Smell and taste disorders

Smell and Taste Loss Associated with COVID-19 Infection

OBJECTIVE

The aim of this study was to quantify the impact of COVID-19 on olfactory and gustatory function in US adults.

METHODS

From the 2021 Adult National Health Interview Survey, demographic and survey-specific module data concerning COVID-19 diagnoses, testing and disease severity, and data quantifying disturbances and eventual recovery of smell and taste were extracted. Sample weights were applied to obtain nationally representative statistics. The overall rate of COVID-19 infection was determined, and those diagnosed with COVID-19 were analyzed with respect to disease severity, smell and taste disturbance, and respective recoveries.

RESULTS

In 2021, 35.8 million or 14% of the adult population (95% CI 13.5-14.7%; mean age, 43.9 years; 53.8% female) had been diagnosed with COVID-19. Among those, 60.5% (58.6-62.5%) and 58.2% (56.2-60.1%) reported accompanying losses  in smell or taste, respectively; there was a significant association between overall COVID-19 symptom severity and smell (p < 0.001) and taste disturbance (p < 0.001). Following infection, 72.2% (69.9-74.3%), 24.1% (22.2-26.2%), and 3.7% (3.0-4.6%) of the patients experienced complete, partial, and no smell recovery, respectively. Recovery rates for gustatory function paralleled olfaction, with 76.8% (74.6-78.9%), 20.6% (18.7-22.7%), and 2.6 (1.9-3.4%) reporting complete, partial, and no recovery of taste, respectively. When sensory disturbance was present, severity of overall symptomatology was negatively associated with smell and taste recovery (p < 0.001 for each).

CONCLUSION

The majority of adults infected with COVID-19 in 2021 experienced olfactory or gustatory dysfunction with a non-negligible population reporting incomplete or no near-term sensory recovery. Our results are useful for providers counseling patients and suggest that interventions lessening overall COVID-19 symptom burden may prevent prolonged sensory dysfunction.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:2357-2361, 2023.

[Mechanisms and Management of COVID-19-Associated Taste Disorders]

The taste buds in the human tongue contain specialized cells that generate taste signals when they are stimulated. These signals are then transmitted to the central nervous system, allowing the human body to distinguish nutritious substances from toxic or harmful ones. This process is critical to the survival of humans and other mammals. A number of studies have shown that dysgeusia, or taste disorder, is a common complication of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, which can severely affect patients' nutritional intake and quality of life. Based on the physiological process of taste perception, the direct causes of dysgeusia include dysfunction of taste receptors and damage to the taste nervous system, while indirect causes include genetic factors, aging-related changes, bacterial and viral infections, and cancer treatments such as radiotherapy and chemotherapy. The pathogenic factors of dysgeusia are complicated, further research is needed to fully understand the underlying mechanisms, and some of the reported findings and conclusions still need further validation. All these form a great challenge for clinical diagnosis of the cause and targeted treatment of dysgeusia. Herein, we reviewed published research on the physiological process of taste perception, the potential mechanisms of taste disorders related to SARS-CoV-2 infection, and strategies for prevention and treatment, providing theoretical support for establishing and improving the comprehensive management of COVID-19 complicated by taste disorders.

The Effectiveness of Zinc Supplementation in Taste Disorder Treatment: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Introduction

Food taste and flavour affect food choice and acceptance, which are essential to maintain good health and quality of life. Reduced circulating zinc levels have been shown to adversely affect the taste, but the efficacy of zinc supplementation to treat disorders of taste remains unclear. In this systematic review and meta-analysis, we aimed to examine the efficacy of zinc supplementation in the treatment of taste disorders.

Methods

We searched four electronic bibliographical databases: Ovid MEDLINE, Ovid Embase, Ovid AMAD, and PubMed. Article bibliographies were also searched, which yielded additional relevant studies. There were no restrictions on the publication date to facilitate the collection and identification of all available and relevant articles published before 7 February 2021. We performed a systematic review and meta-analysis according to the PRISMA Statement. This review was registered at PROSPERO and given the identification number CRD42021228461.

Results

In total, we included 12 randomized controlled trials with 938 subjects. The intervention includes zinc (sulfate, gluconate, picolinate, polaprezinc, and acetate), and the pooled results of the meta-analysis of subjects with idiopathic and zinc-deficient taste disorder indicate that improvements in taste disorder occurred more frequently in the experimental group compared to the control group (RR = 1.38; 95% CI: 1.16, 1.64, p=0.0002). Zinc supplementation appears to confer a greater improvement in taste perception amongst those with chronic renal disease using zinc acetate (overall RR = 26.69, 95% CI = 5.52-129.06, p < 0.0001). The doses are equivalent to 17 mg-86.7 mg of elemental zinc for three to six months.

Conclusion

Zinc supplementation is an effective treatment for taste disorders in patients with zinc deficiency, idiopathic taste disorders, and in patients with taste disorders induced by chronic renal failure when given in high doses ranging from 68 to 86.7 mg/d for up to six months.

Pathogenesis and progression of anosmia and dysgeusia during the COVID-19 pandemic

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is the causative agent of COVID-19 which was detected in late 2019 in Wuhan, China. As of September 2022, there have been over 612 million confirmed cases of COVID-19 with over 6.5 million associated deaths. In many cases, anosmia and dysgeusia have been identified as primary symptoms of COVID-19 infection in patients. While the loss of smell (anosmia) and loss of taste (dysgeusia) due to COVID-19 infection is transient in most patients, many report that these symptoms persist following recovery. Understanding the pathogenesis of these symptoms is paramount to early treatment of the infection. We conducted a literature review of Google Scholar and PubMed to find and analyze studies discussing anosmia and dysgeusia in the context of COVID-19 to understand the progression and management of these symptoms. The mechanism for dysgeusia is largely unknown; however, pathogenesis of anosmia includes inflammation and cytokine release resulting from the infection that alters neuronal signaling, thus inducing the loss of smell that patients experience. Anosmia may be managed and potentially resolved sooner with a combination therapy of olfactory training and budesonide irrigation of the nasal cavity. It is important to note that the variants of SARS-CoV-2 are genetically distinguished from the original virion due to a mutation in their spike proteins, giving them a different symptom profile regarding anosmia and dysgeusia. This variability in symptomatology is an area of study that needs to be further explored.

Bisphosphonate affects the behavioral responses to HCl by disrupting farnesyl diphosphate synthase in mouse taste bud and tongue epithelial cells

Little is known about the molecular mechanisms underlying drug-induced taste disorders, which can cause malnutrition and reduce quality of life. One of taste disorders is known adverse effects of bisphosphonates, which are administered as anti-osteoporotic drugs. Therefore, the present study evaluated the effects of risedronate (a bisphosphonate) on taste bud cells. Expression analyses revealed that farnesyl diphosphate synthase (FDPS, a key enzyme in the mevalonate pathway) was present in a subset of mouse taste bud and tongue epithelial cells, especially type III sour-sensitive taste cells. Other mevalonate pathway-associated molecules were also detected in mouse taste buds. Behavioral analyses revealed that mice administered risedronate exhibited a significantly enhanced aversion to HCl but not for other basic taste solutions, whereas the taste nerve responses were not affected by risedronate. Additionally, the taste buds of mice administered risedronate exhibited significantly lower mRNA expression of desmoglein-2, an integral component of desmosomes. Taken together, these findings suggest that risedronate may interact directly with FDPS to inhibit the mevalonate pathway in taste bud and tongue epithelial cells, thereby affecting the expression of desmoglein-2 related with epithelial barrier function, which may lead to alterations in behavioral responses to HCl via somatosensory nerves.

Olfactory, Auditory, and Vestibular Performance: Multisensory Impairment Is Significantly Associated With Incident Cognitive Impairment

Background

Dysfunction in the olfactory, auditory, and vestibular systems are commonly seen in aging and are associated with dementia. The impact of sensory loss(es) on cognition is not well understood. Our aim was to assess the relationships between performance on objective multisensory testing and quantify the impact of dysfunction on cognition.

Methods

Patients presenting with subjective hearing loss presenting to a tertiary care otologic/audiologic clinic were identified and underwent multisensory testing using the Affordable, Rapid Olfactory Measurement Array (AROMA), pure tone audiometric evaluations, and the Timed “Up and Go” test. Cognitive impairment (CI) was assessed via the Montreal Cognitive Assessment (MoCA) was also administered.

Key Results

180 patients were enrolled. Thirty one percentage (n = 57) screened positive for cognitive impairment. When evaluating single sensory impairments, we found that olfactory dysfunction, gait impairment, and sensorineural hearing loss were all statistically significantly (p &lt; 0.05) associated with a higher risk of cognitive impairment (ORs 3.89, 3.49, and 2.78, respectively) for CI. Multisensory impairment was significantly associated with cognitive impairment. Subjects with dysfunction in all domains were at the highest risk for cognitive impairment (OR 15.7, p &lt; 0.001) vs. those with impairment in 2 domains (OR 5.32, p &lt; 0.001).

Conclusion

Dysfunction of the olfactory, auditory, and vestibular systems is associated with a significantly increased risk of CI. The dramatically increased risk of CI with multisensory dysfunction in all three systems indicated that MSD may synergistically contribute to CI.

BitterMatch: recommendation systems for matching molecules with bitter taste receptors

Bitterness is an aversive cue elicited by thousands of chemically diverse compounds. Bitter taste may prevent consumption of foods and jeopardize drug compliance. The G protein-coupled receptors for bitter taste, TAS2Rs, have species-dependent number of subtypes and varying expression levels in extraoral tissues. Molecular recognition by TAS2R subtypes is physiologically important, and presents a challenging case study for ligand-receptor matchmaking. Inspired by hybrid recommendation systems, we developed a new set of similarity features, and created the BitterMatch algorithm that predicts associations of ligands to receptors with ~ 80% precision at ~ 50% recall. Associations for several compounds were tested in-vitro, resulting in 80% precision and 42% recall. The encouraging performance was achieved by including receptor properties and integrating experimentally determined ligand-receptor associations with chemical ligand-to-ligand similarities.

BitterMatch can predict off-targets for bitter drugs, identify novel ligands and guide flavor design. The novel features capture information regarding the molecules and their receptors, which could inform various chemoinformatic tasks. Inclusion of neighbor-informed similarities improves as experimental data mounts, and provides a generalizable framework for molecule-biotarget matching.

Incidence of Olfactory and Gustatory Dysfunctions in the Early Stages of COVID-19: An Objective Evaluation

Introduction Coronavirus disease 2019 (COVID-19) is a dangerous infectious disease caused by a newly discovered severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that has various clinical presentations. Numerable cases with non-specific olfactory and gustatory dysfunctions in COVID-19 have been reported from all over the globe. This is important as awareness will let people to self-isolate and help in limiting disease spread.

Objective To objectively evaluate the frequency of olfactory and gustatory dysfunction, which may occur independently or with other symptoms, in laboratory confirmed COVID-19 patients at an early stage of the disease.

Methods Objective evaluation of olfactory and gustatory function of 322 COVID-19 patients treated at our hospital, (SMGS, Government Medical College, Jammu), from August 2020 until November 2020.

Results Our study population included 127 (39.4%) males and 195 (60.6%) females. Two hundred and twenty-six (70.2%) COVID-19 patients experienced olfactory and gustatory disorders. One hundred and sixty-five (51.2%) cases experienced both olfactory and gustatory disorders. Isolated olfactory dysfunction was reported in 34 (10.6%) patients, while 27 (8.4%) patients experienced only gustatory dysfunction.

Conclusion The olfactory and gustatory dysfunctions, without any nasal obstruction or rhinorrhea, are significant symptoms in the clinical presentation of early COVID-19 patients. This presentation can be recognized at the earliest one, and it can reduce the high communicability of the COVID-19 disease.

Preparation and application of taste bud organoids in biomedicine towards chemical sensation mechanisms

Taste is one of the most basic and important sensations that is able to monitor the food quality and avoid intake of potential danger materials. Whether as an inevitable symptom of aging or a complication of cancer treatment, taste loss very seriously affects the patient's life quality. Taste bud organoids provide an alternative and convenient approach for the research of taste functions and the underlying mechanisms due to their characteristics of availability, strong maneuverability, and high similarity to the in-vivo taste buds. This review gives a systemic and comprehensive introduction to the preparation and application of taste bud organoids towards chemical sensing mechanisms. For the first, the basic structure and functions of taste buds will be briefly introduced. Then, the currently available approaches for the preparation of taste bud organoids are summarized and discussed, which are mainly divided into two categories, i.e. the stem/progenitor cell-derived approach and the tissue-derived approach. For the next, different applications of taste bud organoids in biomedicine are outlined based on their central roles such as disease modeling, biological sensing, gene regulation, and signal transduction. Finally, the current challenges, future development trends and prospects of research in taste bud organoids are proposed and discussed. This article is protected by copyright. All rights reserved.

Small but Mighty-Exosomes, Novel Intercellular Messengers in Neurodegeneration

Simple Summary

Exosomes are biological nanoparticles recently recognized as intercellular messengers. They contain a cargo of lipids, proteins, and RNA. They can transfer their content to not only cells in the vicinity but also to cells at a distance. This unique ability empowers them to modulate the physiology of recipient cells. In brain, exosomes play a role in neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease and amyotrophic lateral sclerosis.

Abstract

Exosomes of endosomal origin are one class of extracellular vesicles that are important in intercellular communication. Exosomes are released by all cells in our body and their cargo consisting of lipids, proteins and nucleic acids has a footprint reflective of their parental origin. The exosomal cargo has the power to modulate the physiology of recipient cells in the vicinity of the releasing cells or cells at a distance. Harnessing the potential of exosomes relies upon the purity of exosome preparation. Hence, many methods for isolation have been developed and we provide a succinct summary of several methods. In spite of the seclusion imposed by the blood–brain barrier, cells in the CNS are not immune from exosomal intrusive influences. Both neurons and glia release exosomes, often in an activity-dependent manner. A brief description of exosomes released by different cells in the brain and their role in maintaining CNS homeostasis is provided. The hallmark of several neurodegenerative diseases is the accumulation of protein aggregates. Recent studies implicate exosomes’ intercellular communicator role in the spread of misfolded proteins aiding the propagation of pathology. In this review, we discuss the potential contributions made by exosomes in progression of Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. Understanding contributions made by exosomes in pathogenesis of neurodegeneration opens the field for employing exosomes as therapeutic agents for drug delivery to brain since exosomes do cross the blood–brain barrier.

Correlation between olfactory function, age, sex, and cognitive reserve index in the Italian population

Purpose

Loss of smell decreases the quality of life and contributes to the failure in recognizing hazardous substances. Given the relevance of olfaction in daily life, it is important to recognize an undiagnosed olfactory dysfunction to prevent these possible complications. Up to now, the prevalence of smell disorders in Italy is unknown due to a lack of epidemiological studies. Hence, the primary aim of this study was to evaluate the prevalence of olfactory dysfunction in a sample of Italian adults.

Methods

Six hundred and thirty-three participants (347 woman and 286 men; mean age 44.9 years, SD 17.3, age range 18–86) were recruited from 10 distinct Italian regions. Participants were recruited using a convenience sapling and were divided into six different age groups: 18–29 years (N = 157), 30–39 years (N = 129), 40–49 years (N = 99), 50–59 years (N = 106), > 60 years (N = 142). Olfactory function, cognitive abilities, cognitive reserve, and depression were assessed, respectively, with: Sniffin’ Sticks 16-item Odor Identification Test, Montreal Cognitive Assessment, Cognitive Reserve Index, and the Beck Depression Inventory. Additionally, socio-demographic data, medical history, and health-related lifestyle information were collected.

Results

About 27% of participants showed an odor identification score < 12 indicating hyposmia. Multiple regression analysis revealed that OI was significantly correlated with age, sex, and cognitive reserve index, and young women with high cognitive reserve index showing the highest olfactory scores.

Conclusion

This study provides data on the prevalence of olfactory dysfunction in different Italian regions.

Olfactory and Gustatory Dysfunction in 2019 Novel Coronavirus: An Updated Systematic Review and Meta-analysis

Background:

Evidence showed that partial or complete loss of smell and taste might be a possible primary symptom of the 2019 novel coronavirus (COVID-19). This study aimed to systematically review and pool all available evidence on the olfactory and gustatory dysfunction in COVID-19 patients.

Methods:

In this systematic review, a comprehensive search was carried out systematically through e-databases including PubMed, EMBASE, Scopus, and Web of Science (WoS); that was limited to English-language studies published from 2019 up to 6^th May 2020. Afterward, all studies reported the taste and smell dysfunction in the COVID-19 patients were included. The quality of the studies was assessed by the Mixed Methods Appraisal Tool (MMAT). The pooled prevalence of olfactory and gustatory dysfunction was estimated using the random effects meta-analysis method.

Results:

Among 28 eligible included studies in this systematic review, finally, 22 studies met the eligibility criteria and were included in the meta-analysis. According to the random effect meta-analysis, the global pooled prevalence (95% confidence interval) of any olfactory dysfunction, anosmia, and hyposmia was 55% (40%-70%), 40% (22%-57%), and 40% (20%-61%) respectively. The pooled estimated prevalence of any gustatory dysfunction, ageusia, and dysgeusia was 41% (23%-59%), 31% (3%-59%), and 34% (19%-48%) respectively.

Conclusions:

Olfactory and gustatory dysfunction is prevalent among COVID-19 patients. Therefore, olfactory and gustatory dysfunction seems to be part of important symptoms and notify for the diagnosis of COVID-19, especially in the early phase of the infection.

Possible Role of Endocannabinoids in Olfactory and Taste Dysfunctions in COVID-19 Patients and Volumetric Changes in the Brain

Introduction

COVID-19 infection develops neurologic symptoms such as smell and taste loss. We aimed to determine the volumetric changes in the brain and correlation of possible related biochemical parameters and endocannabinoid levels after COVID-19 recovery.

Methods

Brain magnetic resonance images of recovered COVID-19 patients and healthy volunteers, whose olfactory and gustatory scores were obtained through a questionnaire, were taken, and the volumes of the brain regions associated with taste and smell were measured by automatic and semiautomatic methods. Endocannabinoids (EC), which are critical in the olfactory system, and vitamin B12, zinc, iron, ferritin, thyroid-stimulating hormone (TSH), and thyroxine (T4) levels, which are reported to have possible roles in olfactory disorders, were measured in peripheral blood.

Results

Taste and smell disorder scores and EC levels were found to be higher in recovered COVID-19 patients compared to controls. EC levels were negatively correlated with bilateral entorhinal cortex (ENT) volumes in the COVID-19 group. Subgenual anterior cingulate cortex volumes showed correlations with gustatory complaints and ferritin in recovered COVID-19 patients.

Conclusions

The critical finding of our study is the high EC levels and negative correlation between EC levels and left ENT volumes in recovered COVID-19 patients.

Implications

It is possible that ECs are potential neuromodulators in many conditions leading to olfactory disorders, including COVID-19.

Brazilian Nutritional Consensus in Hematopoietic Stem Cell Transplantation: children and adolescents

The Brazilian Nutritional Consensus in Hematopoietic Stem Cell Transplantation: Children and Adolescents was developed by dietitians, physicians, and pediatric hematologists from 10 Brazilian reference centers in hematopoietic stem cell transplantation. The aim was to emphasize the importance of nutritional status and body composition during treatment, as well as the main characteristics related to patient´s nutritional assessment. This consensus is intended to improve and standardize nutrition therapy during hematopoietic stem cell transplantation. The consensus was approved by the Brazilian Society of Bone Marrow Transplantation.

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.

COVID-19-Associated Parosmia and Dysgeusia: A Case Series

Impairment of the chemical senses - smell, taste, and chemesthesis - has been pinpointed as one of the main clinical presentations of coronavirus disease 2019 (COVID-19). Chemosensory dysfunction can be quantitative, involving reduction or loss of perception (e.g., hyposmia, anosmia, hypogeusia), and qualitative, involving distortion of perception (parosmia and dysgeusia). Quantitative chemosensory dysfunction is reported more often among COVID-19 patients than qualitative dysfunction. The following report details four patients with a laboratory-assisted diagnosis of COVID-19 who experienced qualitative chemosensory dysfunction. A discussion of these symptoms in the broader context of upper respiratory tract infections is included, with an emphasis on olfactory dysfunction.

Chemosensory dysfunction in Cushing's syndrome

PURPOSE

Cushing's syndrome (CS) can lead to structural changes in the brain and cognitive impairment, but chemosensory function has not been investigated yet. The aim was to analyze sense of smell and taste in patients with CS and explore the effect of therapy.

METHODS

The study cohort comprised 20 patients with florid CS treated between 2018 and 2020 in the outpatient clinic of the LMU Munich. We compared these 20 patients with CS to 40 healthy subjects matched for age, sex, and smoking status. Patients' sense of smell and taste was examined at diagnosis and 3 months after successful therapeutic surgery leading to clinical and biochemical remission. Odor threshold, discrimination, and identification were measured with "Sniffin' Sticks", taste was measured with "Taste Strips". Perceived sense of smell and taste was retrieved via a questionnaire.

RESULTS

Patients with florid CS had significantly reduced smell (total smell score 30.3 vs. 34.4, p < 0.0005) and taste scores (9.5 vs. 12.0, p < 0.0005) compared to controls and significantly more frequently hyposmia (55 vs. 2.5%, p < 0.0005), hypogeusia (40 vs. 0%, p < 0.0005), and self-reported chemosensory impairment (60 vs. 0%, p < 0.0005). Three months after successful surgery, CS patients showed significant improvement of odor threshold (8.1 vs. 7.0, p < 0.0005), odor discrimination (12.0 vs. 11.0, p = 0.003), total smell score (33.4 vs. 30.3, p < 0.0005), and taste (11.5 vs. 9.5, p = 0.003).

CONCLUSIONS

Chemosensory dysfunction is a novel and clinically relevant feature of CS.

Frequency and Determinants of Olfactory Hallucinations in Parkinson's Disease Patients

Background: Olfactory dysfunctions and hallucinations are considered common nonmotor symptoms in Parkinson’s disease (PD). Visual and auditory hallucinations are well-known; however, olfactory hallucinations (OHs) are not fully investigated. The aim of this study was to evaluate OHs in PD patients, and their correlation to motor impairment, cognitive abilities, visual and auditory hallucinations, and olfactory and gustatory function. Methods: A sample of 273 patients was enrolled: 141 PD patients (mean age ± SD: 70.1 ± 9.5 years) and 132 healthy controls (mean age ± SD: 69.4 ± 9.6 years). In all patients, the following parameters were evaluated: motor symptoms (UPDRS-III), olfactory function, cognitive abilities, and occurrence of OH, gustatory hallucinations (GHs), and visual/auditory hallucinations. Results: OHs were found only in PD patients with a percentage of 11.3%. Among PD patients with OHs, 2.8% also presented GHs. High significant frequencies of females, the presence of visual/auditory hallucinations, and a high mean UPDRS-III score were found in patients with OHs related to patients without them. Binary logistic regression evidenced the presence of visual/auditory hallucinations and sex as main variables predicting the presence of OHs. Conclusions: Our data indicated that OHs occur frequently in PD patients, especially in women, and often concomitant with visual and auditory hallucinations, without any association with olfactory impairment.

Transection of Gustatory Nerves Differentially Affects Dietary Fat Intake in Obesity-Prone and Obesity-Resistant Rats

The current prevalence of obesity has been linked to the consumption of highly palatable foods and may be mediated by a dysregulated or hyposensitive orosensory perception of dietary fat, thereby contributing to the susceptibility to develop obesity. The goal of the current study was to investigate the role of lingual taste input in obesity-prone (OP, Osborne-Mendel) and obesity-resistant (OR, S5B/Pl) rats on the consumption of a high-fat diet (HFD). Density of fungiform papillae was assessed as a marker of general orosensory input. To determine if orosensory afferent input mediates dietary fat intake, surgical transection of the chorda tympani and glossopharyngeal nerves (GLX/CTX) was performed in OP and OR rats and HFD caloric intake and body weight were measured. Fungiform papillae density was lower in OP rats, compared with OR rats. GLX/CTX decreased orosensory input in both OP and OR rats, as measured by an increase in the intake of a bitter, quinine solution. Consumption of low-fat diet was not altered by GLX/CTX in OP and OR rats; however, GLX/CTX decreased HFD intake in OR, without altering HFD intake in OP rats. Overall, these data suggest that inhibition of orosensory input in OP rats do not decrease fat intake, thereby supporting that idea that hyposensitive and/or dysregulated orosensory perception of highly palatable foods contribute to the susceptibility to develop obesity.

Prospective Analysis of the Chronology of Smell and Taste Dysfunction in COVID-19 Positive ENT Doctors

Olfactory and gustatory dysfunction has been reported as an early presentation in COVID-19. We intent to analyze the chronological outline of these chemosensory disturbances in term of onset, progression and resolution in ENT doctors with COVID-19. In six symptomatic otolaryngologists who tested positive for SARS-CoV-2, detailed symptomatology of olfactory and gustatory dysfunction was collected prospectively on regular basis till a period of at least three months. Due to their awareness, sensitivity and reliability, even mild and transient relevant symptomatology could be recorded accurately. Olfactory and gustatory dysfunction was universally present in all the six otolaryngologists. The onset of the symptoms was in first week and resolved completely within 4 weeks in four of them. In two doctors the recovery of olfactory dysfunction to near normal level was delayed and prolonged over 2 and 3 months. The pattern of involvement of basic tastes like sweet, salt, sour and bitter as well as food temperature and texture etc. pointed towards involvement of the gustatory mucosa with non-uniform involvement of the papilla and taste receptors. One of the doctors also experienced reappearance of parosmia and phantosmia in the 3rd month following complete disease resolution. Due to their expertise in the field of Otolaryngology, the recruited doctors represented the precise pattern of progression and resolution of olfactory and gustatory dysfunction in COVID-19. Larger studies are needed to validate our reported universal presence of these symptoms with complete recovery rate following disease resolution.

Loss of Smell and Taste in Patients With Suspected COVID-19: Analyses of Patients' Reports on Social Media

BACKGROUND

The year 2020 was the year of the global COVID-19 pandemic. The severity of the situation has become so substantial that many or even most of the patients with mild to moderate symptoms had to self-isolate without specific medical treatments or even without being tested for COVID-19. Many patients joined internet membership groups to exchange information and support each other.

OBJECTIVE

Our goal is to determine the benefits and limits of using social media to understand the symptoms of patients with suspected COVID-19 with mild to moderate symptoms and, in particular, their symptoms of anosmia (loss of the sense of smell) and ageusia (loss of the sense of taste). The voluntary reports on an internet website of a membership group will be the platform of the analyses.

METHODS

Posts and comments of members of an internet group known as COVID-19 Smell and Taste Loss, founded on March 24, 2020, to support patients with suspected COVID-19 were collected and analyzed daily. Demographic data were collected using the software mechanism called Group Insights on the membership group website.

RESULTS

Membership groups on social media have become rare sources of support for patients with suspected COVID-19 with mild to moderate symptoms. These groups provided mental support to their members and became resources for information on COVID-19 tests and medicines or supplements. However, the membership was voluntary, and often the members leave without notification. It is hard to be precise from the free voluntary reports. The number of women in the group (6995/9227, 75.38% as of October 12, 2020) was about three times more than men (2272/9227, 24.62% as of October 12, 2020), and the peak age of members was between 20-40 years in both men and women. Patients who were asymptomatic other than the senses comprised 14.93% (53/355) of the total patients. Recovery of the senses was higher in the patients who were asymptomatic besides having anosmia and ageusia. Most (112/123, 91.06%) patients experienced other symptoms first and then lost their senses, on average, 4.2 days later. Patients without other symptoms tended to recover earlier (P=.02). Patients with anosmia and ageusia occasionally reported distorted smell and taste (parosmia and dysgeusia) as well as experiencing or perceiving the smell and taste without the sources of the smell or taste (phantosmia and phantogeusia).

CONCLUSIONS

Our analysis of the social media database of suspected COVID-19 patients' voices demonstrated that, although accurate diagnosis of patients is not always obtained with social media-based analyses, it may be a useful tool to collect a large amount of data on symptoms and the clinical course of worldwide rapidly growing infectious diseases.

Molecular and Genetic Factors Involved in Olfactory and Gustatory Deficits and Associations with Microbiota in Parkinson's Disease

Deficits in olfaction and taste are among the most frequent non-motor manifestations in Parkinson’s disease (PD) that start very early and frequently precede the PD motor symptoms. The limited data available suggest that the basis of the olfactory and gustatory dysfunction related to PD are likely multifactorial and may include the same determinants responsible for other non-motor symptoms of PD. This review describes the most relevant molecular and genetic factors involved in the PD-related smell and taste impairments, and their associations with the microbiota, which also may represent risk factors associated with the disease.

Coronavirus Disease 19 from the Perspective of Ageing with Focus on Nutritional Status and Nutrition Management-A Narrative Review

The novel severe acute respiratory syndrome coronavirus (COVID-19) has hit older adults harder due to a combination of age-related immunological and metabolic alterations. The aim of this review was to analyze the COVID-19 literature with respect to nutritional status and nutrition management in older adults. No studies only on people aged 65+ years were found, and documentation on those 80+ was rare. Age was found to be strongly associated with worse outcomes, and with poor nutritional status. Prevalence of malnutrition was high among severely and critically ill patients. The studies found a need for nutrition screening and management, and for nutrition support as part of follow-up after a hospital stay. Most tested screening tools showed high sensitivity in identifying nutritional risk, but none were recognized as best for screening older adults with COVID-19. For diagnosing malnutrition, the Global Leadership Initiative on Malnutrition (GLIM) criteria are recommended but were not used in the studies found. Documentation of olfactory and gustatory dysfunction in relation to nutritional status is missing in older adults. Other COVID-19-associated factors with a possible impact on nutritional status are poor appetite and gastrointestinal symptoms. Vitamin D is the nutrient that has attracted the most interest. However, evidence for supplementation of COVID-19 patients is still limited and inconclusive.

Prevalence and Recovery from Newly Onset Anosmia and Ageusia in Covid 19 Patients at our Teritary Care Centre

Anosmia (loss of smell) and Ageusia (loss of taste) are newly presenting independent symptoms in association with multiple symptoms such as Fever, Dry cough and Breathlessness in COVID 19 Patients.The Study of aims is to estimate Prevalence of Anosmia & Ageusia in Confirmed Covid 19 cases and to assess their Recovery rates. A Study conducted between June 2020 and September 2020 at a tertiary care COVID Dedicated hospital. Total 200 patients with age group 12–70 years Confirmed COVID 19 Positive Patients using RTPCR having mild to moderate symptoms were included. Patients were examined Clinically alongwith all safety measures to analyse prevalence & estimate their recoveries from sensory impairement using 10 item based DyNaCHRON questionnaire(concerned with taste and smell) at 10th, 14th & 21st Day. Out of 200 patients, Prevalence of Isolated Ageusia is 7%, Isolated Anosmia 4.5% and with Anosmia and Ageusia 4%. Complete Recovery regained in Ageusia within 14 days, while Rest all patients of Anosmia and both (Anosmia and Ageusia) within 21 days, Except 2 patients where long term Anosmia persists. Newly onset Anosmia and Ageusia are common in early stages of Covid 19 disease. They are Prevalent in mild to moderate symptomatic form of Diseases. Recovery in most cases is rapid and complete.Early Screening tests performed in suspected COVID 19 patients with loss of taste and smell sensation allows early diagnosis and treatment.

Chemosensory Systems in COVID-19: Evolution of Scientific Research

COVID-19 disease induced by coronavirus SARS-CoV-2 presents among its symptoms alterations of the chemosensory functions. In the first studies on the Chinese population, this symptomatology was not particularly relevant, and hyposmia and hypogeusia were excluded from the symptoms to be evaluated to diagnose the disease. With the pandemic spread of the illness, there has been an augment in reports on chemosensory dysfunctions among patients. The first data analysis showed the presence of these disorders mainly in paucisymptomatic and asymptomatic patients. The interest in chemosensory systems therefore increased considerably, because the olfactory and gustatory symptoms could be the key to stop the infection spread. Furthermore, the degree of alert and attention grew, considering that these types of dysfunctions are prognostic symptoms of serious neurodegenerative diseases. About 9 months have passed since the first anecdotal reports on the involvement of the olfactory and gustatory systems in the COVID-19 pathology. For this reason, a careful review of the literature was conducted to understand if it is clearer which people present chemosensory symptoms and if these are related to the severity of the disease. Furthermore, we have identified which aspects still remain to be clarified.

Self-reported taste and smell alterations and the liking of oral nutritional supplements with sensory-adapted flavors in cancer patients receiving systemic antitumor treatment

PURPOSE

Taste and smell alterations (TAs and SAs) are often reported by patients with cancer receiving systemic antitumor therapy and can negatively impact food intake and quality of life. This study aimed to examine the occurrence of TAs and SAs and investigate the impact of TAs on overall liking of oral nutritional supplements (ONS) with warming and cooling sensations.

METHODS

Patients receiving systemic antitumor therapy completed a questionnaire on sensory alterations and evaluated overall liking of 5 prototype flavors of Nutridrink® Compact Protein (hot tropical ginger (HTG), hot mango (HM), cool red fruits (CRF), cool lemon (CL), and neutral (N)) on a 10-point scale via a sip test. Differences between patients with and without TAs were investigated using permutation analysis.

RESULTS

Fifty patients with various cancer types and treatments were included. Thirty patients (60%) reported TAs and 13 (26%) experienced SAs. Three flavors were rated highly with a liking score > 6 (CRF 6.8 ± 1.7; N 6.5 ± 1.9; HTG 6.0 ± 2.0). Larger variation in ONS liking scores was observed in patients with TAs with or without SAs (4.5-6.9 and 4.6-7.2, respectively) vs. patients without TAs (5.9-6.5). TAs were associated with increased liking of CRF (Δ = + 0.9) and N (Δ = + 1.0) flavors.

CONCLUSIONS

TAs and SAs are common in patients with cancer undergoing systemic antitumor therapy. Patients with TAs were more discriminant in liking of ONS flavors compared to patients without TAs, and sensory-adapted flavors appeared to be appreciated. The presence of TAs should be considered when developing or selecting ONS for patients with cancer.

TRIAL REGISTRATION

Registration at ClinicalTrials.gov (NCT03525236) on 26 April 2018.

Possibilities for Maintaining Appetite in Recovering COVID-19 Patients

COVID-19 and sequelae thereof are known to cause chemosensory dysfunction, posing a risk for intake and adequate nutrition for recovery. The overall objective of this study was to investigate the subjective strategies for maintaining appetite applied by patients recovering from COVID-19. The study included 19 in-depth interviews, focusing on patients suffering from long-term effects of COVID-19. The results were analysed using a thematic analysis for qualitative data. Results on strategies for maintaining appetite included four key themes: (1) a focus on well-functioning senses, (2) a focus on familiar foods, (3) a focus on the eating environment, and (4) a focus on post-ingestive well-being. It was found that factors prior to, during and after food intake, as well as the context, could influence desire to eat and pleasure related to food intake. As ageusia and anosmia make characterization of food difficult, being able to recognize and memorize its flavour was important to engage in consumption. Under normal circumstances, the hedonic value of food relies predominantly on the flavour of foods. When suffering from chemosensory dysfunction, shifting focus towards the texture of food, including trigeminal stimulation during consumption, were beneficial for maintaining appetite and food-related pleasure. Furthermore, a focus on the holistic satisfying feelings of choosing healthy food, as well as a focus on other people’s enjoyment during meals were reported to boost well-being around food intake. The study elaborated our understanding of the complex consequences of COVID-19, and can be applied in health promoting initiatives targeted patients recovering from COVID-19.

Reversible Taste Loss in a COVID-19 Patient With Preexisting Chronic Smell Impairment

Smell loss is important for coronavirus disease-2019 (COVID-19) screening and diagnosis. Particular attention should be paid to individuals with pre-COVID-19 chronic hyposmia or anosmia. We report a case of reversible taste impairment in a COVID-19 patient with chronically impaired sense of smell. This case emphasizes the importance of COVID-19-related taste assessment.

The incidence of anosmia in patients with laboratory-confirmed COVID 19 infection in India: An observational study

BACKGROUND AND AIMS

Acute loss of smell or anosmia is a common and sometimes the only symptom observed in patients with coronavirus disease-2019 (COVID-19). The objective of the study was to determine the prevalence, time of onset, and duration of anosmia in patients with COVID-19 infection and the association of anosmia with other symptoms and eosinophil count.

MATERIAL AND METHODS

Two hundred patients with laboratory-confirmed COVID-19 infection, who were asymptomatic or mildly symptomatic were assessed for olfaction with a nonirritant odor. The presence of anosmia was recorded, and a questionnaire integrating the anosmia reporting tool was filled. Patients with anosmia/hyposmia were followed telephonically at 7 and 14 days for resolution of anosmia and other symptoms. The presence of anosmia was correlated with eosinophil count.

RESULTS

Of the 200 COVID-19 patients, 87% were symptomatic. More than half of the patients had fever (56%). Anosmia was observed in 30% of the patients and hyposmia in 4% of patients. In 41% of the patients, olfactory loss was reported before diagnosis. The mean duration of anosmia was 7.8 (± 5) days; 97% of patients recovered with a resolution of symptoms within 2 weeks. Ageusia was the most commonly and significantly associated symptom with anosmia (66%, n = 45) followed by sore throat (41%), and rhinorrhea (28%). The symptoms in both the sexes were comparable. Absolute eosinophil count of <40/μL was observed in 59 patients (29.5%) and an absolute eosinophil count of 0 in 17 patients (8.5%). Among the 68 anosmic patients, 36 (47%) patients had eosinopenia, which was statistically significant.

CONCLUSION

Anosmia is an early and sometimes the only symptom in approximately one-third of the patients with COVID-19 infection. Eosinophil count should be checked in anosomic patient with suspicion of COVID-19 infection. Objective tools for olfactory and gustatory assessment should be brought into practice for early and prompt diagnosis to control the spread of the disease.

Self-Rated Smell Ability Enables Highly Specific Predictors of COVID-19 Status: A Case-Control Study in Israel

Background

Clinical diagnosis of coronavirus disease 2019 (COVID-19) is essential to the detection and prevention of COVID-19. Sudden onset of loss of taste and smell is a hallmark of COVID-19, and optimal ways for including these symptoms in the screening of patients and distinguishing COVID-19 from other acute viral diseases should be established.

Methods

We performed a case–control study of patients who were polymerase chain reaction–tested for COVID-19 (112 positive and 112 negative participants), recruited during the first wave (March 2020–May 2020) of the COVID-19 pandemic in Israel. Patients reported their symptoms and medical history by phone and rated their olfactory and gustatory abilities before and during their illness on a 1–10 scale.

Results

 Changes in smell and taste occurred in 68% (95% CI, 60%–76%) and 72% (95% CI, 64%–80%) of positive patients, with odds ratios of 24 (range, 11–53) and 12 (range, 6–23), respectively. The ability to smell was decreased by 0.5 ± 1.5 in negatives and by 4.5 ± 3.6 in positives. A penalized logistic regression classifier based on 5 symptoms had 66% sensitivity, 97% specificity, and an area under the receiver operating characteristics curve (AUC) of 0.83 on a holdout set. A classifier based on degree of smell change was almost as good, with 66% sensitivity, 97% specificity, and 0.81 AUC. The predictive positive value of this classifier was 0.68, and the negative predictive value was 0.97.

Conclusions

Self-reported quantitative olfactory changes, either alone or combined with other symptoms, provide a specific tool for clinical diagnosis of COVID-19. A simple calculator for prioritizing COVID-19 laboratory testing is presented here.

Olfactory response as a marker for Alzheimer's disease: Evidence from perceptual and frontal lobe oscillation coherence deficit

High-frequency oscillations of the frontal cortex are involved in functions of the brain that fuse processed data from different sensory modules or bind them with elements stored in the memory. These oscillations also provide inhibitory connections to neural circuits that perform lower-level processes. Deficit in the performance of these oscillations has been examined as a marker for Alzheimer's disease (AD). Additionally, the neurodegenerative processes associated with AD, such as the deposition of amyloid-beta plaques, do not occur in a spatially homogeneous fashion and progress more prominently in the medial temporal lobe in the early stages of the disease. This region of the brain contains neural circuitry involved in olfactory perception. Several studies have suggested that olfactory deficit can be used as a marker for early diagnosis of AD. A quantitative assessment of the performance of the olfactory system can hence serve as a potential biomarker for Alzheimer's disease, offering a relatively convenient and inexpensive diagnosis method. This study examines the decline in the perception of olfactory stimuli and the deficit in the performance of high-frequency frontal oscillations in response to olfactory stimulation as markers for AD. Two measurement modalities are employed for assessing the olfactory performance: 1) An interactive smell identification test is used to sample the response to a sizable variety of odorants, and 2) Electroencephalography data are collected in an olfactory perception task with a pair of selected odorants in order to assess the connectivity of frontal cortex regions. Statistical analysis methods are used to assess the significance of selected features extracted from the recorded modalities as Alzheimer's biomarkers. Olfactory decline regressed to age in both healthy and mild AD groups are evaluated, and single- and multi-modal classifiers are also developed. The novel aspects of this study include: 1) Combining EEG response to olfactory stimulation with behavioral assessment of olfactory perception as a marker of AD, 2) Identification of odorants most significantly affected in mild AD patients, 3) Identification of odorants which are still adequately perceived by mild AD patients, 4) Analysis of the decline in the spatial coherence of different oscillatory bands in response to olfactory stimulation, and 5) Being the first study to quantitatively assess the performance of olfactory decline due to aging and AD in the Iranian population.

Body Localization of ACE-2: On the Trail of the Keyhole of SARS-CoV-2

The explosion of the new coronavirus (SARS-CoV-2) pandemic has brought the role of the angiotensin converting enzyme 2 (ACE2) back into the scientific limelight. Since SARS-CoV-2 must bind the ACE2 for entering the host cells in humans, its expression and body localization are critical to track the potential target organ of this infection and to outline disease progression and clinical outcomes. Here, we mapped the physiological body distribution, expression, and activities of ACE2 and discussed its potential correlations and mutal interactions with the disparate symptoms present in SARS-CoV-2 patients at the level of different organs. We highlighted that despite during SARS-CoV-2 infection ACE2-expressing organs may become direct targets, leading to severe pathological manifestations, and subsequent multiple organ failures, the exact mechanism and the potential interactions through which ACE2 acts in these organs is still heavily debated. Further scientific efforts, also considering a personalized approach aimed to consider specific patient differences in the mutual interactions ACE2-SARS-CoV-2 and the long-term health effects associated with COVID-19 are currently mandatory.

Dysosmia and dysgeusia in patients with COVID-19 in northern Taiwan

Background/Purpose

To investigate the characteristics of dysosmia and dysgeusia among patients diagnosed with coronavirus disease 2019 (COVID-19) in Taiwan.

Methods

Prospective data collection between January 22, 2020 to May 7, 2020 of nucleic acid confirmed COVID-19 hospitalized patients in northern Taiwan by the Taiwan Centers for Disease Control were analyzed.

Results

Of 217 patients enrolled, 78 (35.9%) reported dysosmia (n = 73, 33.6%) and/or dysgeusia (n = 62, 28.6%). The median duration of COVID-19 associated symptom-onset to development of dysosmia and/or dysgeusia was <1 days (interquartile range [IQR], <1–6 days) and 53 of 78 (67.9%) patients developed dysosmia and/or dysgeusia as one of the initial symptoms of COVID-19. Of 59 closely monitored patients, 41 (69.5%) patients recovered within 3 weeks after symptoms onset and the median time to recovery was 12 days (IQR, 7–20 days). Only 6 of the 59 (10.2%) patients reported persistent dysosmia and/or dysgeusia before discharge from hospitals. Multivariate analysis showed that younger individuals (adjusted hazard ratio [AHR], 0.93 per one-year increase; 95% confidence interval [95% CI], 0.89–0.97; P = 0.001), women (AHR, 2.76; 95% CI, 1.05–7.25; P = 0.04) and travel to North America (AHR, 2.35; 95% CI, 1.05–5.26; P = 0.04) were the significant factors associated with dysosmia and/or dysgeusia.

Conclusion

Dysosmia and/or dysgeusia are common symptoms and clues for the diagnosis of COVID-19, particularly in the early stage of the disease. Physicians should be alerted to these symptoms to make timely diagnosis and management for COVID-19 to limit spread.

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.

Facility-Level Case Report of Nursing Care Processes for Patients With Suspected 2019 Novel Coronavirus Disease in Shanghai, China

Introduction

Coronavirus disease emerged in Wuhan, China, on December 31, 2019, and spread rapidly worldwide. Few studies have described the nursing care provided to patients in isolation between suspicion of having the disease and a confirmed diagnosis. The purpose of this study was to describe the treatment of, and nursing care processes for, patients suspected, but not yet confirmed, of having coronavirus disease at 1 facility in Shanghai, China.

Methods

For this retrospective facility case review and patient health record study, data were collected on all patients with suspected coronavirus disease who were treated between January 22, 2020, and February 29, 2020, at 1 hospital. The facility’s nursing care processes were described in detail.

Results

A total of 119 patients were suspected of having coronavirus disease on the basis of the screening criteria. Nine (7.6%) patients had confirmed coronavirus disease and were transferred to a higher level of care. The remaining 110 (92.4%) were treated and discharged. No cross-infection between patients and hospital staff or other patients was detected. The patients’ symptoms included fever (n = 98, 82.4%), cough (n = 79, 66.4%), dizziness (n = 28, 23.5%), headache (n = 26, 21.8%), fatigue (n = 26, 21.8%), myalgia (n = 16, 13.4%), rhinorrhea (n = 6, 5.0%), diarrhea (n = 5, 4.2%), severe nasal congestion (n = 4, 3.4%), and dyspnea (n = 1, 0.8%).

Discussion

Coronavirus disease is very contagious. Nurses need to understand the symptoms and treatment of the disease as well as nursing procedures, and learn how to cut off transmission routes, control transmission sources, and use protective equipment correctly to prevent transmission of the disease within the hospital.

Oral Manifestations in Patients with COVID-19: A Living Systematic Review

This living systematic review aims to summarize evidence on the prevalence of oral signs and symptoms in patients with COVID-19. The review was reported per the PRISMA checklist, and the literature search was conducted in 6 databases and in gray literature. Studies published in any language mentioning oral symptoms and signs in patients with COVID-19 were included. The risk of bias was assessed by the Joanna Briggs Institute appraisal tools. The certainty of evidence was evaluated through GRADE assessment. After a 2-step selection, 40 studies were included: 33 cross-sectional and 7 case reports. Overall, 10,228 patients (4,288 males, 5,770 females, and 170 unknown) from 19 countries were assessed. Gustatory impairment was the most common oral manifestation, with a prevalence of 45% (95% CI, 34% to 55%; I² = 99%). The pooled eligible data for different taste disorders were 38% for dysgeusia and 35% for hypogeusia, while ageusia had a prevalence of 24%. Taste disorders were associated with COVID-19 (odds ratio [OR], 12.68; 95% CI, 6.41 to 25.10; I² = 63%; P < 0.00001), mild/moderate severity (OR, 2.09; 95% CI, 1.25 to 3.49; I² = 66%; P = 0.005), and female patients (OR, 1.64; 95% CI, 1.23 to 2.17; I² = 70%; P = 0.0007). Oral mucosal lesions presented multiple clinical aspects, including white and erythematous plaques, irregular ulcers, small blisters, petechiae, and desquamative gingivitis. Tongue, palate, lips, gingiva, and buccal mucosa were affected. In mild cases, oral mucosal lesions developed before or at the same time as the initial respiratory symptoms; however, in those who required medication and hospitalization, the lesions developed approximately 7 to 24 d after onset symptoms. Therefore, taste disorders may be common symptoms in patients with COVID-19 and should be considered in the scope of the disease's onset and progression. Oral mucosal lesions are more likely to present as coinfections and secondary manifestations with multiple clinical aspects (PROSPERO CRD42020184468).

Olfactory and gustatory dysfunction in COVID-19 patients: A meta-analysis study

COVID-19, caused by a novel coronavirus, is a persistent global pandemic. It is crucial to examine existing reports to effectively summarize and characterize its clinical course. We used a large-scale meta-analysis to establish prevalence rates for loss of olfaction and gustation in COVID-19 positive patients. PubMed/Medline, Embase, and Web of Sciences were searched for articles published until April 30, 2020. Furthermore, to avoid missing papers, more searches were carried out in the reference lists of covered studies. Articles that mentioned olfactory and/or gustatory disorder in patients with COVID-19 were included for further analysis. Articles that did not report the aforementioned information were excluded. Duplicated articles, reviews, and meta-analysis were excluded as well. The quality of the references was assessed according to the checklist provided by JBI (Joanna Briggs Institute). We used independent extraction of data by multiple observers. The pooled frequency with 95% confidence intervals (CI) was assessed using random effect model. The main outcome measures reported were the pooled frequency of olfaction and pooled frequency of gustation disorder in patients with COVID-19 calculated using a random effect model weighted by the study population. The 15 included studies had 3,739 participants which all had confirmed COVID-19. Olfactory and gustatory disorders were assessed and a total number of 1,354 and 1,729 were reported to have taste or smell impairment, respectively. The estimated rate of taste disorder in patients with COVID-19 was 49.0% [95% confidence interval (CI) 34.0-64.0, I2: 96%] (Figure 2). The estimated rate of olfactory disorder in patients with COVID-19 was 61.0% (95% CI 44.0%-75.0%). Our meta-analysis demonstrated high rates of taste (49.0%) and smell (61.0%) disorders in patients with confirmed COVID-19. Results increase the power of recent reports-loss of olfactory and loss of gustation should now routinely be considered in the setting of COVID-19 infection.

A Literature Systematic Review with Meta-Analysis of Symptoms Prevalence in Covid-19: the Relevance of Olfactory Symptoms in Infection Not Requiring Hospitalization

PURPOSE OF REVIEW

To investigate the association between the olfactory dysfunction and the more typical symptoms (fever, cough, dyspnoea) within the Sars-CoV-2 infection (COVID-19) in hospitalized and non-hospitalized patients.

RECENT FINDINGS

PubMed, Scopus and Web of Science databases were reviewed from May 5, 2020, to June 1, 2020. Inclusion criteria included English, French, German, Spanish or Italian language studies containing original data related to COVID19, anosmia, fever, cough, and dyspnoea, in both hospital and non-hospital settings. Two investigators independently reviewed all manuscripts and performed quality assessment and quantitative meta-analysis using validated tools. A third author arbitrated full-text disagreements. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), 11 of 135 studies fulfilled eligibility. Anosmia was estimated less prevalent than fever and cough (respectively rate difference = - 0.316, 95% CI: - 0.574 to - 0.058, Z = - 2.404, p < 0.016, k = 11 and rate difference = - 0.249, 95% CI: - 0.402 to - 0.096, Z = - 3.185, p < 0.001, k = 11); the analysis between anosmia and dyspnoea was not significant (rate difference = - 0.008, 95% CI: - 0.166 to 0.150, Z = - 0.099, p < 0.921, k = 8). The typical symptoms were significantly more frequent than anosmia in hospitalized more critical patients than in non-hospitalized ones (respectively [Q(1) = 50.638 p < 0.000, Q(1) = 52.520 p < 0.000, Q(1) = 100.734 p < 0.000).

SUMMARY

Patient with new onset olfactory dysfunction should be investigated for COVID-19. Anosmia is more frequent in non-hospitalized COVID-19 patients than in hospitalized ones.

The COVID-19 may help enlightening how emotional food is

Olfactory and gustatory stimuli can elicit potent emotional responses and are essential in food perception. Yet, main theories of emotion often under-represent them, and our understanding of affective phenomena relies mostly on experimental studies conducted on visual and auditory stimuli. Although evidence is still accumulating today, recent findings suggest that the COVID-19 is associated with a loss in olfaction and/or taste. Here, I discuss how this unprecedented and uncommon spread of the loss of olfaction and/or taste worldwide may enlighten how emotional both these senses are and how much they influence food perception.

Considerations around the SARS-CoV-2 Spike Protein with Particular Attention to COVID-19 Brain Infection and Neurological Symptoms

Spike protein (S protein) is the virus "key" to infect cells and is able to strongly bind to the human angiotensin-converting enzyme2 (ACE2), as has been reported. In fact, Spike structure and function is known to be highly important for cell infection as well as for entering the brain. Growing evidence indicates that different types of coronaviruses not only affect the respiratory system, but they might also invade the central nervous system (CNS). However, very little evidence has been so far reported on the presence of COVID-19 in the brain, and the potential exploitation, by this virus, of the lung to brain axis to reach neurons has not been completely understood. In this Article, we assessed the SARS-CoV and SARS-CoV-2 Spike protein sequence, structure, and electrostatic potential using computational approaches. Our results showed that the S proteins of SARS-CoV-2 and SARS-CoV are highly similar, sharing a sequence identity of 77%. In addition, we found that the SARS-CoV-2 S protein is slightly more positively charged than that of SARS-CoV since it contains four more positively charged residues and five less negatively charged residues which may lead to an increased affinity to bind to negatively charged regions of other molecules through nonspecific and specific interactions. Analysis the S protein binding to the host ACE2 receptor showed a 30% higher binding energy for SARS-CoV-2 than for the SARS-CoV S protein. These results might be useful for understanding the mechanism of cell entry, blood-brain barrier crossing, and clinical features related to the CNS infection by SARS-CoV-2.

The diagnostic value of detecting sudden smell loss among asymptomatic COVID-19 patients in early stage: The possible early sign of COVID-19

IMPORTANCE

The newly emerged coronavirus disease 19 (COVID-19), is threatening the world. Olfactory or gustatory dysfunction is reported as one of the symptoms worldwide. As reported so far, different clinical features have been reported according to outbreak sites and gender; most of the patients, who complained of anosmia or hyposmia, were Europeans. We had a fast review for novel articles about COVID-19 infection and olfactory function.

OBSERVATIONS

Rapid reviews for COVID-19 or other viral infection and olfactory and/or gustatory dysfunctions were done in this review. Up to date, a lot of reports have shown that olfactory dysfunction is related to viral infections but no exact mechanism, clinical course, and definite treatment have been discovered, which is also same in COVID-19. In general, intranasal steroid (INS) and oral steroid for short time help improve the recovery of the olfactory function in case of olfactory dysfunction after virus infection. Considering severe respiratory complications and immunocompromised state of COVID-19, the use of steroid should be limited and cautious because we do not have enough data to support the usage of steroid to treat olfactory dysfunction in the clinical course of COVID-19.

CONCLUSIONS AND RELEVANCE

In the days of pandemic COVID-19, we should keep in mind that olfactory dysfunctions, even without other upper respiratory infection or otolaryngologic symptoms, might be the early signs of COVID-19.

Prevalence of smell and taste dysfunction in a cohort of CoVID19 outpatients managed through remote consultation from a large urban teaching hospital in Dublin, Ireland

Background

Coronaviruses are known to precipitate disorders of smell and taste function. With the emerging global coronavirus disease (CoVID19) pandemic due to the severe acute respiratory syndrome coronavirus 2, early reports suggested that smell and taste dysfunction were clinical features of CoVID19. Our study aimed to investigate the prevalence of smell and taste disturbances in a cohort of CoVID19 positive patients who were isolated at home and being medically managed through telephone consultation.

Methods

This was a retrospective cross-sectional study conducted at St. James’s Hospital Dublin, an urban 850 bed tertiary referral centre. 46 out of 50 CoVID19 positive patients, managed through a telephone clinic from the hospital infectious disease department, were assessed for olfactory and gustatory function loss.

Results

The median age of participants was 36.5 years (interquartile range (IQR) 27 - 48) and 19 (41%) were male. The majority (31; 67%) never smoked and 17 (37%) reported co-morbidities. Approximately half of patients reported some degree of smell (22; 48%) or taste (25; 54%) function loss. 13 patients (28%) reported a complete loss of sense of smell, 8 (17%) reported a complete loss of sense of taste and 7 (15%) reported simultaneous total loss of both. The median age of patients with any degree of smell disturbance was significantly lower than patients without (median 30.5 years (IQR 24 – 43.25) versus 41 years (IQR 28.25 – 52.75), p = 0.025). The median age of patients with any degree of taste disturbance was lower than those without, but did not reach statistical significance (median 34 years (IQR 24 - 45) versus 40 years (IQR 27.5 – 52.5) p = 0.174).

Conclusion

Smell or taste dysfunction were present in our defined subgroup of patients. Further research is required in different population cohorts to build the evidence base for smell and taste dysfunction as clinical indicators of CoVID19 disease and to assess if these symptoms persist after disease resolution.

SARS-CoV-2 Virologic and Immunologic Correlates in Patients with Olfactory and Taste Disorders

The main object of the study was to investigate the SARS-CoV-2 molecular and serological pattern in patients with mild symptoms including anosmia and ageusia. A cohort of 69 patients with olfactory and taste disorders (OTDs) were enrolled and prospectively monitored. Serological and molecular assays for the characterization of SARS-CoV-2 IgG and SARS-CoV-2 RNA, respectively, were performed at the time of enrolment and after 7 and 14 days. Patients were stratified according to the symptoms’ onset. A total of 52 patients (75.4%) were diagnosed as COVID-19 positive being SARS-CoV-2 RNA and/or SARS-CoV-2 IgG positive. The remaining 17 (24.6%) were negative for COVID-19 and excluded from the analysis. We reported that only 34 out of 52 patients (65.4%) were positive for SARS-CoV-2 RNA. Moreover, the median time from onset of symptoms and enrolment was significantly higher in those patients with negative SARS-CoV-2 RNA in nasal swabs, suggesting that symptoms might last longer than SARS-CoV-2 replication. The great majority of patients (80%) developed SARS-CoV-2 IgG at three weeks after symptoms’ onset while the detectability of SARS-CoV-2 RNA dramatically decreased over time, suggesting the crucial role of combination of molecular and serological assays for the diagnosis of COVID-19 in those patients reporting mild symptoms.

Coincidence of COVID-19 epidemic and olfactory dysfunction outbreak in Iran

Background: The occurrence of anosmia/hyposmia during novel Coronavirus disease 2019 (COVID-19) may indicate a relationship between coincidence of olfactory dysfunction and coronavirus disease 2019 (COVID-19). This study aimed to assess the frequency of self-reported anosmia/hyposmia during COVID-19 epidemic in Iran. Methods: This population-based cross sectional study was performed through an online questionnaire from March 12 to 17, 2020. Cases from all provinces of Iran voluntarily participated in this study. Patients completed a 33-item patient-reported online questionnaire, including smell and taste dysfunction and their comorbidities, along with their basic characteristics and past medical histories. The inclusion criteria were self-reported anosmia/hyposmia during the past 4 weeks, from the start of COVID-19 epidemic in Iran. Results: A total of 10 069 participants aged 32.5±8.6 (7-78) years took part in this study, of them 71.13% women and 81.68% nonsmokers completed the online questionnaire. The correlation between the number of olfactory disorders and reported COVID-19 patients in all provinces up to March 17, 2020 was highly significant (Spearman correlation coefficient = 0.87, P< 0.001). A sudden onset of olfactory dysfunction was reported in 76.24% of the participations and persistent anosmia in 60.90% from the start of COVID19 epidemic. In addition, 80.38% of participants reported concomitant olfactory and gustatory dysfunctions. Conclusion: An outbreak of olfactory dysfunction occurred in Iran during the COVID-19 epidemic. The exact mechanisms by which anosmia/hyposmia occurred in patients with COVID-19 call for further investigations.

New-onset anosmia and ageusia in adult patients diagnosed with SARS-CoV-2 infection

Objectives

We investigated the prevalence of anosmia and ageusia in adult patients with a laboratory-confirmed diagnosis of infection with severe acute respiratory distress syndrome coronavirus-2 (SARS-CoV-2).

Methods

This was a retrospective observational analysis of patients infected with SARS-CoV-2 admitted to hospital or managed in the community and their household contacts across a London population during the period March 1st to April 1st, 2020. Symptomatology and duration were extracted from routinely collected clinical data and follow-up telephone consultations. Descriptive statistics were used.

Results

Of 386 patients, 141 (92 community patients, 49 discharged inpatients) were included for analysis; 77/141 (55%) reported anosmia and ageusia, nine reported only ageusia and three only anosmia. The median onset of anosmia in relation to onset of SARS-CoV-2 disease (COVID-19) symptoms (as defined by the Public Health England case definition) was 4 days (interquartile range (IQR) 5). Median duration of anosmia was 8 days (IQR 16). Median duration of COVID-19 symptoms in community patients was 10 days (IQR 8) versus 18 days (IQR 13.5) in admitted patients. As of April 1, 45 patients had ongoing COVID-19 symptoms and/or anosmia; 107/141 (76%) patients had household contacts, and of 185 non-tested household contacts 79 (43%) had COVID-19 symptoms with 46/79 (58%) reporting anosmia. Six household contacts had anosmia only.

Conclusions

Over half of the positive patients reported anosmia and ageusia, suggesting that these should be added to the case definition and used to guide self-isolation protocols. This adaptation may be integral to case findings in the absence of population-level testing. Until we have successful population-level vaccination coverage, these steps remain critical in the current and future waves of this pandemic.

Prevalence and Duration of Acute Loss of Smell or Taste in COVID-19 Patients

Initially, acute loss of smell (anosmia) and taste (ageusia) was not considered important symptoms for coronavirus disease 2019 (COVID-19). To determine the prevalence of these symptoms and to evaluate their diagnostic significance, we (approximately 150 physicians of the Daegu Medical Association) prospectively collected data of cases of anosmia and ageusia from March 8, 2020, via telephone interview among 3,191 patients in Daegu, Korea. Acute anosmia or ageusia was observed in 15.3% (488/3,191) patients in the early stage of COVID-19 and in 15.7% (367/2,342) patients with asymptomatic-to-mild disease severity. Their prevalence was significantly more common among females and younger individuals (P = 0.01 and P < 0.001, respectively). Most patients with anosmia or ageusia recovered within 3 weeks. The median time to recovery was 7 days for both symptoms. Anosmia and ageusia seem to be part of important symptoms and clues for the diagnosis of COVID-19, particularly in the early stage of the disease.

Mechanisms Linking Olfactory Impairment and Risk of Mortality

Olfaction is a sense involved in a complex set of tasks, influencing eating behavior, increasing awareness of environmental hazards and affecting social communication. Surprisingly, smell disorders are very frequent, especially in the elderly population. Several recent studies conducted mostly in older subjects have demonstrated a strong association between olfactory impairment and overall mortality risk, with anosmia being even more predictive of 5 years mortality risk than cardiovascular disease. Presently, the underlying pathophysiology linking olfactory impairment to mortality remains unknown and only putative mechanisms are suggested. This review aims to examine the link between olfactory impairment and mortality and to discuss existing ideas on underlying existing mechanisms including, (1) the effect of olfactory loss on nutrition, life-threatening situations and social interactions, (2) associated neurodegenerative diseases, (3) accelerated brain aging, and (4) reflection of general health status being reflected in olfactory function.