Characteristics of olfactory dysfunction in patients with long-haul covid-19

Background

A subset of individuals suffering from Coronavirus Disease 2019 (COVID-19) will experience ongoing symptoms that last longer than three months (i.e., long-haul COVID). This includes olfactory dysfunction (OD), which is currently estimated to occur in 1-63.5% of patients at one-year post-infection. However, OD in individuals with long-haul COVID-19 is poorly understood, and there is little information regarding how initial SARS-CoV-2 variants correlate with long-haul symptoms. In this study, we investigated the prevalence and severity of OD in patients with long-haul COVID-19 and investigated how OD severity varied with SARS-CoV-2 variants.

Methods

Patients were recruited from the University of North Carolina-Chapel Hill COVID Recovery Clinic. Each patient completed the University of Pennsylvania Smell Identification Test (UPSIT). The dominant strain at the time of infection was determined using the date of COVID-19 diagnosis, and Centers for Disease Control and Prevention, World Health Organization, and North Carolina Department of Health and Human Services databases.

Results

Nearly 85% of patients with long-haul COVID-19 reported some degree of OD, which persisted in some patients for two or more years from the date of the initial infection. There was no association between the time since COVID-19 infection and severity of OD. No difference was detected between OD in patients with long-haul COVID-19 based on the dominant variant at the time of infection (p=0.0959).

Conclusion

A vast majority of patients with long-haul COVID-19 had some degree of ongoing olfactory complications, although the severity of symptoms was not dependent on the dominant SARS-CoV-2 variant at the time of infection.

COVID-19 related olfactory dysfunction prevalence and natural history in ambulatory patients

Background

Evidence regarding prevalence of COVID-19 related Olfactory dysfunction (OD) among ambulatory patients is highly variable due to heterogeneity in study population and measurement methods. Relatively few studies have longitudinally investigated OD in ambulatory patients with objective methods.

Methods

We performed a longitudinal study to investigate OD among COVID-19 ambulatory patients compared to symptomatic controls who test negative. Out of 81 patients enrolled, 45 COVID-19 positive patients and an age- and sex-matched symptomatic control group completed the BSIT and a questionnaire about smell, taste and nasal symptoms. These were repeated at 1 month for all COVID-19 positive patients, and again at 3 months for those who exhibited persistent OD. Analysis was performed by mixed-effects linear and logistic regression.

Results

46.7% of COVID-19 patients compared to 3.8% of symptomatic controls exhibited OD at 1-week post diagnosis (p<0.001). At 1 month, 16.7%, (6 of 36), of COVID-19 patients had persistent OD. Mean improvement in BSIT score in COVID-19 patients between 1-week BSIT and 1 month follow-up was 2.0 (95% CI 1.00 - 3.00, p<0.001). OD did not correlate with nasal congestion (r= -0.25, 95% CI, -0.52 to 0.06, p=0.12).

Conclusions

Ambulatory COVID-19 patients exhibited OD significantly more frequently than symptomatic controls. Most patients regained normal olfaction by 1 month. The BSIT is a simple validated and objective test to investigate the prevalence of OD in ambulatory patients. OD did not correlate with nasal congestion which suggests a congestion-independent mechanism of OD.

Olfactory Function Test for Early Diagnosis of Vascular Dementia

Olfactory impairment occurs in patients with Alzheimer's disease, and olfactory function tests are performed for the diagnosis of Alzheimer's disease. However, the diagnosis and patient status are not currently outlined for vascular dementia, and many physicians do not consider concurrent vascular dementia in patients complaining of olfactory dysfunction. Here, we report a case of vascular dementia with no symptoms of dementia other than olfactory dysfunction. This case suggested that the olfactory function test is helpful not only for the diagnosis of Alzheimer's disease but also for the early diagnosis of vascular dementia.

The Epidemiology of Olfactory Disorders

Insights into risk factors for olfactory decline are needed, because knowledge about its origin is limited. This impairment has important implications for human health. Several epidemiologic studies of olfaction provide insight into the prevalence of olfactory disorders. Here, we review the major population studies carried out on this topic to date. Our purpose is to characterize knowledge about olfactory disorders from human studies. We also describe the existing methods for measuring the sense of smell in population studies, present recent insights into the epidemiology of smell disorders, and discuss the risk factors identified to date. Synthesis of these data shows that olfactory dysfunction increases as people age and is worse in men. Further study of olfaction is warranted for gaining better information on the etiologies affecting its impairment, research that will have a large public health impact.

Olfactory dysfunction in persian patients suffering from parkinson's disease

BACKGROUND

Looking in literature reveals that aging is accompanied by olfactory dysfunction and hyposmia/anosmia is a common manifestation in some neurodegenerative disorders. Olfactory dysfunction is regarded as non-motor manifestations of Parkinson disease (PD). The main goal of this study was to examine the extent of olfactory dysfunction in Persian PD patients.

METHODS

We used seven types of odors including rosewater, mint, lemon, garlic which were produced by Barij Essence Company in Iran. Additionally, coffee and vinegar were used. Subjects had to distinguish and name between seven previously named odors, stimuli were administered to each nostril separately.

RESULTS

Totally, 92 patients and 40 controls were recruited. The mean (standard deviation) (SD) age patients was 64.88 (11.30) versus 61.05 (7.93) in controls. The male: female ratio in patients was 50:42 versus 22:18 in control group. Also, mean UPDRS score (SD) in patients was 24.42 (5.08) and the disease duration (SD) was 3.72 (3.53). Regarding the number of truly detected odors, there were a significant higher number of correct identified odors in control group in comparison with the PD patients. Furthermore, there was a significant negative correlation between number of correct diagnosed smells and UPDRS (Pearson Correlation= -0.27, P = 0.009); conversely, no significant correlation between the duration of Parkinson disease and number of correct diagnosed smells (P > 0.05).

CONCLUSION

Smelling dysfunction is a major problem in Persian PD patients and it requires vigilant investigation for the cause of olfactory dysfunction exclusively in elder group and looking for possible PD disease.