A patient with suspected long covid gets physical therapy on March 7 at TIRR Memorial Hermann Outpatient Rehabilitation facility in Houston. (Mark Felix for The Washington Post)

The Feb. 9 editorial “Long covid continues to haunt millions of people” underscored the prevalence and extent of the ongoing problems related to covid-19 infection and identified the potential effect that covid symptoms might contribute to memory impairment, “brain fog,” chronic fatigue and other neurological symptoms.

There remains a considerable gap in our understanding of how covid infection produces long-term damage to the nervous system. Most autopsy studies have not shown the virus crossing the blood-brain barrier, but fragments of viral RNA can pass through and induce an immune reaction that can contribute to brain tissue damage. This damage can severely impact a patient’s quality of life and productivity and present ongoing challenges to our health-care system.

In a recently published series from George Washington University Neurology Cognitive Disorders Clinic, 24 post-covid-infected patients with mild respiratory symptoms, age 60 or younger and who were experiencing long-term memory impairment, brain fog or other neurological symptoms were studied using advanced MRI techniques. These measured in three dimensions the volumes of key brain structures important for memory function. Results were compared with a normative database drawn from age- and sex-matched healthy controls. The findings documented a statistically significant loss of volume limited to cortical gray matter whose depletion could be the source of patient’s impairment.

There is a critical need for follow-up research by the government and health-supporting philanthropic organizations. This could involve larger investigations of the consequences of covid infection and determine the extent to which recovery of neurological function and restoration of depleted volumes is possible. Moreover, serial studies could assist in identifying potential neuroprotective therapies to mitigate the adverse effects of this devastating infection and limit its serious long-term personal and economic consequences.

Ted L. Rothstein, Washington

The writer is a professor of neurology at George Washington University.