Differences in Correlation between Subjective and Measured Olfactory and Gustatory Dysfunctions after Initial Ear, Nose and Throat Evaluation

The long-term effect of COVID-19 infection on olfaction and taste; a prospective analysis

PURPOSE

To estimate long-term prognosis of chemosensory dysfunctions among patients recovering from COVID-19 disease.

METHODS

Between April 2020 and July 2022, we conducted a prospective, observational study enrolling 48 patients who experienced smell and/or taste dysfunction during the acute-phase of COVID-19. Patients were evaluated for chemosensory function up to 24 months after disease onset.

RESULTS

During the acute-phase of COVID-19, 80% of patients reported anosmia, 15% hyposmia, 63% ageusia, and 33% hypogeusia. At two years' follow-up, 53% still experienced smell impairment, and 42% suffered from taste impairment. Moreover, 63% of patients who reported parosmia remained with olfactory disturbance. Interestingly, we found a negative correlation between visual analogue scale scores for smell and taste impairments during the acute-phase of COVID-19 and the likelihood of long-term recovery.

CONCLUSION

Our study sheds light on the natural history and long-term follow-up of chemosensory dysfunction in patients recovering from COVID-19 disease. Most patients who initially suffered from smell and/or taste disturbance did not reach full recovery after 2 years follow-up. The severity of impairment may serve as a prognostic indicator for full recovery.

Periodontitis is associated with impaired olfactory function: A clinical study

AIM

To explore the association between periodontitis and olfactory disorders.

METHODS

Clinical data were collected from 198 individuals between the ages of 18 and 60 years living in Denmark. The exposure was periodontitis, and the outcome was olfactory function (Threshold, Discrimination, Identification - TDI score), both measured clinically. Covariates included sex, age, education level, income, usage of nasal spray, tongue coating, halitosis, xerostomia, smoking, and history of COVID-19. Structural equation modeling was used to estimate the association between periodontitis and olfactory function. Periodontitis was defined using the AAP/EFP classification and dichotomized into "no" (healthy subjects) and "yes" (Stages I, II, and III). Olfactory function was treated as a one-factor latent variable, including the different olfactory scores. In addition, extra models were performed considering each olfactory component as a separate outcome and the TDI Global Score.

RESULTS

The results showed that periodontitis was associated with a lower olfactory function [standardized coefficient (SC) -0.264, 95% CI -0.401, -0.118]. Additionally, periodontitis was also associated with a lower olfactory Threshold (odorant concentration required for detection) (SC -0.207, 95% CI -0.325, -0.089), Discrimination (ability to discriminate between odorants) (SC -0.149, 95% CI -0.270, -0.027), Identification (ability to identify odorants) scores (SC -0.161, 95% CI -0.277, -0.045), and TDI Global Score (SC -0.234, 95% CI -0.370, -0.099).

CONCLUSIONS

This study suggests that periodontitis is associated with olfactory impairment.

Using Cooking Schools to Improve the Pleasure of Food and Cooking in Patients Experiencing Smell Loss

Smell loss affects around 15-20% of the population, with a major effect on the quality of life. The most common complaint is the impairment of the eating experience, with around 90% of patients reporting this issue. A study conducted at a specialised Taste and Smell Clinic investigated if food and cooking can positively affect the enjoyment of food, subjective cooking skills, and quality of life in patients with smell loss. The 49 participants in the study received a 5-week cooking school course that focused on emphasizing the other senses to regain the enjoyment of food. Participants gained more confidence in cooking, and their quality of life improved significantly. Positively evaluated recipes were adjusted based on feedback and published as free e-books in Danish, German, and English. Eating and cooking are multisensory experiences, and the perception of food depends on the complex interaction of senses and surroundings. If the olfactory input is reduced or absent, both the enjoyment and cooking experience can be negatively affected. Therefore, focusing on food and cooking can have a positive impact on patients with smell loss.

Quantitive Assessment of Gustatory Function and Its Association with Demographics, and Systemic Morbidity

This study aimed to analyze the associations of gustatory dysfunction as measured by validated taste strips with demographics and co-morbidities. This cross-sectional study retrospectively analyzed records of patients who attended the Orofacial Chemosensory Center of Hadassah Medical Center between 2017 and 2020. Taste strips were used as a validated method to determine taste dysfunction. A total of 272 subjects were included, 137 (50.4%) women and 135 (49.6%) men, with a mean age of 53.5 ± 19.3 years and age range of 18-98 years. The total taste score among the study population was 8.53 ± 4.03 (scale range 0-16). Age had a significant negative correlation with the total taste score (p = 0.001), and men exhibited worse total (p < 0.001), salty (p = 0.003), and bitter (p < 0.001) scores. Major trauma was associated with worse total (p < 0.001) and specialized taste assessments (sweet (p = 0.001), sour (p = 0.002), salty (p = 0.016), and bitter (p < 0.001)). Chemotherapy was associated with reduced total (p < 0.001), salty (p = 0.003), and bitter (p = 0.001) taste scores. Zinc deficiency exhibited worse salty (p = 0.027) and total (p = 0.038) taste scores. Patients with burning mouth syndrome (BMS) showed higher salty scores (p = 0.017). Patients who experienced exposure to toxic chemicals exhibited worse salty scores (p = 0.024). We conclude that gustatory dysfunction is associated with older age, male sex, and co-morbidities of major trauma, current chemotherapy, zinc deficiency, BMS, and exposure to toxins. The study highlights the importance of systemic evaluation and quantitive gustatory dysfunction assessment as part of the diagnostic process of patients with subjective complaints of taste disorders.

Impact of Nasal Cavity CT Opacification Upon Sinonasal Quality of Life

BACKGROUND

Current methods of quantifying inflammation in chronic rhinosinusitis (CRS) on computed tomography (CT) imaging focus on opacification of the paranasal sinuses and show limited correlation with patient-reported outcome measures.

OBJECTIVE

This study aimed to determine if quantifying CT opacification of the nasal cavity correlated with Sino-Nasal Outcomes Test scores (SNOT-22).

METHODS

Thirty patients with CRS were enrolled. Lund-Mackay and SNOT-22 scores were measured. Nasal cavity regions of interest (ROIs) were measured by 2 independent raters using ImageJ at 3 points on coronal CT scans: anteriorly at the lacrimal duct, at the approximate midpoint demarcated by the posterior aspect of the globe, and posteriorly at the transition from the hard to soft palate. Superior and inferior regions were defined based upon the root of the inferior turbinate. Percent opacification was calculated for each ROI. Analyses were conducted bilaterally and for the side with greater opacification (worse side).

RESULTS

Interrater reliability was strong for all ROIs. Lund-Mackay scores correlated with nasal blockage only (r = .495, P = .01) and did not correlate with nasal cavity ROI opacification. Inferior nasal cavity opacification for worse-sided anterior ROI and middle ROI correlated with SNOT-22 scores for nasal blockage (anterior r = .41, P = .03) (middle r = .42, P = .023) and runny nose (anterior r = .44, P = .02) (middle r = .38, P = .04). Posterior ROIs did not correlate with SNOT-22.

CONCLUSIONS

Traditional CT scoring of sinus opacification does not correlate well with nasal cavity opacification or SNOT-22. Inferior nasal cavity inflammation provides unique correlations with SNOT-22 nasal questions and may guide targeted interventions in these regions.

Correlations between gustatory, trigeminal, and olfactory functions and nasal airflow

PURPOSE

To determine the relationship of chemosensory screening and nasal airflow tests among the same set of participants, and to determine other factors that are related to the outcomes of these tests.

METHODS

Participants had no chemosensory complaints. Structured medical history was taken. Participants underwent 5 screening tests: q-sticks (orthonasal olfaction), q-powders (retronasal olfaction), trigeminal lateralization test, taste sprays, and peak nasal inspiratory flow (PNIF). Ratings of smell/taste ability and nasal airflow were obtained using visual analogue scales (VAS). Composite sinusitis symptoms and significance of olfaction questionnaire scores were also determined.

RESULTS

Four hundred participants were included in the study, 156 men, 244 women; aged 18-82 years (mean: 46). The q-powders and taste spray scores were weakly positively correlated with all the other chemosensory tests and PNIF. However, chemosensory test scores were not correlated with VAS, composite sinusitis symptoms, and significance of olfaction questionnaire scores. Various tests showed significant decrease starting at specific ages (in years, PNIF and trigeminal lateralization: 40, q-powders: 60, and q-sticks: 70).

CONCLUSION

Chemosensory screening tests and self-rated chemosensory function showed no correlation in participants without chemosensory complaints. In addition, gustatory function appeared to be correlated with olfactory and trigeminal function but also with nasal airflow, and nasal airflow was related not only to olfactory but also to trigeminal and taste function. Over all, the results suggest that chemosensory functions (orthonasal olfactory, trigeminal, retronasal olfactory, gustatory) and nasal airflow are correlated with each other, which we propose may be possibly mediated, at least in part, through central nervous system interactions.

Remote psychophysical testing of smell in patients with persistent olfactory dysfunction after COVID-19

Olfactory dysfunction associated with coronavirus 2 (SARS-CoV-2) infection is in most cases transient, recovering spontaneously within a few days. However, in some patients it persists for a long time, affects their everyday life and endangers their health. Hence, we focused on patients with persistent loss of smell. The aim of this study was to evaluate olfactory dysfunction using a standardized test. Due to the pandemic, olfactory testing was performed online. Smell tests (Odorized Markers Test, OMT) were sent home to the patients. Together with the smell self-testing, participants reported and assessed several parameters (age, sex, subjective assessment of smell and taste, nasal patency, etc.) in an online questionnaire. Based on the questionnaire outcomes, the results were sent to the patients along with a list of participating otolaryngologists who provided them with professional care. From March to June 2021, 1025 patients requested smell testing, of these, 824 met the inclusion criteria of this study. The duration of the olfactory dysfunction at the time of testing ranged from 1 month to 1 year. Using the OMT, impaired smell ability-anosmia or hyposmia-was confirmed in 82.6% of participants. A total of 17.4% of participants were determined to be normosmic however, more than 50% of them complained of parosmia and/or phantosmia. Our study demonstrates the relevance of psychophysical smell testing and its suitability for remote use during the pandemic. This study also revealed several correlations between prolonged olfactory dysfunction and the monitored parameters.

Persistent post-COVID-19 dysosmia: Practices survey of members of the French National Union of Otorhinolaryngology-Head and Neck Surgery Specialists. CROSS analysis

INTRODUCTION

Persistent dysosmia more than 3 months after SARS-CoV-2 disease (COVID-19) is considered as long-COVID olfactory disease (LCOD). The primary objective of this study was to evaluate the diagnostic and therapeutic management of LCOD in the daily clinical practice of members of the National Union of Otorhinolaryngology-Head and Neck Surgery Specialists (Syndicat national des médecins spécialisés en ORL et chirurgie cervico-faciale) (SNORL). The secondary objective was to identify factors influencing management within the descriptive survey data.

MATERIALS AND METHODS

A questionnaire was designed (GoogleForm®) and e-mailed to all 715 SNORL members in January 2022.

RESULTS

The response rate was 7.4% (n=53/715). In total, 94.3% of respondents (n=50) had managed LCOD cases, and 56% (n=28) used psychophysical olfactory tests. Specific olfactory medical therapy involved local corticosteroid nasal sprays in 49.1% of cases (n=26) and oral corticosteroids in 32.1% (n=17). Olfactory self-training was prescribed by 81.1% of respondents, with associated speech pathologist therapy in 15.1% (n=8) of cases. No predictive factors for specific management were identified.

CONCLUSION

Olfactometry is currently under-applied. Consistent with guidelines, non-drug therapy (olfactory training) is the first-line treatment for LCOD.

Subjective Perception of Recovery and Measured Olfactory Function in COVID-19 Patients

This cross-sectional study aimed to investigate self-rated olfactory dysfunction in relation to measured olfactory function after partial or complete subjective recovery in individuals with a history of coronavirus disease 2019 (COVID-19) infection. A total of 186 individuals (aged 5-62 years) with a history of COVID-19 infection were included. Visual analogue scale (VAS) ratings for olfactory function (before, during, and after infection) and age-appropriate psychophysical olfactory test scores (odor threshold and odor identification: "Sniffin' Sticks" for adults and both "Sniffin' Sticks" and "U-Sniff" for children) were determined. Participants were assigned to four "age groups" and three "recovery classes" (incomplete recovery, complete recovery, no smell loss). Surprisingly, there were no significant differences in odor threshold and adult identification scores between the "recovery classes". However, children with "incomplete recovery" had lower identification scores than those with "complete recovery" (p = 0.033) and those with "no smell loss" (p = 0.022). The pediatric age groups had significantly higher VAS ratings during and after COVID-19 compared to older participants. Older individuals experienced greater magnitude of changes in their sense of smell after COVID-19 infection, but those with parosmia were 3.5 times more likely to report "incomplete recovery" of olfaction after COVID-19. The general prognosis for olfactory recovery after COVID-19 is good but appears to be particularly confounded by the presence of parosmia, leading patients to subjectively report incomplete olfactory recovery. Although it is of high significance to monitor recovery using validated psychophysical olfactory tests, subjective measures of olfaction help provide specific insight, especially for qualitative olfactory dysfunction.

Alzheimer's early detection in post-acute COVID-19 syndrome: a systematic review and expert consensus on preclinical assessments

Introduction

The risk of developing Alzheimer's disease (AD) in older adults increasingly is being discussed in the literature on Post-Acute COVID-19 Syndrome (PACS). Remote digital Assessments for Preclinical AD (RAPAs) are becoming more important in screening for early AD, and should always be available for PACS patients, especially for patients at risk of AD. This systematic review examines the potential for using RAPA to identify impairments in PACS patients, scrutinizes the supporting evidence, and describes the recommendations of experts regarding their use.

Methods

We conducted a thorough search using the PubMed and Embase databases. Systematic reviews (with or without meta-analysis), narrative reviews, and observational studies that assessed patients with PACS on specific RAPAs were included. The RAPAs that were identified looked for impairments in olfactory, eye-tracking, graphical, speech and language, central auditory, or spatial navigation abilities. The recommendations' final grades were determined by evaluating the strength of the evidence and by having a consensus discussion about the results of the Delphi rounds among an international Delphi consensus panel called IMPACT, sponsored by the French National Research Agency. The consensus panel included 11 international experts from France, Switzerland, and Canada.

Results

Based on the available evidence, olfaction is the most long-lasting impairment found in PACS patients. However, while olfaction is the most prevalent impairment, expert consensus statements recommend that AD olfactory screening should not be used on patients with a history of PACS at this point in time. Experts recommend that olfactory screenings can only be recommended once those under study have reported full recovery. This is particularly important for the deployment of the olfactory identification subdimension. The expert assessment that more long-term studies are needed after a period of full recovery, suggests that this consensus statement requires an update in a few years.

Conclusion

Based on available evidence, olfaction could be long-lasting in PACS patients. However, according to expert consensus statements, AD olfactory screening is not recommended for patients with a history of PACS until complete recovery has been confirmed in the literature, particularly for the identification sub-dimension. This consensus statement may require an update in a few years.

Psychophysical Testing in Chemosensory Disorders

Purpose of Review

To provide an overview of psychophysical testing in olfaction and gustation.

Recent Findings

Subjective patient report correlates poorly with objective assessment of olfaction and gustation. It is therefore important that clinicians and researchers perform psychophysical testing during chemosensory assessment. There are several validated psychophysical tests of olfaction and gustation, with ongoing developments accelerated by the COVID-19 pandemic. These tests have been culturally and linguistically adapted globally. Screening tests have been developed with careful consideration to distinguish normosmics from those with olfactory dysfunction.

Summary

Validated chemosensory tools are available for use by the clinician to support screening, diagnosis, or monitoring. There are promising advances in self-assessment and screening that provide avenues for the development of a standardised pathway for identification and formal assessment of patients with smell and taste disorders.

The Effects of Olfactory Loss and Parosmia on Food and Cooking Habits, Sensory Awareness, and Quality of Life-A Possible Avenue for Regaining Enjoyment of Food

Olfactory dysfunction often has severe consequences on patients’ quality of life. The most common complaint in these patients is their reduced enjoyment of food in both patients with olfactory loss and parosmia. How the different types of olfactory dysfunction differ in relation to food and cooking habits, sensory awareness, and food-related quality of life has not yet received much attention. By applying questionnaires on cooking, food, olfactory function, weight changes, sensory awareness, and food-related quality of life, we investigated how various aspects of eating differ between participants with olfactory loss (n = 271), parosmia (n = 251), and normosmic controls (n = 166). Cooking habits in olfactory dysfunction revealed pronounced differences as compared with normosmic controls. Cooking with olfactory dysfunction was associated with, e.g., a lack of comfort and inspiration for cooking and an inability to make new foods successfully. Significant differences in cooking were also found between olfactory loss and parosmia. Food items were less familiar in participants with olfactory loss and parosmia, while the ratings of liking food items differed between olfactory loss and parosmia, indicating the importance of adapting ingredients in meals separately for olfactory loss and parosmia. Parosmia was associated with a higher incidence of weight loss, but we found no difference in food-related quality of life between participants with olfactory loss and parosmia. While olfactory loss and parosmia have wide-ranging consequences on patients’ cooking and food habits, adapting meals to include ‘safer food items’ and integrating multisensory stimulation may be a possible avenue for improving the enjoyment of food.

A follow-up on quantitative and qualitative olfactory dysfunction and other symptoms in patients recovering from COVID-19 smell loss

BACKGROUND

Sudden smell loss is a specific early symptom of COVID-19, which, prior to the emergence of Omicron, had estimated prevalence of ~40% to 75%. Chemosensory impairments affect physical and mental health, and dietary behavior. Thus, it is critical to understand the rate and time course of smell recovery. The aim of this cohort study was to characterize smell function and recovery up to 11 months post COVID-19 infection.

METHODS

This longitudinal survey of individuals suffering COVID-19-related smell loss assessed disease symptoms and gustatory and olfactory function. Participants (n=12,313) who completed an initial survey (S1) about respiratory symptoms, chemosensory function and COVID-19 diagnosis between April and September 2020, were invited to complete a follow-up survey (S2). Between September 2020 and February 2021, 27.5% participants responded (n=3,386), with 1,468 being diagnosed with COVID-19 and suffering co-occurring smell and taste loss at the beginning of their illness.

RESULTS

At follow-up (median time since COVID-19 onset ~200 days), ~60% of women and ~48% of men reported less than 80% of their pre-illness smell ability. Taste typically recovered faster than smell, and taste loss rarely persisted if smell recovered. Prevalence of parosmia and phantosmia was ~10% of participants in S1 and increased substantially in S2: ~47% for parosmia and ~25% for phantosmia. Persistent smell impairment was associated with more symptoms overall, suggesting it may be a key marker of long-COVID illness. The ability to smell during COVID-19 was rated slightly lower by those who did not eventually recover their pre-illness ability to smell at S2.

CONCLUSIONS

While smell ability improves for many individuals who lost it during acute COVID-19, the prevalence of parosmia and phantosmia increases substantially over time. Olfactory dysfunction is associated with broader persistent symptoms of COVID-19, and may last for many months following acute COVID-19. Taste loss in the absence of smell loss is rare. Persistent qualitative smell symptoms are emerging as common long-term sequelae; more research into treatment options is strongly warranted given that even conservative estimates suggest millions of individuals may experience parosmia following COVID-19. Healthcare providers worldwide need to be prepared to treat post COVID-19 secondary effects on physical and mental health.