ABSTRACT
BACKGROUND: Olfactory dysfunction is a cardinal symptom of COVID-19 infection, however, studies assessing long-term olfactory dysfunction are limited and no randomised-controlled trials (RCTs) of early olfactory training have been conducted. METHODOLOGY: We conducted a prospective, multi-centre study consisting of baseline psychophysical measurements of smell and taste function. Eligible participants were further recruited into a 12-week RCT of olfactory training versus control (safety information). Patient-reported outcomes were measured using an electronic survey and BSIT at baseline and 12 weeks. An additional 1-year follow-up was open to all participants. RESULTS: 218 individuals with a sudden loss of sense of smell of at least 4-weeks were recruited. Psychophysical smell loss was observed in only 32.1%; 63 participants were recruited into the RCT. The absolute difference in BSIT improvement after 12 weeks was 0.45 higher in the intervention arm. 76 participants completed 1-year follow-up; 10/19 (52.6%) of participants with an abnormal baseline BSIT test scored below the normal threshold at 1-year, and 24/29 (82.8%) had persistent parosmia. CONCLUSIONS: Early olfactory training may be helpful, although our findings are inconclusive. Notably, a number of individuals who completed the 1-year assessment had persistent smell loss and parosmia at 1-year. As such, both should be considered important entities of long-Covid and further studies to improve management are highly warranted.
ABSTRACT
A full year has passed since patients were first seen in their medical and otolaryngology clinics with reported acute onset and often profound smell and taste loss that were soon linked to the SARS-CoV-2 virus. While studies vary in their prevalence, roughly 50% of patients with COVID-19 are estimated to suffer from viral-induced chemosensory dysfunction with approximately 5-25% experiences some extent of persistent smell and/or taste loss. The widespread screening of COVID-19 has allowed for a heightened clinical awareness in the early onset of one's olfactory dysfunction with a known viral etiology. Despite the high spontaneous recovery rate, persistent smell loss and qualitative olfactory dysfunctions such as parosmias have developed in an unfortunate subset of COVID-19 patients. Thus, consideration for early onset therapy may be appropriate and physicians have the opportunity to recommend treatment options for acute and chronic COVID-19 associated olfactory loss. Preliminary studies have suggested efficacy with the use of olfactory training as well as topical and oral steroids for olfactory loss, and topical sodium citrate for qualitative olfactory symptoms. Early longitudinal data have also suggested that the increased severity of smell dysfunction and the female gender may predispose to long term olfactory loss. Perhaps equally as important as the therapeutic management of smell loss is the counseling provided and the understanding of the impacts of olfactory dysfunction on quality of life and mental health. In this symposium talk, we will review the literature and discuss the approach and management that an otolaryngologist might provide to patients suffering from acute and chronic COVID-19 related olfactory loss.