Experts say neurological effects of long COVID can last for more than a year.
The journal Annals of Clinical and Translational Neurology published a lengthy follow-up study on the neurological symptoms experienced by long COVID patients who were never hospitalized, which found that many commonly reportedly experiencing symptoms such as brain fog, numbness, tingling, headache, dizziness, blurred vision, tinnitus and fatigue.
The study, which was conducted by researchers at Northwestern University, followed-up on a short-term study published last spring that analyzed 100 patients with long COVID and found that 85% reported at least four lasting neurological problems at least six weeks after being infected with the virus.
The newer survey studied 52 of the original participants who were patients at Northwestern's long COVID clinic, Neuro COVID-19 Clinic, during a span of up to 18 months.
Three-quarters of the group was female and the median age was 43, with nearly 80% having been vaccinated and all experiencing mild COVID symptoms that didn't lead to hospitalization.
The study found that neurological symptoms typically occurred at an average of 15 months after infection, with most patients reporting improvements to their cognitive function and fatigue, however, symptoms continuing to linger and play a factor in their quality of life.
“A lot of those patients still have difficulties with their cognition that prevent them from working like they used to,” said, Dr. Igor Koralnik, chief of neuro-infectious diseases and global neurology at Northwestern Medicine, who oversees the Neuro COVID-19 Clinic and served as the co-leader of the study.
The study also found that other symptoms, including heart rate, blood pressure variation and gastrointestinal issues also increased over time, though loss of taste and smell -- long identified as common COVID symptoms -- typically improved.
Researchers reported COVID vaccination didn't alleviate symptoms or make long COVID worse among the individuals studied.