Gustatory Test Research Articles

COGMED: a database for Chinese olfactory and gustatory metaphor

In recent years, metaphors have been used to understand how abstract concepts are processed, and developing metaphorical database can aid this research agenda. Accordingly, the present study aimed to produce a broad Chinese olfactory and gustatory database of metaphors. Expressions for two sensory types (olfaction/gustation) were compiled and classified according to two conditions (metaphorical/literal) and three parts of speech (adjective/noun/verb). To test the validity of this database, we enrolled 199 participants, of whom 97 completed the olfactory test (319 items) and 102 completed the gustatory test (352 items). Each item was rated on seven dimensions: familiarity, meaningfulness, figurativeness, valence, difficulty, imageability, and naturalness. Descriptive statistics and reliability and correlation analyses were conducted for the items under the two sensory types, two conditions, three parts of speech, and seven dimensions mentioned above. The results showed high internal consistency and split-half reliability for the participants’ scores; the correlations between the seven dimensions resembled those of previous studies. We concluded by suggesting several ways the database might be applied to aid future research efforts.

Smell and Taste Alterations in Patients Receiving Curative or Palliative Chemotherapy-The CONKO 021-ChemTox Trial.

Previous data regarding chemotherapy-induced olfactory and gustatory dysfunction (CIOGD) are heterogeneous due to inconsistent study designs and small numbers of patients. To provide consistent, reliable data, we conducted a cohort study using standardized testing. Patients diagnosed with lymphoma, leukemia, or gastrointestinal malignancies were examined up to five times (T1 to T5), beginning prior to chemotherapy. We examined patients receiving temporary treatment up to 12 months post-therapy. Clinical assessment included extensive questionnaires, psychophysical tests of olfactory and gustatory function, and measurement of peripheral neuropathy. Statistical analysis included non-parametric tests to evaluate the longitudinal development of CIOGD. Our data (n = 108) showed a significant decline in olfactory and gustatory testing during chemotherapy (p-values < 0.001). CIOGD appeared stronger among patients above 60 years, while sex did not matter significantly. However, we identified distinct associations between CIOGD and reported anorexia as well as with higher neuropathy scores. Self-assessment appeared less sensitive to chemosensory dysfunction than psychophysical testing. Post-therapy, olfactory and gustatory function regenerated, though baseline levels were not attained within 6 to 12 months. In conclusion, our data highlight the wide prevalence and slow recovery of CIOGD. Understanding CIOGD as a potential neurotoxic effect may disclose new therapeutic prospects.

Subjective versus Psychophysical Measures of Chemosensory Alterations following COVID-19

Introduction: Olfactory dysfunction is a common symptom of COVID-19. However, subjective perception of olfactory function does not always correlate well with more objective measures. This study seeks to clarify associations between subjective and psychophysical measures of olfaction and gustation in patients with subjective chemosensory dysfunction following COVID-19. Methods: Adults with persistent COVID-19-associated chemosensory disturbance were recruited for a prospective, longitudinal cohort study at a tertiary care institution. Participants provided subjective measures of olfactory and gustatory function and underwent psychophysical assessment using Sniffin’ Sticks olfactory and Monell gustatory tests. Results: Data analysis (n = 65) showed a statistically significant association between subjective and psychophysical measures of olfaction (p < 0.001). For each one-point increase in subjectively-reported olfactory ability, there is, on average, a 0.11 (95% CI: 0.06, 0.16; p < 0.001) point increase in TDI score while adjusting for age at baseline assessment, sex, and follow-up time. For each one-point increase in subjectively-reported olfactory ability, there is, on average, a 0.04 (95% CI: 0.02, 0.06; p < 0.001) point and 0.05 (95% CI: 0.03, 0.07; p < 0.001) point increase in discrimination and identification scores, respectively, when adjusting for age at baseline assessment, sex, and follow-up time. Conclusion: Subjective olfaction shows a mild to moderate association with psychophysical measures, but it fails to comprehensively assess persistent COVID-19-associated chemosensory deficits. The lack of significant association between subjective olfaction and threshold limits the utility of subjective olfaction in tracking recovery. These findings support the push for more widespread psychophysical chemosensory testing.

Individuals who have been infected with SARS‐CoV‐2 remain with lowered taste and smell sensory‐processing sensitivity: A case study

AbstractThis research aimed to investigate the occurrence and prevalence of possible changes in the sensory perception of individuals who presented total or partial loss of smell or taste when infected by SARS‐CoV‐2, comparing the results with those of individuals who were not diagnosed with the disease and did not show typical symptoms of the infection. One hundred volunteers were recruited, of whom 50 were from the group of people who had COVID‐19 and had signs of smell or taste dysfunction (COVID group), and 50 were from the group of people who did not have the disease and did not show symptoms of the disease (Control group). Gustatory tests were performed to evaluate four primary tastes: sweet, salty, sour, and bitter, and olfactory tests were performed to assess odors: coffee, pineapple, lime, and cinnamon. To determine the detection and recognition thresholds, three‐alternative forced‐choice sessions of tastes and odors were carried out, and intensity scales were used to verify the sensory perception of the participants. Significant differences were confirmed between the groups (Control and COVID) for the detection and recognition thresholds for all tastes and odors. Sour taste was significantly affected in terms of detection and recognition, suggesting that COVID group shows lower sensitivity concerning this taste. Pineapple odor was the most difficult of being recognized by COVID group. The intensity attributed to the stimuli by the COVID group were lower than those of the Control group and differed statistically at the highest concentrations. Data show that individuals in COVID group remained with gustatory and olfactory alterations in sensitivity, detection, and recognition capacity.Practical ApplicationsThis research demonstrated the prevalence of symptoms of sensory‐processing disorders related to gustatory and/or olfactory functions in individuals who tested positive for COVID‐19, even after been cured of the infection. They had sensory alterations in terms of detection and recognition capacity, as well as sensitivity. In practice, several factors associated with quality of life are impaired due to sensory‐processing disorders, such as food, personal hygiene, safety, and physical or mental illnesses, which lead to a necessity of monitor these individuals as these factors are related to public health.

Interoceptive abilities impairment correlates with emotional eating and taste abnormalities in children with overweight and obesity

Weight problems in children are associated with emotional eating, which has been linked to interoceptive abilities. Previous research also shows altered olfactory and gustatory perception in children with obesity and overweight. Therefore, we aimed to investigate the connection of alterations in olfactory and gustatory perception to interoceptive abilities and emotional eating among children with obesity and overweight. 23 children with overweight and obesity and age-matched controls with normal weight (12–16 years old) underwent olfactory and gustatory testing. Interoceptive abilities were assessed, focusing on interoceptive accuracy and interoceptive sensibility. Children with overweight and obesity showed significantly higher accuracy for detection of sweet taste, but descriptively lower accuracy for all other taste qualities compared to normal weight children. We found no changes in olfactory abilities in children with overweight and obesity. Emotional eating scores were elevated for children with overweight and obesity, and interoceptive accuracy scores were significantly lower. In both groups, interoceptive accuracy was inversely correlated with emotional eating. Our results support prior findings of altered gustatory abilities in children with overweight and obesity. The observed link between impaired interoceptive processes and heightened emotional eating in this group implies that interventions for overweight in children could benefit from targeting interoceptive abilities. This study provides meaningful grounds for further investigations into the roles of taste, emotional eating, and interoceptive abilities for overweight in children and adolescents.

Über Geschmack lässt sich nicht streiten?

ZusammenfassungIn diesem Artikel wird eingehend untersucht, welche auf den Erwerb von Wissen bezogene Rolle die Geschmackswahrnehmung in der Forschung zu den einzelnen Pharmaka bei dem römischen Arzt Galen von Pergamon spielt. Hierzu wird 1.) durch eine Quellenuntersuchung plausibel gemacht, dass die gegenüber seinen Vorgängern – insbesondere Dioskurides und Sextius Niger – mitunter vermehrten, detaillierteren und abweichenden Geschmacksangaben auf eigenen Forschungen Galens beruhen, 2.) die Forschungspraxis Galens rekonstruiert und 3.) die Darstellung seiner Ergebnisse in sprachlicher und logischer Hinsicht untersucht sowie die Besonderheit gegenüber der traditionellen Arzneimittellehre herausgestellt. Ausgehend davon wird dafür plädiert, a) dass der gustatorischen Wahrnehmung bei Galen eine besondere Bedeutung zukommt, die über ihre traditionell deskriptive Funktion weit hinausweist, indem er b) ausgehend von der Erkenntnis, dass Geschmack und Arzneimittelwirkung zusammenhängen, den Geschmacksqualitäten eine Indikatorfunktion zuweist für ein viel grundlegenderes, die Arzneimittelwirkung verursachendes Prinzip, und somit c) den Boden bereitet hat für eine auch nach Geschmacksprinzipien einteilende Pharmakognosie, die ihren Höhepunkt erst sehr viel später erreichen sollte. Mit Blick auf eine bis heute ausgeübte Praxis der gustatorischen Prüfung pflanzlicher Drogen in der Pharmazie, die wie jede andere naturwissenschaftliche Disziplin den sinnlichen Bezug zu ihrem Gegenstand ansonsten weitgehend verloren hat, möchte der Beitrag daher einen Anreiz geben, die „Geschichte pharmazeutisch-medizinischen Schmeckens“ zu studieren.

COVID-19 Induced Elimination of First Taste Phenomenon (P5-10.002)

<h3>Objective:</h3> Correlation of First Taste Phenomenon elimination with COVID-19 infection <h3>Background:</h3> First Taste Phenomenon, whereby perception of flavor occurs at first bite and then dissipates is associated with chemosensory loss (Hirsch, 2018). Elimination of this Phenomenon associated with COVID-19 has not been described. <h3>Design/Methods:</h3> This 62 year old right handed man presented with upper respiratory tract infection induced chemosensory loss that resolved after treatment of 9 g of phosphatidylcholine. His smell declined to 50% of normal. Taste was lost but he retained his first taste phenomenon. He tested positive for COVID-19 presenting with loss of chemosensation which did not resolve despite treatment with nirmatrelvir/ ritonavir. Symptoms of COVID-19 improved after infection resolution, but First Taste Phenomenon never returned. <h3>Results:</h3> Neurological Abnormalities: Gustatory Testing: Taste threshold: Hypogeusia of 10–30% to sucrose. Electrogustometry Testing: left (L) posterior tongue: 34 (abnormal), right (R) posterior tongue: 34 (abnormal), L anterior tongue: 34 (abnormal), R anterior tongue: 30 (abnormal). Right palate: &gt;32 (abnormal), left palate: &gt;32 (abnormal). Taste Quadrant Testing: Front to back: decreased anteriorly to Sodium Chloride, Sucrose, Quinine Hydrochloride. <h3>Conclusions:</h3> The semiology of First Taste Phenomenon includes Classic First Taste Syndrome with full flavor of food followed by rapid, less than 1 minute, decrement in flavor of food (Hirsch, 2018). Retronasal smell inducing flavor perception as nidus to First Taste Syndrome (Djordjevic, 2004) could be eliminated after COVID-19 infection, which reduces retronasal smell, and induce perceived taste loss (Parma, 2020). This First Taste Phenomenon attributes to temporal decrement in saliva as a consequence of persisted mandibulation-reducing taste threshold sensitivity (Weiffenbach, 1995). COVID-19 worsens such hyposalivation (da Mota Santana, 2021). COVID-19 may eliminate first taste and cause CNS dysfunction via ACE type 2 taste receptor cells dysfunction, (Mastrangelo, 2021) and cytokine storm respectively (Hintschich, 2021). Those with preexisting chemosensory dysfunction, association of COVID on remaining chemosensation is warranted. <b>Disclosure:</b> Miss Birwatkar has nothing to disclose. Mrs. Kalita has nothing to disclose. Dr. Hirsch has nothing to disclose.

Too Sweet to Eat: Delusional Hypergeusia

AbstractIntroductionDelusional hypergeusia has not heretofore been reported.Methods: Case reportA 62-year-old right-handed woman described a plethora of complaints after exposure to a solvent aroma, including headaches, diffuse weakness, fatigue, hallucinated smells and tastes, burning mouth syndrome, and panic attacks. The apogee of her symptoms was that salty taste was 800% of normal, making food taste disgustingly salty. She was unable to tolerate potato chips, pizza, spaghetti sauce, Coca Cola, root beer, Sprite, 7 Up, and even bottled water. Sugar was also too sweet, 600% of normal. Foods which were unbearably sweet included cookies, sugar, and breakfast cereals. Sour and bitter were normal.ResultsAbnormalities in Neurological Examination: Mental Status Examination: hyperverbal, loud, overly inclusive, irritable with pressured speech; disheveled, racing thoughts, and tangential. Motor Examination: Drift Test: right pronator drift with right abductor digiti mini sign. Gait Examination: heel walking with bilateral decreased arm swing. Reflexes: bilateral quadriceps femoris 3+, positive left (L) Hoffman’s reflex. Chemosensory Testing: Olfaction: Brief Smell Identification Test: 12 (normosmia). Retronasal Olfactory Testing: Retronasal Smell Index: 1 (Anosmia). Gustatory Testing: Propylthiouracil Disc Taste Test: 10 (normogeusia). Waterless Empirical Taste Test: sweet: 4, sour: 3, salty: 7, bitter: 5, brothy: 0, total: 30 (ageusia to umami, otherwise normogeusia). Neuropsychiatric Testing: Go-No-Go Test: 2/6 (abnormal).DiscussionPerhaps hypergeusia may not have been true hypergeusia but a misperception of retronasal smell associated hyperosmia with physiologic synesthesia manifested as taste. Peradventure, the perceived hypergeusia, is just one component of a generalized delusional paradigm, where many sensory perceptions are intensified. The perceived delusional hyperosmia may be intensification of the sensory misperception due to an underlying dysgeusia. This may represent a variant of the two-factor hypothesis of delusions whereby a distorted sensory perception is then misrepresented in a delusion. Dysfunction of the right hemisphere, which normally acts to censor the left, allows the delusion to manifest. While two different anatomical abnormalities (one left and one right hemisphere) have been postulated to be the foundation of such delusions, it is distinctly possible that a single lesion of the inferior parietal lobule may be sufficient for both sensory distortions to be produced as well as loss of inhibition of delusional interpretation of distorted sensation of the frontal lobe by the right parietal lobe, yclept the sensorialist hypothesis. In those who present with hypergeusia, search for delusional origin is warranted and in those who present with delusions, query as to perceived hypergeusia may be revealing.FundingNo Funding

Gustatory dysfunction is related to Parkinson's disease: A systematic review and meta-analysis.

Olfactory dysfunction has been reported to be involved in Parkinson's disease (PD) pathogenesis. However, gustatory dysfunction in PD has not been evaluated as in-depth as olfactory dysfunction. We reviewed the previously published studies regarding gustatory function in PD patients and suggested the possibility that gustatory dysfunction may also be associated with PD. MEDLINE, Cochrane Library, Embase, and PubMed databases were searched for studies evaluating gustatory function in PD patients. We used the standardized mean difference and a 95% confidence interval (CI) as the effect analysis index regarding the taste strip test. The relative risk and 95% CI were used as the effect analysis index for the questionnaires and propylthiouracil (PTU)/phenylthiocarbamide (PTC) perception test. Statistical heterogeneity was assessed using forest plots, Cochran's Q, and the I2 statistic; heterogeneity was considered high when I2 was over 75%. Publication bias was assessed by funnel plots and the Egger bias test. We identified 19 articles that reported the results of gustatory function tests in PD patients and healthy controls. Most of these studies used various gustatory tests, including taste strips, questionnaires, taste solutions, PTU/PTC perception tests, and electrogustometry, and reported significantly lower gustatory function in PD patients than in the controls. However, several articles reported contradictory results. Based on these studies, gustatory dysfunction is closely related to PD. However, the number of studies and enrolled subjects was small, and a unified gustatory function test was lacking. Therefore, further studies with larger populations and normalized gustatory function tests are needed.

Isolated Insular Stroke: An Interesting Report of Two Cases.

Isolated Insular Stroke: An Interesting Report of Two Cases.

The Influence of Nutritional Status and Sleep Quality on Gustatory Function in Older Adults.

Background and Objectives: Age-related declines in taste function are common. Taste acuity can be affected by nutritional status and sleep quality. This research aims to examine the effect of nutritional status and sleep quality on gustatory function in community-dwelling older adults. Materials and Methods: This cross-sectional study included 119 community-dwelling older adults (50.4% of whom were female). The gustatory function was evaluated using four liquid taste solutions (sweet, bitter, sour, and salty) each at four different concentrations and the Mini Nutritional Assessment (MNA) and Pittsburgh Sleep Quality Index (PSQI) was applied. Additionally, anthropometric measurements were taken. Results: The mean scores on the gustatory test for the sweet, bitter, sour, and salty tastes were 2.11 ± 1.27, 2.12 ± 1.03, 2.28 ± 1.03, and 1.98 ± 1.41, respectively. There were significant differences according to gender, polypharmacy, nutritional status, and sleep quality in identifying sweet tastes (all p < 0.05). It was also found that females and participants without polypharmacy had better scores for bitter tastes. When the gustatory functions were evaluated according to BMI classification, it was determined that underweight participants had a higher sour taste score than the obese ones. Multiple regression analysis revealed that age, MNA score, PSQI score, and gender accounted for a total of 20.4% of the variance in the sweet taste score. Conclusions: Determining the relationship between taste function, nutritional status, and sleep quality in older adults is important in terms of developing new strategies for older adults who have these problems.

Somatosensory and Gustatory Profiling in the Orofacial Region.

Quantitative sensory testing (QST) is a standard procedure in medicine to describe sensory patterns in various pathologies. The aim of this prospective clinical study was to define reference values of the trigeminal nerve (V3), including taste qualities, to create a compatibility for sensory loss or gain in pathologies. Fifty-one patients were included, and a standardized testing battery with 11 QST parameters according to the German Research Network on Neuropathic Pain (DFNS) was applied complemented by quantitative gustatory assessments. Significant somatosensory differences were found between the test sites (MDT at the chin, WDT at the lower lip) but no effect was detected for gender, age, and between body types. Taste sensitivity was dependent on concentration, gender (females being more sensitive) and increasing age (for bitter and sour taste). We provide reference values for somatosensory and gustatory testing of the facial area. Our data facilitate the detection of neurosensory abnormalities in the orofacial region. This might also serve as a control setting for COVID-19.

Chemosensory Dysfunction 3-Months After COVID-19, Medications and Factors Associated with Complete Recovery.

To examine the longitudinal prevalence and recovery of olfactory, gustatory, and oral chemesthetic deficits in a sizable cohort of SARS-CoV-2 infected persons using quantitative testing. To determine whether demographic and clinical factors, mainly the medications used after the COVID-19 diagnosis, influence the test measures. Prospective cohort in a hospital with primary, secondary, tertiary, and quaternary care. Patients with confirmed COVID-19 were tested during the acute infection phase (within 15 days of initial symptom, n = 187) and one (n = 113) and 3 months later (n = 73). The University of Pennsylvania Smell Identification Test, the Global Gustatory Test, and a novel test for chemesthesis were administered at all visits. During the acute phase, 93% were anosmic or microsmic and 29.4% were hypogeusic. No one was ageusic. A deficit in oral chemesthesis was present in 13.4%. By 3 months, taste and chemesthesis had largely recovered, however, some degree of olfactory dysfunction remained in 54.8%. Remarkably, patients who had been treated with anticoagulants tended to have more olfactory improvement. Recovery was greater in men than in women, but was unrelated to disease severity, smoking behavior, or the use of various medications prior to, or during, COVID-19 infection. When using quantitative testing, olfactory disturbances were found in nearly all SARS-CoV-2 infected patients during the acute infection phase. Taste or chemesthetic deficits were low. Olfactory impairment persisted to some degree in over half of the patients at the 3-month follow-up evaluation, being more common in women and less common in those who had been treated earlier with anticoagulants. 3.

Analysis of clinical characteristics in the patient with olfactory disorders

Objective:To analyze the etiology and clinical features of patients with olfactory disorders （OD） , and to explore the importance of gustatory testing in patients with OD. Methods:Clinical data of 335 consecutive patients with OD who seek medical consultation in the smell and taste center from the year 2015 to 2021 was retrospectively analyzed. The clinical characteristics of patients with OD were analyzed thorough a structured interview of medical history, otolaryngologic examinations, olfactory tests（Sniffin' Sticks test） and gustatory function test（whole-mouth taste test）. SPSS 17.0 software was used to analyze the clinical characteristics of patients with OD and related factors which have effect on gustatory function. Results:Among the patients， 36.4% of them caused by head trauma, 22.1% for upper respiratory tract infection（URTI）, 15.5% for rhinosinusitis diseases（RSD）, 11.9% for idiopathic, 9.6% for congenital anosmia, and 4.5% for other causes, respectively. The features were different in patients with different kinds of OD: most patients with head trauma were anosmic（χ²=27.958, P<0.001）, and no difference was found in gender and age（P>0.05 for both）; most patients with URTI were anosmic（χ²=21.568, P<0.001）, and female patients were more than male（χ²=5.898, P<0.05）, elder patients were more than younger（χ²=12.963, P<0.001）; most patients with RSD were anosmic（χ²=12.106, P<0.05）, and male patients were more than female（χ²=4.655, P<0.05）; elder patients were more than younger for idiopathic OD（χ²=5.284, P<0.05）, but no sex difference was found（P>0.05）; patients with congenital anosmia were all lost their smell since they were born, and no sex difference was found in the disease（P>0.05）. Fifty-seven of 146（39%） patients whose gustation was assessed had gustatory dysfunction. Gustatory function was significantly associated with the causes of OD（r=0.368, P<0.05）, but not related to olfactory function, age and sex（P>0.05 for all）. Conclusion:The leading causes of olfactory dysfunction were head trauma, URTI, RSD, and idiopathic causes. Each of OD had its own distinct clinical features. Gustatory dysfunction were common in patients with OD, and gustatory function was related to the causes of OD. High priority should be given to gustatory function evaluation for the patients with OD.

Correlation between Post-COVID-19, Chemosensitive Function, Blood Group, and Oral Health-Related Quality of Life.

Materials and Methods A cross-sectional information on demographics, symptomatic disease status, ABO blood group, and oral health-related quality of life (OHRQoL) was collected among 100 patients who were earlier tested positive for COVID-19 reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and were now reporting to the College of Dentistry for routine treatment after recovery. Objective evaluation of olfactory and gustatory disturbances was elicited using the Connecticut Chemosensory Clinical Research Center (CCCRC) test and gustatory function testing. Furthermore, OHRQoL was assessed using Oral Health Impact Profile (OHIP-14). Results More than half of the patients (62%) had some form of olfactory dysfunction/alteration, and 42% had poor CCCRC scores. About 14% reported ageusia, while 68% reported some form of taste alterations, and 55% reported poor OHRQoL. A statistically significant difference was reported between different ABO blood groups and subjective loss of smell (p < 0.05). The subjective loss of taste, CCCRC score, and dysgeusia were found to be independent of OHIP-14 (p > 0.05), but the taste intensity score was dependent on OHIP 14 (p < 0.05). Moreover, a majority (70.8% and 70.0%) with poor OHIP-14 scores had taste intensity scores of 3 and 4, respectively, while those with moderate (68.4% and 48.6%) OHIP-14 had scored 1 and 2, respectively. Conclusion Olfactory and gustatory disturbances were found to be a long-term feature in post-COVID-19 patients. The blood group is a predisposing factor for persistent smell alterations in post-COVID-19 patients.

Gustatory Function in Acute COVID-19 - Results From Home-Based Psychophysical Testing.

ObjectiveGustatory function during COVID‐19 is self‐reported by around 50% of patients. However, only a few studies assessed gustation using psychophysical testing during acute infection. The objective of this study is to test gustatory function on threshold tests in the very first days of COVID‐19.MethodsPsychophysical testing consisted of validated and blinded tests for olfaction (NHANES Pocket Smell Test) and gustation (Taste Strips Test). These test kits were sent to home‐quarantined patients and self‐administered using a detailed instruction sheet.ResultsA total of 51 patients were included in this study. Testing was performed 6.5 ± 2.7 days after sampling of respiratory swabs. At this time 37% of patients stated to currently experience a gustatory impairment. The mean Taste Strips score was 10.0 ± 3.4 with 28% scoring in the range of hypogeusia. Interestingly, no significant difference in the results of gustatory testing could be observed between the group with subjectively preserved gustation and the group with self‐rated taste impairment.ConclusionDuring the very first days of COVID‐19, psychophysical gustatory testing revealed hypogeusia in 28%. This is far lower than patients' self‐reports. Different from previous studies, we did not find clear evidence for an impairment of only certain taste qualities.Level of Evidence3 Laryngoscope, 132:1082–1087, 2022

Oxalic acid in ginger specifically denatures the acrid raphides in the unprocessed dried tuber of Pinellia ternata

Abstract Objective: Pinellia Tuber, the dried tuber of Pinellia ternata, is widely used in Japanese Kampo medicines and traditional Chinese medicines. The unprocessed Pinellia Tuber is known to cause very strong acrid irritation at oral and laryngopharynx mucosa. Recent studies have shown that the sharp needle-like crystals called raphides, that are composed of calcium oxalate and proteins, are the main causative substances of the irritation. Ginger, the rhizome of Zingiber officinale, has been used in the processing to reduce the acridity of Pinellia Tuber since before the sixth century, however, the mechanisms of reducing acridity have not been scientifically proved yet. Methods: We developed the raphides denaturation assay (RDA) to quantify the degree of denaturation in the raphides to cause irritation. By their lipophilic characters, the raphides could be extracted in petroleum ether (PE) layer from powdered Pinellia Tuber suspended in water, and the contents of the raphides in PE layer were measured by the absorbance. By this assay, we conducted the activity-guided fractionation from the boiling water extract of ginger to find the ingredients to denature the raphides. We also conducted the gustatory tests to detect the change of the irritation of the denatured raphides. Results: The treatment of powdered Pinellia Tuber suspension with ginger extract reduced the distribution of raphides in PE layer in RDA in a concentration-dependent manner. The activity-guided fractionation using RDA revealed that oxalic acid was the main active ingredient in ginger extract to denature the raphides of Pinellia Tuber. Oxalic acid reduced the lipophilicity of the raphides in the thermo-, time-, and concentration-dependent manners, and its activity was affected by pH. The treatment of powdered Pinellia Tuber suspension with oxalic acid significantly reduced its acrid irritation in gustatory test in human. Conclusions: We found that oxalic acid is the main active ingredient in ginger to reduce the acrid irritation of Pinellia Tuber.

Gustatory event-related potential alterations in olfactory dysfunction patients.

The phenomenon that longstanding impaired olfactory function is associated with the decreased gustatory function was described in present studies, which was seems attributed to mutual chemosensory interactions. And the interaction between olfaction and gustation still needs more research to figure out. The objective of the study was to investigate how the taste was influenced by olfactory impairment in the central pathway. We tested 33 subjects with normal (n = 19) or impaired (n = 14) olfactory function for their gustatory event-related potentials (gERPs). Validated tests were used for olfactory and gustatory testing (Sniffin’ Sticks, gERPs, and three-drop test). This study reported an objective gustatory function decline in olfactory dysfunction participants. However, it also reported the increased gustatory event-related potentials of olfactory dysfunction participants, especially at the frontal electrode (FZ) and electrode 16 (E16), and the reduced latency of P2 peak of them at electrode 21 (E21), while no obvious difference was observed at the centro-parietal electrode (PZ). Inferior insula might be the main response area for the increase in gERPs, and this increase averaged amplitude of the P2 component may attribute to compensation of the secondary gustatory response that occurred in the gustatory processing of olfactory-impaired patients.

Exploring the Clinical Utility of Gustatory Dysfunction (GD) as a Triage Symptom Prior to Reverse Transcription Polymerase Chain Reaction (RT-PCR) in the Diagnosis of COVID-19: A Meta-Analysis and Systematic Review.

Background: The diagnosis of COVID-19 is made using reverse transcription polymerase chain reaction (RT-PCR) but its sensitivity varies from 20 to 100%. The presence of gustatory dysfunction (GD) in a patient with upper respiratory tract symptoms might increase the clinical suspicion of COVID-19. Aims: To perform a systematic review and meta-analysis to determine the pooled sensitivity, specificity, positive likelihood ratio (LR+), negative likelihood ratio (LR−) and diagnostic odds ratio (DOR) of using GD as a triage symptom prior to RT-PCR. Methods: PubMed and Embase were searched up to 20 June 2021. Studies published in English were included if they compared the frequency of GD in COVID-19 adult patients (proven by RT-PCR) to COVID-19 negative controls in case control or cross-sectional studies. The Newcastle-Ottawa scale was used to assess the methodological quality of the included studies. Results: 21,272 COVID-19 patients and 52,298 COVID-19 negative patients were included across 44 studies from 21 countries. All studies were of moderate to high risk of bias. Patients with GD were more likely to test positive for COVID-19: DOR 6.39 (4.86–8.40), LR+ 3.84 (3.04–4.84), LR− 0.67 (0.64–0.70), pooled sensitivity 0.37 (0.29–0.47) and pooled specificity 0.92 (0.89–0.94). While history/questionnaire-based assessments were predictive of RT-PCR positivity (DOR 6.62 (4.95–8.85)), gustatory testing was not (DOR 3.53 (0.98–12.7)). There was significant heterogeneity among the 44 studies (I2 = 92%, p < 0.01). Conclusions: GD is useful as a symptom to determine if a patient should undergo further testing, especially in resource-poor regions where COVID-19 testing is scarce. Patients with GD may be advised to quarantine while repeated testing is performed if the initial RT-PCR is negative. Funding: None.

Effects of acoustic fMRI-noise on taste identification, liking, and intensity

• First study to compare gustatory perception in a silent and fMRI-noise setting. • Participants underwent gustatory testing in a silent and fMRI-noise setting in randomised groups. • No significant effect of loud acoustic fMRI noise on taste perception (liking, intensity, or identification) was found. • fMRI noise does not seem to constitute a systematic confounder in gustatory research. • Further research should be conducted with regards to other potential confounders. In this paper, we investigated the possible effect of loud, acoustic noise produced by an fMRI-scanner on gustatory perception compared to a silent setting. The purpose was to assess whether the loud acoustic noise produced during fMRI acquisition could constitute a systematic confounder in most human gustatory research. To date, this issue has not yet been addressed. To evaluate this, fifty participants were tested in a randomised order in an fMRI-noise setting and a quiet setting, respectively. We found no significant effect of loud, acoustic fMRI noise on taste perception, including identification, certainty of identification, perceived intensity and hedonic rating. Thus, the profound acoustic commotion experienced by subjects undergoing an fMRI does not seem to constitute a systematic confounder in gustatory research.