Gustatory Thresholds Research Articles

Unilateral Increase of Gustatory Thresholds in Acute Otitis Media: A Pilot Study.

To evaluate chorda tympani nerve function as measured by unilateral increases of gustatory thresholds in the presence of ipsilateral acute otitis media. Prospective clinical study comparing electrogustometric measurements was conducted to evaluate the taste thresholds of each side of the tongue in a patient during an acute episode of unilateral acute otitis media. Included were patients aged 12-40 who presented to the emergency department and outpatient ear, nose, and throat clinic of a university-affiliate tertiary medical center with unilateral acute otitis media between January 2019 and January 2020 and consented to the study. Eleven patients were initially recruited into the study, and 10 patients aged (mean ± standard deviation) 26.1 ± 11.2 years comprised the final study group. Taste thresholds were significantly elevated on the side ipsilateral to the ear affected by acute otitis media (P < .05). Chorda tympani nerve conductance is impaired during the acute stage of acute otitis media. This may have implications in the understanding of peripheral neural properties during acute middle ear inflammatory conditions and on the diagnosis of acute otitis media.

Gustatory Dysfunction among a Sample of Depressed Egyptian Adults under Antidepressants Therapy: A Retrospective Cohort Study

It is quite clear that the ability to perceive taste sensations significantly affects food choice, which consequently affects health status in the long term. Gustatory dysfunction is a neglected symptom among the depressed patients and those under antidepressants therapy, although these patients are suspectable to oral problems, due to general self-negligence related to mental disease, fear of dental treatment, and side effects of varied medications utilized in psychiatry. This study is aimed at assessing gustatory thresholds (detection and recognition thresholds) among a sample of 30 depressed Egyptian adults under antidepressants therapy for at least 3 months or psychotherapy with age ranging from 20 to 50 years old, seeking the Psychiatric Clinic at the Faculty of Medicine, Cairo University, Egypt. These patients were distributed into three equal groups (tricyclic antidepressants (TCA), selective serotonin reuptake inhibitors (SSRIs), and psychotherapy) and were assessed for gustatory detection and recognition thresholds using the filter paper disc method through a scoring system. The participants were also divided into normal taste group in which both the detection and recognition scores were 1, while the scores from 2 till 5 were considered as hypogeusia group and the score of 6 was considered as dysgeusia group. The TCA group was statistically significant from the other 2 groups in sweet detection thresholds (p = 0.043) and sweet recognition thresholds (p = 0.007). Hypogeusia for sweet was statistically significant (p = 0.041), where it was more common among TCA (70%) than both SSRIs and the psychotherapy group (20%). Gustatory dysfunction was found to be mostly associated with TCA followed by SSRIs particularly for sweet taste thresholds. More attention has to be given to taste changes among these patients as oral health affects general health by causing considerable pain and by changing what people eat, their speech, and their quality of life and wellbeing. Proper awareness and evaluation of this problem will improve the quality of life for the depressed patients and avoid unnecessary treatment. This trial is registered with ClinicalTrials.gov ID: NCT03599011.

Mastication of Hard Gumi Decreases the Gustatory Threshold for Sodium Chloride.

In recent years, there has been an increase in the number of hypertensive diseases and the various diseases associated with them. A major cause of these is excessive salt intake. The purpose of the present study was to examine whether chewing hard foods lowers the saltiness threshold. Fifteen subjects (fourteen women and one man) participated in the present study. Two types of gummies are available as ingredients: hard and soft gummies. The saltiness thresholds before and after chewing of each gummi were studied using 11 different NaCl solutions. Then, points of subjective equality (PSEs) were calculated to detect changes in the saltiness for each subject. In the soft Gumi condition, there was no significant difference in PSE for the saltiness between before and after ingesting Gumi (p>0.05), while in the hard Gumi condition, the PSE for the saltiness significantly decreased after ingesting Gumi compared with the value of before ingesting Gumi (p=0.001). From these results, we concluded that sensitivity to saltiness would increase after mastication of hard foods such as hard Gumi.

Impact of asthma on children´s gustatory sensitivity, masticatory and feeding behaviors

Asthma is a chronic inflammatory disease, in which disturbances in breathing, masticatory and swallowing functions may impact the eating behavior. The aim of the study was to evaluate the impact of asthma on taste sensitivity, masticatory behavior and feeding problems in children. The sample consisted of 91 children (6-7y) divided into two groups: asthma (n=46) and control group (n=45). Interviews were held with parents/guardians and clinical examinations were performed to gather information on medical, dental and feeding aspects. The gustatory sensitivity for sucrose and urea (sweet and bitter, respectively) were measured by staircase method designed for this age-range. The respiratory and masticatory functions were evaluated using the Orofacial Myofunctional Evaluation with Scores-expanded (OMES-e) protocol. Feeding problems were assessed using the Montreal Children's Hospital Feeding Scale, exploring oral motor, sensory, appetite, maternal concerns, child's behavior, and strategy aspects after transcultural adaptation to Brazilian Portuguese. The two groups were homogeneous relative to sociodemographic characteristics and nutritional status. Although the total OMES-e scores did not differ between groups, the frequency of changes in food incision and escape were different (p=0.007 and p=0.0011, respectively). The Asthma group required more time and higher number of masticatory cycles to eat the test-food (p<0.05). The gustatory thresholds for sweet and bitter were different, with asthmatic children requiring significantly higher concentrations to perceive the taste (p<0.001). The frequency of children classified by their parents according to feeding difficulties also differed between groups (p=0.001; Fisher's exact test). Asthmatic children showed remarkable changes in taste, chewing and eating behaviors, thereby pointing out the eating problems they may experience, which should be considered when designing and implementing therapeutic interventions.

Factors associated with gustatory threshold for salty taste in peritoneal dialysis patients

BackgroundTaste disorder is a common problem in patients with chronic kidney disease and end-stage renal disease. Specifically, salty taste disorder is associated with excess salt intake. Many factors affect taste activity; however, data focused on peritoneal dialysis (PD) patients are limited. This study aimed to investigate the distribution of the gustatory threshold for salty taste and to clarify its relevant contributing factors in PD patients.MethodsIn this retrospective cross-sectional study, we enrolled 22 PD patients who were assessed for their detection and recognition thresholds for salty taste using salt-impregnated test strips. We investigated the distribution of the detection and recognition thresholds and analyzed their relevant factors.ResultsIn PD patients, detection and recognition threshold for salty taste were both high. Especially, most of the PD patients could not recognize salty taste even at the highest concentration level. The high detection threshold was associated with young age, long duration of PD, high serum phosphorus, and high transferrin saturation. The high recognition threshold was associated with long duration of PD, high serum phosphorus, high creatinine, high serum β2 microglobulin, low renal Kt/V, and high peritoneal Kt/V. Partition analysis showed that high serum phosphorus was related with high detection threshold and low renal Kt/V was related with high recognition threshold.ConclusionsThis study demonstrated that the gustatory threshold for salty taste was increased in PD patients. In addition, high detection threshold was related with high serum phosphorus and high recognition threshold was related to low renal Kt/V. Based on these findings, we consider that it is important to assess the gustatory threshold for salty taste in PD patients, particularly those with high serum P and low renal Kt/V.

Taste Perception and Cerebral Activity in the Human Gustatory Cortex Induced by Glucose, Fructose, and Sucrose Solutions.

Glucose, fructose, and sucrose are important carbohydrates in Western diets with particular sweetness intensity and metabolisms. No study has compared their cerebral detection and their taste perception. Gustatory evoked potentials (GEPs), taste detection thresholds, intensity perception, and pleasantness were compared in response to glucose, fructose, and sucrose solutions at similar sweetness intensities and at identical molar concentrations. Twenty-three healthy subjects were randomly stimulated with 3 solutions of similar sweetness intensity (0.75 M of glucose, 0.47 M of fructose and 0.29 M of sucrose - sit. A), and with an identical molar concentration (0.29 M - sit. B). GEPs were recorded at gustatory cortex areas. Intensity perception and hedonic values of each solution were evaluated as were gustatory thresholds of the solutions. No significant difference was observed concerning the GEP characteristics of the solutions according to their sweetness intensities (sit. A) or their molar concentration (sit. B). In sit. A, the 3 solutions were perceived to have similar intensities and induced similar hedonic sensations. In sit. B, the glucose solution was perceived to be less intense and pleasant than the fructose and the sucrose solutions (P < 0.001) and the fructose solution was perceived to be less intense and pleasant than the sucrose (P < 0.001). Since GEP recordings were similar for glucose, fructose, and sucrose solutions whatever the concentrations, activation of same taste receptor induces similar cortical activation, even when the solutions were perceived differently. Sweet taste perception seems to be encoded by a complex chemical cerebral neuronal network.

Clinical investigation of gustatory and neurosensory alterations following mandibular third molar surgery: an observational prospective study.

This study aimed to prospectively observe gustatory and neurosensory alterations following surgical removal of mandibular third molars. A prospective clinical study was conducted with patients who required mandibular third molar extraction, recruited from the Division of Oral and Maxillofacial Surgery at the Federal University of Ceará (Brazil). Age, sex, and radiographic signs were recorded. The outcome variables were the presence or absence of gustatory and neurosensory alterations. The patients were observed preoperatively and at 7, 30, 90, and 180days postoperatively by using gustatory and neurosensory tests. The response to sweet (p = 0.509) and sour (p = 0.078) stimulus did not alter significantly over time. The salty threshold significantly increased from the preoperative to 7- and 30-day postoperative periods, returning to baseline values at 90days postoperatively (p = 0.038). The bitter threshold increased significantly from the preoperative to 7-day postoperative period, returning to baseline values at 30days after surgery (p < 0.001). Regarding neurosensory evaluation, there was an altered response to stimulus at 7days postoperatively in specific studied areas, returning to baseline values 30days after surgery (p < 0.05). The present study shows that mandibular third molar removal was associated with slight sensory disturbances related to mechanical, tactile, and gustatory perception. Regarding the recovery period, all patients returned to normal function without intervention, over a period ranging from 30 to 90days. This study highlighted the importance of a sensory evaluation following removal of third molars, notably regarding mechanical perception and gustatory threshold assessment.

Assessing the gustatory threshold and salivary flow rate in very early oral submucous fibrosis

Assessing the gustatory threshold and salivary flow rate in very early oral submucous fibrosis

Sugar Detection Threshold After Laparoscopic Sleeve Gastrectomy in Adolescents.

Obesity in young people is one of the most serious public health problems worldwide. Moreover, the mechanisms preventing obese adolescents from losing and maintaining weight loss have been elusive. Laparoscopic sleeve gastrectomy (LSG) is successful at achieving long-term weight loss in patients across all age groups, including children and adolescents. Anecdotal clinical observation as well as evidence in rodents suggests that LSG induces a shift in preference of sugary foods. However, it is not known whether this shift is due to a change in the threshold for gustatory detection of sucrose, or whether LSG induces behavioral change without affecting the gustatory threshold for sugar. The objective of this study was to determine whether adolescents who undergo LSG experience a change in their threshold for detecting sweet taste. We studied the sucrose detection threshold of 14 obese adolescents (age 15.3±0.5years, range 12-18) who underwent LSG 2weeks before surgery and at 12 and 52weeks after surgery. Matched non-surgical subjects were tested on two occasions 12weeks apart to control for potential learning of the test that may have confounded the results. Seven sucrose concentrations were used and were tested in eight blocks with each block consisting of a random seven sucrose and seven water stimuli. The subjects were asked to report whether the sample contained water or not after they tasted 15ml of the fluid for 10s. The bodyweight of the LSG group decreased from 136.7±5.4 to 109.6±5.1 and 86.5±4.0kg after 12 and 52weeks, respectively (p<0.001). There was no significant difference after surgery in taste detection threshold of patients after LSG (p=0.60), and no difference was observed comparing the taste detection threshold of the LSG group with the non-surgical controls (p=0.38). LSG did not affect the taste detection threshold for sucrose, suggesting that the shift in preference for sugary foods may be due to factors other than fundamental changes in taste sensitivity.

Refined single‐interval adjustment matrix yes‐no task for estimating the absolute thresholds of sweet‐tasting molecules

AbstractDetermining the in vivo gustatory thresholds of sweet‐tasting molecules is more difficult and laborious than other sensory analyses. In this study, we refined the single‐interval adjustment matrix (SIAM) yes‐no task to produce threshold estimates accurately and efficiently. Experimental procedures were optimized such that tasters provided bias‐free results and achieved maximum performance. We found that the refined SIAM yes‐no task accurately estimated the threshold values of the sweet‐tasting protein brazzein within the sensitive threshold range, which was confirmed using the two‐alternative forced‐choice task. Threshold values of various artificial sweeteners were also investigated using the SIAM yes‐no task. Our results suggest that the refined SIAM yes‐no task is advantageous for obtaining thresholds and comparing the biological activity of various sweet‐tasting molecules.Practical applicationsThe refined SIAM yes‐no task suggested in this study would enable researchers to accurately obtain thresholds of various sweet‐tasting molecules, in order to develop potential sugar substitutes and elucidate interactions with their corresponding sweet‐taste receptors T1R2‐T1R3 for sweet‐taste mechanism studies.

A new extension to the Taste Strips test

Assessment of gustatory function in human subjects using the 'taste strips' test is an easy and validated procedure. The aim of this study was to extend this test in order to detect subjects with superior gustatory sensitivity. The investigation included 134 subjects (29.5±12.6 years, range 18-84 years) with normal gustatory function. Four concentrations of sweet, sour, salty, and bitter were augmented with additional low concentrations (sweet: 25/12.5 mg/ml sucrose; sour: 27/15 mg/ml citric acid; salty: 6.4/2.6 mg/ml sodium chloride, bitter: 0.15/0.06 mg/ml quinine hydrochloride), resulting in a maximum extended taste score (ETS) of 24. The mean ETS was 14.5 ± 3.2. Specifically, it was 4.5 ± 1.2 for sweet, 2.8 ± 1.0 for sour, 4.0 ± 1.3 for salty, and 3.2 ± 1.2 for bitter. In contrast to the original version of the taste strips test, no ceiling effect was observed. Cluster analysis separated three groups of subjects by ETS, whereas test scores derived from the original four concentrations were insufficient to discriminate the subgroup with higher gustatory sensitivity. The extended taste strips test seems to be a useful tool for the detection of patients with low gustatory thresholds for sweet, sour, salty, or bitter taste.

Thermal Stimulations Change Perception and Taste Thresholds

Purpose: This study aimed to inbestigate perception thresholds and gustatory thresholds for the four basics tastes (sweet, salty, sour and bitter) in the dorsum of the tongue in conjunction with thermal stimulations. Methods: 10 healthy volunteer subjects were examined. The perception threshold test were used the Semmes-Weinstein Test (SW-test) using Semmes-Weinstein Aesthesiometer (North Coast Medical, Inc., Gilroy CA, USA). The gustatory threshold were used the Taste Disk Gustatory threshold. Thermal stimulations were applied to the tongues before the tests. For the cool stimulation tests, subjects were given ice water that was swished around the mouth in order to keep the temperature at approximately 10-13°C. Similarly, heat stimulation was achieved by giving the subjects water heated to 45°C and having them swish the water around their mouth in order to keep the temperature at approximately 37-39°C. Results: During the cooling stimulations, significant increases of the cognizable forces were observed at the apex of the tongue. During the heat stimulation, significant increases were observed for the cognizable forces in all of the areas monitored. For the taste sensations, cool stimulation caused a significant increase in the taste thresholds for all four tastes, while heat stimulation also caused changes in the thresholds for the four taste sensations. Conclusions: Heat stimulations influenced the perception thresholds to a greater degree than that observed for the cool stimulations. However, thermal stimulations had a much stronger influence on taste compared to perception. Salty tastes were more strongly influenced by cool stimulations; sour tastes were more strongly influenced by heat stimulations.

Decline of gustatory sensitivity with the progression of Alzheimer's disease.

Patients with Alzheimer's disease (AD) manifest various impairments in eating behavior. However, few previous studies have directly investigated the gustatory function of AD patients, and results have been inconsistent. Thirty-two AD patients (Clinical Dementia Rating (CDR) 0.5/1/2, respectively 11/15/6 patients) and 22 normal control participants were examined to measure detection and recognition thresholds of the four elemental tastes (sweet, salty, sour, and bitter), and their ability to discriminate between tastes. Effects of demographic and clinical factors (age, sex, histories of alcohol and tobacco consumption, and CDR grade) on gustatory threshold were examined using ordinal logistic regression analysis. Performance was compared between AD and control groups. Total threshold values (the sum of threshold grades for the four tastes) for detection and recognition of tastes were significantly higher in the AD group. Detection thresholds for sweet, salty, and bitter, and recognition thresholds for sweet and sour, were also significantly higher in the AD group. Ordinal logistic regression analysis revealed that CDR grade was the only factor that significantly affected both total threshold values. Regarding taste discrimination, there were no significant differences between the AD group and control group. These findings suggest that progression of dementia severity accompanies gustatory decline. Although it seemingly paradoxical, weight loss and preference for sweet tastes are frequently, often simultaneously, observed in AD. Gustatory dysfunction may be partially involved in these symptoms. Thus, the nutritional care of patients with AD could be improved by making the taste of meals stronger, while controlling calorie and mineral intake.

Olfactory and gustatory functions and its relation to body weight

In the present study we investigated the influence of body weight as defined by BMI on gustatory and olfactory perception. A total of 66 healthy adults (41 females; 25 males) participated in psychophysical measurements using the “Sniffin' Sticks” test and “Taste Strips” test. Odor thresholds as well as discrimination and identification performance were determined. Tests of gustatory function involved the identification and thresholds of sweet, sour, salty, or bitter taste. In this study, all subjects were healthy participants in a middle age range (between 20 and 56years of age). Persons with an extreme BMI value were excluded.Subjects were classified according to their BMI in four groups: (1) 15–19.9kg/m, (2) 20–24.9kg/m, (3) 25–29.9kg/m, and (4) >30kg/m. We did not observe an overall effect of BMI on general sensory sensitivity. There was a significant influence of BMI on olfactory thresholds (F(3,62)=2.79; p<0.047) which increased with increasing BMI. In a similar line, the gustatory thresholds for “salty” were significantly higher with higher BMI (F(3,62)=3.06; p<0.035). Olfactory discrimination and identification was not affected by BMI. Thresholds for odor and sweet or salty taste were also correlated.Our data show that body weight influences gustatory and olfactory perception in healthy adults. Increasing BMI is associated with a decrease in olfactory and taste sensitivity. These findings may have implications for the understanding of pathophysiological mechanisms in patients.

Changes of Basic Gustatory Thresholds and Gustatory Intensities by Thickener Addition

Changes of Basic Gustatory Thresholds and Gustatory Intensities by Thickener Addition

Development of a new method using narrow band imaging for taste assessment

The observation of fungiform papillae is a useful objective taste examination. The purpose of this study is to develop a new method using narrow band imaging for assessment of taste function. Using a narrow band imaging endoscope, we assessed the number and blood vessel morphology of fungiform papillae and compared with the gustatory threshold by the filter paper disc test. The number of fungiform papillae was counted in 20 mm(2) , and blood vessels in fungiform papillae were evaluated morphologically by a five-point scoring system in 11 patients who had undergone middle ear surgery. The filter taste disc test was performed simultaneously to obtain the gustatory threshold and was compared with the number and blood vessel morphology of fungiform papillae. Using a narrow band imaging endoscope, we could clearly detect not only fungiform papillae but also blood vessel morphology. There was a significant correlation between the values of the number of papillae and blood vessel morphology. Moreover, these two parameters revealed a significant inverse correlation with gustatory function. As expected, both parameters on the affected side were significant lower than those on the unaffected side in patients. The assessment of fungiform papillae using narrow band imaging endoscopy is easy, highly sensitive, and reliable; therefore, it might be useful as an objective examination of taste function. N/A.

Association between Taste Sensitivity and Self-Reported and Objective Measures of Salt Intake among Hypertensive and Normotensive Individuals.

This study investigated the gustatory threshold for salt and its relationship with dietary salt intake among hypertensive (n = 54) and normotensive (n = 54) subjects. Salt intake was evaluated through 24-hour urinary sodium excretion and self-reported measures (discretionary salt, Sodium- Food Frequence Questionnaire (Na-FFQ), and 24-hour recall). Detection and recognition thresholds were higher among hypertensive subjects, as well as the total sodium intake. Detection and recognition thresholds were positively related to discretionary salt and total intake of the group as whole. Hypertensive and normotensive subjects presented positive correlations between taste sensitivity and the different measures of salt intake. To conclude, a positive correlation exists between taste threshold and salt intake and both seem to be higher among hypertensive subjects. The combined use of methods of self-report and assessment of taste thresholds can be useful in health promotion and rehabilitation programs, by screening subjects at higher risk of elevated salt intake and the critical dietary behaviors to be targeted as well to evaluate the result of targeted interventions.

Sugar gustatory thresholds and sugar selection in two species of Neotropical nectar-eating bats

Nectar-feeding bats play an important role in natural communities acting as pollinators; however, the characteristics that affect their food selection are unclear. Here we explore the role that sugar gustatory thresholds and sugar concentration play on sugar selection of Glossophaga soricina and Leptonycteris yerbabuenae. We offered bats paired feeders containing sugar solutions of sucrose (S), glucose (G) or fructose (F) vs. pure water, and sucrose vs. 1:1 equicaloric solutions of glucose–fructose at 5, 15 and 35% (wt./vol.). To see the effect of sweetness on sugar selection, we habituated the bats with a diet containing either sucrose or hexoses and subsequently evaluated sugar preferences. Sugar thresholds were S<G,F for G. soricina and G<S<F for L. yerbabuenae. These thresholds did not match with sugar preferences when the bats fed on dilute nectars. L. yerbabuenae changed its sugar preferences with concentration while G. soricina did not. Finally, the bats consistently preferred the sugar they were habituated to. Our results suggest that bats become accustomed to the sugar found in the most abundant plants they use, and thus prefer the most common sugars included in their diet. This could confer an advantage by allowing them shifting sugar preferences on the most common food present in their environment.

Evaluation of taste acuity by the filter-paper disc in Japanese young women: the relationship with micronutrients status.

The aim of the present study is to investigate the taste acuity in Japanese young women in relation to their micronutrient status. Thirty-eight healthy young women (mean age; 21.3, range; 19-27 years) were enrolled. Gustatory thresholds were estimated for four basic tastes: sweet (sucrose), salty (sodium chloride), sour (tartaric acid), and bitter (quinine hydrochloride) by a filter-paper disk method. Various concentrations at each taste were serially scored from disc number 1 (lowest) to number 5 (highest). The lowest concentration at which the quality of the taste was correctly identified was defined as the recognition threshold. The mean of three measurements for each test on three different days was calculated. We divided our participants into normal taste and hypogeusia groups based on the mean threshold disc numbers, <=3.5 and >3.5, respectively, according to previous literature using the same method. We also measured serum concentrations and dietary intakes of micronutrients including zinc, iron, copper, and selenium. The numbers of participants belonging to the hypogeusia group were 24 (63.2%) for sweet, 19 (50.0%) for sour, 17 (44.7%) for bitter, and 16 (42.1%) for salty taste. Although the hypogeusia group exhibited significantly lower serum iron concentrations, except for the salty taste, the other three micronutrients concentrations did not show any association with the four taste acuities. Dietary micronutrient intake did not show any association with the four taste acuities. This study indicates that in addition to zinc status, iron status should be considered in the study of taste acuity.

Do hummingbirds have a sweet-tooth? Gustatory sugar thresholds and sugar selection in the broad-billed hummingbird Cynanthus latirostris

Nectar is a solution of mainly three sugars: sucrose, glucose and fructose. Studies have demonstrated that pollinators have preferences according to the sugar composition presented in their diet, and these preferences may be caused by sugar assimilation capacities. However, sugar flavor could also play an important role for sugar preferences of nectar-feeding animals. We evaluated the sugar gustatory thresholds of the broad-billed hummingbird Cynanthus latirostris for sucrose, glucose, fructose and a 1:1 mixture of glucose–fructose. We presented eight C. latirostris to paired feeders containing either a sugar solution or pure water. Additionally, we conducted sugar preference tests at three different concentrations (146, 730 and 1022 mmol L − 1 ), to relate sugar preferences with sugar gustatory thresholds. C. latirostris had different gustatory thresholds for the three different sugars tested. At low sugar concentrations (146 mmol L − 1 ), sugar selection followed the gustatory thresholds. Hummingbird sugar preference patterns can be affected by different mechanisms, both pre- and post-ingestive. At low concentrations gustatory thresholds may play an important role to determine sugar selection. However, at intermediate and high concentrations, sugar assimilation rates, and velocity of food processing generated by osmotic constraints, can be the mechanisms that explain the sugar selection of these animals.