Cochrane COVID-19 Study Register
Study record
NCT05133596First Published: 2021 Nov 24Updated Date: 2021 Nov 24

Study of the Evolution of Olfactory Disorders in Patients With Persistent Loss of Smell Following COVID-19

  1. Study Type
  2. Interventional
  1. Study Aim
  2. Other
  3. Epidemiology
  1. Study Design
  2. Single Arm/Controlled Before After
  1. Intervention Assignment
  2. Not Applicable
Reference record

Study of the Evolution of Olfactory Disorders in Patients With Persistent Loss of Smell Following COVID-19

NCT05133596
Trial registry record
No Results
The COVID-19 pandemic is a novel medical challenge, particularly because of the systemic nature of this disease. Indeed, COVID-19 affects several organs and systems at once. The brain is affected in several ways: direct infection of nerve cells by SARS-CoV-2, inflammation of the central nervous system, severe systemic inflammation damaging nerve cells, global cerebral ischaemia related to respiratory failure, thromboembolic events related to increased intravascular coagulation and severe psychological stress. As a result, COVID-19 sometimes manifests as neurological and neuropsychiatric symptoms such as dizziness, sleep disturbances, cognitive deficits, delirium, or severe depression. Sudden loss of smell is a common symptom associated with COVID-19 and SARS-CoV-2 infection of neurons in the olfactory system has been reported in both hamsters and humans. The vast majority of COVID-19 patients recover their olfactory function within a few weeks. However, a significant minority of infected individuals (1 in 5 cases) still suffers from olfactory disorders (anosmia, hyposmia and/or parosmia) several months after the primary infection. These olfactory disorders are frequently associated with depressive behaviour and cognitive complaints. In PET scans, it is even possible to correlate this cognitive dysfunction with hypometabolism of certain brain regions, including the olfactory gyrus. This project proposes, during one year, to evaluate and follow the evolution of the olfactory capacities of patients suffering from persistent smell disorder since one year (+/- 4 months) following COVID-19. We propose to study the link between viral persistence in the olfactory sensory organ, chronic inflammation, and central damage to the olfactory system. The follow-up of the evolution of olfactory and neurocognitive capacities, in an integrative way by means of molecular, physiological and behavioural approaches, will inform us on the specificities of "COVID-long" and on the level of peripheral and/or central damage of the olfactory system