Altered smell and taste: Anosmia, parosmia and the impact of long Covid-19.

BACKGROUND: Qualitative olfactory (smell) dysfunctions are a common side effect of post-viral illness and known to impact quality of life and health status. Evidence is emerging that taste and smell loss are common symptoms of Covid-19 that may emerge and persist long after initial infection. The aim of the present study was to document the impact of post Covid-19 alterations to taste and smell. METHODS: We conducted exploratory thematic analysis of user-generated text from 9000 users of the AbScent Covid-19 Smell and Taste Loss moderated Facebook support group from March 24 to 30th September 2020. RESULTS: Participants reported difficulty explaining and managing an altered sense of taste and smell; a lack of interpersonal and professional explanation or support; altered eating; appetite loss, weight change; loss of pleasure in food, eating and social engagement; altered intimacy and an altered relationship to self and others. CONCLUSIONS: Our findings suggest altered taste and smell with Covid-19 may lead to severe disruption to daily living that impacts on psychological well-being, physical health, relationships and sense of self. More specifically, participants reported impacts that related to reduced desire and ability to eat and prepare food; weight gain, weight loss and nutritional insufficiency; emotional wellbeing; professional practice; intimacy and social bonding; and the disruption of people's sense of reality and themselves. Our findings should inform further research and suggest areas for the training, assessment and treatment practices of health care professionals working with long Covid.

Health-Related Quality of Life in Adult Patients with Craniopharyngioma.

OBJECTIVE: Craniopharyngiomas (CPs) are benign, dysontogenetic tumors associated with complex endocrinologic and neurologic symptoms and high morbidity. The aim of this study is to elucidate modifiable effectors of health-related quality of life (HrQoL) of adult patients with CP following neurosurgical intervention using standardized instruments as well as descriptive analysis. METHODS: HrQoL (European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire C30 and BN20) was evaluated in 20 adult patients with CP. We examined pre- as well as postoperative radiologic, hormonal, and symptom-oriented data in a retrospective analysis. Surgical approach, postoperative complications, and extent of resection were recorded. Additional descriptive analysis was performed on case records of all patients with HrQoL results. RESULTS: Long-term follow-up of HrQoL (mean of 75 months) was lower than the in healthy reference group (CP = 58, reference = 75). The most common postoperative complaints were endocrinologic disturbances (88%). Overall, univariate and multivariate logistic regression analysis revealed no significant predictors of reduced postoperative HrQoL. Descriptive analysis did, however, reveal a cluster of patients among those with the lowest global HrQoL which reported new postoperative anosmia and ageusia. CONCLUSIONS: The global HrQoL of our cohort showed a substantial reduction compared with a healthy reference population. Postoperative hyposmia and ageusia is found in patients with the lowest postoperative HrQoL who otherwise had no new significant endocrinologic or neurologic complications. As these symptoms are not regularly accounted for in the HrQoL instruments used in this study, further analysis is needed to determine the possible significance of this complication in CP surgery, and it may affect the choice of surgical approach as well as the information patients receive before consenting to surgery.

Is loss of smell an early predictor of COVID-19 severity: a systematic review and meta-analysis.

Anecdotal evidence suggests that the severity of coronavirus disease of 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is likely to be distinguished by variations in loss of smell (LOS). Thus, we conducted a meta-analysis of 45 articles that include a total of 42,120 COVID-19 patients from 17 different countries to demonstrate that severely ill or hospitalized COVID-19 patients have a lesser chance of experiencing LOS than non-severely ill or non-hospitalized COVID-19 patients (odds ratio = 0.527 [95% CI 0.373-0.744; p < 0.001] and 0.283 [95% CI 0.173-0.462; p < 0.001], respectively). We also proposed a possible mechanism underlying the association of COVID-19 severity with anosmia, which may explain why patients without sense of smell develop severe COVID-19. Variations in LOS according to the severity of COVID-19 is a global phenomenon, with few exceptions. Since severely ill patients have a lower rate of anosmia, patients without anosmia should be monitored more closely in the early stages of COVID-19, for early diagnosis of severity of illness. An understanding of how the severity of COVID-19 infection and LOS are associated has profound implications for the clinical management and mitigation strategies for the disease.

Validation of Olfactory Questionnaire in Koreans: an Alternative for Conventional Psychophysical Olfactory Tests.

BACKGROUND: The patients with coronavirus disease 2019 (COVID-19), a worldwide pandemic infection, frequently complain of olfactory disorders. However, psychophysical olfactory tests performed by an examiner are very difficult in these highly infectious patients. This study aimed to develop and validate a questionnaire for olfactory function that can be readily used to evaluate olfactory loss. METHODS: Fourteen smell-related questions were created based on smells familiar to Koreans. Among them, questions with a κ value of 0.6 or higher were finally selected through a test-retest reliability analysis. The correlations between the scores of the olfactory questionnaire and those of olfactory function tests (Butanol Threshold Test [BTT] and Cross Cultural Smell Identification Test [CCSIT]) were analyzed. To evaluate the predictive ability of the questionnaire and elicit cutoff values, receiver operating characteristic (ROC) curves were generated. RESULTS: Out of the 14 questions in the questionnaire, 11 (κ > 0.6) were selected for the olfactory questionnaire. We analyzed 2,273 subjects, and there was a significant correlation between the total score of the olfactory questionnaire and the BTT (r = 0.643, P < 0.001) or CCSIT (r = 0.615, P < 0.001) scores. ROC curves for the olfactory questionnaire, BTT, and CCSIT all demonstrated high predictive power to discriminate anosmia and severe hyposmia from normosmia. Regarding mild to moderate hyposmia, however, ROC curve for the olfactory questionnaire alone showed high predictive power of discrimination from normosmia. Based on the results of ROC curves among the subclasses, we suggest the classification of the total score of the questionnaire as 0-4, 5-17, 18-27, 28-41, and 42-44, for anosmia, severe hyposmia, moderate hyposmia, mild hyposmia, and normosmia, respectively. CONCLUSION: The total scores of the questionnaires correlated with the BTT and CCSIT scores. The symptom questionnaire for olfactory dysfunction may be useful as an alternative tool for olfactory function testing, when unavailable.

MT2 melatonin receptors expressed in the olfactory bulb modulate depressive-like behavior and olfaction in the 6-OHDA model of Parkinson's disease.

Melatonin MT1 and MT2 receptors are expressed in the glomerular layer of the olfactory bulb (OB); however, the role of these receptors has not been evaluated until now. Considering the association of the OB with olfactory and depressive disorders in Parkinson's disease (PD), we sought to investigate the involvement of melatonin receptors in these non-motor disturbances in an intranigral 6-hydroxydopamine (6-OHDA)-lesioned rat model of PD. We demonstrate the presence of functional melatonin receptors in dopaminergic neurons of the glomerular layer. Local administration of melatonin (MLT, 1 µg/µl), luzindole (LUZ, 5 µg/µl) or the MT2-selective receptor drug 4-P-PDOT (5 µg/µl) reversed the depressive-like behavior elicited by 6-OHDA. Sequential administration of 4-P-PDOT and MLT (5 µg/µl, 1 µg/µl) promoted additive antidepressant-like effects. In the evaluation of olfactory discrimination, LUZ induced an olfactory impairment when associated with the nigral lesion-induced impairment. Thus, our results suggest that melatonin MT2 receptors expressed in the glomerular layer are involved in depressive-like behaviors and in olfactory function associated with PD.

Psychophysical evaluation of chemosensory functions 5 weeks after olfactory loss due to COVID-19: a prospective cohort study on 72 patients.

PURPOSE: To evaluate the evolution of chemosensation via extended psychophysical testing in patients who suffered from sudden chemosensory loss due to coronavirus disease 2019 (COVID-19). Additionally, this study sought to determine whether odor threshold testing provided additional information on olfactory loss due to COVID-19 compared to the more common odor identification testing. METHODS: Prospective cohort study of patients with sudden chemosensory loss since February 2020 and confirmed COVID-19 infection via RT-PCR or serology testing. Olfactory function was tested extensively using the "Sniffin Sticks" test battery. In addition, we screened gustatory perception and nasal cooling sensations using psychophysical tests. RESULTS: Seventy-two patients completed the study. After a mean of 37 days, 37% of patients showed olfactory dysfunction, 7% were dysgeusic, and 48% showed signs of low sensitivity for cooling sensation. A longer duration of anosmia before smell improvement was correlated with lower olfactory function at 5 weeks. Odor threshold detection was more affected by COVID-19 compared to odor identification. CONCLUSION: Five weeks after developing sudden chemosensory loss due to COVID-19, a high proportion of patients were dysosmic and showed signs of low nasal cooling sensitivity, whereas most of them had normal taste function. SARS-CoV-2 affected mainly odor thresholds, possibly suggesting that the major cause of loss of smell lies at the level of the olfactory neuroepithelium, rather than in the central nervous system.

Consequences of undetected olfactory loss for human chemosensory communication and well-being.

Olfactory perception has implications for human chemosensory communication and in a broader context, it affects well-being. However, most of the studies investigating the consequences of olfactory loss have recruited patients who have already been categorized as having a dysfunctional sense of smell and sought help in an ENT clinic. We revisit these findings by distinguishing subjects with olfactory impairment from a group of subjects who all declared a normal sense of smell when enrolling for this study. In the initial sample of 203 individuals, we found 59 to have impaired olfaction and four with marginal olfactory performance, not useful in daily life. Interestingly, we found a significant between-group difference in cognitive functioning, further supporting the notion of the relationship between cognition and olfactory performance. However, their chemosensory communication and well-being appeared not to be different from subjects with normosmia. Impaired olfactory function certainly has a severe impact on daily life but more so in individuals who are bothered with it and decide to seek treatment. The limited-to-no olfactory perception in the fraction of subjects who neither complain about it nor seek help in ENT clinics does not seem to have a major effect on their social, cognitive, emotional and health functioning. This article is part of the Theo Murphy meeting issue 'Olfactory communication in humans'.

Cultural determinants of food attitudes in anosmic patients.

The decrease in food enjoyment is a major factor why patients suffer from depression when having anosmia, or total loss of smell. While we have some knowledge about how food preferences and attitudes change with dysosmia, these findings are limited because other factors such as culture are not factored in. It is likely that the culture in which an anosmic patient identifies with will influence how their smell loss impacts their relationship with food. This study examined the current attitudes within the United States and Germany towards foods, focusing on the comparison between anosmic patients (N = 53) and those with a healthy sense of smell (N = 121). A survey was used to collect free responses for liking on a variety of foods (N = 15) that were also rated for their overall liking. Additionally, individuals rated and ranked their liking for sensory attributes in relation to their enjoyment of food. Free responses were classified into categories and subcategories, the frequency of those responses were then compared across groups. The patient population of each culture gave lower importance to aroma and flavor; however, the U.S.A. patient population showed a larger decrease from their healthy counterparts. Furthermore, anosmic patients from the U.S.A. showed less overall liking towards the food stimuli compared to their healthy counterparts, while no such effect observed among the German population. Reasons to enjoy a food were largely explained by the culture, and patients within a culture took on different compensation strategies which we use to explain their effectiveness.