Tasting is an important part of the quality of life. Kathrin Ohla examines what happens in the brain during this process and, currently, how COVID-19 affects the sense of taste
A worldwide online survey confirms that an infection with the new coronavirus can impair the senses of taste and smell in a characteristic way.
People who cannot smell or taste anything suffer considerably. “Olfactory and gustatory disorders influence eating behaviour, diminish the ability to enjoy food and have an effect on social life: for example, those affected fear that they will not perceive their own body odour or not be able to recognise dangers such as smoke emission in time,” says psychologist Dr. Kathrin Ohla from the Institute of Neuroscience and Medicine (INM-3).
Picture above: Tasting is an important part of the quality of life. Kathrin Ohla examines what happens in the brain during this process and, currently, how COVID-19 affects the sense of taste
Impairment of the senses of smell and taste is considered a symptom of COVID-19. To find out more about this, the Global Consortium for Chemosensory Research (GCCR) – where Ohla is a member of the steering committee – launched a worldwide online survey already at the beginning of April. All adults who suffer, or have suffered in the last two weeks, from a respiratory disease such as COVID-19, flu or cold are eligible to participate. Even the first analyses of the current survey provide valuable insights.
Firstly, they confirm that infection with the SARS-CoV-2 virus can lead to a complete loss of the sense of smell and also the sense of taste. “These olfactory and gustatory disorders, however, are different from those that occur with colds or flu,” says Ohla. For example, COVID-19 impairments are hardly associated with a blocked nose – unlike in cases of cold or influenza. In addition, respondents infected with SARS-CoV-2 only rarely report phenomena such as smelling things that are not there or smells being more unpleasant than before the illness. Finally, there is evidence that the impairment of smell and taste in COVID-19 already occurs at the very beginning of the disease, whereas in influenza and colds they often do so when the other symptoms are already on the wane. However, the study does not show how frequently the symptoms occur. The researcher suspects that patients with olfactory and gustatory disorders are more likely to participate in the survey than those without such symptoms because of their personal involvement.
The first results are based on the statements of several thousand participants. By now, the researchers are already working on further analyses based on tens of thousands of participants and on a test for use at home, with which those affected can continuously test their senses of smell and taste. “In this way, we want to find out how long the olfactory and gustatory disorders last and how often permanent impairment occurs,” says Ohla. According to the head of the Cognitive Neurophysiology research group, such information is necessary in order to be able to properly advise and treat those affected.
The study on the web: gcchemosensr.org/surveys/de
Photo: Forschungszentrum Jülich/Sascha Kreklau