Is self-report enough?
While there is currently “nothing objective doctors can hang their hats on to say ‘you do’ or ‘you don’t’ have cognitive changes related to COVID,” using the HAND criteria is “not particularly helpful,” said Dr. Hellmuth. “Comparing an individual to a population-based norm in this case is really nuanced, and we shouldn’t rely on this solely to determine whether they do, or don’t, have cognitive changes.”
Perhaps self-reports in this case are “enough” said Dr. Hellmuth. “People know their brains better than anyone else, better than any doctor will.”
A total of 13 in the cognitive PASC group and 4 in the control group consented to a lumbar puncture. Cognitive PASC participants were older than controls (median of 47 vs. 28 years; P = .03) with no other between-group differences.
Overall, 77% of participants with cognitive PASC had a CSF abnormality, compared with 0% of cognitive controls (P = .01). CSF abnormalities included elevated protein levels with no other explainable cause in 2 of the 13 subjects with PASC, which Dr. Hellmuth said is typically a marker of inflammation.
Researchers also noted abnormal oligoclonal banding, a collection of antibodies, in the blood or brain fluid. These were identified in 69% of participants with cognitive PASC, compared with 0% of cognitive controls (P = .03).
“When we find this pattern in both blood and brain, it suggests a systemic inflammatory disorder,” although “we have no idea what these antibodies are targeting,” said Dr. Hellmuth.
The study represents “the very beginning stages” of PASC becoming a medical diagnosis “where doctors know what to call it, how to treat it, and how to do blood and cerebrospinal fluid tests to diagnose it,” said Dr. Hellmuth.
She hopes PASC will receive medical legitimacy just as TBI has. In years past, a player was hit on the head or had their “bell rung,” simply returned to the field. “Now that we understand the science, we call it a mild TBI or concussion, and we have a very different medical approach to it.”
A limitation of the study was the small sample size, which may hinder the results’ validity. In addition, the study demographics may not reflect the broader population of those impacted by PASC.
‘A first substantial step’
Commenting on the research, William Schaffner, MD, professor, division of infectious diseases, Vanderbilt University Medical Center, Nashville, Tenn., said the new results represent “a first substantial step on the road to trying to find out what’s going on” with COVID patients dealing with cognitive issues.
Dr. Schaffner noted that elevated protein levels, identified in some study subjects, “is usually a consequence of previous inflammation” and is “a very interesting” finding. “In people who are otherwise normal, if you do a lumbar puncture, you don’t find elevated proteins.”
However, he noted the “diversity of results” from CSF examinations. “A single pattern does not leap out.”
What the researchers are observing “is not just a phenomenon of the mind or just something psychological,” said Dr. Schaffner. “Something physical is going on here.”
The study was funded by grants from the National Institute of Mental Health and the National Institute of Neurological Disorders and Stroke. Dr. Hellmuth received grant support from the National Institutes of Health/NIMH supporting this work and personal fees for medical-legal consultation outside of the submitted work. Dr. Schaffner has disclosed not relevant financial relationships.
A version of this article first appeared on Medscape.com.