Office Procedures for Quantitative Assessment of Olfactory Function

Remote olfactory assessment using the NIH Toolbox Odor Identification test and the brain health registry

BACKGROUND

Early identification of deficits in our ability to perceive odors is important as many normal (i.e., aging) and pathological (i.e., sinusitis, viral, neurodegeneration) processes can result in diminished olfactory function. To realistically enable population-level measurements of olfaction, validated olfaction tests must be capable of being administered outside the research laboratory and clinical setting.

AIM

The purpose of this study was to determine the feasibility of remotely testing olfactory performance using a test that was developed with funding from the National Institutes of Health as part of a ready-to-use, non-proprietary set of measurements useful for epidemiologic studies (NIH Toolbox Odor ID Test).

MATERIALS AND METHODS

Eligible participants older than 39 years and active (within 6 months) in the Brain Health Registry (BHR), an online cognitive assessment platform which connects participants with researchers, were recruited for this study. Interested participants were mailed the NIH Toolbox Odor ID Test along with instructions on accessing a website to record their responses. Data obtained from subjects who performed the test at home was compared to the normative data collected when the NIH Toolbox Odor ID Test was administered by a tester in a research setting and validated against the Smell Identification Test. The age-range and composition of the population ensured we had the ability to observe both age-related decline and gender-related deficits in olfactory ability, as shown in the experimental setting.

RESULTS

We observed that age-associated olfactory decline and gender-associated performance was comparable to performance on the administered test. Self-administration of this test showed the age-related loss in olfactory acuity, F(4, 1156)=14.564, p<.0001 as well as higher accuracy for women compared to men after controlling for participants' age, F(1, 1160) = 22.953, p <.0001. The effect size calculated as Hedge's g, was 0.41.

CONCLUSION

These results indicate that the NIH Toolbox Odor ID Test is an appropriate instrument for self-administered assessment of olfactory performance. The ability to self-administer an inexpensive olfactory test increases its utility for inclusion in longitudinal epidemiological studies and when in-person testing is not feasible.

The first quick olfactory test specific for Alzheimer's disease and French culture

PURPOSE

Olfactory identification disorder is considered a promising early biomarker of Alzheimer's disease (AD). The QUICK TODA2 can be used as a short olfactory screening tool specific for French AD patients. The selection of AD specific odorants and the design of this screening were the main objectives of this twofold study.

METHODS

In study 1, the TODA2 olfactory test was administered to 43 mild-AD patients and 45 healthy controls (HC) in five memory centres in France. The selection of AD specific odorants was based on the differences in the proportion of correct answers and in the threshold means between AD and HC groups. In study 2, another set of 19 mild-AD patient were included at the memory centre of Nice Hospital. All participants completed the olfactory assessment pipeline including the QUICK TODA2, TODA2 and Sniffin' Sticks Identification sub-Test (SST-i). The individual scores of the three tests were correlated.

RESULTS

In study 1, ten TODA2 odorants could significantly differentiate AD participants from controls. We selected the six most AD-sensitive items to design the QUICK TODA2. In study 2, we reported strong significant correlations between QUICK TODA2 and TODA2 (ρ(17) = 0.68, p = 0.001**), SST-i and QUICK TODA2 (ρ(17) = 0.65, p = 0.002**), SST-i and TODA2 (ρ(17) = 0.57, p = 0.01*).

CONCLUSION

 QUICK TODA2 is a 5-min non-invasive olfactory AD screening tool dedicated to French culture. Its results converge with those of longer, validated olfactory tests. It could be used as a quick screening tool in the general daily practice before an extensive assessment in memory centres.

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

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

Phenotypic effect of GBA1 variants in individuals with and without Parkinson's disease: The RAPSODI study

BACKGROUND

Variants in the GBA1 gene cause the lysosomal storage disorder Gaucher disease (GD). They are also risk factors for Parkinson's disease (PD), and modify the expression of the PD phenotype. The penetrance of GBA1 variants in PD is incomplete, and the ability to determine who among GBA1 variant carriers are at higher risk of developing PD, would represent an advantage for prognostic and trial design purposes.

OBJECTIVES

To compare the motor and non-motor phenotype of GBA1 carriers and non-carriers.

METHODS

We present the cross-sectional results of the baseline assessment from the RAPSODI study, an online assessment tool for PD patients and GBA1 variant carriers. The assessment includes clinically validated questionnaires, a tap-test, the University of Pennsyllvania Smell Identification Test and cognitive tests. Additional, homogeneous data from the PREDICT-PD cohort were included.

RESULTS

A total of 379 participants completed all parts of the RAPSODI assessment (89 GBA1-negative controls, 169 GBA1-negative PD, 47 GBA1-positive PD, 47 non-affected GBA1 carriers, 27 GD). Eighty-six participants were recruited through PREDICT-PD (43 non-affected GBA1 carriers and 43 GBA1-negative controls). GBA1-positive PD patients showed worse performance in visual cognitive tasks and olfaction compared to GBA1-negative PD patients. No differences were detected between non-affected GBA1 carriers carriers and GBA1-negative controls. No phenotypic differences were observed between any of the non-PD groups.

CONCLUSIONS

Our results support previous evidence that GBA1-positive PD has a specific phenotype with more severe non-motor symptoms. However, we did not reproduce previous findings of more frequent prodromal PD signs in non-affected GBA1 carriers.

UPSIT subitems may predict motor progression in Parkinson's disease

Background

The relationship between hyposmia and motor progression is controversial in Parkinson's disease (PD). The aim of this study was to investigate whether preserved identification of Chinese-validated University of Pennsylvania Smell Identification Test (UPSIT) odors could predict PD motor progression.

Methods

PD patients with two consecutive clinical visits while taking medication were recruited. Based on mean changes in Movement Disorder Society Unified Parkinson's Disease Rating Scale part 3 score and levodopa equivalent daily dosage, the participants were categorized into rapid progression, medium progression, and slow progression groups. Odors associated with the risk of PD motor progression were identified by calculating the odds ratios of UPSIT item identification between the rapid and slow progression groups. Receiver operating characteristic curve analysis of these odors was conducted to determine an optimal threshold for rapid motor progression.

Results

A total of 117 PD patients were screened for group classification. Preserved identification of neutral/pleasant odors including banana, peach, magnolia, and baby powder was significantly correlated with rapid motor progression. The risk of rapid progression increased with more detected risk odors. Detection of ≥1.5 risk odors could differentiate rapid progression from slow progression with a sensitivity of 85.7%, specificity of 45.8%, and area under the receiver operating characteristic curve of 0.687.

Conclusion

Preserved identification of neutral/pleasant odors may help to predict PD motor progression, and detection of ≥1.5 UPSIT motor progression risk odors could improve the predictive power. In PD patients with a similar level of motor disability during initial screening, preserved pleasant/neutral odor identification may imply relatively better cortical odor discriminative function, which may suggest the body-first (caudo-rostral) subtype with faster disease progression.

Odour-imagery ability is linked to food craving, intake, and adiposity change in humans

It is well-known that food-cue reactivity (FCR) is positively associated with body mass index (BMI)1 and weight change2, but the mechanisms underlying these relationships are incompletely understood. One prominent theory of craving posits that the elaboration of a desired substance through sensory imagery intensifies cravings, thereby promoting consumption3. Olfaction is integral to food perception, yet the ability to imagine odours varies widely4. Here we test in a basic observational study whether this large variation in olfactory imagery drives FCR strength to promote adiposity in 45 adults (23 male). We define odour-imagery ability as the extent to which imagining an odour interferes with the detection of a weak incongruent odour (the 'interference effect'5). As predicted in our preregistration, the interference effect correlates with the neural decoding of imagined, but not real, odours. These perceptual and neural measures of odour imagery are in turn associated with FCR, defined by the rated craving intensity of liked foods and cue-potentiated intake. Finally, odour imagery exerts positive indirect effects on changes in BMI and body-fat percentage over one year via its influences on FCR. These findings establish odour imagery as a driver of FCR that in turn confers risk for weight gain.

Odor imagery but not perception drives risk for food cue reactivity and increased adiposity

Mental imagery has been proposed to play a critical role in the amplification of cravings. Here we tested whether olfactory imagery drives food cue reactivity strength to promote adiposity in 45 healthy individuals. We measured odor perception, odor imagery ability, and food cue reactivity using self-report, perceptual testing, and neuroimaging. Adiposity was assessed at baseline and one year later. Brain responses to real and imagined odors were analyzed with univariate and multivariate decoding methods to identify pattern-based olfactory codes. We found that the accuracy of decoding imagined, but not real, odor quality correlated with a perceptual measure of odor imagery ability and with greater adiposity changes. This latter relationship was mediated by cue-potentiated craving and intake. Collectively, these findings establish odor imagery ability as a risk factor for weight gain and more specifically as a mechanism by which exposure to food cues promotes craving and overeating.

Heterozygous mutations in SOX2 may cause idiopathic hypogonadotropic hypogonadism via dominant-negative mechanisms

Pathogenic SRY-box transcription factor 2 (SOX2) variants typically cause severe ocular defects within a SOX2 disorder spectrum that includes hypogonadotropic hypogonadism. We examined exome-sequencing data from a large, well-phenotyped cohort of patients with idiopathic hypogonadotropic hypogonadism (IHH) for pathogenic SOX2 variants to investigate the underlying pathogenic SOX2 spectrum and its associated phenotypes. We identified 8 IHH individuals harboring heterozygous pathogenic SOX2 variants with variable ocular phenotypes. These variant proteins were tested in vitro to determine whether a causal relationship between IHH and SOX2 exists. We found that Sox2 was highly expressed in the hypothalamus of adult mice and colocalized with kisspeptin 1 (KISS1) expression in the anteroventral periventricular nucleus of adult female mice. In vitro, shRNA suppression of mouse SOX2 protein in Kiss-expressing cell lines increased the levels of human kisspeptin luciferase (hKiss-luc) transcription, while SOX2 overexpression repressed hKiss-luc transcription. Further, 4 of the identified SOX2 variants prevented this SOX2-mediated repression of hKiss-luc. Together, these data suggest that pathogenic SOX2 variants contribute to both anosmic and normosmic forms of IHH, attesting to hypothalamic defects in the SOX2 disorder spectrum. Our study describes potentially novel mechanisms contributing to SOX2-related disease and highlights the necessity of SOX2 screening in IHH genetic evaluation irrespective of associated ocular defects.

Association of air pollution with olfactory identification performance of São Paulo residents: a cross-sectional study

OBJECTIVE

Exposure to particulate matter of 10 μm or less in diameter (PM₁₀) has been implicated in pulmonary and cardiovascular diseases. However, the effect of PM₁₀ on olfaction has not been well established. We estimated individual acute and chronic PM₁₀ exposure levels in a large Brazilian cohort and related them to the ability to identify odors.

METHODS

Adults from São Paulo (n = 1358) were recruited from areas with different levels of air pollution. To verify individual exposure to air pollution, the averages of 30, 60, 90, 180 and 364 days of PM₁₀ were interpolated to subjects' zip codes using the kriging method. Olfactory identification performance was tested using the University of Pennsylvania Smell Identification Test (UPSIT®). Multiple linear regressions were used to calculate the effect of air pollution on olfactory identification performance, controlling for demographic and other variables that affect the sense of smell.

RESULTS

Acute exposures to PM₁₀ were related to worse UPSIT® scores, including 30- (β =  - 0.94, 95% Confidence Interval [CI]  - 0.98,  - 0.89), 60- (β =  - 1.09, 95% CI = - 1.13,  - 1.04) and 90-day intervals (β =  - 1.06, 95% CI  - 1.10,  - 1.02) (reference for β: 1 µm/m³ increase in PM10 exposure per point decrease in UPSIT® score). Chronic exposures were also associated with worse olfaction for both 180- (β =  - 1.06, 95% CI  - 1.10,  - 1.03) and 364-day (β =  - 0.87, 95% CI  - 0.90,  - 0.84) intervals. As in prior work, men, older, low-income, and low-schooling people demonstrated worse olfactory performance.

CONCLUSION

Acute and chronic exposure to PM₁₀ is strongly associated with olfactory identification performance in Brazilian adults. Understanding the mechanisms which underlie these relationships could help to improve chemosensory function with a large public health impact.

Development and Psychometric Validation of the Olfactory Dysfunction Outcomes Rating

Importance

Olfactory dysfunction (OD) is an increasingly common and morbid condition, especially given the ongoing COVID-19 pandemic. Thus, the ability to reproducibly measure smell loss-associated quality of life (QOL) and its response to treatment is paramount.

Objective

To develop and validate a concise and visually appealing smell loss-associated QOL patient-reported outcome measure for OD.

Design, Setting, and Participants

A secondary analysis of comments to an online survey by 1000 patients with olfactory dysfunction published in 2013 was used as the primary source to generate items of the Olfactory Dysfunction Outcomes Rating (ODOR). In addition, 30 patients with OD enrolled in 2 clinical studies at a tertiary care medical center (Washington University) were asked to identify their main concerns associated with smell loss. And finally, 4 otolaryngologists reviewed the items generated from the online survey and the patients' interviews to identify any additional items. Prospective study design was used for data collection from the 30 patients and 4 otolaryngologists. Prospective study design was used for survey validation. Validation of the ODOR was performed with 283 patients enrolled in several prospective studies at a single institution that completed the ODOR as an outcome measure.

Main Outcomes and Measures

Item generation and selection were the outcomes of ODOR development. The psychometric and clinimetric measures evaluated for validation were internal consistency, test-retest reliability, face and content validity, concurrent validity, and discriminant validity. Minimal clinically important difference was also determined.

Results

The ODOR is a 28-item instrument with each item scored as either no difficulty or very rarely bothered (0) to complete difficulty or very frequently bothered (4) with a total instrument score range of 0 to 112 points. Higher scores indicate higher degree of dysfunction and limitation. Validation in the cohort of 283 patients (mean [SD] age, 47.0 [14.4] years; 198 female participants [73%]; 179 White participants [80%]) revealed that the instrument has high internal consistency (Cronbach α = 0.968), test-retest reliability (r = 0.90 [95% CI, 0.81-0.95]), face validity, content validity, concurrent validity (r = 0.87 [95% CI, 0.80-0.91] compared with the Questionnaire of Olfactory Disorders-Negative Statements; ρ = -0.76 [95% CI, -0.81 to -0.71] compared with a patient-reported symptom severity scale), and divergent validity (mean score difference, -33.9 [95% CI, -38.3 to -29.6] between normosmic patients and hyposmic/anosmic patients). The minimal clinically important difference was 15 points. The estimated time for survey completion was approximately 5 minutes.

Conclusions and Relevance

In this survey creation and validation study, the ODOR was shown to be a novel, concise, reliable, and valid patient-reported outcome measure of OD-associated QOL. It can be used to measure physical problems, functional limitations, and emotional consequences associated with OD and how they change after a given intervention, which is clinically applicable and particularly pertinent given the growing burden of OD associated with COVID-19.

Anterior Pedicled Nasal Flap in Frontal Sinus Drill-Out Patients: A Randomised Controlled Pilot Study

Background: The endoscopic modified Lothrop procedure (EMLP) is a common procedure performed in patients with frontal sinus pathology. While performing this procedure, large segments of bone are exposed, which may lead to the promotion of frontal sinus neo-ostium stenosis. Here we examine the peri-operative differences in time to achieve healing in patients where a mucosal flap is used to cover the exposed bone on one side of the neo-ostium. Design: A randomised pilot study with 12 patients undergoing EMLP surgery participated in this study. Methods: Patients were randomised to undergo a mucosal flap on either the left or right side of the neo-ostium. Prior to surgery, patients completed a SNOT-22 and smell identification test. Patients were reviewed until the neo-ostium had healed on both sides. Once healing had occurred, a post-operative SNOT-22 score and smell identification test were recorded. Results: Average time to healing for the frontal sinus neo-ostium was 4.7 vs. 4.2 (p = 0.3) on the flap vs. non-flap side, respectively. There was an average 24.4 point (range: −75 to +9) decrease in SNOT-22 scores post-surgery. The post-operative USPIT score demonstrated an average increase of 6.6 points (range −13 to +27). Conclusion: We did not detect significant differences in peri-operative time toward healing in neo-ostiums where a single flap is utilised. Further studies are needed to determine whether the usage of a single neo-ostium flap affords any benefit over no flap on either ostium. SNOT-22 and UPSIT scores improved post-surgery.

Advances in Genetic Diagnosis of Kallmann Syndrome and Genetic Interruption

Kallmann syndrome (KS) is a rare hereditary disease with high phenotypic and genetic heterogeneity. Congenital hypogonadotropic hypogonadism and hyposmia/anosmia are the two major characterized phenotypes of KS. Besides, mirror movements, dental agenesis, digital bone abnormalities, unilateral renal agenesis, midline facial defects, hearing loss, and eye movement abnormalities can also be observed in KS patients. Because of the phenotypic heterogeneity, genetic diagnosis become increasingly valuable to distinguish KS from other disorders including normosmic congenital hypogonadotropic hypogonadism, constitutional delay of growth and puberty, CHARGE syndrome, and functional hypogonadotropic hypogonadism. Application of next-generation sequencing has promoted the discovery of novel pathogenic genes in KS pedigrees. Prenatal diagnosis is an effective method in clinical settings to decrease birth defects and block transmission of genetic disorders. However, pregnant women may suffer from physical and psychological distress when fetuses are diagnosed with congenital defects. Preimplantation genetic testing (PGT) is a prospective approach during the in vitro fertilization process that helps to interrupt transmission of hereditary diseases to offspring at an early stage. Thus, genetic testing and counseling are recommended to KS patients with family histories, prenatal diagnosis and PGT are considered to be useful options.

Olfaction and Executive Cognitive Performance: A Systematic Review

Objective tests of olfaction are widely available to aid in the assessment of olfaction. Their clearest role is in the characterization of olfactory changes, either reported by or suspected in a patient. There is a rapidly growing literature concerned with the association of olfactory changes with certain neuropsychiatric conditions and the use of olfactory testing to supplement conventional assessments in clinical and research practice is evolving. Neural pathways important for olfactory processing overlap extensively with pathways important for cognitive functioning, and especially those important for executive functioning, many of which are concentrated in the frontal lobes. Previous work has identified associations between performance on certain olfactory tests (most frequently olfactory identification) and executive functioning and behavioral measures (e.g. of impulsivity). More recently, similar associations have also been identified in non-clinical samples, raising new questions as to the utility of olfactory test scores as proxy measures for non-olfactory phenomena. In this systemic review, we sought to identify studies, both clinical and non-clinical, that investigated the associations of olfaction with performance on tasks sensitive to frontal lobe functioning. Our search criteria led to the identification of 70 studies published in English. We examined in detail and tabulated the data from these studies, highlighted each study's key findings, and critically evaluated these studies. We use the results of this review to reflect on some of the current and future challenges concerning the use of olfactory testing in clinical neuropsychiatric practice and research and speculate on the potential benefits of administering phonemic fluency in combination with olfactory testing to enhance its predictive value.

International consensus statement on allergy and rhinology: Olfaction

BACKGROUND

The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O).

METHODS

Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus.

RESULTS

The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies.

CONCLUSION

This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.

“Anosmia” the mysterious collateral damage of COVID-19

COVID-19 pandemic spreads worldwide, with more than 100 million positive cases and more than 2 million deaths. From the beginning of the COVID-19 pandemic, several otolaryngologists described many cases of a sudden loss of smell (anosmia) associated with the disease with or without additional symptoms. Anosmia is often the first and sometimes the only sign in the asymptomatic carriers of COVID-19. Still, this disorder is underestimated, and it is not life-threatening. However, it significantly decreases the quality of life. This olfactory dysfunction continues in several cases even after the nasopharyngeal swab was negative. The occurrence of anosmia can be used as a screening tool for COVID-19 patients and can be used to identify these patients to accomplish the isolation and tracking procedures. In this review, we highlighted the possible mechanisms of anosmia in COVID-19 patients, major pathologies and features of anosmia, implications of anosmia in early diagnosis of COVID-19, evaluation of the smell function during COVID-19, and management and treatment options of COVID-19 anosmia.

The Toronto Concussion Study: Sense of smell is not associated with concussion severity or recovery

OBJECTIVE

To examine sense of smell as a biomarker for both severity and duration of post-concussion symptoms.

METHODS

Participants were recruited prospectively from an outpatient concussion clinic. Sense of smell was assessed using the University of Pennsylvania Smell Identification Test (UPSIT) within 7 days, and 4, 8 - or 16-weeks post-injury. UPSIT normative data were used as normal controls. The main outcomes were: symptom severity on the Sport Concussion Assessment Tool 3 (SCAT3) symptom inventory and time to physician-declared recovery.

RESULTS

A total of 167 participants (mean age 32.9 [SD, 12.2] years, 59% female [n = 99]) were classified at 1 week post injury as follows: severe hyposmia in 5 (3%), moderate hyposmia in 10 (6%), mild hyposmia in 48 (29%), and normosmia in 104 (62%) individuals. A convenience sample of 81 individuals with concussion were tested at follow-up. Acute impairment of sense of smell following concussion was not associated with symptom severity on the SCAT3 or time to recovery. Sense of smell was stable from baseline to follow-up in this population.

CONCLUSION

This study provides evidence that routine testing of sense of smell in individuals with concussion is not warranted as a biomarker for severity of concussion and concussion recovery.

Validation of the local applicability of the 'TIB' Olfactory Test Device in the era of COVID-19

Objective

To evaluate the validity and test–retest reliability of the novel ‘TIB’ Olfactory Test Device (TIB) and to determine its normative values.

Methods

The study stratified the study subjects into normosmic, hyposmic and anosmic groups according to their olfactory function. The olfactory function of the subjects was evaluated using both the traditional Chinese version of the University of Pennsylvania of Smell Identification Test (UPSIT-TC) and the TIB. The normosmic group was used to retest with the UPSIT-TC and TIB at an inter-test interval of at least 7 days. The cut-off scores of TIB among the three different groups were determined by receiver operating characteristic curve analysis.

Results

This study enrolled 180 subjects: 60 in each group. The mean scores of TIB were 44.1 for the normosmic group, 27.5 for the hyposmic group and 10.9 for the anosmic group. The TIB scores were significantly different across the three groups. There was a significant correlation between the first and second TIB tests (r = 0.506). The cut-off scores were 41 for normosmic subjects and 24 for hyposmic subjects.

Conclusion

The validity and test–retest reliability results suggest that the TIB is an appropriate olfactory test for the Taiwanese population.

Smell tests can discriminate Parkinson's disease patients from healthy individuals: A meta-analysis

BACKGROUND

Olfactory impairment is common in Parkinson's disease (PD). The authors aimed to identify the clinical tests used to assess olfactory function and examine their ability to distinguish PD with different disease duration from healthy individuals with physiological aging.

METHODS

Cross-sectional studies published until May 2020 that assessed the olfaction of individuals with PD using search terms related to PD, olfactory function, and assessment were searched on PubMed, PsycInfo, Cinahl, and Web of Science databases.

RESULTS

Twelve smell tests were identified from the reviewed studies (n = 125) that assessed 8776 individuals with PD. Data of 6593 individuals with PD and 8731 healthy individuals were included in the meta-analyses. Individuals with PD presented worse performance than healthy individuals, regardless of the smell test used. The University of Pennsylvania Smell Identification Test (UPSIT) was used by most studies (n = 2310 individuals with PD) and presented smaller heterogeneity. When the studies were subclassified according to the years of PD duration, there were no significant differences.

CONCLUSION

All smell tests were able to discriminate the olfactory function of PD from that of healthy individuals, although the UPSIT was widely used. The abnormal olfaction was not related to the disease duration. Systematic review protocol registration (PROSPERO/2020-CRD42020160878).

What about using sniffin' sticks 12 items test to screen post-COVID-19 olfactory disorders?

Background

Post-COVID-19 Olfactory impairment has a negative impact on quality of life. The Sniffin Sticks test 12 items (SST-12) can be used in quick olfactory disorders screening. Its evaluation in a post-covid-19 situation was the main objective of this work.

Methods

All patient impaired with a post-COVID olfactory loss were included while consulting to the ENT department. The clinical examination included an olfaction recovery self-assessment (VAS), a nasofibroscopy, a quality of life (QoL) assessment, the complete Sniffin’ Sticks Test (SST), and the SST-12.

Results

Among the 54 patients included, 92% (n = 50) were correctly screened as olfactory impaired by SST-12. We report excellent correlations between SST-12 and SST (rho ₍₅₂₎ = 0.98, p < 0.001), QoL(rho₍₅₂₎ = 0.33 p = 0.016), or VAS (rho₍₅₂₎ = 0.49, p < 0.001) assessments.

Conclusions

SST-12 is a quick and reliable tool to screen large-scale population of post-COVID-19 olfactory impaired patients and could be used in a general daily clinical practice.

Olfactory dysfunction in aging and neurodegenerative diseases

Alterations in olfactory functions are proposed to be early biomarkers for neurodegeneration. Many neurodegenerative diseases are age-related, including two of the most common, Parkinson's disease (PD) and Alzheimer's disease (AD). The establishment of biomarkers that promote early risk identification is critical for the implementation of early treatment to postpone or avert pathological development. Olfactory dysfunction (OD) is seen in 90% of early-stage PD patients and 85% of patients with early-stage AD, which makes it an attractive biomarker for early diagnosis of these diseases. Here, we systematically review widely applied smelling tests available for humans as well as olfaction assessments performed in some animal models and the relationships between OD and normal aging, PD, AD, and other conditions. The utility of OD as a biomarker for neurodegenerative disease diagnosis and future research directions are also discussed.

TCF12 haploinsufficiency causes autosomal dominant Kallmann syndrome and reveals network-level interactions between causal loci

Dysfunction of the gonadotropin-releasing hormone (GnRH) axis causes a range of reproductive phenotypes resulting from defects in the specification, migration and/or function of GnRH neurons. To identify additional molecular components of this system, we initiated a systematic genetic interrogation of families with isolated GnRH deficiency (IGD). Here, we report 13 families (12 autosomal dominant and one autosomal recessive) with an anosmic form of IGD (Kallmann syndrome) with loss-of-function mutations in TCF12, a locus also known to cause syndromic and non-syndromic craniosynostosis. We show that loss of tcf12 in zebrafish larvae perturbs GnRH neuronal patterning with concomitant attenuation of the orthologous expression of tcf3a/b, encoding a binding partner of TCF12, and stub1, a gene that is both mutated in other syndromic forms of IGD and maps to a TCF12 affinity network. Finally, we report that restored STUB1 mRNA rescues loss of tcf12 in vivo. Our data extend the mutational landscape of IGD, highlight the genetic links between craniofacial patterning and GnRH dysfunction and begin to assemble the functional network that regulates the development of the GnRH axis.

Auditory and olfactory findings in patients with USH2A-related retinal degeneration-Findings at baseline from the rate of progression in USH2A-related retinal degeneration natural history study (RUSH2A)

Sensorineural hearing loss (SNHL) is characteristic of Usher syndrome type 2 (USH2), but less is known about SNHL in nonsyndromic autosomal recessive retinitis pigmentosa (ARRP) and olfaction in USH2A-associated retinal degeneration. The Rate of Progression of USH2A-related Retinal Degeneration (RUSH2A) is a natural history study that enrolled 127 participants, 80 with USH2 and 47 with ARRP. Hearing was measured by pure-tone thresholds and word recognition scores, and olfaction by the University of Pennsylvania Smell Identification Test (UPSIT). SNHL was moderate in 72% of USH2 participants and severe or profound in 25%, while 9% of ARRP participants had moderate adult-onset SNHL. Pure-tone thresholds worsened with age in ARRP but not in USH2 participants. The degree of SNHL was not associated with other participant characteristics in either USH2 or ARRP. Median pure-tone thresholds in ARRP participants were significantly higher than the normative population (p < 0.001). Among 14 USH2 participants reporting newborn hearing screening results, 7 reported passing. Among RUSH2A participants, 7% had mild microsmia and 5% had moderate or severe microsmia. Their mean (±SD) UPSIT score was 35 (±3), similar to healthy controls (34 [±3]; p = 0.39). Olfaction differed by country (p = 0.02), but was not significantly associated with clinical diagnosis, age, gender, race/ethnicity, smoking status, visual measures, or hearing. Hearing loss in USH2A-related USH2 did not progress with age. ARRP patients had higher pure-tone thresholds than normal. Newborn hearing screening did not identify all USH2A-related hearing loss. Olfaction was not significantly worse than normal in participants with USH2A-related retinal degeneration.

Association of Olfactory Training With Neural Connectivity in Adults With Postviral Olfactory Dysfunction

Importance

Viral upper respiratory tract infections are a major cause of olfactory loss. Olfactory training (OT) is a promising intervention for smell restoration; however, a mechanistic understanding of the changes in neural plasticity induced by OT is absent.

Objective

To evaluate functional brain connectivity in adults with postviral olfactory dysfunction (PVOD) before and after OT using resting-state functional magnetic resonance imaging.

Design, Setting, and Participants

This prospective cohort study, conducted from September 1, 2017, to November 30, 2019, recruited adults with clinically diagnosed or self-reported PVOD of 3 months or longer. Baseline olfaction was measured using the University of Pennsylvania Smell Identification Test (UPSIT) and the Sniffin' Sticks test. Analysis was performed between December 1, 2020, and July 1, 2020.

Interventions

Participants completed 12 weeks of OT using 4 essential oils: rose, eucalyptus, lemon, and clove. The resting-state functional magnetic resonance imaging measurements were obtained before and after intervention.

Main Outcome and Measures

The primary outcome measure was the change in functional brain connectivity before and after OT. Secondary outcome measures included changes in UPSIT and Sniffin' Sticks test scores, as well as patient-reported changes in treatment response as measured by subjective changes in smell and quality-of-life measures.

Results

A total of 16 participants with PVOD (11 female [69%] and 14 White [88%]; mean [SD] age, 60.0 [10.5] years; median duration of smell loss, 12 months [range, 3-240 months]) and 20 control participants (15 [75%] female; 17 [85%] White; mean [SD] age, 55.0 [9.2] years; median UPSIT score, 37 [range, 34-39]) completed the study. At baseline, participants had increased connectivity within the visual cortex when compared with normosmic control participants, a connection that subsequently decreased after OT. Furthermore, 4 other network connectivity values were observed to change after OT, including an increase in connectivity between the left parietal occipital junction, a region of interest associated with olfactory processing, and the cerebellum.

Conclusions and Relevance

The use of OT is associated with connectivity changes within the visual cortex. This case-control cohort study suggests that there is a visual connection to smell that has not been previously explored with OT and that further studies examining the efficacy of a bimodal visual and OT program are needed.

Clinical assessment of olfactory function

Approximately 5% of the general population is affected by functional anosmia with approximately additional 15% exhibiting decreased olfactory function. Many of these individuals ask for help. Because the subjective rating of olfactory function is biased, assessment of olfactory function is important. Olfactory measurements are needed for patient counseling and the tracking of changes in the sense of smell over time. The present review provides an overview of frequently used psychophysical tests for olfactory function, discusses differences between threshold and suprathreshold aspects of olfactory function, and gives examples on how to apply psychophysical tests.

Olfactory loss and aging: connections with health and well-being

Age-related olfactory dysfunction, or presbyosmia, is a common sensory impairment in aging adults. People in this demographic group with comorbid conditions or exposure to viral, traumatic, or environmental insults remain at the greatest risk for impairment. Several methods for assessing olfaction exist, but they are only available in special settings and require consideration of age, sex, ancestry, and cognition. Perhaps most importantly, olfactory dysfunction has been suggested as an early sign of Alzheimer's and Parkinson's disease and therefore may serve as a tool in the diagnosis and prognosis of these neurodegenerative conditions. Outside of this context, olfactory loss also impacts nutrition, safety, and social relationships, and even predicts mortality itself. This review covers the detection and manifestations of olfactory decline in aging individuals and the myriad ways in which olfactory impairment is connected to their health and well-being.

Reproduction Function in Male Patients With Bardet Biedl Syndrome

PURPOSE

Bardet-Biedl syndrome (BBS) is a ciliopathy with a wide spectrum of symptoms due to primary cilia dysfunction, including genitourinary developmental anomalies as well as impaired reproduction, particularly in males. Primary cilia are known to be required at the following steps of reproduction function: (i) genitourinary organogenesis, (ii) in fetal firing of hypothalamo-pituitary axe, (iii) sperm flagellum structure, and (iv) first zygotic mitosis conducted by proximal sperm centriole. BBS phenotype is not fully understood.

METHODS

This study explored all steps of reproduction in 11 French male patients with identified BBS mutations.

RESULTS

BBS patients frequently presented with genitourinary malformations, such as cryptorchidism (5/11), short scrotum (5/8), and micropenis (5/8), but unexpectedly, with normal testis size (7/8). Ultrasonography highlighted epididymal cysts or agenesis of one seminal vesicle in some cases. Sexual hormones levels were normal in all patients except one. Sperm numeration was normal in 8 out of the 10 obtained samples. Five to 45% of sperm presented a progressive motility. Electron microscopy analysis of spermatozoa did not reveal any homogeneous abnormality. Moreover, a psychological approach pointed to a decreased self-confidence linked to blindness and obesity explaining why so few BBS patients express a child wish.

CONCLUSIONS

Primary cilia dysfunction in BBS impacts the embryology of the male genital tract, especially epididymis, penis, and scrotum through an insufficient fetal androgen production. However, in adults, sperm structure does not seem to be impacted. These results should be confirmed in a greater BBS patient cohort, focusing on fertility.

Olfactory Dysfunction and Its Relationship With Clinical Features of Parkinson's Disease

Objective: To conduct an investigation into the reliability of assessing the olfactory function of patients with Parkinson's disease (PD) in a clinical setting of crowding patients in populated countries, such as China, by the hyposmia rating scale (HRS) and compare other non-motor features between patients with PD with olfactory dysfunction (PD-OD) and patients with PD without olfactory dysfunction (PD-NOD), according to the result of olfactory function assessed by the Sniffin' Sticks test. Methods: A total of 320 patients with clinically confirmed or clinically possible PD were recruited. Olfactory function of all participants was assessed with the HRS and the Sniffin' Sticks test. Demographic data and clinical information were collected, and patients were evaluated using standardized assessment protocols. With reference to the Sniffin' Sticks test, the specificity, sensitivity, coincidence rate, and kappa value of the HRS was computed, and then its reliability was evaluated. We divided patients into PD-OD and PD-NOD groups based on the results of olfactory function assessed by the Sniffin' Sticks test. Clinical manifestations were compared between PD-OD and PD-NOD. Results: The percentage of patients with OD determined by the Sniffin' Sticks test was 65.6%, and the percentage of those with OD was 55.6% when using the HRS measured olfactory function. With reference to the Sniffin' Sticks test, the specificity, sensitivity, coincidence rate, and kappa value of the HRS were 82.73, 75.71, 78.13%, and 0.55, respectively. The area under the receiver operating characteristic curve for the HRS was 0.793. There were no differences in demographic characteristics between the PD-OD and PD-NOD groups. The patients with hyposmia had more severe non-motor symptoms. Conclusion: The HRS is of great value as a self-assessment scale for evaluating olfactory function, especially in PD patients over 55 years old. Moreover, PD patients with hyposmia have more severe non-motor features than PD patients without hyposmia, mainly in terms of mood and constipation.

Olfactory Dysfunction in COVID-19, a Review of the Evidence and Implications for Pandemic Management

There is debate as to whether olfactory dysfunction should be considered a symptom of COVID-19 infection, given the implications for managing the symptom itself, for diagnostic testing, and for implementing isolation measures. We undertook a systematic literature review of the articles indexed in PubMed on olfactory disorders in viral respiratory tract conditions, with special emphasis on COVID-19. The main objective was to find evidence of clinical interest to support the relationship between anosmia and COVID-19. Olfactory disorders in upper respiratory tract infections are frequent, most caused by obstruction due to oedema of the nasal mucosa. Occasionally, post-viral sensorineural olfactory dysfunction occurs, with a variable prognosis. The evidence on anosmia in COVID-19 patients is extremely limited, corresponding to a level 5 or D of the Centre for Evidence-Based Medicine. According to the various medical societies that have issued reports on the subject, it seems reasonable to apply isolation, hygiene and social distancing measures in patients with recent olfactory disorders as the only symptom, although the usefulness of diagnostic tests for this type of patient should be studied.

[Olfactory dysfunction in COVID-19, a review of the evidence and implications for pandemic management]

There is debate as to whether olfactory dysfunction should be considered a symptom of COVID-19 infection. We undertook a systematic literature review of the articles indexed in PubMed on olfactory disorders in viral respiratory tract conditions, with special emphasis on COVID-19. The main objective was to find evidence of clinical interest to support the relationship between anosmia and COVID-19. Olfactory disorders in upper respiratory tract infections are frequent, most caused by obstruction due to oedema of the nasal mucosa. Occasionally, post-viral sensorineural olfactory dysfunction occurs, with a variable prognosis. The evidence on anosmia in COVID-19 patients is extremely limited, corresponding to a level 5 or D of the Centre for Evidence-Based Medicine. According to the available evidence, it seems reasonable to apply isolation, hygiene and social distancing measures in patients with recent olfactory disorders as the only symptom, although the usefulness of diagnostic tests for this type of patient should be studied.

Predictors of Olfactory Impairment among Northern Iranian Population

Introduction

The performance in most smell identification tests is subjected to cultural variations. This study aimed to evaluate age, gender, and smoking-related effects on the test performance in the North of Iran.

Materials and Methods

The olfactory function of 1470 eligible subjects was assessed in this study. Moreover, this study evaluated the influence of age, gender, and education on the test scores.

Results

According to the results, females obtained higher mean test scores, compared to males (18.4 vs. 17.6). In general, the elderly obtained lower scores, and about 30% of the subjects who were ≥65 years of age had severe hyposmia or anosmia. Furthermore, the olfactory impairment frequency in smoker subjects was significantly more than non-smokers (P<0.001). Test scores were generally higher in subjects with higher education levels. Logistic regression analysis revealed that the total number of cigarette doses in smokers and age had a significant association with olfactory dysfunction (P value <0.001 and 0.004, respectively). Cronbach's α of Iran-SIT was obtained at 0.78 which was more than an acceptable value of 0.7.

Conclusion

The findings of this study revealed that a low score in the Iran-SIT correlated with smoking, older age, low education level, and gender (male).

Prognosis of olfactory and gustatory dysfunctions in COVID-19 patients: A case series

Although most COVID‐19 patients feel their olfactory function returns to normal, the smell test demonstrates that a mild impairment of the olfactory function may have remained. Therefore, their olfactory function should be evaluated by a smell test.

Ortho- and retronasal olfactory performance in rhinosurgical procedures: a longitudinal comparative study

Purpose

Testing olfaction should be an integral part of a clinical work-up in rhinosurgical procedures. Importantly, intact olfactory experience also includes retronasally perceived odors (retronasal olfaction). This study aimed at comprehensively assessing olfaction in patients undergoing rhinosurgical procedures in a comparative manner and evaluating relations to patient-reported outcome measurements (PROMs).

Methods

Each nostril odor threshold and discrimination, and birhinal identification were tested using Sniffin’ Sticks in 14 subjects assigned for septoplasty (SP), 21 for septorhinoplasty (SRP), and 30 for endoscopic sinus surgery (ESS). The 27-Candy-Smell-Test was used to quantify retronasal abilities. Tests were repeated 3 months after surgery.

Results

Olfactory dysfunction was preoperatively present in 21% of SP, in 47.6% of SRP, and in 80% of ESS patients. Odor threshold side differences were most frequently found in SRP. Frequently, SRP and ESS patients showed severely impaired retronasal olfaction. Half of included subjects re-visited after 3 months, but olfactory function did not improve overall and rarely on an individual basis to a meaningful extent. Subjective ratings on nasal patency and PROMs were not associated with olfaction nor with changes in olfactory scores.

Conclusion

Olfactory function can decisively be impaired a priori not only in patients awaiting sinus surgery, but also in those assigned for functional septorhinoplasty. This impairment may not improve in the short term, which has to be taken into account in patient counseling. This study adds to the current literature on olfaction in rhinosurgery with the extension of retronasal testing.

Gli3 Regulates Vomeronasal Neurogenesis, Olfactory Ensheathing Cell Formation, and GnRH-1 Neuronal Migration

During mammalian development, gonadotropin-releasing-hormone-1 neurons (GnRH-1ns) migrate from the developing vomeronasal organ (VNO) into the brain asserting control of pubertal onset and fertility. Recent data suggest that correct development of the olfactory ensheathing cells (OEC) is imperative for normal GnRH-1 neuronal migration. However, the full ensemble of molecular pathways that regulate OEC development remains to be fully deciphered. Loss-of-function of the transcription factor Gli3 is known to disrupt olfactory development, however, if Gli3 plays a role in GnRH-1 neuronal development is unclear. By analyzing Gli3 extra-toe mutants (Gli3Xt/Xt), we found that Gli3 loss-of-function compromises the onset of achaete-scute family bHLH transcription factor 1 (Ascl-1)+ vomeronasal progenitors and the formation of OEC in the nasal mucosa. Surprisingly, GnRH-1 neurogenesis was intact in Gli3Xt/Xt mice but they displayed significant defects in GnRH-1 neuronal migration. In contrast, Ascl-1null mutants showed reduced neurogenesis for both vomeronasal and GnRH-1ns but less severe defects in OEC development. These observations suggest that Gli3 is critical for OEC development in the nasal mucosa and subsequent GnRH-1 neuronal migration. However, the nonoverlapping phenotypes between Ascl-1 and Gli3 mutants indicate that Ascl-1, while crucial for GnRH-1 neurogenesis, is not required for normal OEC development. Because Kallmann syndrome (KS) is characterized by abnormal GnRH-1ns migration, we examined whole-exome sequencing data from KS subjects. We identified and validated a GLI3 loss-of-function variant in a KS individual. These findings provide new insights into GnRH-1 and OECs development and demonstrate that human GLI3 mutations contribute to KS etiology.SIGNIFICANCE STATEMENT The transcription factor Gli3 is necessary for correct development of the olfactory system. However, if Gli3 plays a role in controlling GnRH-1 neuronal development has not been addressed. We found that Gli3 loss-of-function compromises the onset of Ascl-1+ vomeronasal progenitors, formation of olfactory ensheathing cells in the nasal mucosa, and impairs GnRH-1 neuronal migration to the brain. By analyzing Ascl-1null mutants we dissociated the neurogenic defects observed in Gli3 mutants from lack of olfactory ensheathing cells in the nasal mucosa, moreover, we discovered that Ascl-1 is necessary for GnRH-1 ontogeny. Analyzing human whole-exome sequencing data, we identified a GLI3 loss-of-function variant in a KS individual. Our data suggest that GLI3 is a candidate gene contributing to KS etiology.

Functional Hypogonadotropic Hypogonadism in Men: Underlying Neuroendocrine Mechanisms and Natural History

CONTEXT

After completion of puberty a subset of men experience functional hypogonadotropic hypogonadism (FHH) secondary to excessive exercise or weight loss. This phenomenon is akin to hypothalamic amenorrhea (HA) in women, yet little is known about FHH in men.

OBJECTIVE

To investigate the neuroendocrine mechanisms, genetics, and natural history underlying FHH.

DESIGN

Retrospective study in an academic medical center.

PARTICIPANTS

Healthy postpubertal men presenting with symptoms of hypogonadism in the setting of excessive exercise (>10 hours/week) or weight loss (>10% of body weight). Healthy age-matched men served as controls.

INTERVENTIONS

Clinical assessment, biochemical and neuroendocrine profiling, body composition, semen analysis, and genetic evaluation of genes known to cause isolated GnRH deficiency.

MAIN OUTCOME MEASURES

Reproductive hormone levels, endogenous GnRH-induced LH pulse patterns, and rare genetic variants.

RESULTS

Ten men with FHH were compared with 18 age-matched controls. Patients had significantly lower body mass index, testosterone, LH, and mean LH pulse amplitudes yet normal LH pulse frequency, serum FSH, and sperm counts. Some patients exhibited nocturnal, sleep-entrained LH pulses characteristic of early puberty, and one FHH subject showed a completely apulsatile LH secretion. After decreased exercise and weight gain, five men with men had normalized serum testosterone levels, and symptoms resolved. Rare missense variants in NSMF (n = 1) and CHD7 (n = 1) were identified in two men with FHH.

CONCLUSIONS

FHH is a rare, reversible form of male GnRH deficiency. LH pulse patterns in male FHH are similar to those observed in women with HA. This study expands the spectrum of GnRH deficiency disorders in men.

Nasal Placode Development, GnRH Neuronal Migration and Kallmann Syndrome

The development of Gonadotropin releasing hormone-1 (GnRH) neurons is important for a functional reproduction system in vertebrates. Disruption of GnRH results in hypogonadism and if accompanied by anosmia is termed Kallmann Syndrome (KS). From their origin in the nasal placode, GnRH neurons migrate along the olfactory-derived vomeronasal axons to the nasal forebrain junction and then turn caudally into the developing forebrain. Although research on the origin of GnRH neurons, their migration and genes associated with KS has identified multiple factors that influence development of this system, several aspects still remain unclear. This review discusses development of the olfactory system, factors that regulate GnRH neuron formation and development of the olfactory system, migration of the GnRH neurons from the nose into the brain, and mutations in humans with KS that result from disruption of normal GnRH/olfactory systems development.

Eosinophilic Upper Airway Inflammation in a Murine Model Using an Adoptive Transfer System Induces Hyposmia and Epithelial Layer Injury with Convex Lesions

Background: Chronic rhinosinusitis with nasal polyps (CRSwNP) is a refractory upper airway disease, accompanied mainly by eosinophilia and/or asthma. In addition, the disease correlates with a high rate of hyposmia, following a marked infiltration of eosinophils into the inflamed site, the paranasal sinus. Although eosinophils are known to contribute to the development of hyposmia and CRSwNP pathology, the underlying mechanisms remain unclear. This study aimed to investigate whether eosinophilic upper airway inflammation induces hyposmia and CRSwNP in a murine model using an adoptive transfer system. Methods: To induce eosinophilic rhinosinusitis, splenocytes, including a high proportion (over 50%) of activated eosinophils (SPLhEos), were collected from interleukin-5 transgenic mice following double intraperitoneal injections of antigens, such as ovalbumin, house dust mite, or fungus. Activated SPLhEos with corresponding antigens were then transferred into the nasal cavity of recipient mice, which were sensitized and challenged by the corresponding antigen four times per week. Olfactory function, histopathological, and computed tomography (CT) analyses were performed 2 days after the final transfer of eosinophils. Results: Hyposmia was induced significantly in mice that received SPLhEos transfer compared with healthy and allergic mice, but it did not promote morphological alteration of the paranasal sinus. Pathological analysis revealed that epithelial layer injury and metaplasia similar to polyps, with prominent eosinophil infiltration, was induced in recipient tissue. However, there was no nasal polyp development with interstitial edema that was similar to those recognized in human chronic rhinosinusitis. Conclusions: This study supports the previously unsuspected contribution of eosinophils to CRS development in the murine model and suggests that murine-activated eosinophilic splenocytes contribute to the development of hyposmia due to more mucosal inflammation than physical airway obstruction and epithelial layer injury with convex lesions.

The Sniffin' Sticks Odor Discrimination Memory Test: A Rapid, Easy-to-Use, Reusable Procedure for Testing Olfactory Memory

OBJECTIVES

Neurodegenerative diseases can alter odor memory in addition to inducing quantitative impairment, and olfactory memory can be tested using the validated olfactory memory test with encapsulated odors (Odor Discrimination Memory Test [ODMT]). The aim of this study was to investigate the new Sniffin' Sticks ODMT (SSODMT), which is comparable with the ODMT.

METHODS

The SSODMT was administered to 48 subjects (30 women, 18 men; mean age, 34.6 ± 16.3 years). Olfactory function was assessed using the 16-item Sniffin' Sticks Identification Test. The ODMT was administered to a subgroup of 10 subjects to assess the comparability of the SSODMT and the ODMT. Test-retest reliability was studied in another 20 subjects (10 women, 10 men; mean age, 32.9 ± 16.4 years).

RESULTS

The mean SSODMT score was 10.7 ± 1.8 (range, 5-12). SSODMT test scores were significantly correlated with Sniffin' Sticks Identification Test scores (r₆₇ = 0.66, P < .001) and were significantly negatively correlated with subject age (r₄₈ = -0.70, P < .001). SSODMT and ODMT scores were highly and significantly correlated, indicating that the test results were comparable (r₁₀ = 0.75, P < .05). Test-retest analysis revealed a significant correlation (r₂₀ = 0.68, P < .001).

CONCLUSIONS

These results demonstrate the usefulness of the new SSODMT and its comparability with the ODMT. The SSODMT is an easy, rapid, and low-cost tool that is suitable for routine use in evaluating odor memory.

Odorant Item Specific Olfactory Identification Deficit May Differentiate Alzheimer Disease From Aging

OBJECTIVES

To explore whether the ability to recognize specific odorant items is differentially affected in aging versus Alzheimer disease (AD); to refine olfactory identification deficit (OID) as a biomarker of prodromal and early AD.

DESIGN

Prospective multicenter cross-sectional study with a longitudinal arm.

SETTING

Outpatient memory diagnostic clinics in New York and Texas.

PARTICIPANTS

Adults aged 65 and older with amnestic mild cognitive impairment (aMCI) and AD and healthy aging (HA) subjects in the comparison group.

MEASUREMENTS

Participants completed the University of Pennsylvania Smell Identification Test (UPSIT) and neuropsychological testing. AD-associated odorants (AD-10) were selected based on a model of ordinal logistic regression. Age-associated odorants (Age-10) were identified using a linear model.

RESULTS

For the 841 participants (234 HA, 192 aMCI, 415 AD), AD-10 was superior to Age-10 in separating HA and AD. AD-10 was associated with a more widespread cognitive deficit across multiple domains, in contrast to Age-10. The disease- and age-associated odorants clustered separately in age and AD. AD-10 predicted conversion from aMCI to AD.

CONCLUSIONS

Nonoverlapping UPSIT items were identified that were individually associated with age and disease. Despite a modest predictive value of the AD-specific items for conversion to AD, the AD-specific items may be useful in enriching samples to better identify those at risk for AD. Further studies are needed with monomolecular and unilateral stimulation and orthogonal biomarker validation to further refine disease- and age-associated signals.

A Pilot Study of the Snap & Sniff Threshold Test

OBJECTIVES

The Snap & Sniff^® Threshold Test (S&S) has been recently developed to determine the olfactory threshold. The aim of this study was to further evaluate the validity and test-retest reliability of the S&S.

METHODS

The olfactory thresholds of 120 participants were determined using both the Smell Threshold Test (STT) and the S&S. The participants included 30 normosmic volunteers and 90 patients (60 hyposmic, 30 anosmic). The normosmic participants were retested using the STT and S&S at an intertest interval of at least 1 day.

RESULTS

The mean olfactory threshold determined with the S&S was -6.76 for the normosmic participants, -3.79 for the hyposmic patients, and -2 for the anosmic patients. The olfactory thresholds were significantly different across the 3 groups ( P < .001). Snap & Sniff-based and STT-based olfactory thresholds were correlated weakly in the normosmic group (correlation coefficient = 0.162, P = .391) but more strongly correlated in the patient groups (hyposmic: correlation coefficient = 0.376, P = .003; anosmic: correlation coefficient = 1.0). The test-retest correlation for the S&S-based olfactory thresholds was 0.384 ( P = .036).

CONCLUSION

Based on validity and test-retest reliability, we concluded that the S&S is a proper test for olfactory thresholds.

Optimizing olfactory testing for the diagnosis of Parkinson's disease: item analysis of the university of Pennsylvania smell identification test

The 40-item University of Pennsylvania Smell Identification Test (UPSIT) is an effective instrument to detect olfactory dusfunction in Parkinson's disease (PD). It is not clear, however, whether tests of this length are necessary to detect such dysfunction. Several studies have suggested that detection of certain odors is selectively compromised in PD, and that a test comprised of these odors could be shorter and more specific for this purpose. Therefore, we attempted to identify a subset of UPSIT odors that distinguish PD from controls with similar or improved test characteristics compared to the full test. The discriminatory power of each odor was examined using UPSIT data from a discovery cohort of 314 PD patients and 314 matched controls and ranked using multiple methods (including odds ratios, regression coefficients and discriminant analysis). To validate optimally discriminant subsets, we calculated test characteristics using data from two independent cohorts (totaling 306 PD and 343 controls). In the discovery cohort, multiple novel 12-item subsets (and the previously described Brief Smell Identification Test-B) performed similarly or improved upon the UPSIT and were better than 12 random items. However, in validation studies from independent cohorts, multiple subsets retained test characteristics similar to the full UPSIT, but did not outperform 12 random items. Differential discriminatory power of individual items is not conserved across independent cohorts arguing against selective hyposmia in PD. However, multiple 12-item subsets performed as well as the full UPSIT. These subsets could form the basis for shorter olfactory tests in the clinical evaluation of Parkinsonism.

Validation of olfactory threshold testing methods

In patients with chemosensory complaints, a head-to-head comparison of unilateral olfaction threshold testing with the Phenyl Ethyl Alcohol Smell Threshold Test (PEA) and the OLFACT-RL Odor Threshold Test (OLFACT-RL) was undertaken. The charts of 23 consecutive patients presenting with chemosensory complaints seen at the Smell and Taste Treatment and Research Foundation were reviewed and information extracted per Institutional Review Board guidelines. All patients had undergone olfactory testing with the PEA test and the OLFACT-RL test in accordance with their published administration manuals. Using Spearman correlation coefficients to measure the statistical correlation between tests, we found evidence of a correlation between PEA and OLFACT-RL values on the left side only, overall (r = 0.49, p = 0.0184); in those who had hyposmia and did not have anosmia (r = 0.42, p = 0.0668); in those who did not have burning mouth syndrome (r = 0.46, p = 0.0304); and in those who did not have dysosmia (r = 0.47, p = 0.0553). There is no evidence of a correlation on the right side. The correlation for the left nostril suggests that these tests may be interchangeable. However, lack of correlation with the right nostril requires further investigation.

Olfactory Dysfunction as an Early Biomarker in Parkinson's Disease

Olfactory dysfunction is common in Parkinson's disease (PD) and often predates the diagnosis by years, reflecting early deposition of Lewy pathology, the histologic hallmark of PD, in the olfactory bulb. Clinical tests are available that allow for the rapid characterization of olfactory dysfunction, including tests of odor identification, discrimination, detection, and recognition thresholds, memory, and tests assessing the build-up of odor intensity across increasing suprathreshold stimulus concentrations. The high prevalence of olfactory impairment, along with the ease and low cost of assessment, has fostered great interest in olfaction as a potential biomarker for PD. Hyposmia may help differentiate PD from other causes of parkinsonism, and may also aid in the identification of "pre-motor" PD due to the early pathologic involvement of olfactory pathways. Olfactory function is also correlated with other non-motor features of PD and may serve as a predictor of cognitive decline. In this article, we summarize the existing literature on olfaction in PD, focusing on the potential for olfaction as a biomarker for early or differential diagnosis and prognosis.

Objective Measurement and Monitoring of Nonmotor Symptoms in Parkinson's Disease

The comprehensive evaluation of nonmotor symptoms (NMS) in Parkinson's disease (PD) starts with the awareness of physicians, patients, and caregivers on their nature, clinical presentation, and effect on patient's daily activities and quality of life. This awareness can be better achieved if the symptoms can be visualized, measured, and monitored. As NMS are largely subjective in nature, a majority of them cannot be visualized (unlike tremor, which is easily seen), making their identification and quantification difficult. While symptoms are nonmotor, it does not mean that they are not measurable, as many NMS are integral to motor symptoms of Parkinson's, yet often neglected. In this review, we attempt to provide the most up-to-date and comprehensive literature review on the objective measurement and monitoring of NMS in PD. The aim is to make it clinically relevant by approaching NMS by domains as identified in the NMS Questionnaire. A section on the assessment of nonmotor fluctuations is also included, providing prospects for future objective monitoring. With the advances of technology, it is likely that many NMS will have objective outcomes, thus making these symptoms easily measurable and hopefully lead to future clinical trials that incorporate nonmotor outcomes. Nevertheless, it still requires a physician's judgment to determine which method, scales, objective measures, or monitoring devices or a combination of these is most appropriate to the individual patient in order to answer a particular clinical question.

Defining the minimal clinically important difference for olfactory outcomes in the surgical treatment of chronic rhinosinusitis

BACKGROUND

Olfactory dysfunction is a common and defining symptom of chronic rhinosinusitis (CRS). Many measures of olfactory dysfunction in CRS are limited by scoring criteria defined within general populations with interpretations of statistical significance to infer clinically meaningful improvement. In this investigation we define a minimal clinically important difference (MCID) for the Brief Smell Identification Test (BSIT) in CRS patients electing endoscopic sinus surgery (ESS).

METHODS

A multicenter cohort of 290 adult patients electing ESS for medically recalcitrant CRS were prospectively enrolled between March 2011 and June 2015 and completed BSIT evaluations before and after ESS. Distribution and anchor-based analytic approaches were utilized to define MCID values of the BSIT across patient cofactors.

RESULTS

A total of 92 (∽32%) patients were found to have preoperative olfactory dysfunction (BSIT <9), significantly associated with nasal polyposis (χ² = 35.0; p < 0.001). The effect-size distribution-based approach identified 1.0 as a MCID criterion value between "small" and "medium" effect (range, 0.61-1.52) overall. Significant mean postoperative change (ΔM) was reported for patients with olfactory dysfunction (ΔM = 2.28; p < 0.001), both with (n = 54; ΔM = 2.52; p < 0.001) and without (n = 38; ΔM = 1.95; p < 0.001) nasal polyposis, significantly exceeding the MCID criterion. Anchor-based approaches with regression modeling confirmed associations between MCID values and postoperative changes to olfactory-specific survey responses (p < 0.001).

CONCLUSION

Clinically meaningful change in BSIT scores may be defined as an absolute value difference of at least 1.0 unit for heterogeneous patients electing ESS for CRS. Significantly exceeding this criterion may be restricted to CRS patients with baseline olfactory dysfunction, regardless of nasal polyposis.