Danish Validation of a Retronasal Olfactory Powder Test and Development of a Novel Quick Retronasal Olfactory Test

Abstract Introduction Quality of life is closely linked to retronasal olfactory function. Familiarity with odors vary, so tests need validation. Testing can be time-consuming, so a quick test and a thorough test are needed for clinical and research settings. Objectives The objectives of this study were to validate the original retronasal powder olfactory test in a Danish population and to develop a novel quick retronasal test for easy application. Methods Ninety-seven participants were included in the study, 59 healthy controls and 38 patients with olfactory impairment. The retronasal test was modified by substituting unfamiliar odors and descriptors and validated with a criterion of correct identification rate of 50% in the original test and 90% in the quick test. Items with over 90% correct identification rate in the modified original test were included in the quick test, resulting in a 10-item test. Results The modified retronasal olfactory test achieved good test characteristics, with a 10th percentile cut-off value of 13: sensitivity was 88.9%, specificity 83.0%, positive predictive value 78%, negative predictive value 91.7%, and the receiver operating characteristics area under the curve (ROC-AUC) was 0.86. The quick test achieved acceptable test characteristics, with a 10th percentile cut-off value of 8.2: sensitivity was 72.2%, specificity 90.6%, positive predictive value 83.9%, negative predictive value was 82.8%, and ROC-AUC 0.81. Conclusion Validation of both tests demonstrated satisfactory accuracy. We recommend the quick test for screening purposes, and the modified original version for a thorough evaluation. The tests are easily implemented as they are easy to understand and very affordable.

Development and Psychometric Validation of the Taste And Smell Tool for Evaluation (TASTE) Questionnaire.

Importance: The human senses of taste and smell are essential in everyday life. However, as clinical testing of the senses and patient-reported sensory problems are often diverging, additional validated questionnaires are essential for the evaluation of chemosensory impairments. Objective: To develop an instrument with all relevant domains concerning chemosensory dysfunction and quality of life using modern psychometrics. Design, Setting, and Participants: The study was designed as a questionnaire study for developing a new instrument. The study started in 2019 and was completed in 2022. Patients with chemosensory dysfunction were recruited from a specialized smell and taste clinic at an ear, nose, and throat department in Denmark. Healthy participants with no history of chemosensory dysfunction were recruited through social media. Main Outcomes and Measures: Eight domains were included (distorted chemosensation, emotional, food and meals, social, hygiene, danger, work, and relationship), and 35 items were generated based on review of the existing literature and interviews with patients and experts. Participants were tested with the Major Depression Inventory, 36-Item Short Form Health Survey, Taste Sprays, and Sniffin' Sticks for chemosensory function. Descriptive statistics were calculated for all items. Reliability, internal consistency, and validity were investigated, and a Rasch model was fitted. Healthy controls (n = 39) filled out the questionnaire for comparison of known-groups validity. Confirmatory factor analysis was performed. Finally, item reduction was performed, resulting in a final version with 21 items in 8 domains. Results: The study included responses from 316 patients, 183 women (58%) and 133 men (42%), with a mean (SD) age of 57 (15.1) years. Rasch model fit was acceptable with P > .05 for all items. An 8-dimensional confirmatory factor analysis model showed a better fit than a bifactor confirmatory factor analysis model. Cronbach α ranged from 0.65 to 0.86. Criterion validity with the Sniffin' Sticks, Taste Sprays, Major Depression Inventory, and the 36-Item Short Form Health Survey was satisfactory. The test-retest reliability was good in all domains, ranging from 0.55 to 0.86. All domains were discriminative, except the social and work domains. Conclusions and Relevance: In this survey study, the instrument was validated with 8 domains related to chemosensory dysfunction and quality of life. All items had good internal consistency, test-retest reliability, interitem correlations, item-total correlations, and Rasch model fit. The questionnaire appears suitable for use in clinical and research settings.

Chemosensory function and food preferences among haemodialysis patients.

INTRODUCTION: Malnutrition and disturbed sense of smell and taste frequently occur in patients treated with chronic haemodialysis. The common denominator between chemosensation and nutrition may be food preferences. Our aim was to investigate smell and taste function as well as food preferences among haemodialysis patients and compare the results with those of age-matched controls. METHODS: An observational case-control study was conducted on 29 patients on chronic haemodialysis and 39 age-matched healthy controls. Chemosensory function was evaluated using validated gustatory and olfactory tests. Food preferences were recorded using a questionnaire of 63 items including a five-point Likert scale of familiarity, liking and frequency. RESULTS: Chemosensory function was significantly poorer among patients than among controls. Patients had significantly lower familiarity and frequency of consumptions of all food categories than controls and they also had significantly lower liking of vegetables, fruits and starches. CONCLUSIONS: Implementation of the provided knowledge about haemodialysis patients' smell and taste function including their food preferences are suggested, such as enhancement of odorant intensity, use of taste amplification, cooking habits and exposure to more varied food items. Assessments of food preferences and chemosensory function prior to determination of individual dietary schedules are therefore recommended. FUNDING: The authors did not receive any financial support for the research or drafting of this article. The authors declare that they have no financial interests to report. TRIAL REGISTRATION: Danish Ethical Committee project number: M-2018-188-18.

Danish Validation of a Retronasal Olfactory Powder Test and Development of a Novel Quick Retronasal Olfactory Test.

Introduction Quality of life is closely linked to retronasal olfactory function. Familiarity with odors vary, so tests need validation. Testing can be time-consuming, so a quick test and a thorough test are needed for clinical and research settings. Objectives The objectives of this study were to validate the original retronasal powder olfactory test in a Danish population and to develop a novel quick retronasal test for easy application. Methods Ninety-seven participants were included in the study, 59 healthy controls and 38 patients with olfactory impairment. The retronasal test was modified by substituting unfamiliar odors and descriptors and validated with a criterion of correct identification rate of 50% in the original test and 90% in the quick test. Items with over 90% correct identification rate in the modified original test were included in the quick test, resulting in a 10-item test. Results The modified retronasal olfactory test achieved good test characteristics, with a 10th percentile cut-off value of 13: sensitivity was 88.9%, specificity 83.0%, positive predictive value 78%, negative predictive value 91.7%, and the receiver operating characteristics area under the curve (ROC-AUC) was 0.86. The quick test achieved acceptable test characteristics, with a 10th percentile cut-off value of 8.2: sensitivity was 72.2%, specificity 90.6%, positive predictive value 83.9%, negative predictive value was 82.8%, and ROC-AUC 0.81. Conclusion Validation of both tests demonstrated satisfactory accuracy. We recommend the quick test for screening purposes, and the modified original version for a thorough evaluation. The tests are easily implemented as they are easy to understand and very affordable.

Olfactory groove meningioma with a 10-year history of smell loss and olfactory recovery after surgery.

A rare cause of olfactory impairment is olfactory groove meningiomas with insidious onset of non-specific symptoms like headache, olfactory dysfunction, psychiatric symptoms such as depression, personality changes, declining cognitive function, visual disturbances or seizures. A common complication of surgery is loss of olfactory function. Still, the preservation of olfactory function should be attempted as olfactory loss often has a severe negative impact on quality of life. This report describes a woman with an olfactory groove meningioma and a 10-year history of olfactory impairment. It includes preoperatively and postoperatively extended olfactory testing, a neurosurgical approach to preserve the olfactory function and postoperative olfactory rehabilitation. After rehabilitation, the patient regained a normal olfactory function, even though the right-sided olfactory nerve could not be preserved during surgery. The case demonstrates the importance of performing neuroimaging in selected patients with olfactory loss and a method for preserving and potentially improving postoperative olfactory function.

COVID-19: Recovery from Chemosensory Dysfunction. A Multicentre study on Smell and Taste.

OBJECTIVE/HYPOTHESIS: With the COVID-19 pandemic, chemosensory dysfunction are among the most prevalent symptoms. Most reports are subjective evaluations, which have been suggested to be unreliable. The objective is to test chemosensory dysfunction and recovery based on extensive psychophysical tests in COVID-19 during the course of the disease. STUDY DESIGN: Prospective cohort study. METHODS: A total of 111 patients from four centers participated in the study. All tested positive for SARS-COV-2 with RT-PCR. They were tested within 3 days of diagnosis and 28 to 169 days after infection. Testing included extensive olfactory testing with the Sniffin' Sticks test for threshold, discrimination and identification abilities, and with the Taste Sprays and Taste Strips for gustatory function for quasi-threshold and taste identification abilities. RESULTS: There was a significant difference in olfactory function during and after infection. During infection 21% were anosmic, 49% hyposmic, and 30% normosmic. After infection only 1% were anosmic, 26% hyposmic, and 73% normosmic. For gustatory function, there was a difference for all taste qualities, but significantly in sour, bitter, and total score. Twenty-six percent had gustatory dysfunction during infection and 6.5% had gustatory dysfunction after infection. Combining all tests 22% had combined olfactory and gustatory dysfunction during infection. After infection no patients had combined dysfunction. CONCLUSIONS: Chemosensory dysfunction is very common in COVID-19, either as isolated smell or taste dysfunction or a combined dysfunction. Most people regain their chemosensory function within the first 28 days, but a quarter of the patients show persisting dysfunction, which should be referred to specialist smell and taste clinics for rehabilitation of chemosensory function. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:1095-1100, 2021.

Positive association between bitter taste threshold and preference of vegetables among adolescents.

AIM: Better understanding of aspects of taste in adolescents is needed since it has bearings on food policies, food industry and pharmaceutical design. Furthermore, taste preferences likely play a role in overeating and anorexia. We aimed to validate a questionnaire about taste preferences and dietary habits along with measurements of sense of smell and taste. METHODS: We included adolescents from nearby schools in Aarhus, Denmark, from 2017 to 2019. Scoring preferences and habits on a Likert scale, they completed a food item questionnaire. Their chemosensation was tested by the Sniffin' Sticks and Taste Drop Test. RESULTS: We included 100 adolescents: 53 males, 47 females; average age: 15.9 years (12-17 years). Retest of the questionnaire showed good reliability (Cohen's kappa: 0.5953). Snacks scored the highest average liking (4.48), whereas starches had the highest frequency of consumption (3.64). Bitter taste threshold was positively associated with liking and familiarity with vegetables (P = .032; P = .012), respectively. Healthy self-reported dietary habits were associated with a higher self-reported consumption of vegetables and a decreased consumption of snacks. CONCLUSION: Adolescents preferred unhealthy food items, but they also reported more frequent consumption of healthy than unhealthy food items. A higher threshold for the bitter taste, that is, being less sensitive to bitter taste, was associated with higher liking and familiarity of vegetables.

Re-Test Reliability of Gustatory Testing and Introduction of the Sensitive Taste-Drop-Test.

The sense of taste holds a key integrate role in assessing the flavor of food before swallowing is initiated. If the expectations for taste are not met, palatability and pleasure of the food can decrease. In patients suffering from taste disorders, this may impair appetite and nutritional state. Testing gustatory function can be important for diagnostics and assessment of treatment effects. However, the gustatory tests applied are required to be both sensitive and reliable. In this study, we investigate the re-test validity of popular Taste Strips gustatory test for gustatory screening. Furthermore, we introduce a new sensitive Taste-Drop-Test, which was found to be superior for detecting a more accurate measure of tastant sensitivity.

Danish validation of sniffin' sticks olfactory test for threshold, discrimination, and identification.

OBJECTIVES: The applicability of olfactory testing is dependent on cultural adaptation. The aim of this study was to validate the Sniffin' Sticks (Burghart Messtechnik, Wedel, Germany) threshold (T), discrimination (D), and identification (I) olfaction test. This data was subsequently used to investigate external validity of international normative values to separate hyposmia from normosmia. METHODS: The study included 388 participants. The first step was a questionnaire study in which 238 adults rated their familiarity with 125 odor descriptors. In the second step, we evaluated the original Sniffin' Sticks (Burghart Messtechnik) in 75 participants. In the third step, we modified our odor descriptors and tested 75 participants with the new version. RESULTS: In the I test, we found that 21 original odor descriptors were unfamiliar and that five odors had I rates < 75%. After modification, all odors had a successful I rate > 75%. By comparing the T, D, and I scores of previous validation studies, we found a significant variation in the scores between countries. CONCLUSION: The original Sniffin' Sticks (Burghart Messtechnik) was not applicable in Denmark. The modification resulted in improvement of familiarity and rate of I, making the test valid for use in Denmark. Furthermore, the study found a large variation in T and D scores between different countries, which should be considered when using these scores to separate hyposmia and anosmia from normosmia. LEVEL OF EVIDENCE: 2b. Laryngoscope, 1759-1766, 2018.

Age-related changes of vertical and horizontal lumbar vertebral trabecular 3D bone microstructure is different in women and men.

The study presents a 3D method for subdividing a trabecular network into horizontal and vertical oriented bone. This method was used to investigate the age related changes of the bone volume fraction and thickness of horizontal and vertical trabeculae in human lumbar vertebral bone estimated with unbiased 3D methods in women and men over a large age-range. The study comprised second lumbar vertebral body bone samples from 40 women (aged 21.7-96.4years, median 56.6years) and 39 men (aged 22.6-94.6years, median 55.6years). The bone samples were µCT scanned and the 3D microstructure was quantified. A voxel based algorithm inspecting the local neighborhood is presented and used to segment the trabecular network into horizontal and vertical oriented bone. For both women and men BV/TV decreased significantly with age, Tb.Th* was independent of age, while SMI increased significantly with age. Vertical (BV.vert/TV) and horizontal (BV.horz/TV) bone volume fraction decreased significantly with age for both sexes. BV.vert/TV decreased significantly faster with age for women than for men. Vertical (Tb.Th*.vert) and horizontal (Tb.Th*.horz) trabecular thickness were independent of age, while Tb.Th*.horz/Tb.Th*.vert decreased significantly with age for both sexes. Additionally, the 95th percentile of the trabecular thickness distribution increased significantly with age for vertical trabeculae in women, whereas it was independent of age in men. In conclusion, we have shown that vertical and horizontal oriented bone density decreases with age in both women and men, and that vertical oriented bone is lost more quickly in women than in men. Furthermore, vertical and horizontal trabecular thickness were independent of age, whereas the horizontal to vertical trabecular thickness ratio decreased significantly with age indicating a relatively more pronounced thinning of horizontal trabeculae. Finally, the age-related loss of trabecular elements appeared to result in a compensatory hypertrophy of vertical trabeculae in women, but not in men.