United States: Today, the latest research published by Imperial College London scholars in the New England Journal of Medicine unveils that patients recuperating from COVID-19’s transient symptoms encounter akin subtle impairments in cognition, such as memory lapses, cognitive lethargy, or difficulty concentrating—commonly known as “brain fog”—similar to those enduring prolonged symptoms.
The researchers devised a composite cognitive index spanning eight tasks by gathering self-assessments of cognitive faculties online from 112,964 adults involved in a study across England. They juxtaposed the outcomes of COVID-19 survivors against their non-infected counterparts, according to cidrap.umn.edu.
The authors of the study remarked, “Objective assessments of cognitive performance are largely scarce, and the duration of such impairments and the cognitive domains most susceptible remain ambiguous.”
Viral variant and infection intensity
Utilizing multiple regression analyses, it emerged that individuals recovering from COVID-19 within four weeks or beyond 12 weeks exhibited comparable minor deficits in cognitive function—or cognitive acuity—compared to uninfected participants (−0.23 and −0.24 standard deviations [SD], respectively). COVID-19 survivors showcased more pronounced deficits than their uninfected counterparts (−0.42 SD), as per cidrap.umn.edu.
A mild cognitive decline was observed post-infection with the original strain of the virus as well as with each subsequent variant, including B.1.1.529 (Omicron). In comparison to uninfected counterparts, even individuals who had fully recuperated from mild COVID-19 displayed cognitive deficits (a 3-point decline in IQ).
Individuals with persistent symptoms experienced the equivalent of a 6-point decrement in IQ, while those requiring intensive care unit (ICU) admission encountered a 9-point decrement.
Participants contracting COVID-19 during the prevalence of the original strain and the Alpha variant exhibited more substantial deficits than those infected with subsequent variants (e.g., −0.17 SD for B.1.1.7 versus B.1.1.529). Analogous trends were observed between hospitalized and non-hospitalized participants (e.g., ICU admission, −0.35 SD) and those enduring prolonged periods of acute illness and hospitalization.
The ramifications of protracted cognitive deficits and their clinical significance remain ambiguous and necessitate continual monitoring.
A comparison of the cohort with persistent unresolved symptoms to the uninfected cohort indicated that tasks involving memory, logical thinking, and executive function were associated with the most pronounced cognitive deficits (−0.33 to −0.20 SD). These tasks exhibited a tenuous correlation with recent symptoms, encompassing memory impairment and brain fog.
COVID-19 vaccination conferred a marginal cognitive advantage, while reinfection correlated with a nearly 2-point decline in IQ compared to no reinfection.
“The implications of protracted cognitive deficits and their clinical relevance remain enigmatic and necessitate continual surveillance,” the researchers affirmed, as per the reports by cidrap.umn.edu.
Understanding the functional repercussions
In a corresponding commentary, Ziyad Al-Aly, MD, of the Veterans Affairs St. Louis Health Care System, and Clifford Rosen, MD, of Tufts University, expressed apprehension regarding the study’s findings, emphasizing the need for further exploration.
“For instance, what are the functional ramifications of a 3-point decrement in IQ?” they queried. “The persistence or resolution of these cognitive deficits, along with predictors and trajectories of recovery, necessitate investigation.”
Al-Aly and Rosen underscored the millions worldwide grappling with COVID, many of whom confront or have faced cognitive challenges. “A deeper comprehension of the neurobiological underpinnings of cognitive dysfunction post-SARS-CoV-2 infection and optimal strategies for prevention and management is imperative for addressing the needs of affected individuals and safeguarding population cognitive well-being,” they concluded.