Uit een recent onderzoek onder leiding van onderzoekers van de University of California, Los Angeles, bleek dat mensen die lange tijd met COVID leven en anosmie (reukverlies) ervaren, andere hersenactiviteitspatronen vertonen in vergelijking met degenen die hun reukvermogen hebben herwonnen of die nooit COVID-19 gehad. De observationele studie maakte gebruik van magnetische resonantie beeldvormingsscans en vond verminderde hersenactiviteit en slechte connectiviteit tussen de orbitofrontale cortex en de orbitofrontale cortex bij mensen met SARS-CoV-2-anosmie. Deze verbinding werd niet aangetast bij degenen die hun reukvermogen herstelden na COVID. De bevindingen suggereren dat langdurig reukverlies door SARS-CoV-2 mogelijk verband houdt met een verandering in de hersenen waardoor geuren niet goed worden verwerkt, maar aangezien het klinisch omkeerbaar is, kan training in het reukvermogen de hersenen helpen dit gevoel terug te krijgen. . Uit de studie bleek ook dat de hersenen van mensen met langdurig reukverlies door COVID-19 dit kunnen compenseren door verbindingen met andere sensorische gebieden te versterken.
Uit een nieuwe studie onder leiding van onderzoekers van University College London (UCL) blijkt dat mensen die langdurig met COVID leven en reukverlies ervaren, verschillende activiteitspatronen vertonen in specifieke hersengebieden.
Het onderzoek gebruikte een MRI-scan om de hersenactiviteit te vergelijken van mensen met langdurige COVID die hun reukvermogen hadden verloren, degenen van wie de geur weer normaal werd na infectie met COVID, en mensen die nooit positief testten.[{” attribute=””>COVID-19.
Published in the journal eClinicalMedicine, the observational study found that people with long COVID smell loss had reduced brain activity and impaired communication between two parts of the brain that process important smell information: the orbitofrontal cortex and the pre-frontal cortex. This connection was not impaired in people who had regained their sense of smell after COVID.
The findings suggest smell loss, known as anosmia, caused by long COVID is linked to a change in the brain that stops smells from being processed properly. Because it’s clinically reversible, as shown in some subjects, it may be possible to retrain the brain to recover its sense of smell in people suffering the side effects of long COVID.
Dr. Jed Wingrove (UCL Department of Medicine) the lead author of the study, said: “Persistent loss of smell is just one way long COVID is still impacting people’s quality of life – smell is something we take for granted, but it guides us in lots of ways and is closely tied to our overall wellbeing. Our study gives reassurance that, for the majority of people whose sense of smell comes back, there are no permanent changes to brain activity.”
Joint senior author, Professor Claudia Wheeler-Kingshott (UCL Queen Square Institute of Neurology), said: “Our findings highlight the impact COVID-19 is having on brain function. They raise the intriguing possibility that olfactory training – that is, retraining the brain to process different scents – could help the brain to recover lost pathways, and help people with long COVID recover their sense of smell.”
Researchers say their findings also suggest that the brains of people with long COVID smell loss might be compensating for this lost sense by boosting connections with other sensory regions: their brains had increased activity between the parts of the brain that process smell and areas that process sight (the visual cortex).
“This tells us that the neurons that would normally process smell are still there, but they’re just working in a different way,” said Dr. Wingrove.
Professor Rachel Batterham (UCL Division of Medicine), also joint senior author of the study said: “This is the first study to our knowledge that looks at how brain activity changes in people with long COVID smell loss. It builds on the work we undertook during the first wave of the pandemic, which was one of the first to describe the link between COVID-19 infection with both loss of smell and taste.”
Reference: “Aberrant olfactory network functional connectivity in people with olfactory dysfunction following COVID-19 infection: an exploratory, observational study” by Jed Wingrove, Janine Makaronidis, Ferran Prados, Baris Kanber, Marios C. Yiannakas, Cormac Magee, Gloria Castellazzi, Louis Grandjean, Xavier Golay, Carmen Tur, Olga Ciccarelli, Egidio D’Angelo, Claudia A.M. Gandini Wheeler-Kingshott and Rachel L. Batterham, 2 March 2023, eClinicalMedicine.
DOI: 10.1016/j.eclinm.2023.101883
The study was funded by the National Institute for Health and Care Research (NIHR).
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