Cognitive decline in people with mild dementia during COVID-19 pandemic

Background: restrictive measures adopted to prevent the spread of COVID-19 infection resulted in pre-existing neuropsychiatric symptoms and cognitive worsening in people with MCI and dementia in the first year of pandemic. Aim: to explore cognitive progression in mild dementia in two years of Covid-19 pandemic; to investigate cognitive differences and daily abilities functioning according to etiological diagnosis of dementia. Methods: MMSE and MoCA scores were collected in patients (n=264) with MCI and mild dementia followed longitudinally by the Memory Clinic at University Hospital of Padua. Patients with baseline MMSE ≥24 or equivalent MoCA≥18, three consecutive visits (V1-V3) over 3 years were retained (N=155) and distributed in 3 clusters according to the last visit time point: 1) pre-pandemic (last visit before February 2020), 2) 1st year post-pandemic (last visit before May 2021); 3) 2-years post-pandemic (last visit before June 2022). The cognitive performance change (%) and the measure of decline (MMSE points lost at V3 compared to V1) were analyzed. Individual slopes were extracted with a linear regression model to describe the speed of cognitive progression in a selective sample of 66 AD and 32 DLB. Results: Cognitive performance in MCI and mild dementia declined at two years post-pandemic compared to pre-pandemic (-17% VS -6%). MMSE point loss doubled in the 1st year-post (-4.50; p=0.036) and remained stable at 2 years-post (-4.48; p=0.02) considering the whole sample. In only DLB and AD patients (DLB n=32; AD n=66) MMSE points were -5 after 1 year (V3-V1 p=0.016) and -8 after 2 years (p=0.00), while ADLs and IADLs deterioration were similarly impaired (p<0.05) in the first and second year after pandemic compared to baseline. The slope of cognitive impairment was significantly steeper in DLB patients than in AD (p=0.035) compared to pre-pandemic. Discussion: The accelerative effects of cognitive decline with the Covid-19 pandemic were sustained over time. As DLB patients may be the most sensitive category among dementia to environmental effects with the pandemic, to work on a multi-center set-up become essential. Conclusion: the progression of cognitive and daily abilities decline in patients with MCI and mild dementia was significantly faster during the first year of pandemic before stabilizing over time. As a long-term effect, DLB patients declined faster than AD patients with the Covid-19 pandemic.