is significant in HCs: p = 0.015; MCI: p = 0.001 and PD: p = 0.038 (adjusted for age, gender and education). Our interaction model olfaction*sex interaction to explore sex difference in the effect of olfaction on anxiety traits, showing that in HCs, for every unit increase in BSIT, trait anxiety decreased by 7.63 in men (p = 0.009) and 1.5 in women (p = 0.225); in MCI, for every unit increase in BSIT, trait anxiety decreased by 1.19 in men (p = 0.048) and 3.03 in women (p = 0.0036); in PD, for every unit increase in BSIT, trait anxiety decreased by 1.73 in men (p = 0.004) and 0.41 in women (p = 0.3632).ConclusionsOlfaction and anxiety are correlated in physiological and pathological aging, but differently in men and women. We show a closer relationship in men compared to women. In HC and PD olfaction is more closely and significantly correlated in men compared to women. In MCI we note an opposite pattern, with women show a slightly closer link between anxiety and olfaction.

Omega-3 Fatty Acid Supplementation for the Treatment of Persistent COVID-Related Olfactory Dysfunction.

To evaluate the efficacy of omega-3 fatty acid (O3FA) supplementation in the treatment of COVID-related olfactory dysfunction (OD). Patients with laboratory-confirmed or clinically-suspected COVID-19 infection and new-onset OD from August 2020 to November 2021 were prospectively recruited. Patients with quantitative OD, defined as a brief smell identification test (BSIT) score of 9 or less, were eligible for study inclusion. The experimental group received 2 g of O3FA supplementation, while the control group received an identical placebo to be taken daily for 6 weeks. The primary outcome was a change in BSIT score between the initial and 6-week follow-up tests. One hundred and seventeen patients were included in the analysis, including 57 patients in the O3FA group and 60 in the placebo group. O3FA group patients demonstrated a mean BSIT improvement of 1.12 ± 1.99 compared to 0.68 ± 1.86 in the placebo group (p = 0.221). Seventy-seven patients, 42 within the O3FA group and 35 in the placebo group, completed a follow-up BSIT survey at an average of 717.8 days from study onset. At long-term follow-up, there was an average BSIT score improvement of 1.72 within the O3FA group compared to 1.76 within the placebo group (p = 0.948). Among patients with persistent COVID-related OD, our study showed no clear evidence of relative short-term or long-term olfactory recovery among patients receiving high doses of O3FA supplementation.

Evaluation of the Effect of Nasogastric Intubation on Olfactory Function

Aim: To evaluate the olfactory functions in patients having had nasogastric intubation.&#x0D; Material and Methods: The study included 40 adult patients who underwent general anesthesia&#x0D; between January 2021 and June 2021 for elective abdominal surgery requiring a nasogastric tube&#x0D; (NGT) insertion. Olfactory function [Brief Smell Identification Test (B-SIT)] was evaluated prior to surgery&#x0D; and four weeks post-surgery in all the patients. The demographic characteristics of the patients, duration&#x0D; of NGT application, and B-SIT scores before and after NGT application were recorded. B-SIT scores&#x0D; were recorded separately for the NGT-applied and non-NGT-applied nasal side.&#x0D; Results: The mean NGT application time was 3.4 ± 1.5 (3-7) days. The mean preoperative and&#x0D; postoperative B-SIT scores of the NGT-applied side were 5.20 ± 2.06 and 5.01 ± 2.02, respectively.&#x0D; There was no statistically significant difference between the mean preoperative and postoperative B-SIT&#x0D; scores of the NGT-applied side (p = 0.421). The mean pre- and postoperative B-SIT scores of the&#x0D; patients in the non-NGT-applied nasal side group were 5.28 ± 2.16 and 5.11 ± 2.07, respectively. No&#x0D; statistically significant difference was found in the mean preoperative and postoperative B-SIT scores in&#x0D; the non-NGT-applied nasal side (p = 0.370). No statistically significant difference was found in the mean&#x0D; preoperative and postoperative B-SIT scores between the NGT-applied and non-NGT-applied nasal&#x0D; sides, respectively (p = 0.890, p = 0.654).&#x0D; Conclusion: The result of our study showed that there was no change in the olfactory function of&#x0D; patients after nasogastric intubation.

Olfactory and Gustatory Outcomes Including Health-Related Quality of Life 3-6 and 12 Months after Severe-to-Critical COVID-19: A SECURe Prospective Cohort Study.

Background: Long-term follow-up studies of COVID-19 olfactory and gustatory disorders (OGDs) are scarce. OGD, parosmia, and dysgeusia affect health-related quality of life (HRQoL) and the ability to detect potential hazards. Methods: In this study, 29 patients reporting OGD 1 month after severe-to-critical COVID-19 were tested at 3–6 months and retested at 12 months in case of hyposmia/anosmia. We used Sniffin Sticks Threshold, Discrimination, and Identification (TDI) test, Sniffin Sticks Identification Test (SIT16), Brief Smell Identification Test (BSIT), taste strips, and HRQoL. The patients were part of the prospective SECURe cohort. Results: Overall, 28% OD (TDI), 12% GD, 24% parosmia, and 24% dysgeusia (questionnaire) at 3–6 months (n = 29) and 28% OD (TDI), 38% parosmia, and 25% dysgeusia (questionnaire) at 12 months (n = 8) were observed. OGD decreased HRQoL: For 13%, it had a negative effect on daily life and, for 17%, it affected nutrition, 17% reported decreased mood, and 87–90% felt unable to navigate everyday life using their sense of smell and taste. A comparison of SIT16 and BSIT to TDI found sensitivity/specificity values of 75%/100% and 88%/86%. Conclusions: This is the first study to examine TDI, SIT16, BSIT, taste strips, and HRQoL up to 1 year after severe-to-critical COVID-19. The patients suffering from prolonged OGD, parosmia, and dysgeusia experienced severely decreasing HRQoL. We recommend including ear–nose–throat specialists in multidisciplinary post-COVID clinics.

Olfactory Dysfunction and Incidence of Motoric Cognitive Risk Syndrome: A Prospective Clinical-Pathologic Study.

To examine associations between olfactory dysfunction, Alzheimer disease (AD) pathology, and motoric cognitive risk syndrome (MCR), a predementia syndrome characterized by cognitive complaints and slow gait that is associated with risk for AD and other dementias. We conducted a retrospective analysis of a prospective cohort study to examine whether baseline olfactory function was associated with the risk of incident MCR in 1,119 adults aged 60 years and older (75.1% female). The association between performance on the Brief Smell Identification Test (BSIT) and incident MCR risk was computed using Cox models and reported as the hazard ratio (HR) with 95% CIs adjusted for demographic, comorbidity, and cognitive factors. Furthermore, we assessed the relationship between postmortem AD pathology and non-AD pathology and olfactory function at the time of MCR diagnosis using linear regression models adjusted for sex, education, age at death, and time from diagnosis to death. There were 544 (48.6%) incident cases of MCR over a median follow-up of 3.94 years. Lower BSIT scores (poor olfaction) at baseline were associated with an increased risk of incident MCR (HR for a 1-point increase in BSIT score 0.92; 95% CI 0.88-0.96) in fully adjusted models. Those with hyposmia (scores of ≤8 on the BSIT) at baseline (26.6%) were at an increased risk of MCR (HR 1.44; 95% CI 1.19-1.74) compared with those with normal olfactory function. Higher levels of the composite measure of global AD pathology and presence of Lewy body pathology were associated with lower BSIT scores at the time of incident MCR diagnosis (n = 118). τ tangle density, a specific component of AD pathology, was inversely associated with olfactory function, and the correlation remained after controlling for mild cognitive impairment syndrome and the presence of Lewy body pathology. The results provide evidence that olfactory dysfunction precedes MCR incidence and is related to Alzheimer pathology, providing a clinical approach to risk stratify and subtype MCR.

Olfaction and kidney function in community-dwelling older adults.

BackgroundIn older adults, kidney function declines with age. People with advanced kidney diseases may have poor olfaction. However, it is unclear whether poor olfaction is a marker for declining renal function or future risk of chronic kidney disease (CKD). We therefore investigated olfaction in relation to kidney function and risk of CKD.MethodsThese secondary data analyses were limited to participants of the year 3 clinical visit of the Health Aging and Body Composition Study. The analytic sample size varied between 1427 to 2531, depending on participant eligibility and data availability for each analysis. Olfaction was tested using the Brief Smell Identification Test (B-SIT), defined as anosmia (score≤6), hyposmia (7–8), moderate (9–10), and good function (10–11) at baseline. We estimated glomerular filter rate (eGFR) at baseline and seven years later using the CKD-EPI creatinine-cystatin C equation, and defined incident CKD as eGFR<60 ml/min/1.73m2 and eGFR decline ≥1 ml/min/1.73m2/year. Further, we identified CKD hospitalization events from hospitalization and death records. We used inverse probability weighting and weighted multivariable regressions to account for censoring in the prospective analyses and used absolute risk regression to account for competing risk of death.ResultsAt baseline, compared to participants with good olfaction, the multivariable-adjusted mean eGFR was 3.00 ml/min/1.73m2 lower (95% confidence interval (CI): -5.25, -0.75) for those with anosmia and 1.87 lower (95% CI: -3.94, 0.21) for those with hyposmia with a P for linear trend < 0.001. Those with anosmia at baseline was had a significantly lower eGFR seven years later (-5.31, 95% CI: -8.58, -2.04, P for trend = 0.002), but the association was attenuated after further accounting for baseline eGFR (-2.37, 95%CI: -4.91, 0.16, P for linear trend = 0.147). Olfactory function was not associated with incident CKD or CKD hospitalization.ConclusionIn older adults > age 70 years, poor olfaction is associated with lower kidney function, but not future CKD risk. These associations should be further investigated in relatively younger population.

Long-Term Subjective and Objective Assessment of Smell and Taste in COVID-19.

Among the first clinical symptoms of the SARS-CoV-2 infection is olfactory–gustatory deficit; this continues for weeks and, in some cases, can be persistent. We prospectively evaluated 162 patients affected by COVID-19 using a visual analogue scale (VAS) for nasal and olfactory–gustatory symptoms. Patients were checked after 7, 14, 21, 28, 90, and 180 days. A total of 118 patients (72.8%) reported an olfactory VAS < 7 at baseline (group B), and 44 (27.2%) reported anosmia (VAS ≥ 7) (group A) and underwent the Brief Smell Identification Test (B-SIT) and Burghart Taste Strips (BTS) to quantify the deficit objectively and repeated the tests to confirm the sense recovery. Group A patients showed B-SIT anosmia and hyposmia in 44.2% and 55.8% of cases, respectively. A total of 88.6% of group A patients reported ageusia with VAS ≥ 7, and BTS confirmed 81.8% of ageusia and 18.2% of hypogeusia. VAS smell recovery was recorded starting from 14 days, with normalization at 28 days. The 28-day B-SIT score showed normosmia in 90.6% of group A patients. The mean time for full recovery (VAS = 0) was shorter in group B (22.9 days) than in group A (31.9 days). Chemosensory deficit is frequently the first symptom in patients with COVID-19, and, in most cases, recovery occurs after four weeks.