A medic watches a Covid-19 patient hospitalized at the Covid-19 Intensive Care Unit of the Pulmonology Department of the Hospital Ruzinov in Bratislava, Slovakia, on February 24, 2021. (AFP via Getty Images)

A study conducted by King's College London suggests that the symptom known as "brain fog", which is associated with long Covid, could be comparable to aging ten years. The researchers investigated the impact of Covid-19 on memory and found that cognitive impairment was most severe in individuals who had tested positive and experienced symptoms for more than three months.

The study, published in a clinical journal by The Lancet, revealed that the cognitive symptoms persisted for almost two years after the initial infection. Some individuals who had been infected with Covid-19 still did not feel fully recovered, and their lives continued to be affected by the long-term effects of the virus.

According to the 2023 government census, an estimated two million people in the UK were experiencing self-reported long Covid, which means their symptoms had been continuing for more than four weeks since their infection. The most commonly reported symptoms included fatigue, difficulty concentrating, shortness of breath, and muscle aches.

The study involved over 5,100 participants from the Covid Symptom Study Biobank, recruited through a smartphone app. Researchers used 12 cognitive tests to measure speed and accuracy and examined working memory, attention, reasoning, and motor controls during two periods in 2021 and 2022.

In the first cohort of 3,335 participants in July and August 2021, individuals with positive Covid-19 infections showed lower cognitive scores, with the greatest deficits observed in those with symptoms lasting for more than 12 weeks. The study said the deficits were comparable to the effect of “an increase in age of approximately 10 years, or exhibiting mild or moderate symptoms of psychological distress”. However, the impact was smaller compared to other factors like lower educational attainment or high levels of fatigue.

In the second round of testing, which included 1,786 participants in April and June 2022 (nine months after the first), researchers found no significant improvement in cognitive scores.

The study also noted that individuals who reported full recovery from coronavirus did not experience cognitive impairment, even among those who had symptoms lasting for more than three months. This was seen as encouraging news by the study's lead author, Dr. Nathan Cheetham.

In conclusion, the study highlights the need to monitor individuals whose brain function is most affected by Covid-19 and provide support for their recovery. Further research is needed to understand why some individuals experience prolonged cognitive symptoms and to find ways to help them.

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