Psychophysical Tracking Method to Assess Taste Detection Thresholds in Children, Adolescents, and Adults: The Taste Detection Threshold (TDT) Test.

This paper describes a two-alternative, forced-choice, staircase, tracking procedure, called the Taste Detection Threshold (TDT) test, that provides a reliable measure of sweet, salty, and umami taste detection thresholds from childhood to adulthood. Advantages of the method include procedures that are identical for children and adults, thus allowing the determination of age-related and individual differences in taste perception, if any, and tasks that can be completed in a relatively short time frame, do not rely on continuous attention or require memorization, control for subjective response biases, and minimize the impact of language development. After a 1 hour fast, participants are presented with pairs of solutions; in each pair, one solution is water, and the other solution contains varying concentrations of the tastant.

Denatonium benzoate bitter taste perception in chronic rhinosinusitis subgroups.

Background: Chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP), and aspirin-exacerbated respiratory disease (AERD) have varying levels of inflammation and disease severity. Solitary chemosensory cells (SCCs) are enriched in nasal polyps, are the primary source of interleukin 25 (IL-25) in upper airways, leading to type 2 inflammation, and are activated by bitter-tasting denatonium benzoate (DB). Thus, we sought to evaluate DB taste perception at a range of concentrations in order to identify 1 that most differentiates CRS subgroups from controls.

Divergent bitter and sweet taste perception intensity in chronic rhinosinusitis patients.

Background: Bitter and sweet taste receptors are present in the human upper airway, where they have roles in innate immunity. Previous studies have shown that 1 of the 25 bitter receptors, TAS2R38, responds to specific bacterial signaling molecules and evokes 1 type of a defense response in the upper airway, whereas ligands of sweet receptors suppress other types of defense responses.

Methods: We examined whether other bitter taste receptors might also be involved in innate immunity by using sensory responses to bitter compounds that are not ligands of TAS2R38 (quinine and denatonium benzoate) to assess the sensitivity of other bitter receptors in chronic rhinosinusitis (CRS) patients.

Tissue-Dependent Expression of Bitter Receptor TAS2R38 mRNA.

TAS2R38 is a human bitter receptor gene with a common but inactive allele; people homozygous for the inactive form cannot perceive low concentrations of certain bitter compounds. The frequency of the inactive and active forms of this receptor is nearly equal in many human populations, and heterozygotes with 1 copy of the active form and 1 copy of the inactive form have the most common diplotype. However, even though they have the same genotype, heterozygotes differ markedly in their perception of bitterness, perhaps in part because of differences in TAS2R38 mRNA expression.

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.

The Role of Quinine-Responsive Taste Receptor Family 2 in Airway Immune Defense and Chronic Rhinosinusitis.

Background: Bitter (T2R) and sweet (T1R) taste receptors in the airway are important in innate immune defense, and variations in taste receptor functionality in one T2R (T2R38) correlate with disease status and disease severity in chronic rhinosinusitis (CRS). Quinine is a bitter compound that is an agonist for several T2Rs also expressed on sinonasal cells, but not for T2R38. Because of this property, quinine may stimulate innate immune defense mechanisms in the airway, and functional differences in quinine perception may be reflective of disease status in CRS.

Nasal Structural and Aerodynamic Features That May Benefit Normal Olfactory Sensitivity.

Nasal airflow that effectively transports ambient odors to the olfactory receptors is important for human olfaction. Yet, the impact of nasal anatomical variations on airflow pattern and olfactory function is not fully understood. In this study, 22 healthy volunteers were recruited and underwent computed tomographic scans for computational simulations of nasal airflow patterns.

WNT10A mutation causes ectodermal dysplasia by impairing progenitor cell proliferation and KLF4-mediated differentiation.

Human WNT10A mutations are associated with developmental tooth abnormalities and adolescent onset of a broad range of ectodermal defects. Here we show that β-catenin pathway activity and adult epithelial progenitor proliferation are reduced in the absence of WNT10A, and identify Wnt-active self-renewing stem cells in affected tissues including hair follicles, sebaceous glands, taste buds, nails and sweat ducts. Human and mouse WNT10A mutant palmoplantar and tongue epithelia also display specific differentiation defects that are mimicked by loss of the transcription factor KLF4.

Correlation of T2R38 taste phenotype and in vitro biofilm formation from nonpolypoid chronic rhinosinusitis patients.

Background: Sinonasal biofilms have been demonstrated in specimens collected from chronic rhinosinusitis (CRS) patients. Mounting evidence suggests that biofilms contribute to therapeutically recalcitrant CRS. Recently, the bitter taste receptor T2R38 has been implicated in the regulation of the sinonasal mucosal innate immune response.

TAS2R38 genotype predicts surgical outcome in nonpolypoid chronic rhinosinusitis.

Background: Over 550,000 sinus surgeries are performed annually in the United States on patients with chronic rhinosinusitis (CRS). Although the results of sinus surgery vary widely, no known genetic factor has been identified to predict surgical outcomes. The bitter taste receptor T2R38 has recently been demonstrated to regulate upper airway innate defense and may affect patient responses to therapy.

Conductive olfactory losses in chronic rhinosinusitis? A computational fluid dynamics study of 29 patients.

Background: Besides sensorineural factors, conductive impediments likely contribute to olfactory losses in chronic rhinosinusitis (CRS) patients, yet no conclusive evidence exists. We aimed to examine possible conductive factors using computational fluid dynamics (CFD) models.

Methods: A total of 29 CRS patients were assessed via odorant detection thresholds (ODTs), rhinomanometry (nasal resistance [NR]), acoustic rhinometry (minimum-cross-sectional area [MCA]) and computed tomography (CT) staging.

Regional peak mucosal cooling predicts the perception of nasal patency.

Objectives/hypothesis: Nasal obstruction is the principal symptom that drives patients with rhinosinus disease to seek medical treatment. However, patient perception of obstruction often bears little relationship to actual measured physical obstruction of airflow. This lack of an objective clinical tool hinders effective diagnosis and treatment.

Gustation assessment using the NIH Toolbox.

The NIH Toolbox for Assessment of Neurological and Behavioral Function (NIH Toolbox) is a set of brief measures for the assessment of cognitive function, emotional health, motor function, and sensory function for use in clinical trials and in epidemiologic and longitudinal studies. Gustatory perception is assessed as 1 of 6 areas of sensory function. A team of 11 scientists with expertise in taste perception selected 2 gustatory measures, 1 of which can be used in young pediatric populations.

The development of salty taste acceptance is related to dietary experience in human infants: a prospective study.

Background: Sodium intake is related to hypertension and other diseases, but little is known about the early development of salty taste acceptance.

Objective: The prospective study asked whether dietary experience with foods containing sodium is associated with development of infant salty taste preference.

Design: Infants (n = 61) were tested at 2 and 6 mo to assess their response to 0.

Age-associated loss of selectivity in human olfactory sensory neurons.

We report a cross-sectional study of olfactory impairment with age based on both odorant-stimulated responses of human olfactory sensory neurons (OSNs) and tests of olfactory threshold sensitivity. A total of 621 OSNs from 440 subjects in 2 age groups of younger (≤ 45 years) and older (≥ 60 years) subjects were investigated using fluorescence intensity ratio fura-2 imaging. OSNs were tested for responses to 2 odorant mixtures, as well as to subsets of and individual odors in those mixtures.

Neuropathology of the olfactory mucosa in chronic rhinosinusitis.

Background: Chronic rhinosinusitis (CRS) is a complex heterogeneous inflammatory disease that affects the nasal cavity, but the pathological examination of the olfactory mucosa (OM) in this disease has been limited.

Methods: Nasal biopsy specimens were obtained from 20 control subjects and 50 CRS patients in conjunction with clinical assessments. Histopathology of these nasal biopsy specimens was performed and immunohistochemistry was used to characterize nonneuronal, neuronal, and inflammatory cells in the OM.

Analysis of the olfactory mucosa in chronic rhinosinusitis.

The impact of chronic rhinosinusitis (CRS) on the olfactory mucosa (OM) is dramatic. Cellular profiles and epithelial integrity in OM biopsies were evaluated using histological and immunohistochemical methods to define a strategy for future histological studies of CRS. We have examined nasal biopsies of 54 CRS patients (18-63 years old) and have defined specific histopathological patterns of the OM: normal pseudostratified, goblet cell hyperplasia, squamous metaplasia, and erosion.

Evaluating the prevalence of olfactory dysfunction in a pediatric population.

Although smell loss has several potential etiologies (e.g., head trauma, allergic rhinitis, and enlarged adenoids) that are common among children, studies evaluating the prevalence of olfactory dysfunction in the pediatric population are rare.

Assessment of smoking status based on cotinine levels in nasal lavage fluid.

Cotinine is a principal metabolite of nicotine with a substantially longer half-life, and cotinine levels in saliva, urine or serum are widely used to validate self-reported smoking status. The nasal cavity and olfactory system are directly exposed to tobacco smoke in smokers and in non-smokers who live with or work around smokers. However, despite the potential for a direct impact of tobacco smoke on the nasal epithelium and olfactory neurons, no prior studies have assessed cotinine levels in nasal mucus.

Smoking-associated squamous metaplasia in olfactory mucosa of patients with chronic rhinosinusitis.

Few studies have examined the induction of squamous metaplasia in human olfactory nasal tissue caused by tobacco use and the implications it may have for olfaction, particularly when there are pre-existing insults, such as chronic rhinosinusitis (CRS). Quantitative histopathological analyses were performed on Alcian blue- and H&E-stained sections of nasal biopsies taken from the upper aspect of the middle turbinate of CRS patients. Chronic rhinosinusitis patients who were current smokers had a predominance of squamous metaplasia in the olfactory sensory epithelium, whereas CRS patients who were nonsmokers and were not exposed to secondhand cigarette smoke had a prevalence of goblet cell hyperplasia.

Numerical modeling of nasal obstruction and endoscopic surgical intervention: outcome to airflow and olfaction.

Background: Mechanical obstruction of odorant flow to the olfactory neuroepithelium may be a primary cause of olfactory loss in nasal-sinus disease patients. Surgical removal of nasal obstruction may facilitate the recovery of olfactory ability. Unfortunately, quantifying the functional impact of nasal obstruction and subsequent surgical outcomes using acoustic rhinometry, rhinomanometry, or CT scans is inadequate.

Prevalence and causes of severe taste loss in a chemosensory clinic population.

Although complete or near-complete olfactory loss has been extensively documented and described, few published reports have documented severe generalized gustatory loss (across qualities and neural fields) with rigorous psychophysical testing, and none have explored the prevalence or causes of such losses in a large clinical population. This study retrospectively reviews our chemosensory clinic's experience of 1,176 patients evaluated for complaints of chemosensory dysfunction in order to address these issues. Our series confirms that despite the complex, bilateral innervation and regenerative capacity of the gustatory system, severe generalized taste loss does occur as a clinical entity, albeit rarely: only 0.