In a recent study published in the journal Alzheimer’s Research & Therapy, researchers investigated whether the coronavirus disease 2019 (COVID-19)-associated lockdown measures had an impact on the cognitive decline rate in a clinical population comprising dementia, subjective cognitive decline (SCD), and mild cognitive impairment (MCI) patients.

Study: Steeper memory decline after COVID-19 lockdown measures. Image Credit: pikselstock/Shutterstock.com

Background

The COVID-19 pandemic-associated lockdown measures led to the disruption of various informal and formal support systems for patients with dementia and cognitive impairments.

The downgrading of home care and health care appointments and the decrease in contact with informal support systems involving loved ones had a major impact on the level of care and well-being of patients.

Cognitive impairments in most cases of MCI and some cases of SCD are associated with an underlying neurodegenerative disease. Structured situations in daily life help in the management of and often slow the progression of cognitive impairments in these diseases.

The social restrictions and lockdowns imposed as disease mitigation measures during the COVID-19 pandemic could have disrupted this structure and increased the rate of cognitive decline in patients with neurodegenerative diseases.

About the study

In the present study, the researchers conducted a longitudinal analysis of the Amsterdam Dementia Cohort.

They examined two cohorts of patients — one cohort comprising patients who had a visit to the memory clinic six months to a week before the COVID-19 lockdown was announced in the Netherlands and a second visit after the lockdown, approximately a year later, and the other cohort comprising patients who visited the memory clinic during 2016 and 2017 and had a second visit one year later.

The lockdown cohort included patients diagnosed with dementia with Lewy Bodies, Alzheimer’s disease, MCI, SCD, primary progressive aphasia, or frontotemporal dementia. The historical cohort included matched patients with the same diagnoses as the lockdown cohort.

All the participants had undergone a baseline diagnostic screening consisting of neurological, neuropsychological, and physical evaluation, laboratory tests, magnetic resonance imaging, and analysis of cerebrospinal fluid.

The cognitive outcomes were assessed using the Trail Making Test, which evaluates speed and attention as well as executive functioning, the Mini-Mental State Examination, and the Rey Auditory Verbal Learning Test (RAVLT), which evaluates language and memory.

Results

The results reported that patients who visited the memory clinic, especially those in pre-dementia stages exhibited a faster cognitive decline during the COVID-19 pandemic-associated lockdown based on the RAVLT scores for immediate and delayed recall tests.

The findings indicated that faster cognitive decline during the COVID-19-associated lockdowns was not observed in patients with dementia but was seen in patients with MCI and SCD.

Other studies have reported that not only patients with neurodegenerative disorders but also individuals with no cognitive impairments have experienced cognitive impairments or failures during the COVID-19-associated lockdowns and restrictions.

However, these studies were based on surveys with self-reported results. The findings from the present study were based on standardized tests to analyze neuropsychological conditions and had a matched historical cohort for comparison.

The stress associated with the COVID-19 pandemic, combined with the loss of structure in daily activities, is thought to accelerate the progress of the underlying neurodegenerative conditions such as Alzheimer’s disease in patients with MCI.

Additionally, the sudden decrease in social activity could also have exacerbated the cognitive decline in patients in pre-dementia stages.

The researchers believe that there are various potential explanations for the absence of an observed impact of the COVID-19-associated lockdown on dementia patients.

The decline in cognitive scores might not be apparent in dementia patients as their cognitive function at baseline was already quite low.

Additionally, the progression of cognitive decline in patients with dementia could manifest as behavioral symptoms rather than cognitive scores, such as apathy, aggression, and changes in sleeping patterns.

The results could also be explained by the absence of follow-up visits at the memory clinic by dementia patients due to disease progression leading to institutionalization or death.

Conclusions

Overall, the results indicated that the lockdowns and social distancing measures implemented during the COVID-19 pandemic increased the rate of cognitive decline in patients in pre-dementia stages such as those with MCI or SCD.

The disruption of structure in daily activities and the decrease in social interactions due to disease mitigation measures during the pandemic, combined with the stress and anxiety of COVID-19 could have exacerbated underlying neurodegenerative diseases, leading to faster cognitive decline.

Written by

Dr. Chinta Sidharthan

Chinta Sidharthan is a writer based in Bangalore, India. Her academic background is in evolutionary biology and genetics, and she has extensive experience in scientific research, teaching, science writing, and herpetology. Chinta holds a Ph.D. in evolutionary biology from the Indian Institute of Science and is passionate about science education, writing, animals, wildlife, and conservation. For her doctoral research, she explored the origins and diversification of blindsnakes in India, as a part of which she did extensive fieldwork in the jungles of southern India. She has received the Canadian Governor General’s bronze medal and Bangalore University gold medal for academic excellence and published her research in high-impact journals.