A China-based study, which tracked more than 1,000 COVID-19 recovered patients aged 60 and above for a year, found that their cognitive abilities declined and pushed them towards dementia .
Looking at changes in these patients after hospital discharge, it is reported that 21 percent of those with severe cases in this group experienced progressive cognitive decline, suggesting that COVID-19 lasted longer than previously thought. The walker can cause damage. The study said its findings imply “this pandemic could contribute significantly to the future world dementia burden.”
The study followed cured patients who were discharged from three COVID-19 designated hospitals in China between February and April 2020, and concluded that “severe COVID-19 is associated with a higher risk of cognitive impairment over 12 months.” was connected.” Severe cases more frequently experienced early-onset cognitive decline, late-onset cognitive decline, and progressive cognitive decline than non-severe cases and control individuals.
How was cognitive decline measured?
With no pre-infection cognitive status available to the participants, the researchers mapped each patient for the first six months after discharge, using family informants as a basis. They circulated the Chinese version of the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), which included 16 items that measured changes in memory and other cognitive domains on a scale of five, with 1 indicating “much better” and five “much better”. ” Is. Worse.” For the study, cognitive decline was defined as a mean item score of 3.5 or higher.
Cognitive changes in the second six-month period after discharge were assessed by changes in TICS-40 scores between six and 12 months. A reduction of three or more points was defined as clinically meaningful cognitive decline. Telephone interviews were conducted to assess cognition using the Chinese version of Telephone Interview for Cognitive Status-40 (TICS-40), consisting of 10 questions with a maximum score of 40.
Post-infection cognitive outcomes have been reported from COVID-19, but the long-term dynamic trajectory of cognitive changes in COVID-19 survivors remains unclear. (representative image)
The questions included as part of TICS-40 included counting backwards, learning word list, subtraction, delay in remembering words, last name of president or vice president etc. A score of 20 or less was considered indicative of mild cognitive impairment (MCI), and a score of 12 or less was considered an indicator of dementia.
Participants with stable cognition in both the first and second half of the follow-up were classified as having stable cognitive function. Participants with cognitive decline in the first half of follow-up but stable cognition in the second half were classified as having early-onset cognitive decline. Participants without cognitive decline in the first half of follow-up were classified as having late-onset cognitive decline with cognitive decline in the second half of follow-up. Participants with cognitive decline in both the first and second half of the follow-up were classified as having progressive cognitive decline.
interpreting findings
The study, published in the March edition of JAMA Neurology, said that at six and 12 months after the patient was discharged, COVID-19 survivors had lower TICS-40 scores than control individuals. Individuals with severe cases had a lower TICS-40 score, indicating worse cognition than those with non-severe cases and control individuals at six months and individuals with severe cases also had a lower TICS-40 score than non-severe cases and controls. had lower TICS-40 scores than individuals with in 12 months. Individuals with non-severe cases and individuals with controls differed in IQCODE scores, but not in TICS-40 scores, during follow-up.
The overall incidence of cognitive impairment among survivors 12 months after discharge was 12.45 percent. Among individuals with severe cases, 26 (10 percent) had dementia and 69 (26 percent) had mild cognitive impairment at six months, with the number rising to 39 (15 percent) for dementia and the remainder to 68 (26.15 percent). . ) for mild cognitive impairment at 12 months. The numbers were higher than in individuals with non-severe cases and controls, indicating that severe COVID-19 was associated with a higher risk of cognitive impairment at 12 months.
Survivors from non-severe COVID-19 and control individuals had comparable frequencies of dementia and mild cognitive impairment at six and 12 months. IQCODE scores (higher scores indicating larger longitudinal cognitive decline) at six months of follow-up were higher in individuals with severe cases than in those with non-severe cases, which in turn was higher than scores in control individuals. Specifically, 158 people with severe cases, 340 individuals with non-severe cases, and 92 control participants reported cognitive decline within the first six months.
Over the second six months, individuals with severe cases had a higher proportion of participants with cognitive decline than individuals with non-severe cases and control individuals. In addition, individuals with severe cases had a higher rate of cognitive decline compared to non-severe cases and control individuals. However, no difference was found in the speed of cognitive decline between individuals with non-severe cases and control individuals.
Compared to individuals with non-severe cases and controls, individuals with severe cases more often experienced early-onset cognitive decline, late-onset cognitive decline, and progressive cognitive decline, whereas individuals with non-severe cases tended to More often experienced early-onset cognitive decline. compared to control non-infected individuals.
Why is the study important and what have earlier studies found?
Post-infection cognitive outcomes have been reported from COVID-19, but the long-term dynamic trajectory of cognitive changes in COVID-19 survivors remains unclear.
While several studies have found that COVID-19 is associated with an increased risk of a diagnosis of dementia within six months after infection, most studies to date have been small-scale (such as 29 in Denmark in March 2021). study of patients) and not a one-year long follow-up period (a US-based retrospective study of 62,354 COVID-19 patients from November 2020, which looked at psychiatric disorders up to three months after contracting the infection) that gives us a longer period of time. May help to understand the impact of COVID-19 on cognitive decline and the resulting dementia burden. Most of the studies, including a UK-based study published in The Lancet in April 2021, had a follow-up period of six months.
Furthermore, the China-based study, by comparing different time periods, establishes the progressive cognitive changes observed in people who reported severe and non-severe COVID-19 infection. The latest study states that “Covid-19, especially severe COVID-19, may be associated with long-term cognitive impairment.”
Studies on the impact of COVID-19 on the brain are ongoing around the world. These include an Amsterdam-based study of 20 recovered individuals targeted, which began in February this year. The study is looking at neuroinflammation through PET scans, brain MRI and psychiatric evaluation to look at cognitive conditions and better understand the pathophysiological mechanisms of the virus.
Who were the participants of the study and who was not?
A total of 1,438 COVID-19 survivors (691 males and 747 females) with a mean age of 69 years and 438 uninfected control individuals with a mean age of 67 years completed the six- and 12-month visits.
Recovered patients or control participants were not included if they had self-reported or cognitive impairments diagnosed prior to COVID-19 infection, if they had a family history of dementia in first-degree relatives, if they had a There was a concomitant neurological disorder potentially affecting cognitive function. , or if they had severe heart, liver, kidney disease, or any type of tumor.