Drug-induced taste disorders

Taste alterations after hematopoietic cell transplantation: a scoping review

PURPOSE

This review aimed to evaluate the prevalence and characteristics of dysgeusia after hematopoietic cell transplantation (HCT).

METHODS

A literature search (in PubMed, Embase.com and Web of Science) for clinical studies evaluating taste before and after HCT was performed up to June 22, 2023, in collaboration with a medical information specialist. After title and abstract review (N = 807) followed by full-text review (N = 61), articles that met the inclusion criteria were summarized in a table and synthesized narratively.

RESULTS

11 articles were analyzed in this review. All studies had a prospective design and patient populations included children (N = 3) and adults (N = 8) undergoing allogeneic or autologous HCT. Taste was assessed objectively (N = 6) and/or subjectively (N = 8) between baseline and 12 months after HCT. Before HCT, the self-reported (0-31%) and objective (2.4-10%) prevalence of dysgeusia was low. During the neutropenic phase, self-reported (20-100%) and objective (21.4%) dysgeusia was highest. In the post-engraftment period, the self-reported (18%) and objective (0-33%) prevalence of dysgeusia decreased. Different taste qualities were assessed in six studies including salt, sour, bitter, sweet, and umami.

CONCLUSIONS

Some patients undergoing HCT experience dysgeusia prior to treatment. During the neutropenic phase, they had highest complaints, with recovery occurring in the post-engraftment period. All basic tastes, except bitter, were affected. Umami and salt were most affected during treatment. These findings have implications for patient management.

Psychiatric Explanations of Poor Oral Intake: A Clinically Focused Review

BACKGROUND

Poor oral intake (POI) among medical-surgical inpatients can cause malnutrition and delay recovery due to medical consequences and the need for more invasive nutritional support. Many psychiatric conditions can cause POI; however, the role that psychiatric conditions play in POI has received limited attention to date.

OBJECTIVE

This review aggregates available information on POI due to psychiatric conditions and provides a framework for the clinical approach to these conditions in hospitalized adult patients.

METHODS

We searched PubMed and EMBASE for reviews of POI due to psychiatric causes, but no relevant publications were identified. Diagnostic criteria for relevant conditions in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision and Rome IV were reviewed, as were C-L psychiatry textbooks and relevant society websites. This review was further supplemented by a case conference at the authors' institution.

RESULTS

We have divided results into five sections for clinical utility: (1) the need to rule out medical causes of POI; (2) unpleasant somatic experiences, including psychotropic causes; (3) mood, psychotic, catatonic, and neurocognitive disorders that can present with POI; (4) eating and feeding disorders; and (5) personal and interpersonal explanations of POI. Within each section, we review how to identify and manage each condition, specifically considering the effects of treatment on oral intake.

CONCLUSIONS

The clinical management of POI varies based on cause. For instance, psychostimulants can cause POI due to inappetence; however, they can treat POI due to abulia by improving motivation. The fact that such a broad range of psychiatric conditions can cause POI calls for a systematic clinical approach that considers the categories of potential causes. We also identified a need for prospective studies focused on the management of POI due to psychiatric conditions, as the literature on this topic is limited to case reports, case series, and retrospective cohort studies.

Assessment of Bitterness in Non-Charged Pharmaceuticals with a Taste Sensor: A Study on Substances with Xanthine Scaffold and Allopurinol

Taste sensors with an allostery approach have been studied to detect non-charged bitter substances, such as xanthine derivatives, used in foods (e.g., caffeine) or pharmaceuticals (e.g., etofylline). In this study, the authors modified a taste sensor with 3-bromo-2,6-dihydroxybenzoic acid and used it in conjunction with sensory tests to assess the bitterness of non-charged pharmaceuticals with xanthine scaffolds (i.e., acefylline and doxofylline), as well as allopurinol, an analogue of hypoxanthine. The results show that the sensor was able to differentiate between different levels of sample bitterness. For instance, when assessing a 30 mM sample solution, the sensor response to acefylline was 34.24 mV, which corresponded to the highest level of bitterness (τ = 3.50), while the response to allopurinol was lowest at 2.72 mV, corresponding to relatively weaker bitterness (τ = 0.50). Additionally, this study extended the application of the sensor to detect pentoxifylline, an active pharmaceutical ingredient in pediatric medicines. These results underscore the taste sensor's value as an additional tool for early-stage assessment and prediction of bitterness in non-charged pharmaceuticals.

Fall risk factors among poly-medicated older Lebanese patients in primary care settings: a secondary cross-sectional analysis of the "MGPIDP-L project"

BACKGROUND

Falling is a major concern for the health of older adults and significantly affects their quality of life. Identifying the various risk factors and the differences between older patients can be challenging. The objective of this study was to identify the risk factors for falls among polymedicated community-dwelling older Lebanese patients following a medication review.

METHODS

In this analytical cross-sectional study, we examined the risk factors for falls in 850 patients aged ≥ 65 years who were taking ≥ 5 medications daily. The study involved conducting a medication review over the course of a year in primary care settings and using multivariate logistic regression analysis to analyze the data.

RESULTS

Our results showed that 106 (19.5%) of the 850 included patients had fallen at least once in the three months prior to the medication review. Loss of appetite and functional dependence were identified as the most significant predictors of falls ORa = 3.020, CI [2.074-4.397] and ORa = 2.877, CI [1.787-4.632], respectively. Other risk factors for falls included drowsiness ORa = 2.172, CI [1.499-3.145], and the use of beta-blockers ORa = 1.943, CI [1.339-2.820].

CONCLUSION

Our study highlights the importance of addressing multiple risk factors for falls among Lebanese older adults and emphasizes the need for customized interventions and ongoing monitoring to prevent falls and improve health outcomes. This study sheds light on a critical issue in the Lebanese older population and provides valuable insight into the complex nature of falls among poly-medicated Lebanese community-dwelling older adults.

TRIAL REGISTRATION

2021REC-001- INSPECT -09-04.

Clinical Neurology in Practice: The Tongue (part 2)

BACKGROUND

The tongue is an essential organ for the development of certain crucial functions such as swallowing and speech. The examination of the tongue can be very useful in neurology, as the various types of lingual alterations can lead to certain specific diagnoses, the tongue being a kind of 'mirror' of some neurological function.

REVIEW SUMMARY

To discuss the elements of clinical examination of the tongue in relation to neurological disorders. After reviewing the different superficial lesions of the tongue, we deal with various movement disorders of the tongue (fasciculations/myokimia, orolingual tremor, choreic movements of the tongue, dystonia of the tongue, lingual myoclonus, and psychogenic movements), disorders of taste and lingual sensitivity and lingual pain.

CONCLUSIONS

Examination of the tongue should not be limited to studying its motility and trophicity. It is equally important to check the sensory function and understand how to interpret abnormal movements involving the tongue. This study also aimed to demonstrate the importance of nonmotor tongue function in neurological practice.

Sodium valproate: cacosmia and dysgeusia as uncommon side effects

Smell and taste disturbances are potential adverse reactions of many drugs used in Psychiatry, such as antidepressants, anti-Parkinson agents, lithium, minor and major tranquilizers. To our knowledge, only one clinical case regarding valproate and cacosmia has been reported so far. However, several anticonvulsants are reported to cause taste and smell disturbances, although the underlying etiology is currently unclear. Our patient developed cacosmia and dysgeusia when taking valproic acid, both effects quickly disappeared upon drug discontinuation. In this article we not only report this uncommon side effect, but we discuss the plausible mechanisms behind such an adverse reaction. Our case is to date the second similar case in the literature. The aim of the present article is to make clinicians informed about this very uncommon and unpleasant side effect.

Delving into the reducing effects of the GABAB positive allosteric modulator, KK-92A, on alcohol-related behaviors in rats

Recent studies have demonstrated the ability of the positive allosteric modulator (PAM) of the GABAB receptor (GABAB PAM), KK-92A, to suppress operant alcohol self-administration and reinstatement of alcohol seeking in selectively bred Sardinian alcohol-preferring (sP) rats. The present study was designed to scrutinize the suppressing effects of KK-92A on alcohol-related behaviors; to this end, four separate experiments were conducted to address just as many new research questions, some of which bear translational value. Experiment 1 found that 7-day treatment with KK-92A (0, 5, 10, and 20 mg/kg, intraperitoneally [i.p.]) effectively reduced alcohol intake in male sP rats exposed to the home-cage 2-bottle "alcohol (10% v/v) vs. water" choice regimen with 1 hour/day limited access, extending to excessive alcohol drinking the ability of KK-92A to suppress operant alcohol self-administration. Experiment 2 demonstrated that the ability of KK-92A to reduce lever-responding for alcohol was maintained also after acute, intragastric treatment (0, 20, and 40 mg/kg) in female sP rats trained to lever-respond for 15% (v/v) alcohol under the fixed ratio 5 schedule of reinforcement. In Experiment 3, acutely administered KK-92A (0, 5, 10, and 20 mg/kg, i.p.) dampened alcohol-seeking behavior in female sP rats exposed to a single session under the extinction responding schedule. Experiment 4 used a taste reactivity test to demonstrate that acute treatment with KK-92A (0 and 20 mg/kg, i.p.) did not alter either hedonic or aversive reactions to a 15% (v/v) alcohol solution in male sP rats, ruling out that KK-92A-induced reduction of alcohol drinking and self-administration could be due to alterations in alcohol palatability. Together, these results enhance the behavioral pharmacological profile of KK-92A and further strengthen the notion that GABAB PAMs may represent a novel class of ligands with therapeutic potential for treating alcohol use disorder.

Endocrinology of Taste with Aging

Taste is one of our five primary senses, and taste impairment has been shown to increase with aging. The ability to taste allows us to enjoy the food we eat and to avoid foods that are potentially spoiled or poisonous. Recent advances in our understanding of the molecular mechanisms of taste receptor cells located within taste buds help us decipher how taste works. The discoveries of "classic" endocrine hormones in taste receptor cells point toward taste buds being actual endocrine organs. A better understanding of how taste works may help in reversing taste impairment associated with aging.

Drug-induced olfactory and gustatory dysfunction: Analysis of FDA adverse events reporting system

OBJECTIVES

With the COVID-19 pandemic, there is growing interest and research in olfactory and gustatory dysfunction (OGD). Drug-induced dysfunction is an often overlooked etiology. While several medications include smell or taste disturbance as a side effect, there are no publications describing which medications are most frequently implicated. We aim to describe the patterns of these adverse drug reactions (ADRs) using the FDA Adverse Events Reporting System (FAERS).

METHODS

The FAERS database was queried from 2011 to 2021 for terms describing ADRs related to OGD. Terms included anosmia, hyposmia, olfactory test abnormal, olfactory nerve disorder, hallucination olfactory, parosmia, ageusia, hypogeusia, dysgeusia, and taste disorder. We identified the top reported medications associated with general smell dysfunction, general taste dysfunction, reduced smell, and altered smell.

RESULTS

From 2011 to 2021, 16,091 ADRs were reported with OGD, of which13,641 (84.8%) and 2,450 (15.2%) were associated with gustatory and olfactory reactions, respectively. Zinc products (370 reports) and fluticasone propionate (214) were most commonly associated with olfactory dysfunction, specifically reduced olfaction. Varenicline (24) and fluticasone propionate (23) were most commonly associated with altered smell. Lenalidomide (490) and sunitinib (468) were most commonly associated with gustatory dysfunction. Antineoplastic and immunomodulating medications accounted for 21.6% and 36.3% of olfactory and gustatory ADRs, respectively. Among this category, immunoglobulin drugs were the most commonly associated with OGD ADRs.

CONCLUSION

Gustatory dysfunction is more commonly reported ADR compared with olfactory dysfunction. Immunologic/rheumatologic medications are the leading culprit of reported OGD. With increasing numbers of patients presenting to otolaryngologists for OGD, it is important to consider drug-induced etiology.

LEVEL OF EVIDENCE

III.

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

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

Scoping Review and Evidence Map of the Relation between Exposure to Dietary Sweetness and Body Weight-Related Outcomes in Adults

Numerous governmental and health organizations recommend reduced intake of added sugars due to the health risks associated with excess intake, including the risk of obesity. Some organizations further recommend avoiding dietary sweetness, regardless of the source. A scoping review and evidence map were completed to characterize the research that investigated associations between dietary sweetness and body weight. The aim was to identify and map published studies that have investigated total dietary sweetness, sweet food/beverages, sugar, or sweetener intake, and body weight-related outcomes and/or energy intake. Using preregistered search terms (osf.io/my7pb), 36,779 publications (duplicates removed) were identified from PubMed, Cochrane Library, and Scopus and screened for inclusion. Eligible studies were clinical trials, longitudinal cohorts, case-control studies, cross-sectional studies, and systematic reviews conducted among adults (age ≥18 y), which were performed to investigate associations between dietary sweetness, sweet foods/beverages, sugar, or sweetener (energetic or nonenergetic) intake and body weight, BMI, adiposity, and/or energy intake. A total of 833 eligible publications were identified, detailing 804 studies. Only 7 studies (0.9% of included studies; 2 clinical trials, 4 cross-sectional studies, and 1 with another design type) investigated associations between total dietary sweetness and body weight-related outcome and/or energy intake. An additional 608 (75.6%) studies investigated intakes of sweet foods/beverages, sugar, or sweetener, and body weight-related outcomes and/or energy intake, including 225 clinical trials, 81 longitudinal cohorts, 4 case-control studies, and 280 cross-sectional studies. Most studies (90.6%) did not measure the sweetness of the diet or individual foods consumed. Ninety-two (11.4%) publications reported data from studies on dietary patterns that included sweet foods/beverages alongside other dietary components and 97 (12.1%) systematic reviews addressed different but related research questions. Although there is a breadth of evidence from studies that have investigated associations between intakes of sweet foods and beverages, sugars, and sweeteners and body weight, there is a limited depth of evidence on the association between total dietary sweetness and body weight.

Taste and smell disturbances in patients with chronic oral graft vs. host disease: An observational study

Background

A common complication of allogeneic hematopoietic stem cell transplantation (alloHSCT) is chronic oral graft vs. host disease (cGvHD). Oral cGvHD may present as mucosal lesions, salivary gland dysfunction, and trismus. Moreover, taste and smell ability may be affected, but the prevalence, nature and severity of altered taste and smell function, and their impact on quality of life (QoL) are understudied.

Aim

To identify the prevalence, nature, and severity of taste and smell disturbances, their impact on QoL and to assess whether altered taste/smell ability is associated with oral mucosal cGvHD or hyposalivation.

Materials and methods

AlloHSCT recipients at least 100 days post-HSCT and referred for oral cGvHD-related oral complaints were eligible for participation in this cross-sectional study. Manifestations of oral mucosal cGvHD were scored, the (un)stimulated salivary flow was measured, and objective taste and smell ability was evaluated. Subjective taste and smell alterations, and overall and oral health (OH)-related QoL were assessed.

Results

In total, 45 patients were included, of which objective reduced taste ability (hypogeusia) was identified in 68.9%; 28.9% had reduced smell ability and 11.1% had complete loss of smell. Nevertheless, only 31.1% of patients reported severe taste alterations and 22% reported moderate taste alterations indicating that not all the patients were aware of their altered taste sense. Taste/smell disturbances were not related to oral mucosal cGvHD or hyposalivation. Most alloHSCT recipients reported a decreased OH-related QoL. However, a relation between taste/smell ability and global or OH-related QoL could not be identified.

Conclusion

Taste and smell disturbances are prevalent among alloHSCT recipients. Most patients reported a decreased OH-related QoL, but the specific impact of taste and smell disturbances remains to be elucidated.

Assessing physical and chemical properties of saliva among tuberculosis patients on anti-tuberculosis treatment - An observational study

Background

Tuberculosis (TB) is one of the major systemic conditions which is a preventable and curable infection but remains a significant cause of death. The WHO, in its global plan to stop TB reports, that poor treatment has resulted in the evolution of Mycobacterium tuberculosis strains that do not respond to treatment with the standard first-line combination of anti- tuberculosis medicines, resulting in the emergence of multidrug-resistant tuberculosis in almost every country of the world.The present study was aimed to assess the physical and chemical property of stimulated and unstimulated saliva and identify if any association exist with alterations in taste perception in patients with antituberculosis medications.

Methods

A total of 30 patients on anti-tuberculosis drugs were considered as cases and 30 healthy volunteers were considered as controls and included in the study. All study subjects were assessed for their physical property like flow rate, viscosity, pH and chemical property like sodium, potassium, calcium, phosphorous of stimulated and unstimulated saliva. All the subjects on Anti-tuberculosis drugs were assessed for change in taste perceptions using the standard questionnaire.

Results

There is a significant decrease in the flow rate (0.34 ± 0.06) and pH (5.89 ± 0.37) of unstimulated saliva of patients and the flow rate (0.38 ± 0.07) and viscosity (1.34 ± 0.28) of stimulated saliva among the case group compare to the control group. All the electrolytes' concentrations such as sodium, potassium, calcium, and phosphorous values were significantly altered in stimulated and unstimulated saliva of the case group compared to the control group in which p-value < 0.05 was considered.

Conclusion

There are significant changes in physical and chemical properties of both stimulated and unstimulated saliva which has an effect on taste perception inpatient with anti-tuberculosis medications. Hence, salivary flow rate, pH, viscosity, and salivary electrolytes of tuberculosis patients should be considered as important parameters in guiding the diet, so that there will be an improvement in their taste perception and medication protocol, thus maintaining their nutritional status which leads to improving their health.

Illicit Drug Use and Smell and Taste Dysfunction: A National Health and Nutrition Examination Survey 2013–2014

Taste and smell dysfunction are suspected to be associated with substance use. However, representative epidemiological studies remain insufficient. This cross-sectional study explored the relationship between drug use (including cannabis or hashish, cocaine, heroin, and methamphetamine) and olfactory/gustatory dysfunction using data from the 2013–2014 National Health and Nutrition Examination Survey. In this study, participants who completed the smell examination with mean age of 59 were classified into four groups: cannabis users (n = 845), participants without cannabis use (n = 794), illicit drug users (n = 450), and participants without illicit drug use (n = 2000). Participants who completed the taste examination with mean age of 58 were also categorised into four groups: cannabis users (n = 810), participants without cannabis use (n = 714), illicit drug users (n = 428), and participants without illicit drug use (n = 1815). Logistic regression models investigated the association between cannabis or illicit drug use and smell or taste dysfunctions among study participants. Odds ratios and 95% confidence intervals were calculated. Finally, we did not find correlations between illicit drug use and dysfunction of taste or smell senses; our findings were consistent in many subgroup analyses. We recommend that further studies explore the mechanism and dose of illicit drug use that could have chemosensory impacts.

Dysgeusia: A review in the context of COVID-19

Background

Taste disorders in general, and dysgeusia in particular, are relatively common disorders that may be a sign of a more complex acute or chronic medical condition. During the COVID-19 pandemic, taste disorders have found their way into the realm of general as well as specialty dentistry, with significance in screening for patients who potentially may have the virus.

Types of Studies Reviewed

The authors searched electronic databases (PubMed, Embase, Web of Science, Google Scholar) for studies focused on dysgeusia, ageusia, and other taste disorders and their relationship to local and systemic causes.

Results

The authors found pertinent literature explaining the normal physiology of taste sensation, proposals for suggested new tastes, presence of gustatory receptors in remote tissues of the body, and etiology and pathophysiology of taste disorders, in addition to the valuable knowledge gained about gustatory disorders in the context of COVID-19. Along with olfactory disorders, taste disorders are one of the earliest suggestive symptoms of COVID-19 infection.

Conclusions

Gustatory disorders are the result of local or systemic etiology or both. Newer taste sensations, such as calcium and fat tastes, have been discovered, as well as taste receptors that are remote from the oropharyngeal area. Literature published during the COVID-19 pandemic to date reinforces the significance of early detection of potential patients with COVID-19 by means of screening for recent-onset taste disorders.

Practical Implications

Timely screening and identification of potential gustatory disorders are paramount for the dental care practitioner to aid in the early diagnosis of COVID-19 and other serious systemic disorders.

Age- and sex-matched comparison of diet quality in patients with heart failure to similarly aged healthy older adults

The aims of this study were to (1) compare diet quality between patients with heart failure (HF) and age- and sex-matched community-dwelling healthy older adults and (2) determine whether having HF was associated with a lower Healthy Eating Index-2015 (HEI-2015) score and risk of micronutrient deficiency. The HEI-2015 and macro- and micronutrient intakes of patients with HF were compared with healthy older adults (N 102; 55-92 years old; 53 % female). A paired t-test or Wilcoxon singed-rank test, McNemar's test, and conditional logistic regression were used to assess the association between diet quality and HF status. Median values for HEI-2015 and the number of micronutrient deficiency were used to dichotomise into groups in the conditional logistic regression. There was no significant between-group difference in the HEI-2015 total score (P 0⋅059), whereas the whole grain component was lower in patients with HF than in healthy older adults (3⋅1 ± 3⋅5 v. 4⋅5 ± 3⋅1, P 0⋅037; respectively). Total caloric intake was lower in patients with HF than in healthy older adults (1683 ± 595 v. 2104 ± 670 kcal; P < 0⋅001). Patients with HF had a higher average number of micronutrient deficiencies than healthy older adults (4[2, 6] v. 1[0, 4], respectively, P < 0⋅001). Patients with HF had four times higher odds of being in a high micronutrient deficiency group than healthy older adults, controlling for socio-demographics and body mass index (adjusted odds ratio [95 % confidence interval]: 4⋅04[1⋅06, 15⋅41]). Our findings demonstrate that diet quality measured by nutritional intake identifies patients with HF with lower caloric intake and higher micronutrient deficiencies compared with age- and sex-matched healthy older adults.

Assessment of Taste Function

Taste disorders, impacting well-being and physical health, can be caused by many etiologies including the use of medication. Recently, taste disturbance is also considered as one of the predominant symptoms of COVID-19 although its pathogenesis requires further research. Localized taste disorders may be overlooked considering that whole-mouth taste perception is insured through several mechanisms. Individuals often fail to discern taste from flavor, and interviews/surveys are insufficient to properly assess taste function. Hence, various taste assessment methods have been developed. Among them, psychophysical methods are most widely applied in a clinical context. Less-biased electrophysiological, imaging, or morphological methods are used to a much lesser degree. Overall, more research is needed in the field of taste.

Evaluation of antibiotic-induced taste and smell disorders using the FDA adverse event reporting system database

Adverse effects can occur owing to anorexia, which can reduce treatment compliance and worsen the patients overall condition. One such side effect, namely drug-induced taste and smell disorders, reduces patients quality of life. Although antibiotics can cause taste and smell disorders, a few studies have examined antibiotic-induced taste and smell disorders. Therefore, this study comprehensively analyzed the relationship between taste and smell disorders and antibiotic usage. The side effects of antibiotics were investigated using the FDA Adverse Event Reporting System database (FAERS). The reporting odds ratios between the listed drugs and taste and smell disorders P values were comprehensively calculated. Adjusted odds ratios were calculated to account for patient background. Furthermore, to clarify the feature of this adverse effect, shape parameters indicating the expression pattern were calculated. Signals that induced taste and smell disorders were detected for six antibiotics, including drugs for which this event is not described in the package insert in Japan. Multiple logistic regression analysis suggested an association of taste and smell disorders with gender, hypertension, mental disorder, and cancer. The median time to onset of antibiotic-induced taste and smell disorders was 2–5 days. Six antibiotics could be analyzed, and four of these drugs matched those with detected signals. Our study supported previous findings on gender and age. Furthermore, antibiotic-induced taste and smell disorders are likely to develop in the early stage of treatment. For these reasons, it is important to remember the risk of developing of taste and smell disorders when administering antibiotics. In addition, it is recommended that the patient be monitored carefully for at least 1 week before initiating treatment, and the patients course should be followed for at least 2 months.

Olfaction and Aging: A Review of the Current State of Research and Future Directions

Olfaction, the sense of smell, is characterized by a notable age-dependency such that aging individuals are more likely to have poor olfactory abilities. These impairments are considered to be mostly irreversible and as having potentially profound effects on quality of life and food behavior, as well as constituting warning signs of mortality, cognitive dysfunction, and dementia. Here, we review the current state of research on aging and olfaction, focusing on five topics which we regard to be of particular relevance for the field: nutrition and health, cognition and dementia, mortality, environment and genetics, and training-based enhancement. Under each of these headlines, we provide a state-of-the-art overview and discuss gaps in our knowledge which might be filled by further research. Understanding how olfactory abilities are diminished in aging, and how they may be alleviated or recovered, involves a set of challenging tasks for researchers in the years to come.

Generation and Culture of Lingual Organoids Derived from Adult Mouse Taste Stem Cells

The sense of taste is mediated by taste buds on the tongue, which are composed of rapidly renewing taste receptor cells (TRCs). This continual turnover is powered by local progenitor cells and renders taste function prone to disruption by a multitude of medical treatments, which in turn severely impacts the quality of life. Thus, studying this process in the context of drug treatment is vital to understanding if and how taste progenitor function and TRC production are affected. Given the ethical concerns and limited availability of human taste tissue, mouse models, which have a taste system similar to humans, are commonly used. Compared to in vivo methods, which are time-consuming, expensive, and not amenable to high throughput studies, murine lingual organoids can enable experiments to be run rapidly with many replicates and fewer mice. Here, previously published protocols have been adapted and a standardized method for generating taste organoids from taste progenitor cells isolated from the circumvallate papilla (CVP) of adult mice is presented. Taste progenitor cells in the CVP express LGR5 and can be isolated via EGFP fluorescence-activated cell sorting (FACS) from mice carrying an Lgr5^{EGFP-IRES-CreERT2} allele. Sorted cells are plated onto a matrix gel-based 3D culture system and cultured for 12 days. Organoids expand for the first 6 days of the culture period via proliferation and then enter a differentiation phase, during which they generate all three taste cell types along with non-taste epithelial cells. Organoids can be harvested upon maturation at day 12 or at any time during the growth process for RNA expression and immunohistochemical analysis. Standardizing culture methods for production of lingual organoids from adult stem cells will improve reproducibility and advance lingual organoids as a powerful drug screening tool in the fight to help patients experiencing taste dysfunction.

Olfactory dysfunction in antineutrophil cytoplasmic antibody-associated vasculitides: A review of the literature

Olfactory dysfunction (OD) has been described in patients with antineutrophil cytoplasmic antibody-associated vasculitides (AAV), but the underlying mechanisms are not completely understood. The causes of altered smell function can generally be divided into conductive, sensorineural or others. To date no specific treatment is available for AAV-related OD and the efficacy of currently available options has not been explored. The aim of this review is to provide an overview of the causes that may lead to OD in patients with AAV. Current available treatments for OD and possible options in patients with AAV presenting with smell impairment are also mentioned.

Taste alteration after gastrectomy in patients with gastric cancer

PURPOSE

To investigate the relationship between changes in taste due to surgical procedures and other clinical factors, we performed a detailed investigation of taste alteration in patients who underwent gastrectomy.

METHODS

Questionnaires on taste alteration were distributed to patients who visited our outpatient clinic from July 2018 to January 2019 for the postoperative evaluation of gastric cancer. Associations of clinical characteristics with changes in sensitivity to the four major taste types (sweet, sour, salty, and bitter) were examined.

RESULTS

Of the 243 eligible patients, 42 (17.3%) experienced taste alteration after gastrectomy; taste sensitivity decreased in 21 (8.6%) patients and increased in 31 (12.7%) patients. The frequency of a decreased sensitivity to sweet was significantly higher in patients who underwent total gastrectomy than in those who underwent distal gastrectomy (18.8% vs. 3.3%, P = 0.001). Patients who underwent total gastrectomy were significantly more likely than those who received distal gastrectomy to experience increased sensitivity to sour (12.5% vs. 2.2%, respectively; P = 0.004) and bitter (15.6% vs. 3.8%, respectively; P = 0.007) tastes. A multivariate analysis revealed that total gastrectomy was an independent risk factor for total taste alteration.

CONCLUSIONS

Patients who underwent total gastrectomy showed a high likelihood of both loss and gain of taste sensitivity.

Taste and smell disturbances in cancer patients: a scoping review of available treatments

PURPOSE

Taste and smell disturbances in patients affected by cancer are very common, but often under-recognized symptoms. If not addressed properly, they may impact nutritional status, food enjoyment, and quality of life. Treatment tools available for clinicians to manage chemosensory alterations are limited and are often based on personal clinical experiences. The aim of this study was to assess current oncological and palliative care literature through a scoping review, in order to identify available treatments for taste and smell alterations in cancer patients.

METHODS

Medline, Embase, CINAHL, ProQuest Dissertations and Theses, and Google Scholar were searched from inception until January 2020, with subject headings relevant to the domains of chemosensory alterations, palliative, and cancer care. A total of 10,718 English and French language publications were reviewed, yielding 43 articles on the researched topic.

RESULTS

The heterogeneity of selected articles led to difficulties in interpretation and analysis of the available evidence. Included publications differed in study design, population sample, anticancer treatments, and measures of assessment for taste and smell disturbances. A broad variety of treatment options were described including zinc and polaprezinc, radio-protectors, vitamins and supplements, anti-xerostomia agents, active swallowing exercises, nutritional interventions, delta-9-tetrahydrocannabinol, and photobiomodulation.

CONCLUSION

This scoping review identifies the current state of knowledge regarding chemosensory alterations within supportive cancer care. Despite not reaching firm conclusions, this article offers therapeutic venues to further explore in larger and more methodologically sound studies.

A review of the flavor profile of metal salts: understanding the complexity of metallic sensation

The oral sensation of metallic is a complex experience. Much of our current understanding of metallic sensation is from the investigation of metal salts, which elicit diverse sensations, including taste, smell, and chemesthetic sensations, and therefore meet the definition of a flavor rather than a taste. Due to the involvement of multiple chemosensory systems, it can be challenging to define and characterize metallic sensation. Here, we provide a comprehensive review of the psychophysical studies quantifying and characterizing metallic sensation, focusing on metal salts. We examine the factors that impact perception, including anion complex, concentration, nasal occlusion, and pH. In addition, we summarize the receptors thought to be involved in the perception of metallic sensation (i.e., TRPV1, T1R3, TRPA1, and T2R7) either as a result of in vitro assays or from studies in knock-out mice. By enhancing our scientific understanding of metallic sensation and its transduction pathways, it has the potential to improve food and pharmaceuticals, help identify suppression or masking strategies, and improve the ability to characterize individual differences in metallic sensation. It also has the potential to translate to clinical populations by addressing the disparities in knowledge and treatment options for individuals suffering from metallic taste disorder (i.e., phantom taste or "metal mouth"). Future psychophysical studies investigating the sensory perception of metal salts should include a range of compounds and diverse food matrices, coupled with modern sensory methods, which will help to provide a more comprehensive understanding of metallic sensation.

Mechanical tongue cleaning is a worthwhile procedure to improve the taste sensation

BACKGROUND

There are still only a few therapeutic strategies to improve taste sensation, which is part of oral health and quality of life.

OBJECTIVE

Therefore, here we aimed to investigate gustatory functions of healthy subjects performing mechanical tongue cleaning (MTC), an easy-to-perform oral hygiene procedure, to demonstrate taste changes and to describe possible negative side effects.

METHODS

Prior to and 14 days following MTC with an Orabrush^® , the following tests were conducted in 65 healthy participants including both non-smokers (n = 50, 76.9%) and smokers (n = 15, 23.1%): 'taste strips' test, the Winkel Tongue Coating Index (WTCI), and subjective self-assessment.

RESULTS

Among non-smokers, subjective self-assessments of gustatory function (P < .01), halitosis (P = .03) and tongue coating (P < .01) improved after 14 days of MTC; furthermore, they exhibited higher total taste (P < .01) and lower WTCI (P < .01) values. Their age and sex did not correlate with the differences between the pre- and post-MTC WTCI scores; however, differences between pre- and post-MTC total taste values were correlated with age. The total taste value improvements were greater in non-smokers aged 45-91 years than in those aged 20-44 years (P = .01). In smokers, total taste values (P < .01), as well as sweet (P = .03) and sour (P = .04) taste values, were significantly improved after 14 days of MTC.

CONCLUSION

Fourteen days of MTC using an Orabrush^® can improve gustatory functions in non-smokers and smokers. Therefore, MTC might be a useful, costless and easy option to improve taste and should be considered as a part of the daily oral care.

Relationship between polypharmacy, xerostomia, gustatory sensitivity, and swallowing complaints in the elderly: A multidisciplinary approach

Oral dysfunctions are common in the elderly but the literature lacks a multidisciplinary approach on the relationship between polypharmacy, saliva flow, xerostomia, taste, and swallowing complaints. This cross-sectional study included 204 non-institutionalized elderly (>60 years; 123 women/81 men), free of severe disabilities and non-alcohol/tobacco consumers, from whom specific pharmacological therapies were evaluated, as well xerostomia (Xerostomia Inventory-XI) and swallowing complaints (EAT-10 questionnaire), salivary flow rate and gustatory sensitivity. Statistical analysis included Chi-square, Mann-Whitney, Two-way ANCOVA, and linear multiple regression. Polypharmacy (≥5 drugs daily), hyposalivation, and severe taste dysfunction were found in 18, 46, and 10% of the participants, respectively. Polypharmacy was related with xerostomia (p = .041) and swallowing complaints (p < .001; power = 94%), but not with taste dysfunction. Dry mouth complaint and higher risk of swallowing disorders were found in 50 and 12% of the elderly, respectively, and angiotensin-converting enzyme (ACE) inhibitors users (n = 36) showed higher EAT-10 scores (p = .038). Regression models showed that stimulated salivary flow rate was dependent on gender and diuretic use, while xerostomia scores were dependent on the number of medications and unstimulated saliva flow (p < .001). In conclusion, the results draw attention to the high frequency of oral and maxillofacial dysfunctions found in non-institutionalized elderly, especially polypharmacy, xerostomia and swallowing complaints, and the side effects of drugs that can disturb the oral functions, the acceptance of food, and the adherence to oral therapies.

Impact of the severity of dementia due to Alzheimer's disease on the gustatory sensitivity of older persons

OBJECTIVE

To evaluate the association between the severity of dementia and taste recognition abilities in older persons with Alzheimer's disease (AD).

METHODS

Anthropometric measurements were performed and body mass index was used to determine the nutritional status. The taste strips were used to test gustatory functions of the five basic tastes (sweet, salty, sour, bitter and umami).

RESULTS

A total of 30 healthy younger subjects, 30 healthy older subjects, 37 with mild stage AD and 23 with moderate stage AD were recruited. The older subjects with moderate AD showed a significant reduction of taste, less recognition of bitter and salty taste (score: 10.6 ± 2.6; 2.6 ± 0.9; 1.7 ± 1.5) when compared to older people without cognitive impairment (score: 13.3 ± 1.8; 3.4 ± 0.9; 3.2 ± 0.9), and less recognition of sweet taste (score: 2.9 ± 1.2) when compared to subjects with mild stage AD (score: 3.6 ± 0.8). Impaired recognition of salty taste was detected since the early stages of AD. Among the factors that possibly influence gustatory function, a significant correlation was detected between taste ability and age, medication intake, mini-mental state examination and the nutritional status.

CONCLUSION

The severity of dementia is directly associated with greater impairment of taste sensitivity, especially among older subjects with moderate stage disease.

Relationships between subjective taste sensations and electrogustometry findings in patients with taste disorders

This study aimed to examine the relationships between subjective taste sensations and electrogustometry (EGM) findings in patients with taste disturbances according to the presence of burning mouth (BM) symptoms. Forty-six patients were included and asked to complete a questionnaire that contained questions on subjective taste sensations for the four basic taste qualities and the pattern of taste disorders such as ageusia, hypogeusia and dysgeusia. EGM was performed to measure detection thresholds. To examine the influence of BM symptoms, patients were divided into two groups: patients with and without BM symptoms. The patients consisted of 11 men and 35 women. The group without BM symptoms (n=26) had significantly lower degrees of subjective taste sensations for all taste qualities and higher correlation levels between subjective taste sensations and EGM thresholds than the group with BM symptoms (n=20). The patterns of taste disorders also showed more significant associations with the levels of subjective taste sensations in the patients without BM symptoms compared with those with BM symptoms. In conclusion, patients with taste disorders without BM symptoms had more severe taste disturbances than those with BM symptoms. The pathophysiology of taste disturbances differs according to the presence or absence of BM symptoms.

Corona Viruses and the Chemical Senses: Past, Present, and Future

A wealth of rapidly evolving reports suggests that olfaction and taste disturbances may be manifestations of the novel COVID-19 pandemic. While otolaryngological societies worldwide have started to consider chemosensory evaluation as a screening tool for COVID-19 infection, the true nature of the relationship between the changes in chemosensory ability and COVID-19 is unclear. Our goal with this review is to provide a brief overview of published and archived literature, as well as the anecdotal reports and social trends related to this topic up to April 29, 2020. We also aim to draw parallels between the clinical/chemosensory symptomology reported in association to past coronavirus pandemics (such as SARS and MERS) and the novel COVID-19. This review also highlights current evidence on persistent chemosensory disturbances after the infection has resolved. Overall, our analysis pinpoints the need for further studies: 1) to better quantify olfaction and taste disturbances associated with SARS-CoV-2 infection, compared to those of other viral and respiratory infections, 2) to understand the relation between smell, taste, and chemesthesis disturbances in COVID-19, and 3) to understand how persistent are these disturbances after the infection has resolved.

Taste disorder's management: a systematic review

BACKGROUND

Taste disorder is a frequent drug-induced or disease-related oral trouble. Various pharmacological, surgical, or physical treatments have previously been proposed for taste function recovery.

OBJECTIVES

The aim of the present systematic review was to assess the effects of palliative and curative interventions on taste recovery in light of recent literature.

MATERIALS AND METHODS

In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, a search of the literature published up to June 2019 was conducted using MEDLINE via PubMed, EMBASE, and The US National Institutes of Health Trials Register (PROSPERO registration reference: CRD 42019139315). The methodological quality of the included trials was rated with the "Delphi list For Quality Assessment of Randomized Clinical Trials" and the Newcastle-Ottawa scale.

RESULTS

From the 1842 titles first identified, 28 articles met the inclusion criteria. Interventions included zinc (aspartate, sulfate, gluconate, acetate, picolinate, and Polaprezinc®), esomeprazole, L-thyroxin, bethanechol, oral glutamine, delta-9-tetrahydrocannabinol, alpha-lipoic acid, Ginkgo biloba, artificial saliva, pilocarpine, local anesthesia, and improved oral hygiene. The quality of evidence ranged from poor to high.

CONCLUSION

Improving oral hygiene may promote taste ability. Zinc may prevent and alleviate taste disorder in patients undergoing head and neck radiotherapy.

CLINICAL RELEVANCE

The systematic review provided evidence about the clinical efficacy of oral procedures, zinc supplementation, and palliative cares in dysgeusic patients. Further research is needed to find effective treatments with low adverse effects.

Bitter Taste Perception of the Human Tongue Mediated by Quinine and Caffeine Impregnated Taste Strips

Objectives:

Tests for gustatory function have become increasingly important in diagnosis and treatment of patients with taste disorders. While caffeine and quinine hydrochloride solutions have been used for global testing of bitter perception, only quinine has been used to test regional bitter perception by means of taste strips. The aim of the present study was to validate caffeine impregnated taste strips as an alternative to quinine taste strips for assessment of regional bitter perception.

Methods:

A total of 46 healthy volunteers (mean age/range, 23/19-27 years) were included in this study. Quinine and caffeine impregnated taste strips were pairwise presented at different parts of the tongue. Perceived intensity and hedonic dislike were evaluated using labeled magnitude scales. Additionally, gustatory function was assessed using the taste strips test and overall sense of taste was rated using visual analog scales.

Results:

Assessment of gustatory function demonstrated scores within the normogeusic range in most included subjects (mean/SD, 13.1/2.5). Notably, equally concentrated quinine and caffeine impregnated taste strips placed on different regions of the tongue did not lead to significant differences in perceived intensity or hedonic dislike, whereas quinine and caffeine impregnated taste strips of different concentrations placed on the same region on the tongue led to significant differences of perceived intensity and hedonic dislike. Furthermore, no correlation was found between self-assessment of gustatory function and taste strips scores.

Conclusion:

Caffeine seems to be a valid bitter compound for regional testing using taste strips and may be used alternatively to quinine.

Ranking Self-reported Gastrointestinal Side Effects of Pharmacotherapy in Sarcoidosis

BACKGROUND

Clinical manifestations of sarcoidosis vary widely, depending on the intensity of the inflammation and the organ systems affected. So far, no curative treatment exists; the disease can only be suppressed. All treatment options cause side effects affecting quality of life. The aim of this study was to establish and rank the prevalence of self-reported gastrointestinal side effects of drugs used in the treatment of sarcoidosis.

METHODS

A cross-sectional web-based anonymous survey about complaints and side effects was conducted among sarcoidosis patients in the Netherlands, United Kingdom, and United States of America.

RESULTS

Of the participants, 70% were being treated with one or more drugs. The most important reported side effect was weight gain, associated with increased appetite among prednisone users (as monotherapy as well as in combination with other drugs). Methotrexate (MTX) users especially experienced nausea, with monotherapy as well as combination therapy. Vomiting and weight loss were most prominent among azathioprine and mycophenolate mofetil (MMF) users, whereas diarrhoea was frequently mentioned by MMF and MTX users. The reported side effects of hydroxychloroquine were generally rather mild.

CONCLUSION

The current study ranked the gastrointestinal side effects associated with pharmacotherapy in sarcoidosis patients. Pharmacotherapy does have multiple gastrointestinal side effects. The strongest association between a reported side effect and drug use was that of weight gain associated with increased appetite among prednisone users. It would therefore be useful for future research to look further into dietary interventions to counter these side effects and reduce their burden.

Barriers to Oral Food Intake for Children Admitted to Hospital

Children are at risk for malnutrition in hospital, and a contributing factor may be poor oral intake. Barriers to intake have been studied in adults, but there is a lack of research in children. The purpose of this study was to identify the potential barriers to oral intake for children in hospital. Patients and families (n = 58) admitted to surgery and medicine units at the Stollery Children’s Hospital completed a survey on barriers to oral food intake. Barriers were classified into 6 domains and major barriers were those identified by at least 30% of the population. On average each patient was affected by 22% of the barriers. Within each domain, the proportion of patients identifying at least 1 barrier was as follows: organization (74%), hunger (67%), quality (60%), effects of illness (53%), choice (38%), and physical limitations (29%). Having food brought in from home due to hunger, not wanting what was ordered once it arrives, food quality, decreased appetite, sickness, fatigue, and pain were identified as major barriers. Children have unique barriers to oral food intake in hospital which have not been previously identified. Food service models should consider these barriers to better meet the needs of this population.

Taste test using an edible taste film kit: a randomised controlled trial

OBJECTIVES

We developed an edible taste film test that can be stored easily as a kit. This study was conducted to confirm the agreement between the results of the edible taste film kit test and the conventional taste solution test.

DESIGN

Prospective, randomised, controlled trial.

SETTING

Single tertiary hospital.

PARTICIPANTS

Sixty-two healthy volunteers with no self-described taste problems.

INTERVENTIONS

A randomisation scheme was used to determine the order of use of the edible taste film kit and the taste solution test for each subject. The taste solution test was performed using a cotton swab. In the taste film kit test, an edible taste film was placed on the tongue, and the subject detected the taste after the film was dissolved by saliva.

OUTCOME MEASURES

For each test, we measured the taste identification threshold, taste detection time and total test time.

RESULTS

We confirmed the consistency of the taste identification thresholds of the two tests, and the results were consistent with each other except for the bitter taste results, which used coffee in the edible taste film kit and quinine in the taste solution test. Although the detection time for each taste quality was faster for the taste solution test, the mean total time was significantly shorter for the taste film kit test than for the taste solution test (6.16±2.27 min vs 7.04±1.98 min, respectively; p=0.004).

CONCLUSIONS

The edible taste film kit along with the taste solution test will be useful for quantitative taste testing.

TRIAL REGISTRATION NUMBER

KCT0002865.

Toxic exposures and the senses of taste and smell

This review addresses the adverse influences of neurotoxic exposures on the ability to smell and taste. These chemical senses largely determine the flavor of foods and beverages, impact food intake, and ultimately nutrition, and provide a warning for spoiled or poisonous food, leaking natural gas, smoke, airborne pollutants, and other hazards. Hence, toxicants that damage these senses have a significant impact on everyday function. As noted in detail, a large number of toxicants encountered in urban and industrial air pollution, including smoke, solvents, metals, and particulate matter can alter the ability to smell. Their influence on taste, i.e., sweet, sour, bitter, salty, and savory (umami) sensations, is not well documented. Given the rather direct exposure of olfactory receptors to the outside environment, olfaction is particularly vulnerable to damage from toxicants. Some toxicants, such as nanoparticles, have the potential to damage not only the olfactory receptor cells, but also the central nervous system structures by their entrance into the brain through the olfactory mucosa.

Neurolocalization of taste disorders

Neurolocalization of taste disorders requires a knowledge of the functional anatomy involved in mediating taste information from the peripheral mucosal surfaces through numerous peripheral cranial nerves to complex subcortical and cortical brain regions. Our understanding of this functional anatomy has advanced in recent years. Taste is an experience that is both innate and learned, and the "taste" experience involves the integration of information from other sensory modalities, such as olfaction and somatosensation. Normal taste perception is influenced by different neurophysiologic states, which involve endocrine function, emotions, and even attitudes and expectations toward eating. At its core, the normal effective ability to taste is a reflection of the proper function of many organ systems within the body and may be considered a marker for good health. Clinical taste disorders, on the other hand, involve the dysfunction of the normal neural taste pathways and/or aberrant influences on multisensory integration and cortical taste processing. The number of disease processes, which can adversely affect taste, are numerous and quite varied in their presentation. There may be contributory involvement of other organ systems within the body, and the appropriate management of taste disorders often requires a multidisciplinary approach to fully understand the disorder. Depending on the underlying cause, taste disorders can be effectively managed when identified. Treatments may include correcting underlying metabolic disturbances, eliminating infections, changing offending medications, replenishing nutritional deficiencies, operating on structural impairments, calming autoimmune processes, and even stabilizing electrochemical interactions.

Treatments for smell and taste disorders: A critical review

A key concern of both the patient and physician is whether treatment is available that will eliminate or quell a given chemosensory disturbance. In cases where obvious oral, nasal, or intracranial pathology is involved, rational straightforward approaches to treatment are often available. In cases where damage to the sensory pathways is secondary to chronic inflammatory disease, trauma, viral invasion, toxic exposure, or unknown causes, the direction for therapy is more challenging. Indeed, many chemosensory disorders, if present for any period of time, cannot be reversed, while others spontaneously remit without any therapeutic intervention. This review assesses the strengths and weaknesses of more than two dozen approaches to treatment that have been suggested for a wide range of taste and smell disorders.

Assessment of taste functions in allergic rhinitis patients undergoing allergen-specific immunotherapy

BACKGROUND

We evaluated taste functions of patients with perennial allergic rhinitis (AR) before and after allergen-specific immunotherapy (AIT).

METHODS

The study was designed as a prospective clinical study in our tertiary care hospital. Patients (n = 21) who were diagnosed with perennial AR on the basis of physical examination, skin prick test of at least 3* for HDM allergen and treated with AIT were enrolled in this study. A control group (n = 21) was selected from patients who were given intranasal steroids (INS) for perennial AR. Both groups had self-reported hyposmia and subjective loss of the sense of taste before treatment. Taste strips (Burghart, Wedel, Germany) were used for the taste identification scores before and after 6 months treatment.

RESULTS

A total of 42 subjects were included, with a mean age of 24.1 ± 7.9 years (range 15-43 years). Overall, the AIT group showed more of an improvement of taste function, observed in the total average test scores, compared to the INS group (p < 0.05), but no change was detected between the groups before treatment. No difference was found for the bitter taste scores between the study groups (p = 0.053).

CONCLUSION

Subcutaneous allergen immunotherapy resulted in more of an improvement in taste function than intranasal steroids. Further studies are needed.

A longitudinal study of altered taste and smell perception and change in blood pressure

BACKGROUND AND AIMS

Previous studies suggest that olfactory receptors, which mediate smell chemosensation, are located in the kidney and involved in blood pressure regulation. Mammalian epithelial sodium channels located in taste receptor cells are also found to participate in blood pressure regulation. However, there is currently no human study that has examined the association between taste and smell function and blood pressure. We thus conducted a longitudinal study to examine whether participants with altered taste and smell perception had larger increases in blood pressure compared with those without altered perception in a community-based cohort.

METHODS AND RESULTS

The study included 5190 Chinese adults (4058 men and 1132 women) who were normotensive at baseline. Taste and smell perception were assessed via questionnaire in 2012 (baseline). Blood pressure was measured in 2012 and 2014 to determine relative change in blood pressure. Mean differences of 2-year blood pressure change and 95% confidence intervals (CIs) across four categories of taste and smell perception were calculated after adjusting for known risk factors for hypertension. After adjusting for potential confounders, individuals with altered taste and smell perception had larger increases in systolic blood pressure (adjusted mean difference = 5.1 mmHg, 95% CI: 0.1-10.0, p-value: 0.04) and mean arterial pressure (adjusted mean difference = 3.8 mmHg, 95% CI: 0.4-7.1, p-value: 0.03) after two years of follow-up compared with those having neither altered taste nor altered smell perception. No significant association was observed in individuals with altered taste or smell perception only.

CONCLUSION

Our results suggest an association between chemosensory function and blood pressure.

Disorders of Taste and Smell

PURPOSE OF REVIEW

This article aims to educate clinical neurologists on the importance of taste and smell disorders in clinical neurology. These disorders commonly occur in head trauma, multiple sclerosis, seizure disorders, and neurodegenerative diseases such as idiopathic Parkinson disease and dementia, mild cognitive impairment, and Alzheimer disease, just to name a few. This article covers the basic anatomy of smell and taste, notes the important points of taking a proper history, and discusses smell and taste testing, which are inexpensive, minimally time-consuming procedures. Recurrent bad smells and tastes are not uncommon in these disorders, which cause major impairment in quality of life, including loss of appetite, decreased eating, and weight loss. The diagnosis and treatment of these disorders will also be discussed.

RECENT FINDINGS

Despite past widespread negative prognoses of taste and smell disorders, more recent work in the last 10 years has shown an improved prognosis for smell and taste recovery in most disorders, and recommendations for changes in food preparation have helped many patients enjoy their food and increase their appetite. Recent experimental evidence has shown that smell loss and testing can assist in separating idiopathic Parkinson disease from other parkinsonian syndromes, can suggest which patients with rapid eye movement (REM) sleep behavior disorder will more likely develop Parkinson disease, and can be predictive of the progression of cognitive impairment and Alzheimer dementia.

SUMMARY

This article discusses the common smell and taste disorders that a clinical neurologist will encounter in practice. The anatomy and function of smell and taste will be reviewed, followed by office evaluation and testing. The common disorders will be reviewed, along with their prognosis and management.

Influence of medications on taste and smell

Medications frequently have chemosensory side effects that can adversely affect compliance with medical treatment regimens. Hundreds of drugs have been reported to induce unpleasant tastes and/or odors as well as altered chemosensations when administered alone or in combination with other medications. Some chemosensory complaints are due to the sensory properties of the drug itself such as aversive bitter and metallic tastes. However, most chemosensory side effects of drugs are due to alterations in the transduction pathways, biochemical targets, enzymes, and transporters by the offending medications. Studies of chemosensory perception in medicated older individuals have found that taste and smell loss is greatest for those consuming the largest number of prescription drugs. There are no standard treatments for drug-induced chemosensory disorders because each drug has unique biological effects. However, there are a few treatment options to ameliorate chemosensory alterations including addition of simulated flavors to food to compensate for losses and to override offending tastes and smells.

Observational study on the palatability and tolerability of oral prednisolone and oral dexamethasone in children in Saudi Arabia and the UK

BACKGROUND

Short-course oral corticosteroids are routinely used to treat acute asthma and croup. We evaluated their tolerability and palatability in Saudi Arabian (SA) and UK children.

METHODS

Prospective observational/interview study (3 months in each country). Palatability was evaluated using a 5-point facial Hedonicscale and tolerability by direct questioning of patient/parents.

RESULTS

In SA, of 122 patients (2-10 years) recruited, 52 received prednisolone base tablets, 37 prednisolone sodium phosphate syrup and 33 received dexamethasone elixir. In the UK, of 133 patients (2-16 years), 38 received prednisolone base tablets (mainly crushed and dispersed), 42 prednisolone sodium phosphate soluble tablets and 53 received dexamethasone sodium phosphate oral solution.In both countries, dexamethasone had the highest palatability scores (SA mean: 1.97; UK mean: 3) and prednisolone base tablets had the lowest (SA mean: 1.12; UK mean: 1.39). Palatability scores improved for all formulations of prednisolone with each subsequent daily dose.In SA, prednisolone base tablets were associated with more nausea (24vs7 patients) and vomiting (5vs0 patients) than sodium phosphate syrup (p=0.008 and p=0.073, respectively). In the UK, vomiting occurred more frequently with prednisolone base (8 patients) than sodium phosphate soluble tablets (2 patients) (p=0.041).In both centres, dexamethasone was associated with less side effects. Vomiting (1vs0 patients), nausea (7vs3 patients) and abdominal pain (10vs8 patients) occurred more with dexamethasone sodium phosphate solution than dexamethasone elixir.

CONCLUSIONS

Dexamethasone sodium phosphate solution was the most palatable preparation. Prednisolone base tablets were rated least palatable and were least well tolerated. Palatability scores improved with each dose taken.

Common oral complications of head and neck cancer radiation therapy: mucositis, infections, saliva change, fibrosis, sensory dysfunctions, dental caries, periodontal disease, and osteoradionecrosis

Patients undergoing radiation therapy for the head and neck are susceptible to a significant and often abrupt deterioration in their oral health. The oral morbidities of radiation therapy include but are not limited to an increased susceptibility to dental caries and periodontal disease. They also include profound and often permanent functional and sensory changes involving the oral soft tissue. These changes range from oral mucositis experienced during and soon after treatment, mucosal opportunistic infections, neurosensory disorders, and tissue fibrosis. Many of the oral soft tissue changes following radiation therapy are difficult challenges to the patients and their caregivers and require life-long strategies to alleviate their deleterious effect on basic life functions and on the quality of life. We discuss the presentation, prognosis, and management strategies of the dental structure and oral soft tissue morbidities resulting from the administration of therapeutic radiation in head and neck patient. A case for a collaborative and integrated multidisciplinary approach to the management of these patients is made, with specific recommendation to include knowledgeable and experienced oral health care professionals in the treatment team.