Objective: The risk of rapid cognitive decline in Alzheimer's disease (AD) during the coronavirus disease 2019 (COVID-19) pandemic has been recognized. The purpose of this study was to investigate the cognitive decline in such patients during the COVID-19 pandemic by evaluating changes in their cognitive measure parameters before and after the pandemic.
Methods: This was a retrospective cohort study conducted in AD patients during their first visit and one-year regular follow-up for testing cognitive function at the Geriatric Psychiatry Clinic of Seoul St. Mary's Hospital. Changes in the Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), and Sum of Box for CDR (CDR-SB) scores were investigated. A time series analysis was performed to determine whether there was a significant difference in the MMSE, CDR, and CDR-SB scores of AD patients in pre- and post-COVID-19 periods.
Results: Overall, 130 AD patients aged 60 to 93 years were assessed. Their baseline mean MMSE score was 22.30 which had decreased to 21.08 at the one-year follow-up. Before November 2019, the average CDR differences for one year was 0.06, but after November 2019, it increased to 0.36 (p<0.001). Before November 2019, the average of the CDR-SB change value for one year was 1.69, but after November 2019, it increased to 3.00 (p<0.001). The difference in MMSE values for one year was not statistically significant. The time series analysis revealed a significant increase in the CDR and CDR-SB scores by approximately 0.47 (p=0.005) and 2.39 (p=0.002), before and after November 1, 2019, respectively.
Conclusion: This study revealed that the COVID-19 pandemic and social distancing worsen cognitive function in AD patients rapidly. Exposure to the COVID-19 pandemic and social distancing for at least seven months worsen cognitive decline significantly. Therefore, in order to minimize the adverse effects of the cognitive decline in these patients, the period of social distancing should be minimized.
Keywords: Alzheimer’s disease; COVID-19; Cognition; Dementia; Social distancing.