Assessment Of Olfactory Function Research Articles

Neurochemical Alterations Linked to Persistent COVID-19-Induced Anosmia: Probing Into Orbitofrontal Cortex by Magnetic Resonance Spectroscopy.

While many COVID-19-induced anosmia patients recover their sense of smell within a few months, a substantial number of them continue to experience olfactory impairment. In our primary study, the metabolic patterns in orbitofrontal cortex (OFC) were observed to exhibit more alterations than other regions. Hence, this study specifically probes into alterations within OFC region in subjects with persistent COVID-19-induced anosmia. In a new categorization, 54 subjects were studied as two major groups of COVID-19-related anosmia and normal each of which includes 27 subjects. Iran Recognition-Smell Identification Test (IR-SIT) over a three-month follow-up period was utilized for olfactory function assessment and anosmia diagnosis. Proton Magnetic Resonance Spectroscopy (1H-MRS) was employed to examine changes of metabolites in OFC, including N-acetyl aspartate (NAA), choline (Cho), and creatine (Cr), as well as their ratios. Additionally, a linear regression was applied to investigate the potential correlation between MRS data and IR-SIT scores. Patients with COVID-19-induced anosmia exhibited a significant reduction in NAA, Cho, and Cr levels in the OFC region compared to the control group. Moreover, NAA/Cho and NAA/Cr ratios were lower in the anosmia patients, whereas the Cho/Cr ratio elevated. The NAA/Cho ratio had the highest linear correlation with IR-SIT scores in anosmia. This study highlights remarkable neurochemical patterns associated with COVID-19-induced anosmia in brain orbitofrontal cortex detectable by proton MRS, shedding light on the link between OFC function impairment and anosmia. The NAA/Cho ratio derived from MRS data emerged as a potential biomarker that correlates with anosmia severity and recovery examination.

Рroblems of diagnostics of dysfunctions of the olfactory analyzer of laboratory animals on the basis of behavioral and electrophysiological methods of research

Olfactory impairment (decreased acuity, impaired adequate identification of odorants) reduces the quality of life of patients and can be a symptom of a wide range of pathologies of the organism, in particular neurodegenerative processes in the brain. Quantitative measurement of olfactory acuity is necessary for diagnostics of olfactory dysfunctions, monitoring the dynamics of olfaction after pharmacological or surgical treatment. The searching for optimal methods of analyzing olfactory thresholds on animal models of human diseases accompanied by anosmia and comparing them with those in humans seems to be especially urgent problem at the moment. This is necessary for the selection of a valid animal model for the evaluation of new drugs and development the therapy for a wide range of pathologies. The review analyzes publications devoted to the study of diseases accompanied by anosmia or hyposmia, their zootropic models, and methods of olfactory function assessment. Models for COVID19, Alzheimer’s disease, Parkinson’s disease, diabetes types (1 and 2 type), Kalman syndrome, and Bardet-Biedl syndrome, for which olfactory dysfunction and/or defects of olfactory system are present, were analyzed. The review notes the paucity of data on the measurement of olfactory thresholds in model animals.

Intra and inter-regional functional connectivity of the human brain due to Task-Evoked fMRI Data classification through CNN & LSTM

Background and purposeOlfaction is an early marker of neurodegenerative disease. Standard olfactory function is essential due to the importance of olfaction in human life. The psychophysical evaluation assesses the olfactory function commonly. It is patient-reported, and results rely on the patient's answers and collaboration. However, methodological difficulties attributed to the psychophysical evaluation of olfactory-related cerebral areas led to limited assessment of olfactory function in the human brain. Materials and MethodsThe current study utilized clustering approaches to assess olfactory function in fMRI data and used brain activity to parcellate the brain with homogeneous properties. Deep neural network architecture based on ResNet convolutional neural networks (CNN) and Long Short-Term Model (LSTM) designed to classify healthy with olfactory disorders subjects. ResultsThe fMRI result obtained by k-means unsupervised machine learning model was within the expected outcome and similar to those found with the conn toolbox in detecting active areas. There was no significant difference between the means of subjects and every subject. Proposing a CRNN deep learning model to classify fMRI data in two different healthy and with olfactory disorders groups leads to an accuracy score of 97 %. ConclusionsThe K-means unsupervised algorithm can detect the active regions in the brain and analyze olfactory function. Classification results prove the CNN-LSTM architecture using ResNet provides the best accuracy score in olfactory fMRI data. It is the first attempt conducted on olfactory fMRI data in detail until now.

Significant Underreporting of Preoperative Hyposmia in Patients Undergoing Endoscopic Skull Base Surgery: Discrepancies Between Subjective and Objective Measurements.

Objective The assessment of baseline olfactory function before endoscopic skull base surgery (ESBS) has been relatively limited compared with analysis before functional endoscopic sinus surgery (FESS). Our study addresses this knowledge gap, assessing preoperative olfactory function in ESBS and FESS and elucidating any differences. Study Design We conducted a retrospective review of patients undergoing anterior ESBS or FESS at a single institution between 2021 and 2022. We included 171 patients and compared their reported and measured preoperative olfactory function using the Sino-Nasal Outcome Test questionnaire and the 40-item University of Pennsylvania Smell Identification Test. Results Of the 171 patients included in this study, 30% of patients underwent ESBS and 70% underwent FESS. Of all patients, only 57% correctly reported their objective preoperative olfactory function. Of the 36 ESBS patients with measured preoperative hyposmia, only 31% correctly reported hyposmia, while 69% incorrectly reported normosmia. This distribution significantly differs ( p < 0.0001) from the FESS subset (89 patients), with 64% correctly reporting hyposmia and 36% incorrectly reporting normosmia. Conclusion Our analysis demonstrates higher than anticipated underreporting of preoperative hyposmia in patients undergoing ESBS as well as discrepancies between subjective and objective olfactory functions in the FESS population. The results highlight several gaps in knowledge regarding perioperative olfactory function that would be best examined with more thorough pre- and postoperative objective olfactory testing. This analysis demonstrates significant prognostic uncertainty for patients and providers and creates significant medicolegal uncertainty regarding the appropriate attribution of postoperative olfactory loss in cases without objective preoperative testing.

Olfactory function assessment of migraine patients by using the Sniffin’ sticks test: A clinical study

ObjectiveThis as a cross-sectional controlled clinical study. We hypothesis that the olfactory functions in migraine patients may differ from the healthy controls. In this study, we evaluated the olfactory functions by using a Sniffin’ Sticks test battery, which is a reliable and semi quantitative test to evaluate for olfactory dysfunction. MethodsPatients above 18 years of age who had migraine received a definitive diagnosis of migraine from experienced headache specialists based on the criteria of The International Classification of Headache Disorders-3 were included. Odor threshold, discrimination, and identification parameters were assessed using the “Sniffin’ Sticks” test. ResultsOne-hundred and one migraine patients (age [mean ± SD], 36.9 ± 10.4 years; range, 18–60 years) and sixty healthy volunteers (age 34.5 ± 13.2 years, range 18–65 years) participated in our study.The median odor threshold score [percentiles 25th–75th] was 8.3 [6.5–9.8] for the migraine group during attack free period and 4.5[3.6–6.0] for the control group. It was found that the migraine group had a median odor discrimination score of 10.0 [10.0–13.0] and the control group 12.0 [11.0–13.0]. These differences were statistically significant (p < 0.001 and p = 0.032 respectively).The median odor discrimination and identification scores were statistically significant higher for the participants with higher educational level group than in those of lower educational group (p < 0.0001). The median odor discrimination and identification scores of those without allodynia (12.0 [10.0–14.0] and 13.0 [10.0–13.0] respectively) were higher than that of those with allodynia (11.0 [9.0–12.0] and 11.0 [10.0–13.0] respectively) (p = 0.037 and p = 0.034 respectively). ConclusionsWe found that the odor thresholds, discrimination and identification scores of the migraine group demonstrate differences from those of the healthy group and in relation to allodynia.

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.

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.

Is Olfactory Testing a Useful Diagnostic Tool to Identify SARS-CoV-2 Infections Early? A Cross-Sectional and Longitudinal Analysis.

Genesis and the prognostic value of olfactory dysfunction (OD) in COVID-19 remain partially described. The objective of our study was to characterize OD during SARS-CoV-2 infection and to examine whether testing of OD may be a useful tool in clinical practice in order to early identify patients with SARS-CoV-2 infection. Olfactory function assessment was objectively carried out using the u-Smell-it® test. In a cross-sectional study part, we evaluated this test in a control cohort of SARS-CoV-2 negative tested patients, who attended the University Hospital Frankfurt between May 2021 and March 2022. In a second longitudinal study part, sensitivity and specificity of OD was evaluated as a diagnostic marker of a SARS-CoV-2 infection in Frankfurt am Main, Germany in SARS-CoV-2 infected patients and their close contacts. Among 494 SARS-CoV-2 negative tested patients, OD was detected in 45.7% and was found to be significantly associated with the male gender (p < 0.001), higher age (p < 0.001), cardiovascular and pulmonary comorbidities (p < 0.001; p = 0.03). Among 90 COVID-19 positive patients, OD was found in 65.6% and was significantly associated with male gender and positive smoking status (p = 0.04 each). Prevalence and severity of OD were significantly increased in infections with the Delta variant (B.1.617.2) compared to those with the Omicron variant (BA.1.1.529). Diagnostic sensitivity and specificity of OD for diagnosis of SARS-CoV-2 infection were 69% and 64%, respectively. OD is common in COVID-19 negative and positive tested patients with significantly different prevalence rates observed between different variants. Diagnostic accuracy of OD is not high enough to implement olfactory testing as a tool in diagnostic routine to early identify patients with a SARS-CoV-2 infection.

The effect of nasal surgeries on olfactory functional outcome

Abstract Background: Nasal pathologies can alter the olfactory function there by the quality of life. In this study, we did an olfactory assessment in patients undergoing nasal surgeries, and the preoperative values were compared with the postoperative values. Objective: The objective of the study is to assess the role of nasal surgeries on olfactory functions in patients with nasal pathologies. Materials and Methods: In total, 70 participants undergoing nasal surgeries were subjected to olfactory function assessment using the Modified I smell test, which comprises olfactory threshold testing and odor identification, and the Numerical Rating Scale. Olfactory assessment was done preoperatively, 4th week and 12th week after the surgery. Results: Among 70 cases, 18 were sinonasal polyposis (25.75%), 16 (22.85%) were chronic rhinosinusitis cases, 35 (50%) deviated nasal septum cases and only one (1.4%) bilateral inferior turbinate hypertrophy case. The overall mean preoperative combined olfactory score (COS) value was 16.03 ± 2.55, 18.06 ± 1.68 in the 4th week of the postoperative period, and in the 12th week, it was 17.99 ± 1.83. There was a significant improvement in olfactory function when preoperative COS was compared with postoperative COS in different nasal surgeries. The olfactory impairment in nasal polyposis and chronic rhinosinusitis was more when compared to other nasal pathologies like nasal obstructions due to deviated nasal septum and turbinate hypertrophy. Overall, 91.7% of participants who underwent functional endoscopic sinus surgery (FESS) and 90% of FESS + septoplasty cases showed improvement in olfactory function. Only 50% of septoplasty cases showed improvement. Conclusion: Nasal pathologies are more common among men of the age group 21–30 years. Olfactory impairment in nasal polyposis and chronic rhinosinusitis was more compared to other nasal pathologies like nasal obstructions due to deviated nasal septum. FESS significantly improves the olfactory function in chronic rhinosinusitis and sino-nasal polyposis patients.

Psychophysical assessment of olfactory and gustatory function in post-mild COVID-19 patients: A matched case-control study with 2-year follow-up.

The aim of this study was to psychophysically evaluate the prevalence of smell and taste dysfunction 2 years after mildly symptomatic severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection compared to that observed at 1-year follow-up and while considering the background of chemosensory dysfunction in the no-coronavirus disease 2019 (COVID-19) population. This is a prospective case-control study on 93 patients with polymerase chain reaction (PCR)-positive SARS-CoV-2 infection and 93 matched controls. Self-reported olfactory and gustatory dysfunction was assessed by 22-item Sino-Nasal-Outcome Test (SNOT-22), item "Sense of smell or taste." Psychophysical orthonasal and retronasal olfactory function and gustatory performance were estimated using the extended Sniffin' Sticks test battery, 20 powdered tasteless aromas, and taste strips test, respectively. Nasal trigeminal sensitivity was assessed by sniffing a 70% solution of acetic acid. The two psychophysical assessments of chemosensory function took place after a median of 409 days (range, 366-461 days) and 765 days (range, 739-800 days) from the first SARS-CoV-2-positive swab, respectively. At 2-year follow-up, cases exhibited a decrease in the prevalence of olfactory (27.9% vs. 42.0%; absolute difference, -14.0%; 95% confidence interval [CI], -21.8% to -2.6%; p=0.016) and gustatory dysfunction (14.0%vs. 25.8%; absolute difference, -11.8%; 95% CI, -24.2% to 0.6%; p=0.098). Subjects with prior COVID-19 were more likely than controls to have an olfactory dysfunction (27.9%vs. 10.8 %; absolute difference, 17.2%; 95% CI, 5.2% to 28.8%)but not gustatory dysfunction (14.0%vs. 9.7%; absolute difference, 4.3%; 95% CI, -5.8% to 14.4% p=0.496) still 2 years after the infection. Overall, 3.2% of cases were still anosmic 2 years after the infection. Although a proportion of subjects recovered from long-lasting smell/taste dysfunction more than 1 year after COVID-19, cases still exhibited a significant excess of olfactory dysfunction 2 years after SARS-CoV-2 infection when compared to matched controls.

Olfactory impairment in COVID-19: Two methods for the assessment of olfactory function

BackgroundOlfactory impairment is a major symptom of COVID-19. Is it necessary for COVID-19 patients to perform the detection of olfactory function, even how to select the olfactory psychophysical assessment tool. MethodsPatients infected with SARS-CoV-2 Delta variant were firstly taken into three categories (mild, moderate, and severe) according to the clinical classification. The Odor Stick Identification Test for the Japanese (OSIT-J) and the Simple Olfactory Test were used to assess olfactory function. Moreover, these patients were divided into three groups based on the results of the olfactory degree (euosmia, hyposmia, and dysosmia), too. The statistical analysis of the correlations between olfaction and clinical characteristics of patients were performed. ResultsOur study demonstrated that the elderly men of Han were more susceptible to infected SARS-CoV-2, the clinical symptoms of the COVID-19 patients showed a clear correspondence with the disease type and the degree of olfactory disturbance. Whether or not to vaccinate and whether to complete the whole course of vaccination was closely related to the patient's condition. OSIT-J Test and Simple Test were consistent in our work, indicating that olfactory grading would worsen with the aggravation of symptoms. Furthermore, the OSIT-J method maybe better than Simple Olfactory Test. ConclusionThe vaccination has an important protective effect on the general population, and vaccination should be vigorously promoted. Moreover, it is necessary for COVID-19 patients to perform the detection of olfactory function, and the easier, faster and less expensive method for determination of olfactory function should be utilized to COVID-19 patients as the vital physical examination.

Self-assessment of olfactory function using the “Sniffin’ Sticks”

BackgroundA precise and reliable test of the olfactory function is indispensable for the diagnosis of the olfactory disorder (OD). Despite of this, in a clinical context, often there is no place in daily routine for time-consuming procedures. This study aimed to examine if the assessment of olfactory function using the “Sniffin’ Sticks” is suitable for self-assessment.MethodsParticipants comprised 84 healthy control subjects (HC) and 37 OD patients. The “Sniffin’ Sticks” test battery consisting of odor threshold (T), discrimination (D) and identification (I) tests was used for self- and assisted assessments. To save time, we applied the 8-item wide step version of the T test and the 8-item D test, whereas the I task remained the same as the original version. The whole test included two sessions, with each session comprising a self-assessment part performed by the participants themselves, and an assisted-assessment part performed by the examiner.ResultsSniffin’ Sticks self-assessment was efficient in distinguishing between self-reported HC subjects and OD patients (p’s < 0.01), and the scores did not differ significantly from the assisted-assessment (p’s > 0.05). In the self-administered I and TDI tests, there was a moderate to excellent test–retest reliability (ICC = 0.51–0.93, p’s < 0.01), and a strong to excellent correlation with the assisted assessment (r = 0.71–0.92, p’s < 0.01). However, the self-administered T and D tests only exhibited low to moderate test–retest reliability (ICC = 0.30–0.72, p’s < 0.05) and correlations with the assisted test (r = 0.31–0.62, p’s < 0.05).ConclusionsThe Identification self-test is appropriate to be solely applied, and is therefore an easy-to-use alternative for olfactory screening in a larger segment of patients. The whole “Sniffin’ Sticks” self-test also shows good measurement properties and is therefore a suitable backup in clinical practice, but improvement is needed due to the simplified D and T self-test.

Odor identification and discrimination as markers of early Alzheimer’s disease

AbstractBackgroundReliable markers are essential in order to achieve accurate diagnosis in the early stages of Alzheimer’s disease (AD). Olfactory impairment has been identified as a possible non‐invasive biomarker of AD. Odor identification tasks are most commonly used for measuring olfactory abilities. However, odor identification is associated to verbal abilities and cultural context. The aim of this study was to determine whether odor discrimination could be a valid marker of early AD.Method65 participants were enrolled in the study. 26 patients with mild cognitive impairment due to AD (MCI‐AD), 26 patients with mild dementia due to AD (MD‐AD) and 13 cognitively normal elderly subjects (CN). All participants underwent cognitive examination (MMSE, CDR, ADAS‐Cog 13, fluency tests) and olfactory function assessment (Burghart Sniffin’ Sticks odor identification and odor discrimination tests).ResultMD‐AD and MCI‐AD subjects performed significantly worse than CN subjects in both odor identification (mean correct responses ± SD was 6.77±1.91; 9.08±2.30; 13.31±1.55 respectively; p&lt;0.001) and odor discrimination (mean correct responses ± SD was 6.27±1.66; 8.19±1.65; 12.92±1.71 respectively; p&lt;0.001) tests. MD‐AD subjects performed significantly worse than MCI‐AD subjects in both odor identification (p&lt;0.05) and odor discrimination (p&lt;0.001) tests.Both odor identification and odor discrimination tests had AUC&gt;0.9 on ROC analysis for differentiating MCI‐AD subjects from CN subjects (AUC 0.938 and 0.982) and for differentiating MD‐AD subjects from CN subjects (AUC 0.99 for both). Neither odor identification, nor odor discrimination test reached AUC&gt;0.8 on ROC analysis for differentiating MCI‐AD from MD‐AD subjects (AUC 0.777 and 0.793).Odor identification differentiated MCI‐AD from CN subjects with sensitivity of 69% and specificity of 100% at cut‐off score of ≤10 correct responses. Odor discrimination differentiated MCI‐AD from CN subjects with sensitivity of 77% and specificity of 100% at cut‐off score of ≤9 correct responses.ConclusionThe study confirmed that tests for olfactory dysfunction can reliably differentiate patients with mild cognitive impairment due to AD from cognitively normal subjects. Both odor identification and discrimination are reliable markers for identification of patients with early Alzheimer’s disease.

Olfactory Evaluation in Clinical Medical Practice.

The subjective and demanding nature of olfactory testing means that it is often neglected in clinic despite loss of smell leading to significant limitations in everyday life. The list of diseases associated with loss of olfaction far exceeds the field of otorhinolaryngology and can also be seen in neurodegenerative disorders. Knowledge of possible clinical testing is essential to determine a proper differential diagnosis for the loss of olfactory sense. Causes of olfactory impairment can be divided into either failure in transferring odour to the organ of perception or damage to the olfactory pathway structure itself. Examination should therefore include methods evaluating cross-sectional area and patency of the nasal cavity as well as subjective or objective assessment of olfactory function. In this report we summarize several articles, studies, and our own experiences to provide a comprehensive review of their current clinical usage including their benefits, limitations, and possible outcomes. We also discuss the mechanism of olfaction step by step to provide a full understanding of the possible errors depending on the localization in the pathway and the methods designed for their detection. We discuss the correlation of the microbiome in nasal polyposis and chronic rhinitis with olfactory impairment using objective olfactometry. The topic of objective olfactometry and the examination of olfactory event-related potentials (OERP) is commented upon in detail.

Assessment of olfactory function by Sniffin' sticks in bakery workers exposed to flour dust.

This study used the Sniffin' Sticks test battery to evaluate olfactory function in employees of a bakery exposed to flour dust. The study enrolled 43 individuals with exposure (i.e., to flour) plus 41 healthy volunteers as controls. Olfactory function was assessed in these subjects through the use of the Sniffin' Sticks test battery. The overall score was calculated by adding up the scores for each of the 12 separate odors. A score of 6 or less was deemed anosmia, from 7 to 10 hyposmia, and a score of 11 or 12 was taken to indicate no impairment of olfaction. There was a statistically significant difference between the scores obtained in the exposure group (10.09±2.29) and the control group (10.73±2.07), the exposure group having a lower score (p<0.05). Within the exposure group, men and women did not score differently (p>0.05). Furthermore, in this group, the overall score did not correlate significantly with age, sex, length of employment, or use of tobacco or alcohol use (p>0.05). Using the scheme employed in this study, 9.3% of the exposed workers were anosmic, compared to 9.8% in the controls, whereas 34.9% of baker workers were hyposmic, compared to just 14.6% of the controls. Thus, our study shows that impairment of the ability to smell was present in 44.2% of individuals exposed occupationally to flour dust. This study reveals that being exposed to flour dust reduces the ability to smell normally. In order to minimize the impact of being exposed, workplaces should ensure adequate ventilation and provide workers with protective facemasks.

Smell, taste and trigeminal function: similarities and differences between results from home tests and examinations in the clinic.

This study aimed to examine an easy-to-conduct home chemosensory test as a screening tool prior to clinical testing and to investigate the associations between home and clinical tests. We examined 200 participants who performed a chemosensory test including subjective ratings as well as psychophysical smell, taste and trigeminal function tests at their homes. Following that, they were invited to the clinic for standardized testing using the Sniffin sticks test for assessment of olfactory function, taste sprays and strips for taste function, and a lateralization test for trigeminal function. The home smell test correlated well with the Sniffin sticks test. The home test had acceptable sensitivity for detecting smell loss (sensitivity of 67% at a specificity of 92%). The home test could distinguish between patients with olfactory loss and healthy controls. In contrast, the home tests for taste and trigeminal function did not provide valid results. When comparing home and clinical smell and taste tests older age and olfactory loss were the most influencing confounders in various models, while participants who had olfactory loss and admitted to drink alcohol regularly were more likely to have consistency between home and clinical smell measurements. Although the standardized psychophysical tests are valid and reliable and should be recommended, simple methods used at home could reflect the patients' information to some degree and provide useful data prior to clinical testing. The present home chemosensory test allows motivated individuals to screen their olfactory function in a simple way at home. Results from smell tests, but not from tests of taste or trigeminal function, obtained at home correlate with tests obtained at the clinic. Moreover, tests conducted at home or in the clinic have confounders that should be considered by researchers and clinicians.

Olfactory function after total laryngectomy – the review of rehabilitation efficacy and methods

Total laryngectomy removes the larynx and separates the oral and nasal cavities from the lower respiratory tract. In the process of speech therapy of laryngectomiezed patients, the main element is the voice rehabilitation, and the olfactory functions are often neglected. The work contains contemporary literature review on the methods of olfactory function assessment, techniques of its stimulation and the possibility of monitoring the progress of rehabilitation.

Evaluation of olfactory dysfunction persistence after COVID-19: a prospective study.

Alterations of the olfactory function in patients affected by COVID-19 often have an early onset and a variable duration ranging from a few weeks to months. The aim of this study was to evaluate olfactory dysfunction persistence after recovery from COVID-19, and potential related clinical-demographic conditions. A total of 76 patients recovered from COVID-19 from at least 20 days with olfactory dysfunction during the infection were included in the study. For the subjective evaluation of olfactory function, a visual analogic scale (VAS) was used. The objective evaluation was performed with the use of the Sniffin' Sticks test. Objective assessment of olfactory function revealed that 48 (63.16%) patients were found to be normosmic (TDI ≥ 30.5), 26 (34.21%) were hyposmic (TDI from 30.5 to 16.5) and two (2.63%) were anosmic (TDI ≤ 16.5) at the time of the evaluation. These results did not show a significant difference between subjective and objective tests (p = 0.45). Most patients recovered their sense of smell within the first two months after recovery while a portion (22.2%) still experienced olfactory alterations 4-6 months after SARS-CoV-2 infection. Patients who had not recovered their sense of smell had a significantly longer period of SARS-CoV-2 positivity compared to patients that fully recovered (36.07 ± 7.78 days vs. 29 ± 7.89 days; p = 0.04). Our results suggest that the duration of the infection negatively correlates with the recovery of olfactory function.

Associations Between Cognitive Function, Depression, and Olfactory Function in Elderly People With Dementia in Korea.

Early detection is important for delaying or preventing cognitive impairment. Since olfactory dysfunction and depression are common symptoms of cognitive dysfunction, they may serve as measurable risk indicators. This study was designed to identify the relationship between olfaction, depression, and each domain of cognitive function in elderly dementia patients in South Korea. Study participants were 108 patients who visited the outpatient clinic between March and September 2019. More significant impairment of olfactory function was found in those with mild (7.48 ± 1.28) or moderate (7.37 ± 2.22) test scores of the Expanded Clinical Dementia Rating (CDR) scale than in those with questionable scores (20.58 ± 6.18). The language domain of cognitive function, age, and education level showed 39.2% explanatory power for olfactory function (F = 5.591, p < 0.001). It is expected that assessment of olfactory function in elderly people can lead to the early detection, diagnosis, and treatment of dementia. Furthermore, it is important for future studies to confirm the relationship between each domain of cognitive function and olfactory function according to the type of dementia and to establish criteria for screening dementia in order to utilize olfactory function as a clinical marker.

The Adaptive Olfactory Measure of Threshold (ArOMa-T): a rapid test of olfactory function.

Many widely used psychophysical olfactory tests have limitations that can create barriers to adoption. For example, tests that measure the ability to identify odors may confound sensory performance with memory recall, verbal ability, and prior experience with the odor. Conversely, classic threshold-based tests avoid these issues, but are labor intensive. Additionally, many commercially available tests are slow and may require a trained administrator, making them impractical for use in situations where time is at a premium or self-administration is required. We tested the performance of the Adaptive Olfactory Measure of Threshold (ArOMa-T)-a novel odor detection threshold test that employs an adaptive Bayesian algorithm paired with a disposable odorant delivery card-in a non-clinical sample of individuals (n = 534) at the 2021 Twins Day Festival in Twinsburg, OH. Participants successfully completed the test in under 3 min with a false alarm rate of 7.5% and a test-retest reliability of 0.61. Odor detection thresholds differed by sex (~3.2-fold lower for females) and age (~8.7-fold lower for the youngest versus the oldest age group), consistent with prior studies. In an exploratory analysis, we failed to observe evidence of detection threshold differences between participants who reported a history of COVID-19 and matched controls who did not. We also found evidence for broad-sense heritability of odor detection thresholds. Together, this study suggests the ArOMa-T can determine odor detection thresholds. Additional validation studies are needed to confirm the value of ArOMa-T in clinical or field settings where rapid and portable assessment of olfactory function is needed.