Smell and taste disorders

Taste dysfunction as a predictor of depression in schizophrenia: A systematic review and meta-analysis

OBJECTIVE

This study aims to investigate the relationship between taste dysfunction and depression among patients with schizophrenia, to achieve early detection of depression in clinical practice.

METHODS

Following PRISMA guidance, a comprehensive literature search was conducted globally, covering papers published from 1961 to June 2023. A total of 17 manuscripts were selected through meta-analysis and sensitivity analysis after examining available materials from seven databases to determine the correlation between depression and taste dysfunction.

RESULTS

The comparison of the 17 selected manuscripts revealed that individuals with gustatory dysfunction may be more likely to experience depressive symptoms (SMD, 0.51, 95% CI, 0.08 to 0.93, p = 0.02). Depression is associated with taste dysfunction in certain aspects, as indicated by the pleasantness ratings of sucrose solutions (SMD, -0.53, 95% confidence interval [CI] -1.11 to 0.05, p = 0.08), gustatory identification ability (SMD, 0.96, 95% CI, 0.03 to 1.89, p = 0.04), and the perception threshold of sweet taste (MD, 0.80, 95% CI, 0.79 to 0.81, p < 0.00001).

CONCLUSIONS

Due to variations in the methods, designs, and selection criteria employed in the included studies, it is necessary to establish a feasible framework. Future research using detailed and targeted approaches can provide clearer and more unified conclusions on the relationship between taste dysfunction and depression. Moreover, further high-quality research is needed to obtain clearer conclusions and explore the potential of taste dysfunction as an effective tool for early screening of depression.

TRIAL REGISTRATION

This review has been registered in the PROSPERO on April 2022 with the identifier CRD42023400172.

Taste and smell abnormalities in advanced cancer: Negative impact on subjective food intake

BACKGROUND

Taste and smell abnormalities (TSAs) are present in all cancer stages and may contribute to malnutrition. Despite this, they are rarely screened for. This study examined the prevalence and characteristics of TSAs and their influence on subjective food intake in advanced cancer.

METHODS

Consecutive patients with advanced cancer were recruited. A modified Taste and Smell Survey assessed subjective TSAs. Objective TSAs were assessed with validated taste strips and "Sniffin Sticks." A six-item food intake questionnaire identified any effect TSAs had on food preferences/aversions. Nutrition status was evaluated with the abridged Patient-Generated Subjective Global Assessment.

RESULTS

All 30 participants had either subjective or objective TSAs. The prevalence of TSAs varied based on the assessment tool used. Participants were more aware of taste changes (TCs) than smell changes (SCs). TCs caused reduced food intake in 13 participants. Six reported SCs affected food intake. Food choices caused by TSAs were inconsistent. Some foods preferred because of TSAs were avoided by other participants. None received nutrition counseling on TSA management. Almost all were at malnutrition risk (97%). Almost half (47%) felt TSAs reduced quality of life (QoL). Participants reported "not looking forward to meals" and "can't sit down and eat anything" because of TSAs.

CONCLUSION

TSAs were highly prevalent and impactful on food intake. Both TCs and SCs were complex and varied on an individual basis. Despite the effect on health and QoL, no patients received any nutrition counseling on TSA management. Individualized screening and advice are needed for TSAs in advanced cancer.

Oro-facial mucocutaneous manifestations of Coronavirus Disease-2019 (COVID-19): A systematic review

We reviewed the prevalence, the likely aetiopathogenesis, and the management of oro-facial mucocutaneous manifestations of Coronavirus Disease-2019 (COVID-19), caused by the Severe Acute Respiratory Syndrome Coronavirus -2 (SARS-CoV-2). English language manuscripts searched using standard databases yielded 26 articles that met the inclusion criteria. In total, 169 cases (75 females; 94 males) from 15 countries with a spectrum of COVID-19 severities were reviewed. Gustatory perturbations were prevalent in over 70%. Mucocutaneous manifestations were reported predominantly on the tongue, palate, buccal mucosa, gingivae, and lips and included ulcers, blisters, erosions, papillary hyperplasia, macules, glossitis, and mucositis. Ulcerative lesions, present in over 50 percent, were the most common oral manifestation. Lesions resembling candidal infections, with burning mouth, were prevalent in 19%. Petechiae and angina bullosa were generally seen, subsequent to COVID-19 therapies, in 11%. Ulcerated, necrotic gingivae were documented in severely ill with poor oral hygiene. These manifestations, present across the COVID-19 disease spectrum, were commonly associated with the immunosuppressed state and/ or the concurrent antimicrobial/steroidal therapies. In summary, a wide variety of orofacial mucocutaneous lesions manifest in COVID-19. They are likely to be secondary to the disease-associated immune impairment and/or pharmaco-therapy rather than a direct result of SARS-CoV-2 infection per se.

Taste and smell function in long-term survivors after childhood medulloblastoma/CNS-PNET

Purpose

To investigate taste and smell function in survivors, with a minimum of 2 years since treatment of childhood medulloblastoma (MB)/central nervous system supratentorial primitive neuroectodermal tumor (CNS-PNET).

Methods

This cross-sectional study included 40 survivors treated ≤ 20 years of age. Taste strips with four concentrations of sweet, sour, salt, and bitter were used to assess taste function in all participants. Score from 0 to 16; ≥ 9 normogeusia, < 9 hypogeusia, and complete ageusia which equals no sensation. No sensation of a specific taste quality equals ageusia of that quality. Thirty-two participants conducted smell testing using three subtests of Sniffin’ sticks: threshold, discrimination, and identification. Together they yield a TDI-score from 1 to 48; functional anosmia ≤ 16.00, hyposmia > 16.00– < 30.75, normosmia ≥ 30.75– < 41.50, and ≥ 41.50 hyperosmia. Results were compared with normative data. Survivors rated their taste and smell function using a numerical rating scale (NRS) score 0–10.

Results

Forty survivors with a mean time since treatment of 20.5 years, 13 (32.5%) were diagnosed with hypogeusia, nine (22.5%) of these being ageusic to one or more taste qualities. Seventeen (53%) of 32 participants were diagnosed with hyposmia. The mean scores of the olfactory subtests, and TDI score were significantly lower than normative data (P < 0.0001). The mean NRS scores of smell and taste function were 7.9 ± 1.5 and 8 ± 1.3, respectively.

Conclusion

Our study showed impaired taste and smell function in survivors of childhood MB/CNS-PNET using objective measurements. However, subjective ratings did not reflect objective findings.

Supplementary information

The online version contains supplementary material available at 10.1007/s00520-022-07048-9.

International consensus statement on allergy and rhinology: Olfaction

BACKGROUND

The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O).

METHODS

Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus.

RESULTS

The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies.

CONCLUSION

This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.

Neuroradiological Basis of COVID-19 Olfactory Dysfunction: A Systematic Review and Meta-Analysis

Objective

Olfactory dysfunction (OD) is a common presenting symptom of COVID‐19 infection. Radiological imaging of the olfactory structures in patients with COVID‐19 and OD can potentially shed light on its pathogenesis, and guide clinicians in prognostication and intervention.

Methods

PubMed, Embase, Cochrane, SCOPUS were searched from inception to August 1, 2021. Three reviewers selected observational studies, case series, and case reports reporting radiological changes in the olfactory structures, detected on magnetic resonance imaging, computed tomography, or other imaging modalities, in patients aged ≥18 years with COVID‐19 infection and OD, following preferred reporting items for systematic reviews and meta‐analyses guidelines and a PROSPERO‐registered protocol (CRD42021275211). We described the proportion of radiological outcomes, and used random‐effects meta‐analyses to pool the prevalence of olfactory cleft opacification, olfactory bulb signal abnormalities, and olfactory mucosa abnormalities in patients with and without COVID‐19‐associated OD.

Results

We included 7 case–control studies (N = 353), 11 case series (N = 154), and 12 case reports (N = 12). The pooled prevalence of olfactory cleft opacification in patients with COVID‐19 infection and OD (63%, 95% CI = 0.38–0.82) was significantly higher than that in controls (4%, 95% CI = 0.01–0.13). Conversely, similar proportions of cases and controls demonstrated olfactory bulb signal abnormalities (88% and 94%) and olfactory mucosa abnormalities (2% and 0%). Descriptive analysis found that 55.6% and 43.5% of patients with COVID‐19 infection and OD had morphological abnormalities of the olfactory bulb and olfactory nerve, respectively, while 60.0% had abnormal olfactory bulb volumes.

Conclusion

Our findings implicate a conductive mechanism of OD, localized to the olfactory cleft, in approximately half of the affected COVID‐19 patients. Laryngoscope, 132:1260–1274, 2022

Potential pharmacologic treatments for COVID-19 smell and taste loss: A comprehensive review

The acute loss of taste and smell following COVID-19 are hallmark symptoms that affect 20-85% of patients. However, the pathophysiology and potential treatments of COVID-19 smell and taste loss are not fully understood. We searched the literature to review the potential pathologic pathways and treatment options for COVID-19 smell and taste loss. The interaction of novel coronavirus with ACE-2 receptors expressed on sustentacular cells and taste buds results in direct damage to the olfactory and gustatory systems. Also, the invasion of the virus to the olfactory neurons and consequent local inflammation are other proposed mechanisms. Therefore, COVID-19 patients with smell or taste loss may benefit from neuroprotective, anti-inflammatory, or depolarizing agents. Based on the current evidence, phosphodiesterase inhibitors, insulin, and corticosteroids can be promising for the management of COVID-19 smell and taste loss. This review provided crucial information for treating COVID-19-related smell and/or taste loss, urging to perform large clinical trials to find optimum treatment options.

Smell and Taste in Severe CoViD-19: Self-Reported vs. Testing

One of the most striking reported symptoms in CoViD-19 is loss of smell and taste. The frequency of these impairments and their specificity as a potential central nervous system function biomarker are of great interest as a diagnostic clue for CoViD-19 infection as opposed to other similar symptomatologic diseases and because of their implication in viral pathogenesis. Here severe CoViD-19 was investigated by comparing self-report vs. testing of smell and taste, thus the objective severity of olfactory impairment and their possible correlation with other symptoms. Because a significant discrepancy between smell and taste testing vs. self-report results (p < 0.001) emerges in our result, we performed a statistical analysis highlighting disagreement among normosmia (p < 0.05), hyposmia, severe hyposmia, and anosmia (p < 0.001) and, in hypogeusia and severe hypogeusia, while no differences are observed in normogeusia and ageusia. Therefore, we analyzed the olfactory threshold by an objective test revealing the distribution of hyposmic (34%), severe hyposmic (48%), and anosmic (13%) patients in severe CoViD-19. In severe CoViD-19 patients, taste is lost in 4.3% of normosmic individuals, 31.9% of hyposmic individuals, 46.8% of severe hyposmic individuals, and 17% of anosmic individuals. Moreover, 95% of 100 CoViD-19 patients objectively tested were affected by smell dysfunction, while 47% were affected by taste dysfunction. Furthermore, analysis by objective testing also highlighted that the severity of smell dysfunction in CoViD-19 subjects did not correlate with age and sex. In conclusion, we report by objective testing that the majority of CoViD-19 patients report severe anosmia, that most of the subjects have olfactory impairment rather than taste impairment, and, finally, that the olfactory impairment correlate with symptom onset and hospitalization (p < 0.05). Patients who exhibit severe olfactory impairment had been hospitalized for about a week from symptom onset; double time has taken place in subjects with normosmia. Our results may be limited by the relatively small number of study participants, but these suggest by objective testing that hyposmia, severe hyposmia, and anosmia may relate directly to infection severity and neurological damage. The smell test assessment could be a potential screening symptom that might contribute to the decision to test suspected cases or guide quarantine instructions, further therapeutic approach, and evaluation of neurological damage.

Olfactory and Oral Manifestations of COVID-19: Sex-Related Symptoms-A Potential Pathway to Early Diagnosis

Objective

The coronavirus disease 2019 (COVID-19) pandemic poses a threat to global health. Early diagnosis is an essential key to limit the outbreak of the virus.

Study Design

Case series, study conducted between March 25, 2020, and April 15, 2020.

Setting

Ambulatory, nonhospitalized patients who were quarantined in a designated hotel for COVID-19 patients and were recruited by an advertisement at the hotel.

Subjects and Methods

In total, 140 patients participated in a web-based questionnaire assessing initial symptoms of common viral diseases, olfactory and taste functions, xerostomia, and orofacial pain.

Results

A total of 58 men and 70 women participated. Initial symptoms were cough (59.4%), weakness (47.7%), myalgia (46.9%), fever (42.2%), headache (40.6%), impaired sense of smell (38.3%), impaired sense of taste (32.8%), sore throat (26.6%), runny nose (26.6%), and nasal congestion (22.7%). All symptoms were more frequent among women; however, only runny nose was statistically significant (P = .018). The most common combination of symptoms was cough and weakness (37.5%). A total of 25.8% reported olfactory and taste dysfunctions in the absence of other symptoms. In a comparison between the sexes, cough and runny nose were the most common combination in women (P = .018). A total of 38.3% of patients reported olfactory dysfunction as an initial symptom. Anosmia and facial pain were more common among women (P < .001 and P = .01, respectively), and 56% of patients reported xerostomia.

Conclusion

A considerable number of patients presented with olfactory and oral disorders. Interestingly, women presented with a different cluster of symptoms than men, which may suggest a new clinical approach to diagnosing COVID-19 disease.

Diseases of the nasal cavity

Despite garnering minimal attention from the medical community overall, olfaction is indisputably critical in the manner in which we as humans interact with our surrounding environment. As the initial anatomical structure in the olfactory pathway, the nasal airway plays a crucial role in the transmission and perception of olfactory stimuli. The goal of this chapter is to provide a comprehensive overview of olfactory disturbances as it pertains to the sinonasal airway. This comprises an in-depth discussion of clinically relevant nasal olfactory anatomy and physiology, classification systems of olfactory disturbance, as well as the various etiologies and pathophysiologic mechanisms giving rise to this important disease entity. A systematic clinical approach to the diagnosis and clinical workup of olfactory disturbances is also provided in addition to an extensive review of the medical and surgical therapeutic modalities currently available.

Association of alterations in smell and taste with depression in older adults

Objective

Examine the relationship between depression and changes in smell or taste.

Study Design

Cross‐sectional analysis of 2011–2012 and 2013–2014 National Health and Nutrition Examination Survey (NHANES).

Methods

We examined 5,275 adults ≥40 years old who completed smell and taste questionnaires as well as a validated depression assessment instrument, the Patient Health Questionnaire (PHQ‐9). Analyses incorporated sampling weights to account for the complex sampling design and associations were analyzed using multivariate logistic regression adjusted for related demographics and socioeconomic data.

Results

The prevalence of altered smell and taste was 23.0% (95% CI: 20.7–25.3%) and 11.9% (95% CI: 10.7–13.1%), respectively. Among those who met criteria for major depressive disorder, the prevalence of altered smell and taste was higher at 39.8% (95% CI: 33.4–46.1%) and 23.7% (95% CI: 18.7–28.7%), respectively. In a multivariate model adjusting for age, gender, education, major comorbidities, smoking history, heavy alcohol use, sinus disease, cold symptoms, and trauma history, adults ≥40 and <65 years old who reported alterations in smell (OR: 1.64, p = 0.004) and adults ≥40 years old who reported alterations in taste (OR: 1.77, p = 0.001) were more likely to meet criteria for major depressive disorder.

Conclusion

There is a strong association between major depression and alterations in smell and taste among certain age groups in the general U.S. population. Primary care providers should screen for depression when patients report changes in smell or taste.

Level of Evidence

4.

Olfactory dysfunction in patients with chronic rhinosinusitis

Objectives. To measure the prevalence of and identify the clinical characteristics associated with olfactory decline in patients with chronic rhinosinusitis. Methods and Materials. There is analytical, prospective, and observational study in adult patients with a diagnosis of chronic rhinosinusitis. The olfactory test used was the Connecticut Chemosensory Clinical Research Center (CCCRC). Results. They are 33 patients total. Within the group of patients aged 18 to 39, 9% had normosmia, 73% hyposmia, and 18% anosmia (P < 0.001). Between 40 and 64 years old, there was no patient with normosmia, 63% hyposmia, and 37% anosmia (P < 0.001). Of patients older than 65 years old, 33% showed mild hyposmia, 34% severe hyposmia, and 33% anosmia (P < 0.001). 52% were females, and 48% were males. Conclusion. Nasal polyposis, asthma, septal deviation, turbinate hypertrophy, tobacco, and allergic rhinitis are predicting factors of olfactory dysfunction. Antecedents of previous endoscopic surgeries, age, and gender would not be associated with olfactory loss.

Predictors of olfactory dysfunction in patients with chronic rhinosinusitis

OBJECTIVES

To measure the prevalence of and identify clinical characteristics associated with poor olfactory function in a large cohort of patients with chronic rhinosinusitis (CRS).

STUDY DESIGN

Multi-institutional, cross sectional analysis.

METHODS

An objective measure of olfactory dysfunction, the Smell Identification Test, demographic data, clinical factors, and comorbidity data were collected from a cohort of 367 patients who presented with CRS at three tertiary care centers. Data were analyzed using univariate and multivariate analyses.

RESULTS

Sixty-four percent of men and women aged 18 to 64 had olfactory dysfunction whereas 95% of patients older than or equal to 65 years had olfactory dysfunction (P < .001); no significant difference was noted by gender. By multivariate logistic regression analysis, patients with nasal polyposis [Odds ratio (OR) 2.4, 95% confidence interval (CI) 1.3-4.2, P = .003] and patients older than or equal to 65 years (OR 10.0, 95% CI 2.3-43.7, P = .002) were at increased risk of hyposmia. Patients with nasal polyposis (OR 13.2, 95% CI 5.7-30.7, P < .001), asthma (OR 4.2, 95% CI 1.8-9.8, P = .001), older than or equal to 65 years (OR 15.6, 95% CI 2.3-104.9, P = .005), and smokers (OR 7.6, 95% CI 1.8-31.6, P = .005) were at increased risk of anosmia.

CONCLUSIONS

Poor olfactory function is common in patients with CRS. Age, nasal polyposis, smoking, and asthma were significantly associated with olfactory dysfunction in patients with CRS. Neither prior endoscopic sinus surgery nor a history of allergic rhinitis was associated with olfactory dysfunction. Septal deviation and inferior turbinate hypertrophy were associated with normal olfactory function.