Severe COVID-19 may cause 10-point IQ drop, 20-year brain agingCognitive impairment from severe COVID-19 is equivalent to losing 10 IQ points or 20 years of aging, and any recovery is slow at best, suggests a small study published late last week in eClinicalMedicine.A team led by Imperial College London and University of Cambridge researchers tested 46 COVID-19 patients admitted to a single hospital 6 to 10 months earlier, from Mar 10 to Jul 31, 2020, and matched controls.
Sixteen of the COVID-19 patients (34.8%) had required mechanical ventilation.Participants underwent computerized cognitive assessment at an average follow-up of 6 months after their initial infection.
The researchers transformed scores from patients and controls into standard deviations (SDs) from expected scores for participants' age and demographic characteristics and calculated global accuracy and response time composites.The team used linear modeling to predict composite score deficits from illness severity, mental health status at assessment, and time since hospitalization compared with scores from normal age-related cognitive decline and early-stage dementia.Relative to controls, COVID-19 survivors were both less accurate (G_SScore, -0.53 SDs) and slower in responding (G_RT, +0.89 SDs).
COVID-19 severity, rather than mental health status, significantly predicted deviation from expected scores.The tasks most affected by COVID-19 dealt with higher cognition and processing speed, which was qualitatively different from those of normal aging and dementia but comparable to those of advancing from the age of 50 to the age of 70.