COVID-19-related neurological symptoms, such as memory and concentration issues, can last half a year or more in some patients, according to a small study.

Among 27 patients who had such symptoms weeks after recovering from COVID-19, only nine reported complete resolution six months after joining the study, researchers reported  in Annals of Clinical and Translational Neurology, Reuters reports. The remaining 18 still had nervous system abnormalities - most often, impaired memory and trouble concentrating - although generally the symptoms had become less severe.

Early in the neuro-PASC syndrome, fatigue and headache are the most commonly reported symptoms. At 6 months, memory impairment and decreased concentration were most prominent. Only one-third of participants had completed resolution of neuro-PASC at 6 months, although persistent symptoms trended toward improvement at follow-up", concludes the scientific team.
 

"Some of these participants are high-level professionals who we'd expect to score above average on cognitive assessments, but months after having COVID-19, they're still scoring abnormally," Dr. Jennifer Graves of UC San Diego Health said in a statement. Most study participants had mild or moderate COVID-19. Graves said she suspects the neurological symptoms are caused by an immune response to the virus.

In four patients, her team saw a previously unidentified set of symptoms that included cognitive deficits, tremor and difficulty balancing. "These are folks who had no neurological problems before COVID-19, and now they have an incoordination of their body and possible incoordination of their thoughts," said Graves. "We did not expect this."