At the end of 2019 a new pandemic was declared due to the worldwide major health problem caused by the coronavirus disease 2019 (COVID-19), produced by a new type of coronavirus (SARS-CoV-2). Initially, COVID-19 was considered as a respiratory disease associated with pneumonia symptoms. However, neurologic conditions caused by the disease were described in several studies. Indeed, different patterns have been detected in electroencephalographic (EEG) signals of COVID-19 patients with neurological symptoms caused by the disease. Some of these patterns were found in the frontal areas of the brain. This fact reinforced the theory that SARS-CoV-2 enters the central nervous system (CNS) by the olfactory structures and spreads through the frontal lobes. This hypothesis concurs with the significant percentage of patients suffering anosmia at the early stages of the infection.
The causes of the olfactory dysfunction are yet unknown. Even though in most cases the symptoms spontaneously resolve within weeks, there are also patients that remain olfactory impaired after a year. Due to the lack of evidence of the existent anosmia or hyposmia treatments, this project explores the use of tDCS (transcraneal Direct Current Stimulation) as a potential treatment for the olfactory disfunction.