Auditory Disturbances and SARS-CoV-2 Infection: Brain Inflammation or Cochlear Affection? Systematic Review and Discussion of Potential Pathogenesis

Clinical utility of inflammatory biomarkers in COVID-19-related sudden sensorineural hearing loss

BACKGROUND

The etiology and pathophysiological mechanisms of sudden sensorineural hearing loss (SSNHL) remain unclear, but it is generally believed to be associated with viral infections, vascular diseases, and autoimmune disorders. Considering that coronavirus disease 2019 (COVID-19) is promising candidates for SSNHL, we studied the immune cells changes by COVID-19 in patients with SSNHL.

METHODS

We collected data from 47 patients with SSNHL and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) positive. Patients were divided into ineffective or effective groups based on the degree of hearing recovery at discharge. Clinical information was collected and processed for both groups. Logistic regression models were used to determine the risk factors for an unfavorable prognosis in COVID-19-related SSNHL. Receiver operating characteristic (ROC) curves were used to estimate the predictive value.

RESULTS

There was statistically significant difference in C-reactive protein (CRP), auditory curve, degree decline, pretreatment hearing, posttreatment hearing, systolic blood pressure, diastolic blood pressure, total bilirubin, neutrophil-to-lymphocyte ratio (NLR), systemic immune-inflammation index (SII), indirect-bilirubin and platelet count between groups (p < 0.05). In the logistic regression model, high levels of SII and NLR were associated with treatment ineffectiveness, pre- and postcorrectively (both, p < 0.05). And ROC curve analysis showed higher AUC of 0.765 for SII, 0.697 for NLR,0.681 for CRP, and 0.553 for platelet-to-lymphocyte ratio (PLR) in predicting treatment outcomes.

CONCLUSION

The prognosis of COVID-19-related SSNHL was associated with inflammation. SII, NLR and CRP could serve as predictive markers of unfavorable outcomes in COVID-19-related SSNHL. SII may be considered an independent risk factor for poor prognosis in COVID-19-related SSNHL.

Prevalence of self-perceived audiovestibular symptoms in Egyptian COVID-19 patients

BACKGROUND

According to National Institute for Health and Care Excellence (NICE), UK, common audiovestibular symptoms of COVID-19 include dizziness, tinnitus, and otalgia. The pathogenesis of otologic disorders ranges from direct damage to the inner ear structures to immune-mediated damage. Since the start of the pandemic, the prevalence of audiovestibular symptoms linked to COVID-19 has not been thoroughly investigated in Egypt. Our objective is to study and analyze the prevalence of the audiovestibular symptoms in the Egyptian population with history of COVID-19 infection.

METHODS

A cross-sectional study was conducted among Egyptian adults on the presence and nature of the audiovestibular manifestations in COVID-19 patients. An online questionnaire was used. The questionnaire was developed using Google Form. It was disseminated to the target population through social platforms from October 2021 till February 2022.

RESULTS

Data from 245 respondents were collected through online assessment of a convenient sample. The following de novo audiovestibular symptoms were experienced by the participants: Vertigo 20.8%, hearing loss 13.9%, tinnitus 12.7% and ear fullness 11.4%. No correlation was found between the investigations done (D-Dimer, CT chest) and the audiovestibular symptoms.

CONCLUSION

Audiovestibular symptoms are fairly common among COVID-19 patients, with higher prevalence, particularly of vertigo, in our study sample compared to the literature. It is recommended that patients with audiovestibular symptoms undergo early testing so that prompt interventions can be taken.

Efficacy of Palmitoylethanolamide and Luteolin Association on Post-Covid Olfactory Dysfunction: A Systematic Review and Meta-Analysis of Clinical Studies

Post-Covid Olfactory Dysfunction (PCOD) is characterized by olfactory abnormalities, hyposmia, and anosmia, which are among the most often enduring symptoms in individuals who have recovered from SARS-CoV-2 infection. This disorder has been reported to persist in subsets of patients well after 12 months following infection, significantly affecting their quality of life. Despite the high prevalence of PCOD among patients who suffered from SARS-CoV-2 infection, specific therapeutic strategies are still limited. Among these, emerging evidence seems to indicate the administration of CoUltraPEALut, a combination of micronized Palmitoylethanolamide (PEA), an endogenous fatty acid amide, and Luteolin, a natural antioxidant flavonoid, as a viable therapy, especially when given as an adjuvant to olfactory training. Based on the above, a systematic review and a meta-analysis of the literature were conducted, with the aim of evaluating the efficacy of CoUltraPEALut as an addition to olfactory training (OT), in treating PCOD symptoms. Pubmed (MEDLINE), Embase (OVID), and Web of Science scientific databases were screened from the inception until 31 May 2023, and a total of 407 articles were recovered; only five of these studies (441 total patients between treated and control groups) were included in the systematic review. CoUltraPEALut demonstrated significant efficacy in the overall recovery of the olfactory function, compared to the conventional therapy, suggesting that it could represent a possible future adjuvant treatment for PCOD.

Vertigo symptom scores and videonystagmographic examinations in recovered coronavirus disease 2019 patients

OBJECTIVE

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) may be among the viral agents that affect the audio-vestibular system. This study aimed to investigate vestibular symptoms and videonystagmographic examinations in recovered coronavirus disease 2019 (Covid-19) patients compared with the control group.

METHOD

The patients were evaluated with Vertigo Symptom Scale questionnaire and audiometric, tympanometric, stapedial reflex and videonystagmographic examinations.

RESULTS

A total of 92 of the patients in the coronavirus disease 2019 patients group and 25 of the volunteers in the control group were included in the study. The mean Vertigo Symptom Scale score was found to be significantly higher (p < 0.001) in the coronavirus disease 2019 group. Furthermore, one of the hospitalised patients was diagnosed with vestibular neuritis.

CONCLUSION

The vestibular system may also be affected in some coronavirus disease 2019 patients. Although this may be seen as dizziness in some patients, in rare cases it can cause severe issues, such as vestibular neuritis.

The Pathogenesis of Cytomegalovirus and Other Viruses Associated with Hearing Loss: Recent Updates

Virus infection is one of the most common etiologies of hearing loss. Hearing loss associated with viral infection can be unilateral or bilateral, mild or severe, sudden or progressive, and permanent or recoverable. Many viruses cause hearing loss in adults and children; however, the pathogenesis of hearing loss caused by viral infection is not fully understood. This review describes cytomegalovirus, the most common virus causing hearing loss, and other reported hearing loss-related viruses. We hope to provide a detailed description of pathogenic characteristics and research progress on pathology, hearing phenotypes, possible associated mechanisms, treatment, and prevention measures. This review aims to provide diagnostic and treatment assistance to clinical workers.

An online survey on clinical characteristics of otologic symptoms linked to COVID-19 infection

Objective

To report the otologic symptoms that present in patients with COVID-19 infection and investigate the pathogenic characteristics during the period of the pandemic.

Materials and methods

This cross-sectional descriptive study included participants with COVID-19 infection. COVID-19 infection was verified in these patients by nucleic acid test or antigen test. An online questionnaire was developed to analyze the association between the COVID-19 pandemic and the characteristics of otologic symptoms.

Results

This study included 2,247 participants, of which nearly half had one or more otologic symptoms. The presents of otologic symptoms were associated with gender (OR = 1.575, p < 0.0001), age (OR = 0.972, p < 0.0001), and occupation (healthcare worker: p < 0.0001; personnel of enterprises or institutions: OR = 1.792, p < 0.0001; student: OR = 0.712, p < 0.044). The otologic symptoms following COVID-19 infection in order were vertigo (25.95%), tinnitus (19.05%), otalgia (19.00%), aural fullness (17.18%), hearing loss (11.62%), otorrhea (1.25%), and facial paralysis (0.27%).

Conclusion

The present study shows that otologic symptoms are common among the COVID-19 infected participants and that these symptoms mostly recover spontaneously. During the corona-virus pandemic, the involvement of the cochleovestibular system and facial nerve should not be overlooked while treating the COVID-19 infected individuals.

Hearing loss and COVID-19: an umbrella review

INTRODUCTION

COVID-19 can result in an extensive range of extrapulmonary, and neurological signs and symptoms such as olfactory and/or taste dysfunction, and otologic symptoms. The aim of this study was to investigate the hearing loss manifestation from COVID-19.

METHODS

The goal of this umbrella review was to examine hearing loss associated with COVID-19 disease. English literature published until October 15, 2022 in online databases including PubMed, Scopus, Web of Science, and Embase was considered for this purpose. Eligibility of the articles for subsequent data extraction was evaluated in a two-step selection process with consideration to an inclusion/exclusion criterion. This review followed the PRISMA protocol and the Amstar-2 checklist for quality assessment.

RESULTS

A total of four treatment strategies were used by different studies which included oral corticosteroids, intratympanic corticosteroids, combined oral and intratympanic corticosteroids, and hyperbaric oxygen therapy. Five studies investigated corticosteroid use in the forms of oral or intratympanic injection; four studies reported (complete or partial) hearing improvements after steroid treatment, while one study stated no significant improvement in hearing function. One study reported that oral corticosteroid monotherapy alone was not effective, while vestibular symptoms were ameliorated by a combination of oral prednisone, intratympanic dexamethasone injection, and hydroxychloroquine.

CONCLUSION

The findings suggest that despite being one of the rare complications of COVID-19, hearing loss can impact a patient's quality of life. The most common type reported was sensorineural hearing loss, which can be diagnosed with variable techniques.

Audiometry-Confirmed Sudden Sensorineural Hearing Loss Incidence among COVID-19 Patients and BNT162b2 Vaccine Recipients

OBJECTIVE

To compare sudden sensorineural hearing loss (SSNHL) incidence rates over the coronavirus disease 2019 (COVID-19) outbreak and the COVID-19 vaccination campaign periods to pre-COVID-19 periods.

STUDY DESIGN

Retrospective cohort.

SETTING

Secondary hospital.

PATIENTS

Patients >12 years with auditory-confirmed SSNHL were enrolled. COVID-19 status and BNT162 inoculation records ≤28 days before SSNHL diagnosis were retrieved. Patients were categorized according to their date of presentation over four equal periods: 1) July 2018-April 2019 (first prepandemic period), 2) May 2019-February 2020 (second prepandemic period), 3) March 2020-December 2020 (COVID-19 outbreak), and 4) January 2021-October 2021 (BNT162b2 vaccinations campaign).

INTERVENTIONS

Pre- and post-COVID-19 emergence; BNT162b2 vaccine.

MAIN OUTCOME MEASURES

Incidence rate ratios (IRRs) were calculated to compare SSNHL cases during the COVID-19 and vaccination periods with pre-COVID-19 periods.

RESULTS

Of the 100 patients with SSNHL over the four periods, 1 had COVID-19 and 8 were vaccinated. The annual SSNHL incidence was 12.87, 12.28, 13.45, and 19.89 per 100,000 over periods 1 to 4, respectively. SSNHL incidence over the third period was not significantly different than the first/second periods (IRR = 1.045, 95% confidence interval [CI] = 0.629-1.85, ρ = 0.788, and IRR = 1.095, 95% CI = 0.651-1.936, ρ = 0.683, respectively), whereas SSNHL incidence rate over the fourth period was higher (IRR = 1.545, 95% CI = 0.967-2.607, ρ = 0.068, and IRR = 1.619, 95% CI = 1-2.73, ρ = 0.05, respectively). SSNHL incidence in vaccine recipients was lower than prepandemic unvaccinated patients (IRR = 0.584, 95% CI =0.464-1.67, ρ = 0.984, and IRR = 0.612, 95% CI =0.48-1.744, ρ = 0.92, respectively).

CONCLUSION

There were fewer SSNHL cases during the first COVID-19 months. Although the SSNHL rate over the COVID-19 vaccination campaign increased, it was not higher for patients who received the BNT162b2 vaccine.

Targeting Neuroinflammation to Alleviate Chronic Olfactory Dysfunction in Long COVID: A Role for Investigating Disease-Modifying Therapy (DMT)?

Chronic olfactory dysfunction after SARS-CoV-2 infection occurs in approximately 10% of patients with COVID-19-induced anosmia, and it is a growing public health concern. A regimen of olfactory training and anti-neuroinflammatory therapy with co-ultramicronized palmitoylethanolamide with luteolin (um-PEA-LUT) has shown promising results in clinical trials; however, approximately 15% of treated patients do not achieve full recovery of a normal olfactory threshold, and almost 5% have no recovery. Disease-modifying therapies (DMTs), which are used to treat autoimmune neuroinflammation in multiple sclerosis (MS), have not been studied for treating persistent inflammation in refractory post-COVID-19 smell disorder. This study evaluated COVID-19-related smell loss and MS-related smell loss, comparing the responses to different therapies. Forty patients with MS and 45 reporting post-COVID-19 olfactory disorders were included in the study. All patients underwent nasal endoscopy and were evaluated by using validated Sniffin' Sticks testing. The patients with long COVID were treated for three months with um-PEA-LUT plus olfactory training. The patients with MS were treated with DMTs. Olfactory functions before and after treatment were analyzed in both groups. At the experimental endpoint, 13 patients in the COVID-19 group treated with um-PEA-LUT had residual olfactory impairment versus 10 patients in the MS group treated with DMTs. The severity of the persistent olfactory loss was lower in the MS group, and the patients with MS treated with IFN-beta and glatiramer acetate had the preservation of olfactory function. These data provide a rationale for considering prospective trials investigating the efficacy of DMTs for post-COVID-19 olfactory disorders that are refractory to um-PEA-LUT with olfactory training. This study is the first to consider the role of DMT in treating refractory post-viral olfactory loss in patients with long COVID.

[Speech intelligibility in adults after the new coronavirus infection (COVID-19)]

OBJECTIVE

The research was aimed to assess speech intelligibility in adults after the new coronavirus infection (COVID-19), state of peripheral and central parts of auditory system and cognitive functions.

MATERIAL AND METHODS

26 people complaining about hearing loss, poor speech intelligibility and/or tinnitus after COVID-19 were examined. All the patients underwent the basic audiological assessment before COVID-19. Extended testing in patients after COVID-19 included: pure tone audiometry, impedancemetry, speech audiometry in quiet and noise (evaluation of monosyllabic words intelligibility and the Russian matrix sentence test RuMatrix), the alternating binaural speech test, the dichotic digits test and the Montreal Cognitive Assessment (MoCA).

RESULTS

The most significant deviations from the normative values were obtained in the RuMatrix test and the dichotic digits test that may be due to both central auditory processing disorder and memory impairment. Low MoCA scores were obtained in 62% of patients.

CONCLUSION

Deterioration of speech intelligibility after COVID-19 was revealed, both in patients with hearing loss and with normal hearing that corresponded to their complaints. It may be caused by central auditory disorder, memory impairment or cognitive status lesion. The correlation found between the results of the RuMatrix test in noise and the severity of the COVID-19 may indicate the impact of the virus on the auditory cortex.

Common and uncommon audio-vestibular findings in COVID-19 patients

Background

COVID-19 is the new version of the old coronavirus known since 1960, which caused the Middle East respiratory syndrome (MERS-CoV) in 2012 and the severe acute respiratory syndrome (SARS) in 2003.

Symptoms included fever and cough, diarrhea and vomiting, and neurological symptoms like anosmia.

Methods

One hundred twenty-eight patients diagnosed as COVID-19 with audio-vestibular complaints were subjected to audio-vestibular assessment and were included in the study.

Results

In our study on COVID-19 patients who reported audio-vestibular complaints, hearing loss was found in 43.8% of patients in comparison to vertigo that represented 40.6% of cases. The most common type was sensorineural hearing loss representing 29.7% of patients and which was unilateral and sudden in 35.7% of them. Less commonly conductive hearing loss (CHL) was found in 14.1% of cases the most common form was bilateral mild to moderate CHL (83.3%) due to bilateral middle ear effusion.

Among cases with vertigo, the most common etiology was benign paroxysmal positional vertigo (BPPV) (42.5%) then uncompensated vestibular neuritis (VN) (31.5%), and lastly, combined BPPV with VN (25%) of cases. Less frequently we found tinnitus in (13.3%) which was bilateral in (64.7%), labyrinthitis (5.5%), and acute VN 5.5%).

The significant increase in the number of audiovestibular complaining cases that were observed in the course of the recurrent waves’ peaks pushed us to study the relationship between the pandemic and the audiovestibular system. The effect of COVID on AV systems is well noticed and management would be mandatory.

Effect of Ultra-Micronized Palmitoylethanolamide and Luteolin on Olfaction and Memory in Patients with Long COVID: Results of a Longitudinal Study

In this study, we investigated whether treatment with palmitoylethanolamide and luteolin (PEA-LUT) leads to improvement in the quantitative or qualitative measures of olfactory dysfunction or relief from mental clouding in patients affected by long COVID. Patients with long COVID olfactory dysfunction were allocated to different groups based on the presence (“previously treated”) or absence (“naïve”) of prior exposure to olfactory training. Patients were then randomized to receive PEA-LUT alone or in combination with olfactory training. Olfactory function and memory were assessed at monthly intervals using self-report measures and quantitative thresholds. A total of 69 patients (43 women, 26 men) with an age average of 40.6 + 10.5 were recruited. PEA-LUT therapy was associated with a significant improvement in validated odor identification scores at the baseline versus each subsequent month; assessment at 3 months showed an average improvement of 10.7 + 2.6, CI 95%: 6–14 (p < 0.0001). The overall prevalence of parosmia was 79.7% (55 patients), with a significant improvement from the baseline to 3 months (p < 0.0001), namely in 31 patients from the Naïve 1 group (72%), 15 from the Naïve 2 group (93.7%), and 9 from the remaining group (90%). Overall, mental clouding was detected in 37.7% (26 subjects) of the cases, with a reduction in severity from the baseline to three months (p = 0.02), namely in 15 patients from the Naïve 1 group (34.8%), 7 from the Naïve 2 group (43.7%), and 4 from the remaining group (40%). Conclusions. In patients with long COVID and chronic olfactory loss, a regimen including oral PEA-LUT and olfactory training ameliorated olfactory dysfunction and memory. Further investigations are necessary to discern biomarkers, mechanisms, and long-term outcomes.

Entorhinal Cortex and Persistent Olfactory Loss in COVID-19 Patients: A Neuroanatomical Hypothesis. Comment on Fiorentino et al. Correlations between Persistent Olfactory and Semantic Memory Disorders after SARS-CoV-2 Infection. Brain Sci. 2022, 12, 714

Recently, Fiorentino et al. [...]

The New Coronavirus Infection (COVID-19) and Hearing Function in Adults

In this study, we assessed the impact of COVID-19 on the hearing function in adults. A total of 161 subjects were examined, and the results of a previous audiological examination of 24 patients were reviewed. Pure tone audiometry, impedancemetry, speech audiometry in quiet and noise, the Binaural Fusion Test, the dichotic digits test, and a cognitive status examination were performed. A total of 81% of patients complained about hearing disorders, and 43% noted memory impairment. According to pure tone audiometry, 24% of the subjects had normal hearing, while 76% had some degree of hearing loss. No significant changes in hearing thresholds were found in comparison with audiological examinations performed before COVID-19. Disorder of monosyllabic words’ intelligibility in quiet was found in 33% of patients, and in 42% in noise, along with low indicators in the dichotic digits test in 54% of patients. Moreover, 71% of patients had low scores on the MoCA scale that indicated cognitive impairment. Conclusions: The deterioration of speech test scores in patients after COVID-19 can occur due to central auditory processing disorders (CAPD), memory impairment, or changes in cognitive status in general.

Long COVID, audiovestibular symptoms and persistent chemosensory dysfunction: a systematic review of the current evidence

Objective

The persistence of auditory, vestibular, olfactory, and gustatory dysfunction for an extended time after COVID-19 has been documented, which represents an emerging challenge of which ENT specialists must be aware. This systematic review aims to evaluate the prevalence of persistent audiovestibolar and olfactory/gustatory symptoms in patients with “long-COVID”.

Methods

The literature was systematically reviewed according to PRISMA guidelines; PubMed, Scopus and Google Scholar were screened by searching articles on audiovestibular symptoms and olfactory/gustatory dysfunction after SARS-CoV-2 infection. The keywords used were hearing loss, tinnitus, vertigo, smell disorders, parosmia, anosmia, hyposmia, dysgeusia combined with COVID-19 or SARS-CoV-2.

Results

1100 articles were identified. After removal of duplicates (382), 702 articles were excluded, and 16 were included in the systematic review. All articles included identified an association between SARS-CoV-2 infection and persistent hearing or chemosensory impairment. The studies were published over a period of 2 years, between 2019 and 2021.

Conclusions

The likelihood of patients with persistent audiovestibular symptoms related to COVID-19 was different among the articles; however, olfactory and gustatory disturbances were more consistently reported. Studies with longer follow-up are required to fully evaluate the long-term impact of these conditions.

The Impact of COVID-19 Confinement on Tinnitus and Hearing Loss in Older Adults: Data From the LOST in Lombardia Study

Background

Although a direct relationship between tinnitus or hearing difficulties and COVID-19 has been suggested, current literature provides inconsistent results, and no research has been undertaken in older adults.

Methods

In November 2020, we conducted the LOST in Lombardia survey, a telephone-based cross-sectional study on a sample of 4,400 individuals representative of the general population aged ≥65 years from Lombardy region, Northern Italy. Individuals with diagnosed tinnitus and/or hearing loss were asked whether their conditions had improved or deteriorated in 2020 compared to 2019.

Results

Overall, 8.1% of older adults reported a diagnosis of tinnitus and 10.5% of hearing loss. In 2020 compared to 2019, among individuals with tinnitus, those with increasing severity (5.0%) were similar to those decreasing it (5.3%). Among individuals with hearing loss, more people reported an increase (13.6%) than a decrease (3.2%) in their disease severity. No individual with a diagnosis in 2020 of tinnitus (n = 6) or hearing loss (n = 13) had COVID-19. The incidence of tinnitus was lower in 2020 (rate: 14.8 per 10,000 person-years) than in previous years (rate in 1990–2019: 36.0 per 10,000 person-years; p = 0.026). There was no change in the incidence of hearing loss (p = 0.134).

Conclusions

In this large representative sample of older adults, on average neither COVID-19 confinement nor SARS-CoV-2 infection appeared to increase the severity or incidence of tinnitus. The increased severity of hearing difficulties may totally or partially be explained by physiologic deterioration of the condition, or by a misperception due to the use of face-masks.

Vestibular Cochlear Manifestations in COVID-19 Cases

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a high transmissible infectious disease that primarily impacts the respiratory system and leads to death as it worsens. Ever since the World Health Organization declared the disease as a global pandemic, the pathophysiology, clinical manifestations, and disease prognosis has been discussed in various literature. In addition to impaired respiratory health, the symptoms also indicated the involvement of the cardiovascular and neurological system after SARS-CoV-2 infection. Despite the pulmonary, cardiovascular, and neurological complications, many reports also revealed the prevalence of vestibulocochlear symptoms like dizziness, vertigo, vestibular neuritis, sudden sensorineural hearing loss, and tinnitus. Though many clinical reports and scientific reviews reported the vestibular and cochlear impairments associated with coronavirus disease 2019 (COVID-19) infection, the underlying pathological mechanisms are still unclear and unexplored. In this review, we discussed the published clinical reports, research articles, and literature reviews related to vestibulocochlear manifestations following SARS-CoV-2 infections. We also summarized the current knowledge about the prevalence, epidemiological and clinical features, and potential pathological mechanisms related to vestibular and cochlear manifestations resulting from COVID-19 infections.

Neuro-Ophthalmic Implications of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Related Infection and Vaccination

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic created a unique opportunity to study the effects of infection and vaccination on disease. The year 2020 was dominated by infection and its consequences. The year 2021 was dominated by vaccination and its consequences. It will still take several years for full maturation of databases required for robust epidemiological studies. Therefore, this review on the implications for neuro-ophthalmology draws on resources presently available including reported adverse reactions to vaccination. Illustrative clinical cases are presented.The spectrum of pathology following infection with SARS-CoV-2 falls into 4 main categories: autoimmune, vascular, sequelae of brain damage, and miscellaneous. This review is exhaustive, but the most common conditions discussed relate to headaches and associated symptoms; vertigo, diplopia, and nystagmus; vascular complications of the eye and brain; cranial nerve (mono-)neuropathies; photophobia, ocular discomfort, and optic neuritis. Of the 36 main adverse reactions reviewed, vaccine-induced immune thrombotic thrombocytopenia is a novel complication requiring specific hematological management. Updated diagnostic criteria are summarized. It is relevant to remember taking a medication history because of side effects and to recognize the relevance of comorbidities. The clinical assessment can frequently be performed virtually. Consensus recommendations on telemedicine and the virtual assessment are summarized in a practical and compressed format.The review concludes with an epidemiological tetralogy to interrogate, in future studies, associations with (1) SARS-CoV-2 pandemic infection, (2) SARS-CoV-2 worldwide vaccination, and (3) the possibility of a rebound effect of infections in the pandemic aftermath.

Olfactory Dysfunction, Headache, and Mental Clouding in Adults with Long-COVID-19: What Is the Link between Cognition and Olfaction? A Cross-Sectional Study

Smell alteration and cognitive impairment are common features of the Long-COVID Syndrome. Mental clouding, often described as brain fog, might affect smell by altering recollection of odors or through a share mechanism of neuroinflammation. We investigated mental clouding, headache, and cognitive function in adult patients with persistent COVID-19 olfactory dysfunction. This multi-center cross-sectional study enrolled 152 adults with self-reported olfactory dysfunction from 3 tertiary centers specialized in COVID-19 olfactory disorders. Inclusion criteria were smell alterations after COVID-19 persisting over 6 months from infection, age >18 and < 65. Exclusion criteria included smell alterations, headache, or memory problems prior to COVID-19 infection. The patients were evaluated by olfactometry, nasal endoscopy, headache scale, cognitive assessment, Mini Mental State Examination (MMSE), and self-reported measures. Smell dysfunction was stratified and classified based on olfactory deficit severity and presence of olfactory distortion (parosmia, cacosmia). Data on smell disorder, mental clouding, MMSE, and headache were analyzed to assess correlations. Among the 152 patients studied, 50 (32.8%) presented with anosmia, 25 (16.4%) with hyposmia, 10 (6.6%) with parosmia/cacosmia, and 58 patients (38.2%) with a combination of hyposmia and parosmia; seven (4.6%) patients suffered from headache exclusively, and two (1.4%) had headache and mental clouding as their primary symptom. Headache was reported by 76 (50%) patients, and mental clouding by 71 (46.7%). The patients reporting headache, mental clouding, or both, had significantly increased risk of suffering from anosmia and/or hyposmia when compared with their counterparts without these neurological symptoms. No patients had reduced MMSE scores. In our cohort of adult patients with post-COVID-19, smell alterations persisting over 6 months, cognitive impairment and headache were associated with more severe olfactory loss, consistent with neuroinflammatory mechanisms mediating a variety of Long-COVID symptoms.