Relationship between olfactory and gustatory functions: The Iwaki health promotion project 2019.

OBJECTIVE: Olfactory and gustatory functions are important sensory aspects in humans. Although they are believed to influence each other, their interrelationship is not well understood. In this study, we aimed to investigate the relationship between the olfactory and gustatory functions based on the results of a large-scale epidemiological study (Iwaki Health Promotion Project) of the general local population. METHODS: We analyzed 565 participants who underwent taste and olfactory tests in the 2019 Iwaki Project. Gustatory function was tested for four taste qualities (sweet, sour, salty, and bitter) using whole-mouth taste tests. Olfactory function was tested using the University of Pennsylvania Smell Identification Test modified for Japanese (UPSIT-J). We evaluated sex-related differences between olfactory and gustatory functions and the effects of various factors on olfactory identification using multivariate analysis. Furthermore, we compared the percentage of accurate UPSIT-J responses between the normal and hypogeusia groups. We also analyzed the effects of taste and olfactory functions on eating. RESULTS: Olfactory and gustatory functions were lower in men than in women. Among the four taste qualities, salty taste was the most closely associated with olfactory identification ability, with lower olfactory scores of salty taste in the hypogeusia group than in the normal group. Moreover, the hyposmia group had higher daily salt intake than the normal olfaction group in women. CONCLUSION: These results suggest that olfactory identification tests may be useful in predicting elevated salt cognitive thresholds, leading to a reduction in salt intake, which may contribute to hypertension prevention.

Quantitive Assessment of Gustatory Function and Its Association with Demographics, and Systemic Morbidity.

This study aimed to analyze the associations of gustatory dysfunction as measured by validated taste strips with demographics and co-morbidities. This cross-sectional study retrospectively analyzed records of patients who attended the Orofacial Chemosensory Center of Hadassah Medical Center between 2017 and 2020. Taste strips were used as a validated method to determine taste dysfunction. A total of 272 subjects were included, 137 (50.4%) women and 135 (49.6%) men, with a mean age of 53.5 ± 19.3 years and age range of 18-98 years. The total taste score among the study population was 8.53 ± 4.03 (scale range 0-16). Age had a significant negative correlation with the total taste score (p = 0.001), and men exhibited worse total (p < 0.001), salty (p = 0.003), and bitter (p < 0.001) scores. Major trauma was associated with worse total (p < 0.001) and specialized taste assessments (sweet (p = 0.001), sour (p = 0.002), salty (p = 0.016), and bitter (p < 0.001)). Chemotherapy was associated with reduced total (p < 0.001), salty (p = 0.003), and bitter (p = 0.001) taste scores. Zinc deficiency exhibited worse salty (p = 0.027) and total (p = 0.038) taste scores. Patients with burning mouth syndrome (BMS) showed higher salty scores (p = 0.017). Patients who experienced exposure to toxic chemicals exhibited worse salty scores (p = 0.024). We conclude that gustatory dysfunction is associated with older age, male sex, and co-morbidities of major trauma, current chemotherapy, zinc deficiency, BMS, and exposure to toxins. The study highlights the importance of systemic evaluation and quantitive gustatory dysfunction assessment as part of the diagnostic process of patients with subjective complaints of taste disorders.

Pure Sensory Lacunar Infarction in the Thalamus Presented as Bilateral Hypogeusia: A Case Report.

PURPOSE: While the gustatory pathway of animals has been well-researched, that of humans is still a mystery. Several theories have been established, and some earlier reports hypothesized the relation to laterality. However, some cases could not be fully explained by the laterality theory (1). To clarify the gustatory pathway, we reported a case with bilateral hypogeusia after right thalamic infarction. CASE: This 55-year-old, right-handed man suffered from sudden decreased sensitivity of taste. He was unable to differentiate sweetness and saltiness at bilateral anterior parts of tongue. Additionally, there was numbness at the upper palate and the lips. Neurological examination revealed decreased taste sense at both sides of his anterior tongue and decreased pin-prick sensation of the left part of his lips. Brain magnetic resonance imaging (MRI) revealed acute ischemic stroke at the right ventral posteromedial nucleus (VPM). Thus, single antiplatelet therapy was administered. Two weeks later, the symptoms improved significantly and completely recovered without sequelae. CONCLUSION: The exact gustatory pathway in humans remains uncertain nowadays. First, there were few reports about dysgeusia, which might be related to clinical neglect of taste deficits. Second, our knowledge of the human gustatory pathway depends solely on sporadic cases of taste-involved brain lesions. We reported a case of bilateral hypogeusia after right thalamic infarction. This finding indicates that, although there might be laterality of gustatory fibers to the left hemisphere, anatomical variations may exist in the human gustatory system. More research is needed to elucidate the understanding of the gustatory pathway in humans.

Olfactory and gustatory disorders associated with SARS-CoV-2 infection in children and adults: a topic review.

This paper is aimed at comprehensively reviewing olfactory and gustatory disorders caused by SARS-CoV-2 in children and adults. An electronic and manual search was done on three databases: MEDLINE, Embase, and Web of Science. Inclusion criteria included publications written in English, involving humans in the age range of 0 to 99 years that were captured by a controlled vocabulary of thesaurus terms. Olfactory and gustatory disorders rates in COVID-19 ranged from 22% to 71.9% in adults and 16.6% to 25.8% in children. Olfactory and gustatory disorders might appear as the first symptom, and in adults might even be the only symptom (4.8% to 10%). Anosmia is the most common olfactory disorder and hypogeusia is the most common gustatory disorder. In 33% to 89% of cases, olfactory and gustatory disorders resolve spontaneously within a few weeks, coinciding with the resolution of other COVID-19 symptoms, both in adults and children. However, in some patients, olfactory and gustatory disorders persist beyond the resolution of other symptoms. Notably, children generally experience a swifter and more favorable recovery compared to adults. The precise pathogenesis underlying olfactory and gustatory disorders in the context of COVID-19 remains unclear and is likely multifactorial. Presently, no established treatment protocol exists for olfactory and gustatory disorders and current treatments reviewed lack robust evidence and are not readily available for clinical use. Olfactory training represents the only therapy currently recommended by international authorities. Pediatric practitioners and general dental practitioners should be aware of olfactory and gustatory disorders in both pediatric and adult populations, including their biologic mechanisms, treatment options, and recovery rates.

Resting saliva volume as a risk factor for hypogeusia: A retrospective study.

OBJECTIVES: The causes of hypogeusia include zinc deficiency, systemic illness, and consumption of drugs. Notably, patients with oral cavity diseases such as oral candidiasis and salivary gland hypofunction may present with risk factors that remain unreported. Hence, this study aimed to investigate the relationship between age, sex, smoking status, serum zinc concentration, oral candidiasis, saliva volume, and taste function in patients with hypogeusia. SUBJECTS AND METHODS: Overall, 335 participants who complained of taste abnormalities underwent a taste test. Based on the recognition threshold value, the participants were classified as normal individuals (recognition threshold of 1 and 2) and patients with hypogeusia (recognition threshold of ≥3). The clinical characteristics, including resting saliva volume (RSV) and stimulated saliva volume (SSV), were compared, and a multivariate logistic regression analysis focusing on RSV was performed. RESULTS: Patients with hypogeusia had a lower RSV than normal individuals for all tastes, but not for SSV. Based on the results of regression analysis, RSV was identified as an independent predictor of hypogeusia for salty and bitter tastes. Moreover, the proportion of patients with decreased RSV increased as the number of taste qualities exceeding the reference recognition threshold increased. Furthermore, a decrease in RSV was associated with an increase in the recognition threshold for salty and bitter tastes. CONCLUSIONS: Based on the results of the present study, moisturizing the oral cavity may be useful against hypogeusia.

Short- and long term hyposmia, hypogeusia, dysphagia and dysphonia after facial burn injury - A prospective matched cohort study.

BACKGROUND: Facial burns frequently occur in occupational or household accidents. While dysphagia and dysphonia are known sequelae, little is known about impaired smell and taste after facial burns. METHODS: In a prospective observational controlled study, we evaluated hyposmia via the Sniffin' Stick Test (SnS), hypogeusia via a taste strip test, and dysphonia and dysphagia via validated questionnaires acutely and one-year after burn, respectively. A matched control group consisting of a convenience sample of healthy volunteers underwent the same assessments. RESULTS: Fifty-five facial burn patients (FB) and 55 healthy controls (CTR) were enrolled. Mean burn size was 11 (IQR: 29) % total body surface area (TBSA); CTR and FB were comparable regarding age, sex and smoking status. Acutely, hyposmia was present in 29% of the FB group (CTR: 9%, p = 0.014) and burn patients scored worse on the SnS than CTR (FB: 10; CTR: 11; IQR: 2; p = 0.013). Hyposmia per SnS correlated with subjective self-assessment. Hyposmia and SnS scores improved over time (FB acute: 10.5 IQR: 2; FB one year: 11; IQR: 2; p = 0.042) and returned to normal at one-year post burn in most patients who completed the study (lost to follow-up: 21 patients). Taste strip scores were comparable between FB and CTR, as was the acute prevalence of dysphagia and dysphonia. CONCLUSION: Hyposmia acutely after facial thermal trauma appeared frequently in this study, especially when complicated by inhalation trauma or large TBSA involvement. Of all complete assessments, a fraction of burn patients retained hyposmia after one year while most improved over time to normal. Prevalence of dysphonia, dysphagia and hypogeusia was comparable to healthy controls in this study, perhaps due to overall minor burn severity.

Post-discharge persistent headache and smell or taste dysfunction after hospitalisation for COVID-19: a single-centre study.

OBJECTIVES: To evaluate the frequency, characteristics, and persistence of headache in coronavirus disease-19 (COVID-19) patients who are hospitalised and to determine if there is a link between headache and smell and/or taste dysfunction. MATERIALS AND METHODS: In April and May 2020, patients who were hospitalised due to COVID-19 and had headache complaints were evaluated by a neurologist. In addition to clinical COVID-19 features, the characteristics and course of the patients' headaches were evaluated. The patients were contacted by phone 3 months after they were discharged from the hospital to determine the persistence of their symptoms. RESULTS: Eighty-five patients were included in the study, 54.1% were female; the mean age was 47.5 ± 13.9 years (between the ages of 21 and 84). Fifty-four patients (65.3%) presented with smell and/or taste dysfunction, and 14 patients (n = 14, 25.9%) still reported that dysfunction 3 months later. Moreover, 17 (20%) still had headaches 3 months after being discharged from the hospital. Persistent smell/taste disorders were significantly (p < 0.001) more frequent in patients with persistent headaches (59%) compared to those without (6%) (p < 0.001). CONCLUSION: In this prospective study in COVID-19 patients presenting with headache upon admission, a correlation between persistent headache 3 months after discharge and persistent smell/taste dysfunction was found that could point to common underlying pathophysiology.

Gustatory dysfunction in euthyroid primary hypothyroidism.

Objectives: The study assessed gustatory functions in patients with primary hypothyroidism who are euthyroid on supplemental hormone therapy with levothyroxine over six months' duration and to evaluate the association of gustatory dysfunction, if any, with the serum TSH levels. Design: This analytical community-based cross-sectional study was conducted in April 2021, following participants' ethical approval and written informed consent. Setting: The study was conducted in a tertiary health care centre in Bangalore, Karnataka, India. Participants: Sixty-eight subjects participated in this study: 34 primary hypothyroid patients and an equal number of healthy controls. Interventions: Gustatory sensations were assessed by the triple drop test, and scores were given depending on the identification of the tastants (sweet, sour, salty, and bitter). The taste scores were compared, and the association between TSH levels and gustatory parameters were evaluated. Results: Overall taste scores were lesser in hypothyroid patients. This finding depicted that their taste thresholds were increased and were statistically significant (p < 0.001), though the association between the degree of hypogeusia and TSH levels was not statistically significant. Conclusion: Patients with primary hypothyroidism can suffer from hypogeusia, which may revert to normal once they achieve euthyroid status with levothyroxine supplementation. However, this has not been conclusively shown in studies. Our study concluded that hypogeusia was present in primary hypothyroidism despite patients being euthyroid on hormone supplementation, and it was not dependent on the serum TSH levels. Funding: None declared.

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

Background: A common complication of allogeneic hematopoietic stem cell transplantation (alloHSCT) is chronic oral graft vs. host disease (cGvHD). Oral cGvHD may present as mucosal lesions, salivary gland dysfunction, and trismus. Moreover, taste and smell ability may be affected, but the prevalence, nature and severity of altered taste and smell function, and their impact on quality of life (QoL) are understudied. Aim: To identify the prevalence, nature, and severity of taste and smell disturbances, their impact on QoL and to assess whether altered taste/smell ability is associated with oral mucosal cGvHD or hyposalivation. Materials and methods: AlloHSCT recipients at least 100 days post-HSCT and referred for oral cGvHD-related oral complaints were eligible for participation in this cross-sectional study. Manifestations of oral mucosal cGvHD were scored, the (un)stimulated salivary flow was measured, and objective taste and smell ability was evaluated. Subjective taste and smell alterations, and overall and oral health (OH)-related QoL were assessed. Results: In total, 45 patients were included, of which objective reduced taste ability (hypogeusia) was identified in 68.9%; 28.9% had reduced smell ability and 11.1% had complete loss of smell. Nevertheless, only 31.1% of patients reported severe taste alterations and 22% reported moderate taste alterations indicating that not all the patients were aware of their altered taste sense. Taste/smell disturbances were not related to oral mucosal cGvHD or hyposalivation. Most alloHSCT recipients reported a decreased OH-related QoL. However, a relation between taste/smell ability and global or OH-related QoL could not be identified. Conclusion: Taste and smell disturbances are prevalent among alloHSCT recipients. Most patients reported a decreased OH-related QoL, but the specific impact of taste and smell disturbances remains to be elucidated.

Neurological manifestations of post-COVID-19 syndrome S1-guideline of the German society of neurology.

Infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) leads to COVID-19 (COrona VIrus Disease-2019). SARS-CoV-2 acute infection may be associated with an increased incidence of neurological manifestations such as encephalopathy and encephalomyelitis, ischemic stroke and intracerebral hemorrhage, anosmia and neuromuscular diseases. Neurological manifestations are commonly reported during the post-acute phase and are also present in Long-COVID (LCS) and post-COVID-19 syndrome (PCS). In October 2020, the German Society of Neurology (DGN, Deutsche Gesellschaft für Neurologie) published the first guideline on the neurological manifestations of COVID-19. In December 2021 this S1 guideline was revised and guidance for the care of patients with post-COVID-19 syndrome regarding neurological manifestations was added. This is an abbreviated version of the post-COVID-19 syndrome chapter of the guideline issued by the German Neurological society and published in the Guideline repository of the AWMF (Working Group of Scientific Medical Societies; Arbeitsgemeinschaft wissenschaftlicher Medizinischer Fachgesellschaften).

Trastornos del gusto: actualización y aproximación clínica / Taste disorders: update and clinical approach

Resumen Los trastornos del gusto constituyen un grupo de alteraciones relativamente frecuentes en la práctica clínica. Son de etiología diversa, pudiendo afectar la vía gustativa en distintos niveles, manifestándose, clínicamente, con alteraciones cuantitativas y/o cualitativas de la sensibilidad gustativa. En gran parte de los casos se puede lograr un diagnóstico etiológico con una anamnesis adecuada, examen físico y exploraciones complementarias básicas. No obstante, existe poco entendimiento de su patogénesis, así como limitadas opciones terapéuticas, lo que implica la falta de algoritmos de diagnóstico y tratamiento completamente validados. El objetivo de la presente revisión es otorgar una actualización y un abordaje práctico de los trastornos del gusto.

Abstract Taste disorders represent a group of alterations relatively frequent in clinical practice. They have a diverse etiology, and they can affect the gustatory pathway at different levels, clinically manifesting with quantitative/qualitative alterations on taste sensitivity. In most of cases it is possibly to achieve an etiologically diagnosis with appropriate anamnesis, physical exploration, and basic complementary tests. However, their pathogenesis is not well understood, and they have limited therapeutic options, which determines a lack of well-validated diagnosis and treatment algorithms. The objective of this review is to provide and update and a practical approach to taste disorders.

Prevalence Of Gustatory And Olfactory Impairment In Different Stages Of Sars-Cov-2 Infected Pateints In Isolation Ward.

BACKGROUND: To evaluate the prevalence of gustatory and olfactory impairment and its correlation with the severity of SARS-Cov-2 infection as per WHO guidelines. METHODS: A total of 241 patients of both gender having age from 15-80 years were included in the study. It was cross Sectional study conducted at SARS-COV-2 Isolation wards of Pakistan institute of medical science Islamabad from 15thSeptember 2020 to 15th January 2021. Convenient sampling technique was used to collect data. A proforma was designed for this purpose. Participants were divided into 3 groups on the basis of age. Group-1 (15-30 years), group-2 (31-50 years) and group 3 (51-80 years). Further the participants were graded into mild, moderate and severe stages of Sars-Cov-2 infection according to WHO guidelines. Statistical analysis was performed by using SPSS version 20. RESULTS: In this study 66% were male and 34% population were the female. Regarding the age groups 72% population were from the group-3. Results of study shows 47% in mild stage, 45% in moderate stage and 8% severe stage. The results regarding the Gustatory and Olfactory impairment showed that 126 had gustatory impairment while 130 patients had olfactory impairment. CONCLUSIONS: We found strong relationship of olfactory and gustatory changes associated with SARS-COV-2 patients. It is premature to conclude that taste and smell changes are strongly linked to SARS-COV-2 diagnosis. Further multi center researches are required to find out possible pathophysiological mechanism.

Neurological and Mental Health Symptoms Associated with Post-COVID-19 Disability in a Sample of Patients Discharged from a COVID-19 Ward: A Secondary Analysis.

Recent studies suggest that COVID-19 survivors may experience long-term health consequences: in particular, neurological and mental health symptoms might be associated with long-term negative outcomes. This study is a secondary analysis of a larger cohort study and aims to determine the extent to which neurological and mental health sequelae are associated with survivors' disability. Participants include COVID-19 survivors, with no pre-morbid brain conditions, who were discharged from the COVID-19 Unit of the ASST Spedali Civili Hospital between February and April 2020. At an average of 3.5 months after discharge, they were submitted to a neurological examination and completed the WHO Disability Assessment Schedule (WHODAS-12), the Hospital Anxiety and Depression Score, the Pittsburgh Sleep Quality Index and the Montreal Cognitive Assessment. Multivariable regression analysis was carried out to analyze variables that explain WHODAS-12 variation. In total, 83 patients (63 males, average age 66.9, 95% CI: 64.2-69.7) were enrolled; average WHODAS-12 was 13.2 (95% CI: 9.7-16.6). Cognitive dysfunction, anxiety, fatigue, and hyposmia/hypogeusia explained 28.8% of WHODAS-12 variation. These findings underline the importance and need for longitudinal follow-up assessments after recovery from COVID-19 and suggest the need for early rehabilitation of residual symptoms to enhance patients' functioning.

Therapeutic diminution of Interleukin-10 with intranasal theophylline administration in hyposmic patients.

OBJECTIVE: To determine changes in nasal mucus Interleukin-10 (IL-10) before and after intranasal theophylline treatment in hyposmic patients, and the relationship of these changes to orally administered theophylline treatment. DESIGN: IL-10 was measured in nasal mucus samples of 17 normal subjects and 39 patients with hyposmia of multiple etiologies by use of a sensitive spectrophotometric ELISA assay. Hyposmia is defined clinically by standardized evaluation of impaired olfactometry, as well as subjectively self reported by the patient. RESULTS: Prior to treatment, IL-10 levels in nasal mucus were increased in hyposmic patients compared to controls. Following intranasal theophylline administration, over half of treated patients experienced a decrease of nasal mucus IL-10 toward control levels, correlated with a significant improvement in taste and smell function. Patients who increased with intranasal administration, similar to previously reported oral administration, showed no significant improvement in taste or smell function. CONCLUSIONS: Nasal mucus IL-10 decreased in patients treated with intranasal theophylline. Mechanisms of action include phosphodiesterase and nuclear factor kappa-B inhibition, correlated with an improvement in both olfaction and gustation. IL-10 is induced by therapeutic and systemic administration of theophylline as with oral dosage, but reduced by lower and localized treatment.

Emergence and Evolution of Olfactory and Gustatory Symptoms in Patients with COVID-19 in the Outpatient Setting.

The present study aimed at evaluating the prevalence of general and sinonasal symptoms in patients with olfactory symptoms and mild coronavirus disease-2019 (COVID-19) and determining the patterns in emergence and resolution of olfactory/gustatory symptoms relative to general and sinonassal symptoms. This was a prospective cross-sectional study conducted at the outpatient otorhinolaryngology clinic at a COVID-19-designated referral Hospital. We included consecutive patients with new-onset olfactory dysfunction and positive polymerase chain reaction (PCR) assay of COVID-19. We asked the patients to fill in a questionnaire about general and sinonasal symptoms in association with anosmia, hyposmia or hypogeusia, and recorded the time course of the olfactory/gustatory symptoms during 2-weeks of follow-up. 76 patients with average age of 38.5 ± 10.6 years were included. Majority of participants (94.7%) had general or sinonasal symptom. There was anosmia in 60.5% and hyposmia in 39.5%, with sudden onset of olfactory symptoms reported in 63.2% of patients. During the follow-up, 30.3% of patients completely and 44.7% partially recovered from anosmia/hyposmia. Regardless of whether the general or olfactory symptoms appeared initially, the general symptoms resolved first while a degree of olfactory dysfunction persisted during the follow-up. Our study showed that hyposmia and anosmia in mild COVID-19 are frequently associated with general and sinonasal symptoms and tend to persist longer than the general and sinonasal symptoms during the course of the disease.

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.

Course of Hyposmia and Hypogeusia and their Relationship with Severity of COVID-19 Disease among Indian Population.

AIMS: Hyposmia and hypogeusia are one of the symptoms of COVID-19. Occurrence and course of these symptoms and their relationship with severity of COVID-19 disease are studied. MATERIALS AND METHODS: This was a prospective cohort study, including consenting adult SARS CoV-2 positive patients of both genders, admitted to a Covid Hospital in Puducherry, India. This questionnaire- based study was conducted for a period 4 months from 1st October 2020 to 31st January 2021, and collected data was analyzed using SPSS version 24.0 software. RESULTS: Out of 639 participants, 412 (64.5%) were males, 227 (35.5%) were females. Total cases of new onset hyposmia were 167 (26.1%), and total patients with new onset hypogeusia were 172 (26.91%). 216 (33.80%) had either hyposmia/hypogeusia. First symptom as hyposmia was noted in 49 (7.67%) patients, and as hypogeusia in 20 (3.13%) patients before development of any other symptoms. 216 (33.80%) patients had either smell or taste disturbance as one of their symptoms. By the end of 5 weeks of illness, 96.41% of hyposmic patients, and 97.67% of hypogeusic patients recovered fully. There was no statistically significant difference between presence or absence of hyposmia/hypogeusia and severity of COVID-19 disease (p value = 0.95). CONCLUSION: The occurrence of hyposmia and hypogeusia among Indian COVID-19 patients is more than 26%. Presence or absence of hyposmia/hypogeusia is not a predictor of severity of COVID-19 disease. More than 96% of the patients fully recovered their sense of smell and taste sensation by the end of 5 weeks.

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.

Neurological symptoms and axonal damage in COVID-19 survivors: are there sequelae?

The persistence of neurological symptoms after SARS-CoV-2 infection, as well as the presence of late axonal damage, is still unknown. We performed extensive systemic and neurological follow-up evaluations in 107 out of 193 consecutive patients admitted to the COVID-19 medical unit, University Hospital of Verona, Italy between March and June 2020. We analysed serum neurofilament light chain (NfL) levels in all cases including a subgroup (n = 29) of patients with available onset samples. Comparisons between clinical and biomarker data were then performed. Neurological symptoms were still present in a significant number (n = 49) of patients over the follow-up. The most common reported symptoms were hyposmia (n = 11), fatigue (n = 28), myalgia (n = 14), and impaired memory (n = 11) and were more common in cases with severe acute COVID-19. Follow-up serum NfL values (15.2 pg/mL, range 2.4-62.4) were within normal range in all except 5 patients and did not differentiate patients with vs without persistent neurological symptoms. In patients with available onset and follow-up samples, a significant (p < 0.001) decrease of NfL levels was observed and was more evident in patients with a severe acute disease. Despite the common persistence of neurological symptoms, COVID-19 survivors do not show active axonal damage, which seems a peculiar feature of acute SARS-CoV-2 infection.