Tailored Approach for Persistent Olfactory Dysfunction After SARS-CoV-2 Infection: A Pilot Study

Treatment of Olfactory Disorders After SARS - CoViD 2 Virus Infection

OBJECTIVE

The benefit of a nasal corticosteroid in the treatment of persistent post-infectious smell disorders is not as clear in previous studies as is assumed for olfactory training. This study would therefore like to describe the treatment strategies using the example of a persistent olfactory dysfunction as a result of a proven infection with SARS-CoViD-2-virus.

METHODS

Twenty patients (average age of 33.9 ± 11.9 years) with hyposmia were included in this study from December 2020 to July 2021. Every second patient received additionally a nasal corticosteroid. The two resulting randomized groups of equal size were screened with the TDI test, a 20-item taste powder test for the assessment of retronasal olfaction and otorhinolaryngological examination. The patients were asked to train twice daily using a standardized odor training kit and followed up after 2 months and 3 months, respectively.

RESULTS

We documented a significant overall improvement in olfactory ability over the investigation period in both groups. While the TDI score steadily increased on average under the combination therapy, the rise under olfactory training alone was initially steeper. This short-term interaction effect over mean two months was not statistically significant. According to Cohen, however, a moderate effect (eta2 = 0.055, Cohen`s d = 0.5) can still be assumed. This effect could be explained by a possibly higher compliance at the beginning of the sole olfactory training due to the lack of further drug treatment offers. When the training intensity decreases, the recovery of the sense of smell stagnates. Adjunctive therapy ultimately outweighs this short-term benefit.

CONCLUSIONS

The results reinforce the recommendation of early and consistent olfactory training on patients with dysosmia due to COVID-19. For continuous improvement of the sense of smell, an accompanying topical treatment seems at least to be worth consideration. The results should be optimized with larger cohorts and using new objective olfactometric methods.

Cognitive impairment, neurodegenerative disorders, and olfactory impairment: A literature review

<br><b>Introduction:</b> The early detection and diagnosis of dementia are of key importance in treatment, slowing disease progression, or suppressing symptoms. The possible role of changes in the sense of smell is considered with regard to potential markers for early detection of Alzheimer's disease (AD).</br> <br><b>Materials and methods:</b> A literature search was conducted using the electronic databases PubMed, Scopus, and Web of Science between May 30, 2022 and August 2, 2022. The term "dementia" was searched with keyword combinations related to olfaction.</br> <br><b>Results:</b> A total of 1,288 records were identified through the database search. Of these articles, 49 were ultimately included in the analysis. The results showed the potential role of changes in the sense of smell as potential biomarkers for early detection of AD. Multiple studies have shown that olfactory impairment may be observed in patients with AD, PD, MCI, or other types of dementia. Even though smell tests are able to detect olfactory loss caused by neurodegenerative diseases, they cannot reliably distinguish between certain diseases.</br> <br><b>Conclusions:</b> In individuals with cognitive impairment or neurodegenerative diseases, olfactory assessment has repeatedly been reported to be used for early diagnosis, but not for differential diagnosis.</br>.

Intranasal immunotherapy with M2 macrophage soluble factors in post-COVID hyposmia: A pilot study

Olfactory dysfunction is an early marker of COVID-19 infection. However, individuals may develop chronic olfactory impairment for more than six months in 1-10 % of cases. The study's objective is to evaluate the efficacy and safety of intranasal immunotherapy using bioactive substances produced by M2 macrophages for the treatment of people with long-term post-COVID-19 hyposmia. Seven individuals with long-term persistent hyposmia (7 to 24 months), associated with PCR-confirmed coronavirus infection were evaluated for olfactory function at baseline, one, and six to twelve months after therapy. The intranasal inhalation of M2 macrophage conditioned medum (one time per day for 28-30 days) was well tolerated. Furthermore, olfactometry demonstrated that the patients restored their capacity to perceive (Kruskal-Wallis H test 14.123, p = 0.0009) and recognize odours (H = 11.674, p = 0.0029). In addition, the subjective evaluation of smell significantly improved (H = 11.935, p = 0.0026). At the 6- to 12-month follow-up, the majority of patients (5/7) reported extremely high levels of satisfaction with the outcomes, and the remaining two patients also felt generally positive about the therapy's success. Overall, our study showed that the use of intranasal inhalations as a method of delivering bioactive factors and the conditioned medium of M2 macrophages as a therapeutic agent are both safe, well tolerated and, according to preliminary data, clinically effective in the treatment of patients with long-term post-COVID-19 hyposmia.

Mechanism and treatment of olfactory dysfunction caused by coronavirus disease 2019

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the start of the pandemic, olfactory dysfunction (OD) has been reported as a common symptom of COVID-19. In some asymptomatic carriers, OD is often the first and even the only symptom. At the same time, persistent OD is also a long-term sequela seen after COVID-19 that can have a serious impact on the quality of life of patients. However, the pathogenesis of post-COVID-19 OD is still unclear, and there is no specific treatment for its patients. The aim of this paper was to review the research on OD caused by SARS-CoV-2 infection and to summarize the mechanism of action, the pathogenesis, and current treatments.

Septorhinoplasty and the Late Impact on Olfactory Function: A Review and Meta-analysis

Septorhinoplasty (SRP) is one of the most commonly performed procedures worldwide. There is a recognized debate about the impact of nasal surgery on olfactory function (OF). The study's objective was to assess the effect of SRP on late postoperative OF. A comprehensive review and meta-analysis were employed to assess OF after SRP. All the integrated studies used objective instruments to quantify OF before and after surgery. A literature search was conducted, and the selected works were evaluated, computed, and finally included in a meta-analysis. The risk of bias was assessed using the NIH Guidance for Evaluating the Quality of Before-After (Pre-Post) Studies with No Control Group. Only the latest follow-up OF measurements provided by each research were considered in the analysis. The 95% confidence interval of the effect magnitude for each study was calculated to elucidate effect sizes. Eleven studies were included in the analysis. Five studies reported late OF improvement (45.5%), five reported no alteration in OF (45.5%), and only one study reported OF impairment after SRP (9%). Some works described a transitory decline in OF shortly following surgery, followed by postoperative improvement. A pooled meta-analysis showed that OF was not significantly altered after SRP (p = 0.10) in the late follow-up. SRP surgery seems to constitute a safe procedure concerning OF in the long term. According to research, OF may deteriorate temporarily after surgery with later improvement, sometimes to higher values than baseline. The anticipated evolution of OF after intervention could be discussed during the preoperative consultation for SRP.

Visual Analog Scale and Olfactory Objective Tests in Hyposmia Patients: Is There a Link?

Introduction Olfactory dysfunction (OD) is often a devaluated sensorial affection. The objective evaluation of this dysfunction does not evaluate its compromise in patients' daily life. It is unclear to what extent there is a correlation between the objective evaluation of OD and patient-reported impairment. Objective We aim to search if Sniffin Sticks® correlates with the Visual Analog Scale (VAS) of Hyposmia Symptoms, and therefore if it is a useful method for clinical use. Methods A prospective study was carried out to evaluate and compare consecutive patients who had olfactory impairment due to COVID-19 that were referred to an otolaryngology office. The variables evaluated were gender, age, co-morbidities, and olfactory thresholds (measured according to Sniffin Sticks®). Patients were also enquired about their sense of impairment according to VAS from 1 (worst possible) to 10 (best possible). Statistical analysis was performed using SPSS (IBM SPSS Statistics 26). Normal distribution was checked using both skewness and kurtosis and Kolmogorov-Smirnov tests. Pearson correlation test was used to seek a correlation between VAS and olfactory thresholds. All reported p-values are two-tailed, with a p-value ≤ 0.05 indicating statistical significance. Results Our sample of 47 patients was composed of 30 females (63.8%) and 17 females (36.2%). We found a mean variation between olfactory thresholds before and after the intervention of 3.91±2.466, and an average improvement of 2.29±2.93 in the visual analog scale for subjective evaluation of olfactory impairment. According to the Pearson correlation test, with 95% confidence, there is evidence to claim a moderate association (0.512) between an improvement in olfactory thresholds and VAS (p=0.05). Conclusions There was a moderate correlation between ratings and measures of olfactory function. On an individual basis, there were remarkable differences between measures and ratings of olfactory function. VAS should be considered in the evaluation of the hyposmic patient, due to its simplicity and quick applicability.

Therapies for COVID-19-Related Persistent Olfactory Disorders: One of the Good Fruits of the Pandemic

At the beginning of 2021, the scientific community realized the burden of COVID-19-related persistent olfactory disorders (ODs). The percentage of those infected with COVID-19 who developed severe and persistent ODs [1-3] with devastating effects on their quality of life was 5 to 40% [4,5].

Adaptation and Validation of Portuguese Version of Olfactory Disorders Questionnaire (PT-ODQ)

Introduction

Olfactory dysfunction (OD) is often a devaluated sensorial affection. The objective evaluation of this dysfunction doesn’t evaluate its compromise in patients’ daily life. Therefore, the use of a Portuguese-validated tool is of uttermost importance to objectively scale the pathology presented by these patients.

Objective

We aim to validate and cross-culturally adapt the Olfactory Disorders Questionnaire (ODQ) in the Portuguese language.

Methods

A prospective study was carried out to evaluate and compare 56 consecutive patients who had olfactory disorders and 54 asymptomatic controls. A cross-cultural adaptation process was taken into account in order to transform the original English tool into a valid Portuguese version. We explored the psychometric properties of the European-Portuguese version of the Portuguese version of ODQ (PT-ODQ) concerning its internal consistency, reproducibility, feasibility, and discriminatory validity.

Results

Cronbach alpha for the tool was 0.924 showing strong internal consistency. We also found a statistically significant difference in PT-ODQ between patients with olfactory disorders and patients without olfactory disorders, according to the Mann-Whitney test.

Conclusions

The PT-ODQ seems to be a valid tool for assessing the individual effect of olfactory disorders on patients’ quality of life and, therefore, could be applied in olfactory disorders research and daily practice.