An increasing number of patients under age 60 report persistent inattention, impaired executive function, and memory difficulties following COVID-19—a constellation of symptoms described as “brain fog,” according to recent study published in Case Reports in Neurological Medicine.

The analysis involving patients at the Duke Memory Disorders Clinic (MDC) was designed to help specialists better understand the neurological severity of long COVID, says Andy Liu, MD, MS, a Duke behavioral neurologist, and senior author. Thomas J. Farrer, PhD, a Duke Neurology faculty member, was a co-author.

The MDC study assessed patients’ long-term neuropsychological symptoms, neuropsychological test results, and brain MRI findings after infection with SARS-CoV-2 in a cohort of patients under the age of 60. Thankfully, the symptoms usually diminished over time, the authors reported.

However, if symptoms persist for three to six months following the acute phase of COVID-19, Liu recommends that patients be referred for neurological assessment and treatment.

When COVID-19’s acute symptoms end, patients often notice changes as they return to work or re-start daily routines. “They discover that normal processes are now more difficult,” Liu says. “That’s the most significant characteristic. Among patients, the biggest concern is when these symptoms will resolve. And our most important message to patients is that they will improve,” Liu adds. “That’s the clinical trajectory we emphasize.”

Researchers hypothesize that the brain fog conditions following long COVID are related to white matter inflammation in the brain. “Our analysis shows that the inflammation occurs within the white matter affecting the frontal lobes,” Liu says. “This would have an effect on executive function and concentration.”

Long COVID is defined as a condition lasting three months or longer, but during that time, patients experience acute symptoms and are preoccupied with recovery, Liu says. Researchers note that most patients with long COVID-19 do not receive hospital care; as a result, analysis of post-COVID-19 neurological conditions has been limited.

“Long-COVID occurs among 5 to 50 percent of patients who have the conditions,” Liu says. “This is a very novel area of active study right now.”

As of March 2022, more than 78 million cases of COVID-19 have been reported in the United States resulting in 900,000 deaths related to the condition. Beyond the direct effects of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) involving the lung parenchyma, the study authors report that many post-viral complications within the central nervous system remain unknown. The study authors emphasize the need for longitudinal evaluations to assess long-term neurophysiological results.

The Duke Memory Disorders Clinic (MDC) team monitors and treats many neurodegenerative conditions, including Alzheimer's disease, vascular problems, and other neurological disorders. The MDC team offers comprehensive evaluations as well as outpatient care.

Neurologists, neuropsychologists, geriatricians, geriatric psychiatrists, nurse practitioners, social workers, and clinical coordinators work with the patient and family to offer medical, behavioral, and caregiver support.

After a thorough diagnostic evaluation, the MDC staff meets with family members to discuss the patient's diagnosis, care, and treatment. The staff also provides treatment recommendations to the primary care provider to help with care management closer to the patient.