Effect of COVID-19 Related Social Isolation on Cognitive Decline in Neurocognitive Disorder Patients: A Systematic...

The COVID-19 lockdown placed individuals at significant risk of social isolation. Particularly, older people were more vulnerable to the deleterious effects on mental and physical health caused by the COVID-19 pandemic quarantine, in which social confinement was associated with aggravated cognitive function among older adults. Correspondingly, it concerns the repercussions of the lockdown on the cognitive function of patients with dementia or Mild Cognitive Impairment (MCI) during the pandemic. This study aimed to assess the hypothesis that COVID-19 might cause cognitive decline in dementia patients due to social isolation by assessing changes in Mini-Mental State Examination (MMSE) scores between the pre and post-pandemic era. We systematically searched PubMed, Embase, and Cochrane Library for eligible studies from inception to April 2023. We included studies reporting the MMSE in patients with dementia or MCI one year prior to the beginning of the COVID-19 pandemic and one year after the lockdown. Standardized mean differences (SMD) with 95% confidence intervals (CI) were pooled with a random-effects model. Among 4,160 studies, twelve were included, comprising 4,096 patients with dementia or MCI. Patients with dementia exhibited significant MMSE decline compared to pre-pandemic levels (SMD = 0.341, P < 0.001). Similarly, MCI patients demonstrated an MMSE decline during lockdown (SMD = 0.315, P = 0.015). Sub-analyses of dementia types also indicated cognitive decline during lockdown, and a 12-month follow-up revealed an MMSE decline among dementia patients. During the COVID-19 lockdown, there was an overall decline in MMSE scores amongst those with dementia or MCI when compared to pre-pandemic parameters.