Studies investigate impact of COVID-19 pandemic on memory and thinking changes

COVID-test-1

By Quang Tran | Monday 01 August 2022

  • Researchers present findings at world’s largest dementia research conference
  • Persistent loss of smell after COVID-19 linked to memory and thinking changes associated with diseases like Alzheimer’s
  • Links between life changes during pandemic, and memory, investigated
  • Intensive care admissions (not necessarily COVID-19) associated with dementia risk

Research presented today (Sunday 31 July) at the 2022 Alzheimer’s Association International Conference (AAIC) in San Diego look at the impact of the COVID-19 pandemic on memory and thinking. These headlines are revealed across three presentations.

What we know already

In previous research, separate to these studies, scientists suggested that almost a third of older adults infected with COVID-19 in 2020 developed at least one new condition that required medical attention in the months after initial infection. Scientists have also linked COVID-19 and highlighted a link between cases of COVID-19 that include neurological symptoms, with biological markers of Alzheimer’s disease.

Our expert comment

Speaking about these new findings, Dr Sara Imarisio, Head of Research from Alzheimer’s Research UK, said:
“With one in three people born today expected to develop dementia in their lifetime, there is a pressing need to identify risk factors for the condition as well as developing treatments for people with the disease.

“Relatively little is known about the long-term impacts of COVID-19 on brain health, and Alzheimer’s Research UK remains committed to monitoring the emerging evidence in this field. If anyone is worried about their memory and thinking, or long-term effects of COVID-19, they should speak to their doctor.”

COVID-19 induced loss of smell linked with memory and thinking impairment post infection

In this study, researchers in the US followed 766 volunteers over the age of 60, for three to six months following infection with COVID-19.

They found memory impairment in two thirds of infected patients, with half of patients having severe impairment.

The extent to which participants’ sense of smell was affected predicted whether people had poorer long-term memory and thinking three to six months post infection, but the severity of COVID infection did not.

Dr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:
“Previous research, before the COVID-19 pandemic, has highlighted a potential link between changes to people’s sense of smell and dementia risk, and some researchers have explored using smell tests as a way to identify people in the very earliest stages of diseases like Alzheimer’s.

“Studies like these are good for highlighting links, but we need research to explore the mechanisms between COVID-19 and long-term memory and thinking changes. This research didn’t look at whether people went on to develop dementia and, as the diseases like Alzheimer’s develop in the brain over many years, it will require longer follow-up to reveal whether these changes are linked to dementia.

“We are just beginning to develop an understanding of the long-term consequence of COVID-19 infections, and it will take much larger studies to understand if there are specific factors that could be relevant to dementia risk.

“Changes to our sense of smell are not necessarily an indication of future memory problems or a consequence of COVID-19. Anyone with concerns should speak to their GP.”

Life changes associated in older adults during COVID-19 pandemic linked to memory changes

Researchers asked Spanish speaking adults between the ages of 55-95 living in Latin America to complete an online survey between May and December 2020.

Participants self-reported their negative and positive life-changes associated with the pandemic.

Negative changes included economic difficulties and limited social activities, while positive changes included more quality time with others, and an increased time spent in nature.

Researchers assessed volunteers’ memory and thinking skills using a questionnaire. They found women not in work, from lower socioeconomic backgrounds, were most likely to develop cognitive problems during this period.

The findings also showed negative life changes were associated with more cognitive problems, but this link was more limited in those who reported at least one positive change in the course of the pandemic.

Dr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:
“A person’s risk of dementia is a complex mix of age, genetics, and lifestyle factors. While this research didn’t look at whether people went on to develop dementia, it suggests that positive lifestyle changes during the pandemic may help stave off memory and thinking problems.

“Staying active and socially engaged are important ways to keep our brains healthy, and this was more difficult for everyone during the pandemic. The COVID-19 related lockdowns were unprecedented in recent history and this research highlights the need to study the impacts of the huge changes in lifestyle brought about by the pandemic. Dementia researchers trying to make sense of the long-term health impact of COVID-19 will need to account for the effect of the virus itself, alongside the broader social, financial and psychological disruption that has accompanied it.

“There are lifestyle changes we can all adopt to boost our brain health and reduce the risk of dementia. As well as staying physically, socially and mentally active, the best evidence also suggests that eating healthily, maintaining a healthy weight, controlling high blood pressure and cholesterol levels, not smoking and only drinking within NHS guidelines, are all important.”

Being in intensive care linked with increased risk of dementia in older adults

Researchers found that older adults who are admitted to intensive care units (ICU) are twice as likely to have dementia compared to those not admitted to ICU.

Using five different volunteer groups, researchers looked at 3,822 people with a mean age of 77. They followed them for an average of nearly eight years.

Over 50% (1.992) volunteers went to ICU, and those who did were more likely to also have Alzheimer’s disease and dementia.

Dr Sara Imarisio, Head of Research, said:
“Age is the biggest risk factor for dementia, and this research is an important reminder that many people living with dementia could also be living with a range of health problems. This study didn’t attempt to account for COVID-19 on the impact of admissions to intensive care unit (ICU) hospitalisations. While admissions to ICU increased rapidly during the COVID-19 pandemic, particularly in older people, it is important that future studies investigate this specifically and we should be wary of extrapolating these findings.

“This research should in no way deter people from seeking any treatment they need. Given one quarter of hospital beds in the UK are occupied by someone with dementia, it’s important to understand the impact of that stay on an individual and develop approaches to limit any negative effect on their long-term health.”

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Quang Tran