Isolated taste disorders in patients referred to a flavor clinic with taste and smell loss

Determination of objective taste perception among Iranian medical sciences students during COVID‑19 pandemic in Yazd, Eastern Iran: a case-control pilot study

BACKGROUND

Taste disorders in patients suffering from COVID-19 were popular. Some people even after recovery report residual effects of loss of smell and taste. This study aimed to investigate the taste Perception of Iranian Medical Sciences students during the COVID-19 pandemic.

METHODS

The case-control study evaluated 50 Medical Sciences students with a history of COVID-19 infection, as confirmed by the Novel Coronavirus (2019-nCOV) CFX96™ Real-Time PCR Detection System. The other participants consisted of 50 volunteer students with COVID-19 negative. The taste perception was measured with 4 different concentrations of the basic tastes. The stimuli were applied to the protruded tongue. Subjects were asked to identify the researcher when they felt the taste. Data are expressed as frequency distribution and analyzed with the Chi-Square test (P < 0.05).

RESULTS

In this survey, 54% of participants were male and 46% were female, the mean age of participants was 22.96 ± 5 years. The results showed a significant difference in the sweet and bitter taste perception score according to the history of dietary supplement use. The bitter taste perception score declared a considerable difference since COVID-19 infection. There was no significant difference between the taste perception in the two studied groups for all 4 basic tastes according to gender, COVID-19 infection status, history of taste and smell disorders, and the elapsed time since COVID-19 infection.

CONCLUSION

Our findings could provide important insights into taste perception. The history of dietary supplementation may influence how sweetness and saltiness are perceived. There was a noticeable difference in bitter taste perception depending on the time that had elapsed since the most recent COVID-19 infection.

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.

The Revived Interest in Ageusia Research during the COVID-19 Pandemic: A Bibliometric Analysis

The evolution of ageusia research literature has yet to be investigated. This bibliometric study analyzed the entire ageusia research literature indexed in Web of Science, to reveal its growth and the most productive entities in terms of authors, institutions, countries, journals, and journal categories. In addition, this study aimed to identify medical conditions (and their treatments) that were frequently associated with ageusia. On 7 March 2022, the Web of Science Core Collection database was accessed with the following search query: TS = (ageusia OR "taste loss" OR "loss of taste" OR "loss of gustat*" OR "gustatory loss"). The search identified publications mentioning these terms in their title, abstract, or keywords. No additional filters were placed on publication year, language, etc. The basic publication and citation counts were extracted from the in-built functions of the database. The complete record of the publications was exported into VOSviewer, a bibliometric software for visualizations. The search yielded 1170 publications. The cumulative publication and citation counts of the ageusia research sharply increased in 2020. The most productive author was Professor Thomas Hummel from Technische Universität Dresden. Ageusia research had heavy contributions from the United States, Italy, the United Kingdom, Germany, and India. The top 5 most productive journals mainly belonged to the otorhinolaryngology and medicine categories. The medical conditions frequently investigated in ageusia research included COVID-19, cancers (head and neck, and advanced basal cell), Guillain-Barré syndrome, neurodegenerative diseases, diabetes, and Sjogren's syndrome. This study could act as a begvinner's guide for (1) clinicians who are not familiar with ageusia so that they might better understand which scenarios they need to be more aware of since ageusia could be a co-morbidity of a patient's underlying disease, and (2) for those who wish to search for relevant authors and journals for suitable publications related to the topic.

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.

Isolated taste disorders in patients referred to a flavor clinic with taste and smell loss

BACKGROUND AND AIM

Approximately five percent of the general population are suffering from taste disorders. Usually, subjective loss of taste is caused by smell disorders; thus, isolated loss of the sense of taste is relatively rare. Despite the influence on quality of life, isolated taste disorders (ITD) are sparsely represented in literature and clinical research. In particular, there is need for sufficient diagnostic and treatment algorithms. Aim of study is to add further information to the sparse literature on ITD and suggest an appropriate diagnostic algorithm for ITD.

METHODS

We present a retrospective study on patients with ITD diagnosed at the Flavour clinic, ENT department, Regional Hospital West Jutland, between 2017 and 2020. All patients underwent a thorough rhinolaryngological and otoneurologic examination, including olfactory and gustatory assessment, and a wide spectrum of biochemical, microbiological, and radiological examinations.

RESULTS

In total, 522 patients referred due to smell and/or taste disorders, 423 (81%) complained of a subjective taste disorder, only 19 (3.4%) patients were diagnosed with ITD. According to etiology, the patients were categorized in following groups: medicine-related (25%), mixed (21%), iatrogenic (21%), idiopathic (11%), radiotherapy-related (11%), and autoimmune/inflammatory (11%). Based on etiology, individualized treatment was recommended with very discouraging results.

INTERPRETATION

Diagnostics of taste disorders is a delicate and expertise demanding task. The mechanisms underlying isolated loss of taste are heterogeneous. ENT and otoneurologic examination, and specific olfactory and gustatory testing are required in all patients, whereas biochemical, microbiological, and radiological examinations are only necessary on an individual basis.