Gustation assessment using the NIH Toolbox

Prediction of alcohol intake patterns with olfactory and gustatory brain connectivity networks

Craving in alcohol drinkers is often triggered by chemosensory cues, such as taste and smell, which are linked to brain network connectivity. This study aimed to investigate whether these brain connectivity patterns could predict alcohol intake in young adults. Resting-state fMRI data were obtained from the Human Connectome Project (HCP) Young Adult cohort, comprising 1003 participants. Functional connectomes generated from 100 independent components were analyzed, identifying significant connections correlated with taste and odor scores after applying a false discovery rate (FDR) correction using the Benjamini-Hochberg (BH) method. These significant connections were then utilized as predictors in general linear models for various alcohol intake metrics. The models were validated in an independent sample to assess their accuracy. The training sample (n = 702) and the validation sample (n = 117) showed no significant demographic differences. Out of 742 possible connections, 41 related to odor and 25 related to taste passed the significance threshold (P < 0.05) after FDR-BH correction. Notable predictors included visual-visual connectivity (node32-node13: β = 0.028, P = 0.02) for wine consumption and connectivity between the ventral attention network (VAN) and the frontal parietal/caudate nucleus (FP/CN) (node27-node9: β = -0.31, P = 0.04) for total alcohol intake in the past-week and maximum number of drinks per day in the past-year. The predictive models demonstrated strong accuracy, with root mean square error (RMSE) values of 5.15 for odor-related models and 5.14 for taste-related models. The F1 scores were 0.74 for the odor model and 0.71 for the taste model, indicating reliable performance. These findings suggest that specific patterns of brain connectivity associated with taste and olfactory perception may serve as predictors of alcohol consumption behaviors in young adults. Our study highlight the need for longitudinal research to evaluate the potential of taste- and smell-related brain connectivity patterns for early screening and targeted interventions, as well as their role in personalized treatment strategies for individuals at risk of AUD.

Sweet taste preference on snack choice, added sugars intake, and diet quality- a pilot study

Humans seek to eat what is palatable, especially when snacking. Theoretically, a person who enjoys sweet taste more may choose snacks with higher sugar and calories, leading to lower overall diet quality, yet individual eating behavior traits may interfere with this relationship. We investigated the influences of sweet taste preference (assessed using a forced-choice paired-comparison method) and eating behaviors (i.e., uncontrolled eating, emotional eating, and cognitive restraint using the Three-Factor Eating Questionnaire-R18) on diet quality and added sugars intake (validated short Healthy Eating Index survey) in 65 adults (23.0 ± 5.5 years). Participants were divided into sweet dislike, moderate sweet liker, and extreme sweet liker groups by preferred sucrose concentration tertiles. Most participants selected a low-calorie, high-sweetness snack, and neither sweet preference nor eating behavior traits were associated with snack choice. Compared to extreme sweet likers, sweet dislikers and moderate sweet likers had a lower added sugars intake, F(2, 62) = 7.32, p = 0.001, and better diet quality, F(2, 62) = 4.06, p = 0.02. Preferred sucrose concentration correlated only with higher added sugars intake (r = 0.49, p < 0.001) and lower diet quality (r = -0.27, p = 0.03) but not with the intake of other food groups. Higher sweet preference increased the odds of consuming medium (OR = 2.18, 95% CI = 0.32, 6.08) and high (OR = 3.17, 95% CI = 1.85, 7.86) amounts of added sugars. Adding other covariates did not improve the statistical model. Interestingly, only sweet preference, but not added sugars intake and eating behaviors, was associated with diet quality. Thus, our data suggest that sweet preference may have a stronger influence on added sugars intake and diet quality compared to eating behaviors, although these findings should be replicated in other populations and with a larger sample size. Future studies may also assess liking for other sensory qualities (e.g., fat liking) to understand the contributions of taste preference to nutrient intake and diet quality.

Differences in Perceived Versus Actual Sensory Perception in Avoidant/Restrictive Food Intake Disorder

BACKGROUND

Individuals with avoidant/restrictive food intake disorder (ARFID) self-report heightened sensitivity to taste and smell, but neither phenomenon has been systematically explored in the laboratory. We hypothesized that, compared to healthy controls (HC, n = 34), children, adolescents, and adults with full/subthreshold ARFID (n = 100; ages 9 to 23 years) would self-report heightened response to taste/smell stimuli and exhibit stronger bitter taste perception and heightened smell perception in performance-based tasks, and these differences would be especially prominent in those with the ARFID-sensory sensitivity presentation.

METHOD

We measured self-reported sensitivity to taste/smell with the adolescent/adult sensory profile (AASP). We measured performance-based bitter taste perception with the regional taste intensity test (RTIT) and 6-N-propylthiouracil (PROP) test, and olfactory performance with the Sniffin' Sticks test (including the odor threshold, odor detection, and odor identification subscales).

RESULTS

As expected, the ARFID group self-reported heightened response to taste/smell on the AASP, compared to HC, with an especially large effect size in the subset with the ARFID-sensory sensitivity presentation. Contrary to hypotheses, on performance-based measures, neither the ARFID group-nor the ARFID-sensory sensitivity group specifically-demonstrated heightened sensitivity to bitter taste on the RTIT or PROP tests, nor heightened smell perception on the Sniffin' Sticks test.

CONCLUSION

These first laboratory findings in a clinically diagnosed sample of individuals with full/subthreshold ARFID highlight the discrepancy between perceived versus actual sensitivity to taste/smell stimuli. Future research should explore whether this discrepancy can be replicated and therapeutically leveraged to facilitate successful food exposures.

Disparities in seeking care for olfactory and gustatory dysfunction: A population analysis

INTRODUCTION

Despite effects on quality of life from olfactory and gustatory dysfunction (OD and GD), screening practices are limited, and patients' self-reporting of symptoms remains the only way to understand the burden of chemosensory dysfunction (CSD). Using a large population-based database, we sought to understand factors leading to reduced likelihood of discussing CSD with a provider.

METHODS

The 2013‒2014 National Health and Nutrition Examination Survey (NHANES) chemosensory protocol was queried for factors influencing discussion of OD/GD with a healthcare provider. Sociodemographic, comorbidity, and objective OD/GD testing results were assessed with a multivariate analysis.

RESULTS

Out of 146.1 million US adults, there were an estimated 41.4 million individuals with self-reported OD/GD in the prior 12 months (28.3%). A total of 86.8% of participants did not discuss their problem with a healthcare provider. Men were about half as likely to speak with a healthcare provider (odds ratio [OR] 0.42; 0.26-0.66; p < 0.001) and those with a college education were about nine times more likely to discuss the problem compared to those with less than a ninth-grade educational achievement (OR 8.83; 1.86-41.98; p = 0.02). Those with objective confirmation of CSD were still unlikely to speak with a provider (OR 0.77; 0.44-1.33; p = 0.36).

CONCLUSION

Men and those with less education are less likely to discuss OD/GD with a healthcare provider. These populations tend to be at increased risk for CSD, and there are severe downstream health and quality of life implications related to CSD. Dedicated screening and increased public awareness are critical to ensure more equitable care.

Home screening of taste and oral trigeminal function: a feasibility study

PURPOSE

gustatory ability is a marker of health not routinely tested in the medical practice. The current study wants to assess whether taste strips can be useful to monitor taste function from home.

METHODS

we performed simple sensory tests in lab setting vs. unassisted testing at home, and compared the results with self-reports ability to taste and smell. Using paper strips impregnated with sweet, bitter, salty, or sour tastants, and with two trigeminal stimuli (capsaicin, tannins) in high and low concentrations, we assessed gustatory and trigeminal function in 74 participants (47 women) in the lab, where paper strips were administered by an experimenter, and in 77 participants (59 women) at home, where they self-administered the test.

RESULTS

we found that high (but not low) concentration taste strips are correctly identified by vast majority of participants. On average, taste identification, intensity and pleasantness scores did not differ for the 8 taste strips, while identification of capsaicin was significantly better in the lab. Taste identification scores correlated with intensity ratings in both settings (r = 0.56, in the lab, r = 0.48, at home, p < 0.005). Self-rated taste ability correlated with self-rated smell ability (r = 0.68, and r = 0.39, p ≤ 0.005), but not with scores in the strips test.

CONCLUSION

home testing with impregnated taste strips is feasible, and can be used for telemedical purposes.

A Multivariate Exploration of Resting-State Networks and Sensory Measures of Olfaction and Taste

In neurodegenerative conditions such as Alzheimer's and Parkinson's diseases, a common symptom is the impairment of senses, particularly olfaction and gustation. More comprehensive neuroimaging studies are needed to elucidate the links between these sensory functions and neural circuit alterations. In this study, we used a subset of the Human Connectome Project (HCP) S1200 data containing both the neuroimaging and sensory test data (n = 50). Using high-order Group Independent Component Analysis (ICA) in combination with Multivariate Analysis of Covariance (MANCOVA), we studied the interplay between odor and taste sensory measures and spatiotemporal features of the resting-state networks. The findings revealed that a decline in olfaction was associated with decreased connectivity within the posterior default mode network, central executive network, and dorsal attention network. Similarly, a lower capacity for taste detection was linked to changes in the connectivity within the dorsal attention network. Conversely, enhanced taste detection was correlated with increased connectivity in the thalamus. We also found that olfaction was associated with the connectivity between the olfactory network and a cognitive network, which includes the inferior frontal orbital gyrus and Rolandic operculum. Taste, on the other hand, was associated with functional connectivity between the central executive network and the cerebellar network. Our study brings new insights into the relationship between olfaction, taste, and various resting-state networks.

Machine Learning Exploration of Brain Morphological Features and Sensory Measures

Previous investigations have implicated the neuroanatomical basis of sensory systems; however, definitive neuroimaging biomarkers remain elusive. The present study employs machine learning techniques to probe the relationship between brain morphological features and sensory measures of audition, olfaction, taste, and visual contrast sensitivity using a large dataset from the publicly available Human Connectome Project (n = 874). Applying both 5-fold cross-validation and leave-one-out cross-validation methods, performance of several machine learning models was evaluated. Feature selection methods including Random Forest, SelectKBest, Recursive Feature Elimination, and SHapley Additive exPlanations (SHAP) were utilized to identify the most significant neuroanatomical features for sensory performance. Binary classification via machine learning was also conducted to distinguish individuals with high vs. low sensory test scores based on brain morphological features, achieving a satisfactory accuracy of 67% and 71% for olfaction and visual contrast sensitivity, respectively. By integrating machine learning with high-dimensional neuroimaging data, this preliminary study offers new insights into the neural correlates of sensory performance.

Acute Taste Dysfunction in Oropharyngeal Cancer Patients after Transoral Robotic Surgery

OBJECTIVES

To compare taste changes after transoral robotic surgery (TORS) to taste changes in healthy controls.

METHODS

Oropharyngeal cancer patients receiving TORS and healthy controls were recruited. Participants underwent posterolateral and whole-mouth psychophysical taste testing (identification, intensity, and hedonics) at baseline and at 2 weeks postoperatively (patients) or follow-up (controls). Surgeons reported suspension time and glossopharyngeal nerve injury (GNI) based on the identification and sacrifice of the nerve. A Clinical Global Impression (CGI) of taste symptoms was completed at each session ("My sense of taste bothers me" on a 5-point scale from Never [1] to Always [5]). A taste disorder (TD) was a CGI of 3 (Sometimes) or worse. Within-subject changes in CGI and psychophysical scores were computed. "Worsened taste" was a CGI increase by ≥1 point at follow-up.

RESULTS

Of 69 participants, most (33/37 tumor, 31/32 controls) had normal baseline taste (CGI < 3). 14/33 (42%) TORS patients and no controls developed new TDs at follow-up. More smokers (7/9) had worsened taste than nonsmokers (19/60, difference = 46% [95% CI 16%-76%]). More patients without GNI (6/22) than with GNI (0/15) had postoperative phantogeusia (difference = 27% [95% CI 9-45%]). Tumor-ipsilateral taste identification (TI) decreased more in patients (-11.3%) than controls (0.8%, difference = 12.2% [95% CI 5.0-19.3%]). Suspension time was not associated with worsened taste symptoms or psychophysical changes.

CONCLUSIONS

Patient-reported taste changes after TORS are frequent. Compared to healthy controls, TORS patients have decreased tumor-ipsilateral TI. Suspension time and GNI are unlikely to cause symptomatic TDs. Further investigations of the etiology and long-term symptom burden of TORS-associated TDs will aid in the management of oropharyngeal cancer patients.

LEVEL OF EVIDENCE

3 (non-randomized controlled cohort study) Laryngoscope, 133:3520-3528, 2023.

Baseline characterization of the ARMADA (Assessing Reliable Measurement in Alzheimer's Disease) study cohorts

INTRODUCTION

The National Institutes of Health (NIH) Toolbox (NIHTB) provides computerized measures of cognition, emotion, sensation, and motor abilities across the lifespan. The ARMADA (Assessing Reliable Measurement in Alzheimer's Disease and Cognitive Aging) study validated the NIHTB in individuals across the cognitive aging spectrum. This article reports the characteristics of our sample of participants.

METHODS

Participants were recruited across nine sites and classified clinically as cognitively normal (NC), with mild cognitive impairment (MCI), or with dementia of the Alzheimer's type (DAT.) They completed the NIHTB at multiple time points and many had at least one Alzheimer's biomarker previously obtained.

RESULTS

Groups differed with respect to dementia severity levels, as anticipated, but were well-matched across many demographic characteristics.

DISCUSSION

The ARMADA study demographics and baseline characteristics provide a suitable sample for validating the NIHTB across the cognitive aging spectrum. Other enriched samples (African American participants, Spanish NIHTB, 85+ years of age) will be reported elsewhere.

HIGHLIGHTS

There is a need for assessments that can detect the early stages of cognitive decline in older adults. The ARMADA (Assessing Reliable Measurement in Alzheimer's Disease and Cognitive Aging) study will validate the National Institutes of Health (NIH) Toolbox across the aging spectrum, including mild cognitive impairment (MCI) and dementia of the Alzheimer's type (DAT). Here we report the characteristics of participants. Groups were well-matched across most demographic characteristics, and clinical characteristics differed as expected. ARMADA study cohorts reflect their respective clinical syndromes for validating the NIH Toolbox.

Enhancement of taste by retronasal odors in patients with Wolfram syndrome and decreased olfactory function

Wolfram syndrome is a rare disease characterized by diabetes, neurodegeneration, loss of vision, and audition. We recently found, in a young sample of participants (mean age 15 years), that Wolfram syndrome was associated with impairment in smell identification with normal smell sensitivity and whole-mouth taste function. However, these senses were assessed separately, and it is unknown whether smell-taste interactions are altered in Wolfram syndrome, which was the focus of this study. Participants with Wolfram syndrome (n = 36; 18.2 ± 6.8 years) and sex-age-equivalent healthy controls (n = 34) were assessed with a battery of sensory tests. Using sip-and-spit methods, participants tasted solutions containing gustatory and olfactory stimuli (sucrose with strawberry extract, citric acid with lemon extract, sodium chloride in vegetable broth, and coffee) with and without nose clips, and rated perceived taste and retronasal smell intensities using the generalized Labeled Magnitude Scale. Participants also completed n-butanol detection thresholds and the University of Pennsylvania Smell Identification Test (UPSIT). Retronasal smell increased taste intensity of sucrose, sodium chloride, and coffee solutions similarly in both groups (P values <0.03). Compared with the control group, participants in the Wolfram group had lower UPSIT scores and reduced smell sensitivity, retronasal intensity, and saltiness (P values <0.03), but rated other taste intensities similarly when wearing the nose clip. Despite impairments in orthonasal smell identification, odor-induced taste enhancement was preserved in participants with Wolfram syndrome who still had some peripheral olfactory function. This finding suggests that odor-induced taste enhancement may be preserved in the presence of reduced olfactory intensity.

Sodium Intake Tracked from Infancy and Salt Taste Preference during Adolescence: Follow-up of a Randomized Controlled Field Trial in Brazil

Background

Effective interventions to promote healthy sodium intakes require understanding factors driving liking for salt taste.

Objectives

To examine effects of an early feeding intervention among low-income mothers on their children's energy and sodium intake and salt taste preferences at 12 years; and to identify age-related changes in dietary sodium sources.

Methods

Secondary analyses were conducted on dietary intake and taste preference data collected from children in a longitudinal trial (NCT00629629). Mothers randomized to the intervention group received counseling on healthy eating practices for 1 year postpartum; the control group received no counseling. Two-day dietary recalls were obtained at 1 year (intervention end) and at 4-, 8-, and 12-year follow-up visits, from which foods were categorized as unprocessed, processed, or ultra-processed. At the 12-year visit, children's most preferred concentration of salt was measured using a validated, forced-choice, paired-comparison tracking method, and pubertal stage was self-assessed.

Results

The intervention group had reduced energy intake compared with controls in all food categories at 1 year (P = 0.04) but not at the other time points. Sodium intake from processed foods increased from 4 to 12 years and from ultra-processed foods from 1 to 4; intake from unprocessed foods decreased from 1 to 8 year (all P < 0.01). At 12 years, children in early stages of puberty (Tanner stages 1-3; P = 0.04) or in the ≥75th percentile of sodium intake (P < 0.01) preferred significantly higher concentrations of salt than the other children.

Conclusions

Both dietary intake of sodium and early puberty were associated with preferences for higher salt concentrations. Childhood and adolescence are important periods for understanding how experience and growth shape diet by changing salt taste.

Clinical Trial Registration

This manuscript reports secondary analysis of data collected in trial NCT00629629 (2001-3) and follow-up [https://clinicaltrials.gov/ct2/show/NCT00629629?term=NCT00629629&draw=2&rank=1].

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.

ARMADA: Assessing reliable measurement in Alzheimer's disease and cognitive aging project methods

INTRODUCTION

Early detection of cognitive decline in older adults is a public health priority. Advancing Reliable Measurement in Alzheimer's Disease and Cognitive Aging (ARMADA), a multisite study, is validating cognition, emotion, motor, and sensory modules of the National Institutes of Health Toolbox for Assessment of Neurological and Behavioral Function (NIHTB) in the aging spectrum from cognitively normal to dementia of the Alzheimer's type (DAT).

METHODS

Participants 65 to 85 years old, in demographic groups racially proportional to the general US population, are recruited in one of three groups to validate the NIHTB: cognitively normal, amnestic mild cognitive impairment (aMCI), or mild DAT. Additional special emphasis cohorts include (1) Blacks in the three clinical groups; (2) Spanish-speakers in the three clinical groups; (3) cognitively normal, population-proportional, over age 85.

DISCUSSION

Longitudinal study will determine whether NIHTB can predict cognitive decline and is associated with Alzheimer's disease biomarkers. Here, we detail the methods for the ARMADA study.

Future Directions for Chemosensory Connectomes: Best Practices and Specific Challenges

Ecological chemosensory stimuli almost always evoke responses in more than one sensory system. Moreover, any sensory processing takes place along a hierarchy of brain regions. So far, the field of chemosensory neuroimaging is dominated by studies that examine the role of brain regions in isolation. However, to completely understand neural processing of chemosensation, we must also examine interactions between regions. In general, the use of connectivity methods has increased in the neuroimaging field, providing important insights to physical sensory processing, such as vision, audition, and touch. A similar trend has been observed in chemosensory neuroimaging, however, these established techniques have largely not been rigorously applied to imaging studies on the chemical senses, leaving network insights overlooked. In this article, we first highlight some recent work in chemosensory connectomics and we summarize different connectomics techniques. Then, we outline specific challenges for chemosensory connectome neuroimaging studies. Finally, we review best practices from the general connectomics and neuroimaging fields. We recommend future studies to develop or use the following methods we perceive as key to improve chemosensory connectomics: (1) optimized study designs, (2) reporting guidelines, (3) consensus on brain parcellations, (4) consortium research, and (5) data sharing.

Massively collaborative crowdsourced research on COVID19 and the chemical senses: Insights and outcomes

In March 2020, the Global Consortium of Chemosensory Research (GCCR) was founded by chemosensory researchers to address emerging reports of unusual smell and taste dysfunction arising from the SARS-CoV-2 pandemic. Over the next year, the GCCR used a highly collaborative model, along with contemporary Open Science practices, to produce multiple high impact publications on chemosensation and COVID19. This invited manuscript describes the founding of the GCCR, the tools and approaches it used, and a summary of findings to date. These findings are contextualized within a summary of some of the broader insights about chemosensation (smell, taste, and chemesthesis) and COVID19 gained over the last 18 months, including potential mechanisms of loss. Also, it includes a detailed discussion of some current Open Science approaches and practices used by the GCCR to increase transparency, rigor, and reproducibility.

The association between olfactory and gustatory dysfunction and chronic kidney disease

BACKGROUND

Olfactory and gustatory changes may contribute to poor appetite and food aversion in chronic kidney disease (CKD), though the prevalence of olfactory and gustatory dysfunction is not known in the CKD population.

METHODS

We conducted a cross-sectional study among 3527 US adults aged ≥40 years old in the National Health and Nutrition Examination Survey (NHANES) between 2013 and 2014. We measured the prevalence of olfactory and gustatory dysfunction among patients with CKD defined as eGFR < 60 ml/min/1.73m² using the "scratch and sniff" NHANES Pocket Smell Test and quinine whole-mouth test. We also examined the association between CKD and olfactory/gustatory dysfunction, and nutritional markers.

RESULTS

The prevalence of olfactory dysfunction was 30% among CKD and 15% among non-CKD (p < 0.001). The prevalence of gustatory dysfunction was 13% among CKD and 17% among non-CKD (p = 0.10). After adjusting for confounders, CKD was significantly associated with olfactory dysfunction (OR = 1.47, 95% CI [1.07, 2.01]; p = 0.02) but not gustatory dysfunction (OR = 1.76, 95%CI [0.99, 3.11]; p = 0.05). Among the CKD population, the odds of olfactory dysfunction was 72% higher for every 10 kg decrease in grip strength (OR = 1.72, 95% CI [1.39, 2.13]; adjusted p = 0.005).

CONCLUSION

CKD was associated with higher odds of olfactory but not gustatory dysfunction. Olfactory dysfunction was associated with lower grip strength among those with CKD. Screening and early intervening on olfactory dysfunction among CKD may preserve muscle strength and improve nutritional status in this vulnerable population.

Characterizing Individual Differences in Sweet Taste Hedonics: Test Methods, Locations, and Stimuli

Sweetness drives the consumption of added sugars, so understanding how to best measure sweet hedonics is important for developing strategies to lower sugar intake. However, methods to assess hedonic response to sweetness vary, making results across studies difficult to integrate. We compared methods to measure optimal sucrose concentration in 21 healthy adults (1) using paired-comparison preference tracking vs. ratings of liking, (2) with participants in the laboratory vs. at home, and (3) using aqueous solutions vs. vanilla milk. Tests were replicated on separate days to assess test-retest reliability. Test-retest reliability was similar between laboratory and home testing, but tended to be better for vanilla milk and preference tracking. Optimal sucrose concentration was virtually identical between laboratory and home, slightly lower when estimated via preference tracking, and about 50% lower in vanilla milk. However, optimal sucrose concentration correlated strongly between methods, locations, and stimuli. More than 50% of the variability in optimal sucrose concentration could be attributed to consistent differences among individuals, while much less variability was attributable to differences between methods. These results demonstrate convergent validity between methods, support testing at home, and suggest that aqueous solutions can be useful proxies for some commonly consumed beverages for measuring individual differences.

NCS Assessments of the Motor, Sensory, and Physical Health Domains

As part of the National Children's Study (NCS) comprehensive and longitudinal assessment of the health status of the whole child, scientific teams were convened to recommend assessment measures for the NCS. This manuscript documents the work of three scientific teams who focused on the motor, sensory, or the physical health aspects of this assessment. Each domain team offered a value proposition for the importance of their domain to the health outcomes of the developing infant and child. Constructs within each domain were identified and measures of these constructs proposed. Where available extant assessments were identified. Those constructs that were in need of revised or new assessment instruments were identified and described. Recommendations also were made for the age when the assessments should take place.

Psychosocial, Functional, and Emotional Correlates of Long-Term Opioid Use in Patients with Chronic Back Pain: A Cross-Sectional Case-Control Study

INTRODUCTION

The opiate epidemic has severe medical and social consequences. Opioids are commonly prescribed in patients with chronic pain, and are a main contributor to the opiate epidemic. The adverse effects of long-term opioid usage have been studied primarily in dependence/addiction disorders, but not in chronic pain. Here, we examine the added iatrogenic effects, psychology, and brain morphology of long-term opioid use in matched patients with chronic pain with and without opioid use (case-controlled design).

METHODS

We compared psychosocial, functional, and psychological measures between patients with chronic back pain (CBP) who were managing their pain with or without opioids, thereby controlling for the effect of pain on these outcomes. In addition, we investigated brain morphological differences associated with long-term opioid usage. We recruited 58 patients with CBP, 29 of them on long-term opioids and 29 who did not use opioids, and who were matched in terms of age, sex, pain intensity, and pain duration. Questionnaires were used to assess pain quality, pain psychology, negative and positive emotions, physical, cognitive, sensory, and motor functions, quality of life, and personality traits.

RESULTS

Patients with CBP on opioids displayed more negative emotion, poorer physical function, and more pain interference (p < 0.001), whereas there were no statistical differences in cognitive and motor functions and personality traits. Voxel-based morphometry using structural brain imaging data identified decreased gray matter density of the dorsal paracingulate cortex (family-wise error-corrected p < 0.05) in patients with opioids, which was associated with negative emotion (p = 0.03). Finally, a volumetric analysis of hippocampal subfields identified lower volume of the left presubiculum in patients on opioids (p < 0.001).

CONCLUSION

Long-term opioid use in chronic pain is associated with adverse negative emotion and disabilities, as well as decreased gray matter volumes of specific brain regions.

Taste and Smell Function in Head and Neck Cancer Survivors

Survivors of head and neck squamous cell cancers (HNSCC) frequently complain of taste dysfunction long after radiation therapy is completed, which contradicts findings from most sensory evaluation studies that predict dysfunction should resolve few months after treatment. Therefore, it remains unclear whether taste and smell function fully recovers in HNSCC survivors. We evaluated HNSCC survivors (n = 40; age 63 ± 12 years, mean ± standard deviation) who received radiation therapy between 6 months and 10 years before recruitment and compared their responses to those of a healthy control group (n = 20) equivalent in age, sex, race, smoking history, and body mass index. We assessed regional (tongue tip) and whole-mouth taste intensity perception using the general Labeled Magnitude Scale and smell function using the University of Pennsylvania Smell Identification Test (UPSIT). To determine possible differences between groups in retronasal smell perception, we used solutions of sucrose with strawberry extract, citric acid with lemon extract, sodium chloride in vegetable broth, and caffeine in coffee and asked participants to rate perceived smell and taste intensities with and without nose clips. We found groups had similar UPSIT and taste intensity scores when solutions were experienced in the whole mouth. However, HNSCC survivors were less likely to identify low concentrations of bitter, sweet, or salty stimuli in the tongue tip relative to healthy controls. Our findings suggest persistent and subtle localized damage to the chorda tympani or to the taste buds in the fungiform papillae of HNSCC survivors, which could explain their sensory complaints long after completion of radiotherapy.

Association Between Chemosensory Dysfunction and Diet Quality in United States Adults

BACKGROUND

Evidence suggests chemosensory dysfunction (CSD) patients have altered diet, but population-level evidence assessing diet quality in CSD patients is lacking.

OBJECTIVE

We examined the association between CSD and diet quality in a representative sample of United States adults.

METHODS

This cross-sectional study included 2831 adults aged greater than 40 years from the 2013-2014 National Health and Nutrition Examination Survey who completed the taste/smell questionnaire and examination. Mean nutrient intake in subjects with self-reported olfactory/gustatory dysfunction (sOD/sGD) and measured olfactory/gustatory dysfunction (mOD/mGD) were compared to those without CSD using univariate Wilcoxon rank-sum tests. The Healthy Eating Index (HEI), a validated measure of diet quality, was calculated. The proportion of subjects with CSD with bottom-quartile HEI was compared to those without CSD using multivariate logistic regression, adjusting for demographic and socioeconomic covariates.

RESULTS

The population-weighted prevalence of sOD, sGD, mOD, and mGD was 20.1%, 14.4%, 15.9% and 25.6%, respectively. Subjects with mOD had lower mean intake of total calories, total fat, protein, sodium, and potassium compared to normal subjects (1873.4 ± 49.6 vs 2010.2 ± 24.2 kcal, 72.3 ± 2.7 vs 78.6 ± 1.0 gm, 74.0 ± 2.5 vs 80.4 ± 0.6 gm, 3122 ± 97.2 vs 3353.2 ± 37.0 mg, 2509.8 ± 69.8 vs 2684.7 ± 26.1 mg, P < 0.05 respectively). When controlling for sociodemographic factors and comorbidities, subjects with sOD were more likely to have bottom-quartile HEI compared to normal subjects (OR 1.33, 95% CI 1.04-1.70).

CONCLUSIONS

This population-level study suggests an association between poor diet quality and variation in dietary intake in patients with CSD, which warrants further investigation and suggests the possible need for nutritional counseling for CSD patients.

NIH Workshop Report: sensory nutrition and disease

In November 2019, the NIH held the "Sensory Nutrition and Disease" workshop to challenge multidisciplinary researchers working at the interface of sensory science, food science, psychology, neuroscience, nutrition, and health sciences to explore how chemosensation influences dietary choice and health. This report summarizes deliberations of the workshop, as well as follow-up discussion in the wake of the current pandemic. Three topics were addressed: A) the need to optimize human chemosensory testing and assessment, B) the plasticity of chemosensory systems, and C) the interplay of chemosensory signals, cognitive signals, dietary intake, and metabolism. Several ways to advance sensory nutrition research emerged from the workshop: 1) refining methods to measure chemosensation in large cohort studies and validating measures that reflect perception of complex chemosensations relevant to dietary choice; 2) characterizing interindividual differences in chemosensory function and how they affect ingestive behaviors, health, and disease risk; 3) defining circuit-level organization and function that link and interact with gustatory, olfactory, homeostatic, visceral, and cognitive systems; and 4) discovering new ligands for chemosensory receptors (e.g., those produced by the microbiome) and cataloging cell types expressing these receptors. Several of these priorities were made more urgent by the current pandemic because infection with sudden acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the ensuing coronavirus disease of 2019 has direct short- and perhaps long-term effects on flavor perception. There is increasing evidence of functional interactions between the chemosensory and nutritional sciences. Better characterization of this interface is expected to yield insights to promote health, mitigate disease risk, and guide nutrition policy.

Associations of Taste Perception with Tobacco Smoking, Marijuana Use, and Weight Status in the National Health and Nutrition Examination Survey

Habitual smoking of tobacco and marijuana can lead to weight changes and poor diet quality. These effects may be caused by taste changes related to smoking and marijuana use. This study examined the associations among taste perceptions of a bitterant (quinine) and salt, tobacco and marijuana use, and weight status. We conducted a cross-sectional analysis of adults who responded to the National Health and Nutrition Examination Survey in 2013-2014. Participants (n = 2808; female = 51.7%) were adults ≥40 years with an average body mass index (BMI) of 29.6 kg/m2. Participants completed whole mouth and tongue tip assessments of bitter (quinine) and salty (NaCl) tastes, and questionnaires on demographics, cigarette, tobacco, and drug use. Measured height and weight were used to calculate BMI. Compared with never smokers, current smokers reported increased bitter ratings. Smoking status was not associated with salty taste intensity ratings after adjustment for demographic variables. Current marijuana users reported lower tongue tip quine ratings than never users. Among current smokers, current marijuana users had lower whole mouth quinine ratings than never users. Taste perception for salt and quinine for current and former smokers as well as marijuana smokers varied in whole mouth and tongue tip assessment. Changes in taste perception among cigarette smokers and marijuana consumers may be clinically relevant to address to improve diet and weight status.

Perspective: Measuring Sweetness in Foods, Beverages, and Diets: Toward Understanding the Role of Sweetness in Health

Various global public health agencies recommend minimizing exposure to sweet-tasting foods or beverages. The underlying rationale is that reducing exposure to the perception of sweet tastes, without regard to the source of sweetness, may reduce preferences for sweetness, added sugar intake, caloric intake, and body weight. However, the veracity of this sequence of outcomes has yet to be documented, as revealed by findings from recent systematic reviews on the topic. Efforts to examine and document the effects of sweetness exposure are needed to support evidence-based recommendations. They require a generally agreed-upon methodology for measuring sweetness in foods, beverages, and the overall diet. Although well-established sensory evaluation techniques exist for individual foods in laboratory settings, they are expensive and time-consuming, and agreement on the optimal approach for measuring the sweetness of the total diet is lacking. If such a measure could be developed, it would permit researchers to combine data from different studies and populations and facilitate the design and conduct of new studies to address unresolved research questions about dietary sweetness. This narrative review includes an overview of available sensory techniques, their strengths and limitations, recent efforts to measure the sweetness of foods and diets across countries and cultures, and a proposed future direction for improving methods for measuring sweetness toward developing the data required to support evidence-based recommendations around dietary sweetness.

The association of frailty with olfactory and gustatory dysfunction in older adults: a nationally representative sample

BACKGROUND

Olfaction and gustation are associated with age-related decline. Deficits in these chemosenses have been associated with significant comorbidities. Meanwhile, frailty, defined as a reduced physiological reserve, is well correlated with mortality and worse health outcomes. We sought to analyze a nationally representative patient population to determine the association between chemosensory dysfunction and frailty.

METHODS

Cross-sectional analysis of U.S. National Health and Nutrition Examination Survey (NHANES) 2013-2014 was performed, using multivariate logistic regression to examine the association between chemosensory dysfunction and frailty in adults aged ≥40 years (n = 3547). Self-reported olfactory dysfunction (sOD) and gustatory dysfunction (sGD), and measured olfactory dysfunction (mOD) and gustatory dysfunction (mGD) were assessed for all participants. Frailty was operationalized using a 39-item frailty index (FI) and stratified into 4 groups using validated cutoffs.

RESULTS

Participants with sOD and mOD had significantly higher mean FI scores (sOD: 0.18 vs 0.13, p < 0.001; mOD: 0.20 vs 0.14, p < 0.001), whereas subjects with sGD, but not mGD, had higher mean FI scores (sGD: 0.21 vs 0.13, p < 0.001; mGD: 0.14 vs 0.14, p = 0.953). Multivariate logistic regression demonstrated frail participants had significantly greater odds of sGD (odds ratio [OR] 4.11; 95% confidence interval [CI], 3.46 to 4.88), sOD (OR 2.35; 95% CI, 1.98 to 2.78), and mOD (OR 1.58; 95% CI, 1.22 to 2.05), but not mGD (OR 1.21; 95% CI, 0.91 to 1.61). This association was strongest in the frailest group.

CONCLUSION

Self-reported chemosensory dysfunction and mOD are independently associated with measures of frailty, suggesting a novel method to assess or predict frailty.

Identifying Treatments for Taste and Smell Disorders: Gaps and Opportunities

The chemical senses of taste and smell play a vital role in conveying information about ourselves and our environment. Tastes and smells can warn against danger and also contribute to the daily enjoyment of food, friends and family, and our surroundings. Over 12% of the US population is estimated to experience taste and smell (chemosensory) dysfunction. Yet, despite this high prevalence, long-term, effective treatments for these disorders have been largely elusive. Clinical successes in other sensory systems, including hearing and vision, have led to new hope for developments in the treatment of chemosensory disorders. To accelerate cures, we convened the "Identifying Treatments for Taste and Smell Disorders" conference, bringing together basic and translational sensory scientists, health care professionals, and patients to identify gaps in our current understanding of chemosensory dysfunction and next steps in a broad-based research strategy. Their suggestions for high-yield next steps were focused in 3 areas: increasing awareness and research capacity (e.g., patient advocacy), developing and enhancing clinical measures of taste and smell, and supporting new avenues of research into cellular and therapeutic approaches (e.g., developing human chemosensory cell lines, stem cells, and gene therapy approaches). These long-term strategies led to specific suggestions for immediate research priorities that focus on expanding our understanding of specific responses of chemosensory cells and developing valuable assays to identify and document cell development, regeneration, and function. Addressing these high-priority areas should accelerate the development of novel and effective treatments for taste and smell disorders.

The NIH Toolbox: Overview of Development for Use with Hispanic Populations

OBJECTIVE

Hispanics/Latinos are the largest and fastest-growing minority population in the United States. To facilitate appropriate outcome assessment of this expanding population, the NIH Toolbox for Assessment of Neurological and Behavioral Function® (NIH Toolbox®) was developed with particular attention paid to the cultural and linguistic needs of English- and Spanish-speaking Hispanics/Latinos.

METHODS

A Cultural Working Group ensured that all included measures were appropriate for use with Hispanics/Latinos in both English and Spanish. In addition, a Spanish Language Working Group assessed all English-language NIH Toolbox measures for translatability.

RESULTS

Measures were translated following the Functional Assessment of Chronic Illness Therapy (FACIT) translation methodology for instances where language interpretation could impact scores, or a modified version thereof for more simplified translations. The Spanish versions of the NIH Toolbox Cognition Battery language measures (i.e., Picture Vocabulary Test, Oral Reading Recognition Test) were developed independently of their English counterparts.

CONCLUSIONS

The Spanish-language version of the NIH Toolbox provides a much-needed set of tools that can be selected as appropriate to complement existing protocols being conducted with the growing Hispanic/Latino population in the United States.

Relationship between Sucrose Taste Detection Thresholds and Preferences in Children, Adolescents, and Adults

To address gaps in knowledge, our objectives were to (1) to determine whether there are age-related changes in sweet taste detection thresholds, as has been observed for sweet taste preferences, and (2) determine whether detection thresholds and taste preferences were significantly related to each other from childhood to adulthood. We combined data from studies that used the same validated psychophysical techniques to measure sucrose taste detection threshold and the most preferred sucrose concentration in children (n = 108), adolescents (n = 172), and adults (n = 205). There were significant effects of age group on both sucrose detection thresholds (p < 0.001) and most preferred sucrose concentration (p < 0.001). While children had higher sucrose detection thresholds than adolescents, who in turn tended to have higher detection thresholds than adults, both children and adolescent most preferred sucrose concentrations were higher than that of adults (all p < 0.05). Among each age group, and when combined, the lowest sucrose concentration detected was not significantly correlated with the most preferred sucrose concentration (all p > 0.18). These data provide further evidence that age-related changes in sucrose taste preferences that occur during adolescence cannot be explained by changes in taste sensitivity and that these two dimensions of sweet taste undergo distinct developmental trajectories from childhood to adulthood.

Reliability and Validity of the Spanish-Language Version of the NIH Toolbox

The psychometric properties of the English-language NIH Toolbox for Assessment of Neurological and Behavioral Function (NIH Toolbox) have been examined in numerous populations. This study evaluated the reliability and validity of the Spanish-language NIH Toolbox. Participants were children aged 3 to 7 years and adults aged 18 to 85 years who took part in the NIH Toolbox norming study in Spanish. Results supported the internal consistency reliability of included measures. Test-retest reliability was strong for most tests, though it was weaker for the test of olfaction among children and the test of locomotion among adults. Spearman's correlations and general linear models showed Spanish tests were often associated with age, sex, and education. Convergent validity for the two language measures that underwent more intensive development, evaluated via Spearman's correlations with legacy measures, was strong. Results support using the Spanish-language NIH Toolbox to measure neurological and behavioral functioning among Spanish-speaking individuals in the United States.

Pain reduction in burning mouth syndrome (BMS) may be associated with selective improvement of taste: a retrospective study

OBJECTIVE

The aim of this study was to examine taste function in patients who reported improvement in their pain level after treatment to determine if pain reduction is associated with change in taste function in patients with burning mouth syndrome (BMS).

STUDY DESIGN

This retrospective study of patients with BMS was conducted at a private oral medicine clinic.

RESULTS

Thirty-nine patients with BMS (31 females and 8 males; mean age 56.1 ± 9.4 years) reported improvement in their pain in 1 to 22 months after the initial visit (mean 5.13 ± 4.18). The most commonly used medication was clonazepam 0.25 to 0.5 mg/day. Twenty-eight patients were treated with a combination of medications. "Salt" and "bitter" responses at the fungiform papillae were increased after treatment (P = .026 and P = .044, respectively). "Salt" responses at the circumvallate papillae also increased (P < .001). Pain reduction was significant after treatment in the morning (P = .002) and in the evening (P < .001).

CONCLUSIONS

Treatment of BMS can significantly decrease pain symptoms, resulting in improvement in taste function. Pain reduction often requires a combination of medications.

Taste and smell function in Wolfram syndrome

BACKGROUND

Wolfram syndrome is a rare genetic disease characterized by insulin-dependent diabetes, optic nerve atrophy, sensorineural hearing loss and neurodegeneration. Although olfactory dysfunction, a classical clinical marker of neurodegenerative processes, has been reported in Wolfram syndrome, its use as a clinical marker in Wolfram is limited due to data scarcity. In addition, it is unknown whether Wolfram syndrome affects the sense of taste.

METHODS

Smell and taste perception were assessed in participants with Wolfram syndrome (n = 40) who were 15.1 ± 6.0 years of age (range: 5.1-28.7 years) and two sex- and age-matched control groups: one group with type 1 diabetes mellitus (T1D; n = 25) and a healthy control group (HC; n = 29). Smell sensitivity was assessed by measuring n-butanol detection thresholds and smell identification by using the University of Pennsylvania Smell Identification Test (UPSIT). Taste function was assessed using NIH Toolbox, which includes the assessment of sucrose (sweet) taste preference, and perceived intensity of sucrose, sodium chloride (salty), and quinine hydrochloride (bitter) both in the tip of the tongue (regional test) and the whole mouth.

RESULTS

Smell sensitivity was not significantly different among groups; however, smell identification was impaired in Wolfram syndrome, as reflected by significantly lower UPSIT scores in Wolfram syndrome compared to HC and T1D (P < 0.001). Compared to participants in the control groups, participants with Wolfram syndrome had a blunted perception of sweetness and saltiness when taste stimuli were applied regionally (P < 0.05), but differences in perceived intensity were no longer significant among groups when taste stimuli were tasted with the whole mouth. Groups preferred similar sucrose concentrations.

CONCLUSION

Wolfram syndrome was associated with olfactory dysfunction. However, the olfactory dysfunction was qualitative (related to smell identification) and not secondary to olfactory insensitivity or diabetes, suggesting is arising from dysfunction in central olfactory brain regions. In contrast to olfaction, and despite decreased perception of taste intensity in the anterior tongue, the sense of taste was overall well-conserved in individuals with Wolfram syndrome. Future longitudinal studies of taste and smell perception in Wolfram syndrome will be important to determine the use of the chemical senses as clinical markers of disease progression.

Tobacco use and chemosensory impairments among current adult tobacco users in the US: Data from NHANES 2013-2014

INTRODUCTION

Among US adults 40 years and older, about 23% report problems with their ability to smell, and 19% report problems with their ability to taste. Chemosenses are a first line of defence against environmental hazards (e.g. fires and leaking gas). A potential risk factor of chemosensory disorders includes nicotine product use, such as cigarette use. This study aims to assess the relationship of taste and smell alterations with type of recent nicotine product use (e.g. inhaled versus smokeless), recent cigarette use, and mentholation status based on data from NHANES 2013–2014.

METHODS

A total of 3186 men and women, 40 years and older, from NHANES 2013–2014 were assessed for smell and taste impairment, according to their recent nicotine product use. Taste impairment was identified as inability to identify quinine as bitter in the whole-mouth taste test. Impairment of smell was defined as failing to identify six or more of eight specific odors. Logistic regression models were adjusted for age, gender, and race/ethnicity.

RESULTS

Approximately 13% of participants failed the smell examination. No significant association between smell examination outcome and recent nicotine product use was found, though recent cigarette use showed a trend toward positive association (OR=1.66, 95% CI: 0.76–3.63) and mentholation status showed a trend toward negative association (OR=0.57, 95% CI: 0.22–1.49) on smell examination results. About 17% of participants failed the taste examination, and trends toward positive association were seen between taste examination outcomes and both recent nicotine product use (OR=1.28, 95% CI: 0.99–1.65) and recent cigarette use (OR=1.30, 95% CI: 0.50–3.40).

CONCLUSIONS

Findings indicate that recent use of nicotine products has an inconsistent relationship to dysfunctions in taste and smell. However, limiting the use of inhaled nicotine products, such as from cigarette use, could prove beneficial to a person’s taste and smell ability.

Effects of Weight Loss on Sweet Taste Preference and Palatability following Cognitive Behavioral Therapy for Women with Obesity

OBJECTIVE

Current evidence suggests that obesity is associated with alteration of sweet taste perception. The purpose of this study was to determine if nonsurgical cognitive behavioral therapy (CBT)-based weight loss can cause a change in sweet taste perception.

METHODS

This case-control study consisted of 51 women aged 21-64 years. Twenty-seven with obesity or overweight were assigned to an obesity (OB) group (BMI: 29.8 ± 0.5 kg/m2) and 24 to a normal control (NC) group (BMI: 20.9 ± 0.3 kg/m2). The OB group underwent a 30-week weight loss intervention using CBT-based group therapy. The results of measurement of detection threshold, suprathreshold perceived intensity, preference, and palatability, elements of sweet taste perception, were compared before and after the intervention. Psychological variables and appetite-related hormonal levels were measured.

RESULTS

Twenty-three patients and 22 controls completed the study. The OB group showed a 14.6% weight loss after the intervention. At baseline, the OB group preferred significantly higher sucrose concentrations than did the NC group; however, this difference was no longer significant after intervention. In the OB group, persistent pleasure and reduced desire for other taste, measured by repeated exposure to sweetness, normalized after weight loss to levels comparable to those seen in the NC group. No significant difference in discriminative perception of the threshold concentration or the suprathreshold sensory value was found between the two groups before or after intervention. A significant correlation was found between the basal preferred sucrose concentration and the serum leptin level of the OB group after adjusting for confounding factors, such as BMI, depressive symptom score, and trait-anxiety scores.

CONCLUSIONS

Weight loss induced by CBT-based nonsurgical intervention resulted in the normalization of the sucrose preference and palatability of women with obesity. Leptin activity may be associated with the altered sweet taste preference of people with obesity.

The oral microbiome of early stage Parkinson's disease and its relationship with functional measures of motor and non-motor function

Changes in the function and microbiome of the upper and lower gastrointestinal tract have been documented in Parkinson’s disease (PD), although most studies have examined merely fecal microbiome profiles and patients with advanced disease states. In the present study we sought to identify sensitive and specific biomarkers of changes in the oral microbiome of early stage PD through shotgun metatranscriptomic profiling. We recruited 48 PD subjects and 36 age- and gender-matched healthy controls. Subjects completed detailed assessments of motor, cognitive, balance, autonomic and chemosensory (smell and taste) functions to determine their disease stage. We also obtained a saliva sample for profiling of microbial RNA and host mRNA using next generation sequencing. We found no differences in overall alpha and beta diversity between subject groups. However, changes in specific microbial taxa were observed, including primarily bacteria, but also yeast and phage. Nearly half of our findings were consistent with prior studies in the field obtained through profiling of fecal samples, with others representing highly novel candidates for detection of early stage PD. Testing of the diagnostic utility of the microbiome data revealed potentially robust performance with as few as 11 taxonomic features achieving a cross-validated area under the ROC curve of 0.90 and overall accuracy of 84.5%. Bioinformatic analysis of 167 different metabolic pathways supported shifts in a small set of distinct pathways involved in amino acid and energy metabolism among the organisms comprising the oral microbiome. In parallel with the microbial analysis, we also examined the evidence for changes in human salivary mRNAs in the same subjects. This revealed significant changes in a set of 9 host mRNAs, several of which mapped to various brain functions and showed correlations with some of the significantly changed microbial taxa. Unexpectedly, we also observed robust correlations between many of the microbiota and functional measures, including those reflecting cognition, balance, and disease duration. These results suggest that the oral microbiome may represent a highly-accessible and informative microenvironment that offers new insights in the pathophysiology of early stage PD.

Sensory nutrition: The role of taste in the reviews of commercial food products

Many factors play a role in choosing what to eat or drink. We explored the role of sensation to explain these differences, drawing on consumer reviews for commercially available food products sold through an online retailer. We analyzed 393,568 unique food product reviews from Amazon customers with a total of 256,043 reviewers rating 67,553 products. Taste-associated words were mentioned more than words associated with price, food texture, customer service, nutrition, smell, or those referring to the trigeminal senses, e.g., "spicy". We computed the overall number of reviews that mentioned taste qualities: the word taste was mentioned in over 30% of the reviews (N = 142,768), followed by sweet (10.7%, N = 42,315), bitter (2.9%, N = 11,424), sour (2.1%, N = 8252) and salty (1.4%, N = 5688). We identified 38 phrases used to describe the evaluation of sweetness, finding that 'too sweet' was used in nearly 0.8% of the reviews and oversweetness was mentioned over 25 times more often than under-sweetness. We then focused on 'polarizing' products, those that elicited a wide difference of opinion (as measured by the ranges of the product ratings). Using the products that had more than 50 reviews, we identified the top 10 most polarizing foods and provide representative comments about the polarized taste experience of consumers. Overall, these results support the primacy of taste in real-world food ratings and individualized taste experience, such as whether a product is 'too sweet'. Analysis of consumer review data sets can provide information about purchasing decisions and customer sensory responses to particular commercially available products and represents a promising methodology for the emerging field of sensory nutrition.

Associations between brain structure and perceived intensity of sweet and bitter tastes

Functional neuroimaging studies have identified brain regions associated with human taste perception, but only a few have investigated the associations with brain structure. Here, in this exploratory study, we examined the association between the volumes of 82 regions of interest (ROI) and the perceived intensities of sweet (a weighted mean rating of glucose, fructose, aspartame, neohesperidin dihydrochalcone) and bitter (propylthiouracil, quinine, caffeine) substances in a large Australian healthy cohort from the Queensland Twin IMaging (QTIM, n = 559) study and the perceived intensity of quinine in a large U.S. healthy cohort from the Human Connectome Project (HCP, n = 1101). In QTIM, the volumes of 3 cortical (right cuneus gyrus, left transverse temporal gyrus, right inferior temporal gyrus) and one subcortical structure (both left and right caudate) were associated with more than one taste stimulus (P < 0.05) and tended to be associated with both sweet and bitter tastes in the same direction, suggesting these ROIs were more broadly tuned for taste sensation. A further 11 ROIs were associated with a specific taste (sweetness: 4; propylthiouracil: 3; caffeine: 2; quinine: 2). In HCP, volumes of 5 ROIs were associated with quinine bitterness. The quinine-left entorhinal cortex association was found in both QTIM (r = -0.12, P = 3.7 × 10^-3) and HCP (r = -0.06, P = 2.0 × 10^-2). This study provides the first evidence that, even in healthy people, variation in brain structure is associated with taste intensity ratings, and provides new insights into the brain gustatory circuit.

Development of a Regional Taste Test that uses Edible Circles for Stimulus Delivery

Introduction

Measurements of chemosensory function within specific regions of the tongue can yield important information about the sensitivity of lingual areas to chemosensory stimuli, and may identify possible nerve damage. A novel regional chemosensory test that uses thin edible circles was developed for human testing.

Methods

Edible circles placed at six different regions of the tongue were used to examine regional sensitivity to quinine for bitter taste, NaCl for salt taste, sucralose for sweet taste, and capsaicin for pungency. The six regions included the anterior tip of the tongue, the left and right lateral margins of the tongue (anterior and posterior), and the circumvallate region. Testing was completed with the mouth open, and the mouth closed.

Results

Intensity ratings at all sites were higher in the closed mouth condition for the three taste stimuli. Quinine intensity was highest at the circumvallate region with the mouth closed. NaCl and sucralose intensity were highest at the anterior tip and circumvallate regions. Capsaicin intensity was most highly perceived at the anterior tip of the tongue, but open and closed mouth intensity ratings showed no significant differences.

Conclusions

Regional differences in chemosensory perception were observed on the tongue, and these differences were dependent on the chemosensory stimulus, tongue region, and tasting mode.

Implications

Edible circles show minimal diffusion with saliva, can be used to examine both taste and irritation, and may be used to identify regional papillae counts on the tongue. Finally, edible circles should be invaluable for examining damage to the oral cavity.

Associations between Weight Loss, Food Likes, Dietary Behaviors, and Chemosensory Function in Bariatric Surgery: A Case-Control Analysis in Women

We tested the hypothesis that successful weight loss post-bariatric surgery would be associated with healthier chemosensory function, food likes, and dietary behaviors than either unsuccessful weight loss or pre-surgery morbid obesity. In a case-control design, pre-surgical women with morbid obesity (n = 49) were compared with those 1-year post-surgery (24 Roux-en-Y Bypass, 24 Sleeve Gastrectomy) and defined by excess or percent weight loss as successful/unsuccessful. For self-reported smell/taste perception, more post-surgery than pre-surgery reported improved/distorted perception, especially if weight loss successful. Measured taste function (perceived quinine and NaCl intensity) was lower among weight loss unsuccessful versus pre-surgery patients, yet a genetic variation in taste probe (propylthiouracil bitterness) matched expected frequencies without significant pre/post-surgery difference. Regarding survey-reported liking, higher diet quality was seen in the weight loss successful (independent of surgery type) versus pre-surgical patients, with differences driven by lower sweet and refined carbohydrate liking. The post versus pre-surgical patients had greater restraint but less hunger and disinhibition. Patients reporting both higher diet quality and lower hunger showed greater % weight loss, independent of surgery type. Thus, successful weight loss 1-year post-bariatric surgery was associated with improved or distorted chemosensation and patterns of liking associated with healthier diets, especially if coupled with less hunger.

Exposure to a slightly sweet lipid-based nutrient supplement during early life does not increase the level of sweet taste most preferred among 4- to 6-year-old Ghanaian children: follow-up of a randomized controlled trial

BACKGROUND

The impact of feeding a slightly sweet nutrient supplement early in life on later sweet taste preference is unknown.

OBJECTIVE

We tested the hypothesis that the level of sucrose most preferred by 4-6-y-old children exposed to a slightly sweet lipid-based nutrient supplement (LNS) early in life would not be higher than that of children never exposed to LNS.

DESIGN

We followed up children born to women (n = 1,320) who participated in a randomized trial in Ghana. In one group, LNS was provided to women on a daily basis during pregnancy and the first 6 mo postpartum and to their infants from age 6 to 18 mo (LNS group). The control groups received daily iron and folic acid or multiple micronutrients during pregnancy and the first 6 mo postpartum, with no infant supplementation (non-LNS group). At age 4-6 y, we randomly selected a subsample of children (n = 775) to assess the concentration of sucrose most preferred using the Monell 2-series, forced-choice, paired-comparison tracking procedure. We compared LNS with non-LNS group differences using a noninferiority margin of 5% weight/volume (wt/vol).

RESULTS

Of the 624 children tested, most (61%) provided reliable responses. Among all children, the mean ± SD sucrose solution most preferred (% wt/vol) was 14.6 ± 8.6 (LNS group 14.9 ± 8.7; non-LNS group 14.2 ± 8.4). However, among children with reliable responses, it was 17.0 ± 10.2 (LNS group 17.5 ± 10.4; non-LNS group 16.5 ± 10.0). The upper level of the 95% CI of the difference between groups did not exceed the noninferiority margin in either the full sample or those with reliable responses, indicating that the LNS group did not have a higher sweet preference than the non-LNS group.

CONCLUSION

Exposure to a slightly sweet nutrient supplement early in life did not increase the level of sweet taste most preferred during childhood. This trial was registered at clinicaltrials.gov as NCT00970866.

Association Between Olfactory and Gustatory Dysfunction and Cognition in Older Adults

Background

The association between olfactory dysfunction (OD) and cognitive decline is becoming apparent in the emerging literature. However, the literature demonstrating a similar effect between gustatory dysfunction (GD) and cognition is not well established.

Objective

To determine whether OD and GD are independently associated with cognitive impairment.

Methods

The 2013–2014 National Health and Nutrition Examination Survey was queried for 1376 older adults, corresponding to a weighted population sample of 50 816 529, to assess olfactory and gustatory status and cognition using univariate and multivariate regression analyses. OD and GD were determined using objective measurements with validated protocols. Participants were stratified as normal or abnormal cognition status using accepted cutoff values as indicated for the Consortium to Establish a Registry for Alzheimer’s Disease (CERAD) neuropsychological test, Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST).

Results

OD was associated with both mild cognitive impairment (odds ratio [OR] 1.809, P = .004) and dementia (OR 3.173, P < .001) with CERAD testing, abnormal AFT (OR 2.424, P < .001), and abnormal DSST (OR 4.028, P < .001). GD based on 1M NaCl whole mouth taste testing was associated with dementia on CERAD testing (OR 2.217, P = .004). When smell and taste parameters were included together in the regression model, both OD and GD remained significant independent predictors of dementia status based on CERAD testing (OR 3.133, P < .001, OR 1.904, P = .015).

Conclusions

OD and severe GD represent independent predictors of cognitive impairment in a nationally representative sample of older adults.

Body mass variability is represented by distinct functional connectivity patterns

Understanding weight-related differences in functional connectivity provides key insight into neurocognitive factors implicated in obesity. Here, we sampled three groups from human connectome project data: 1) 47 pairs of BMI-discordant twins (n = 94; average BMI-discordancy 6.7 ± 3.1 kg/m2), 2) 47 pairs of gender and BMI matched BMI-discordant, unrelated individuals, and 3) 47 pairs of BMI-similar twins, to test for body mass dependent differences in between network functional connectivity. Across BMI discordant samples, three networks appeared to be highly sensitive to weight status; specifically, a network comprised of gustatory processing regions, a visual processing network, and the default mode network (DMN). Further, in the BMI-discordant twin sample, twins with lower BMI had stronger connectivity between striatal/thalamic and prefrontal networks (pFWE = 0.04). We also observed that individuals with a higher BMI than their twin had stronger connectivity between cerebellar and insular networks (pFWE = 0.04). Connectivity patterns observed in the BMI-discordant twin sample were not seen in a BMI-similar sample, providing evidence that the results are specific to BMI discordance. Beyond the involvement of gustatory and visual networks and the DMN, little overlap in results were seen between the two BMI-discordant samples. In concordance with previous findings, we hypothesize that stronger cortical-striatal-thalamic connectivity associated with lower body mass in twins may facilitate increased regulation of hedonically motivated behaviors. In twins with higher body mass, increased cerebellar-insula connectivity may be associated with compromised satiation signaling, an interpretation dovetailing prior research. The lack of overlapping results between the two BMI discordant samples may be a function of higher study design sensitivity in the BMI-discordant twin sample, relative to the more generalizable results in the unrelated sample. These findings demonstrate that distinct connectivity patterns can represent weight variability, adding to mounting evidence that implicates atypical brain functioning with the accumulation and/or maintenance of elevated weight.

Taste Exam: A Brief and Validated Test

The emerging importance of taste in medicine and biomedical research, and new knowledge about its genetic underpinnings, has motivated us to supplement classic taste-testing methods in two ways. First, we explain how to do a brief assessment of the mouth, including the tongue, to ensure that taste papillae are present and to note evidence of relevant disease. Second, we draw on genetics to validate taste test data by comparing reports of perceived bitterness intensity and inborn receptor genotypes. Discordance between objective measures of genotype and subjective reports of taste experience can identify data collection errors, distracted subjects or those who have not understood or followed instructions. Our expectation is that fast and valid taste tests may persuade researchers and clinicians to assess taste regularly, making taste testing as common as testing for hearing and vision. Finally, because many tissues of the body express taste receptors, taste responses may provide a proxy for tissue sensitivity elsewhere in the body and, thereby, serve as a rapid, point-of-care test to guide diagnosis and a research tool to evaluate taste receptor protein function.

Sweet taste preference in binge-eating disorder: A preliminary investigation

Research suggests that individuals with high liking for sweets are at increased risk for binge eating, which has been minimally investigated in individuals with binge-eating disorder (BED). Forty-one adults (85% female, 83% white) with binge eating concerns completed a sweet taste test and measures of eating disorder behaviors and food cravings. A subset of participants with BED completed an oral glucose tolerance test (OGTT; N=21) and a 24-hour dietary recall (N=26). Regression models were used to compare highest sweet preferers (HSP [N=18]) to other sweet preferers (OSP [N=23]) and were used to assess associations between sweet taste preference and outcome variables. Effect sizes (ηp²) for differences between HSP and OSP ranged from small (≤0.01) to large (≥0.24); group differences were statistically nonsignificant except for 24-hour caloric intake (ηp²=0.16, p=0.04), protein intake (ηp²=0.16, p=0.04), and insulin sensitivity index (ηp²=0.24, p=0.04), which were higher in HSP, and postprandial insulin, which was smaller in HSP (ηp²=0.27, p=0.03). Continuous analyses replicated postprandial insulin response. Compared with OSP, HSP reported numerically higher binge-eating frequency (ηp²=0.04), over-eating frequency (ηp²=0.06), and carbohydrate intake (ηp²=0.14), and they exhibited numerically smaller postprandial glucose AUC (ηp²=0.16). Sweet taste preference may have implications for glucose regulation, binge-eating frequency, and nutrient intake in BED.

Effects of Sleeve Gastrectomy vs. Roux-en-Y Gastric Bypass on Eating Behavior and Sweet Taste Perception in Subjects with Obesity

The goal of this study was to test the hypothesis that weight loss induced by Roux-en-Y gastric bypass (RYGB) has greater effects on taste perception and eating behavior than comparable weight loss induced by sleeve gastrectomy (SG). We evaluated the following outcomes in 31 subjects both before and after ~20% weight loss induced by RYGB (n = 23) or SG (n = 8): (1) sweet, savory, and salty taste sensitivity; (2) the most preferred concentrations of sucrose and monosodium glutamate; (3) sweetness palatability, by using validated sensory testing techniques; and (4) eating behavior, by using the Food Craving Inventory and the Dutch Eating Behavior Questionnaire. We found that neither RYGB nor SG affected sweetness or saltiness sensitivity. However, weight loss induced by either RYGB or SG caused the same decrease in: (1) frequency of cravings for foods; (2) influence of emotions and external food cues on eating behavior; and (3) shifted sweetness palatability from pleasant to unpleasant when repetitively tasting sucrose (all p-values ≤ 0.01). Therefore, when matched on weight loss, SG and RYGB cause the same beneficial effects on key factors involved in the regulation of eating behavior and hedonic component of taste perception.