Persistent loss of smell due to COVID-19 may better predict long-term cognitive and functional impairment

New insights into factors that may predict, increase or protect the impact of COVID-19 and the pandemic on memory and thinking skills are revealed by multiple studies reported today at the Alzheimer’s Association International Conference.® (AAIC®2022 in San Diego approx.

Among the key findings reported at AAIC 2022:

  • A group from Argentina has found that persistent loss of smell may be a better predictor of long-term cognitive and functional impairment than the severity of the initial COVID-19 illness.
  • Hospitalization in the intensive care unit has been associated with a doubling of the risk of dementia in older adults, according to a study by the Alzheimer’s Disease Center in Chicago.
  • During the epidemic, female gender, not worker, and lower socioeconomic status were associated with more cognitive symptoms in a large study population drawn from nine Latin American countries.
  • In the same Latin American population, experiencing positive life change during the pandemic (such as spending more time with friends and family or spending more time in nature) reduced the negative impact of the pandemic on memory and thinking skills.

said Heather M. Snyder, Ph.D., vice president of medical and scientific relations at the Alzheimer’s Association. “Because this virus is likely to be with us for a long time, identifying risk factors and protective factors for cognitive symptoms can help with treatment and prevention of ‘long-term COVID’ moving forward.”

Persistent loss of smell predicts cognitive impairment better than severity of COVID-19
Researchers in Argentina working with the Alzheimer’s Association Consortium on Chronic Neuropsychiatric Consequences of SARS-CoV-2 infection followed 766 adults aged 55 to 95 who had been exposed to COVID-19 for one year, and performed a series of regular physical, cognitive and neuropsychological exams. Of the study group, 88.4% became infected and 11.6% of the control group.

Clinical evaluation demonstrated functional memory impairment in two thirds of affected participants, which was severe in half. Another set of cognitive tests identified three groups with low performance:

  • Only 11.7% showed poor memory.
  • 8.3% had impairments in attention and executive function.
  • 11.6% showed impairment in multiple domains (including memory, learning, attention, and executive function).

Statistical analysis revealed that persistent loss of smell was a significant predictor of cognitive impairment, but initial COVID-19 disease severity was not.


The more we can see about what causes or at least anticipate who will experience the significant long-term cognitive impact of COVID-19 infection, the better we can track it and begin developing ways to prevent it.”


Gabriela Gonzalez-Aleman, LCP, Ph.D., Professor, Pontificia Universidad Catolica Argentina, Buenos Aires

Staying in an intensive care unit may indicate an increased risk of dementia

Researchers from the Rush Alzheimer’s Center (RADC), part of the Rush University Health System in Chicago, used data from five diverse studies of older adults without known dementia (n=3822) to monitor hospitalization in the intensive care unit (ICU). Hospitalization in the intensive care unit has previously been linked to cognitive impairment in older patients, but few studies have examined whether it increases the risk of dementia.

They reviewed Medicare claim records from 1991 to 2018 (pre-pandemic), and annually examined them for the development of Alzheimer’s disease and all types of dementia using a standardized cognitive assessment. During an average follow-up of 7.8 years, 1,991 (52%) participants experienced at least one hospitalization in the ICU; 1031 (27%) had an ICU stay prior to enrollment in the study; and 961 (25%) had an ICU stay during the study period.

The researchers found that in the analyzes adjusted for age, sex, education and ethnicity, hospitalization in the intensive care unit was associated with a 63% increased risk of Alzheimer’s dementia and a 71% increased risk of all types of dementia. In models adjusted for other health factors such as risk factors, vascular disease, other chronic medical conditions, and functional impairments, the association was stronger: hospitalization in the intensive care unit was associated with an 110% increased risk of Alzheimer’s disease and a 120% increased risk of all types. mental illness.

said Brian D. James, PhD, an epidemiologist at RADC: “We found that hospitalization in the intensive care unit was associated with a doubling of the risk of dementia in older adults in the community.” “These findings could be important given the high rate of ICU hospitalizations in the elderly, and especially due to the dramatic rise in ICU hospitalizations during the COVID-19 pandemic. Understanding the link between ICU hospitalization and the development of dementia is important. paramount now more than ever.”

“More research is necessary to replicate these findings and clarify factors that may increase the risk of developing dementia. For example, is it the serious illness that sends someone to the hospital or procedures that can be modified during hospitalization that lead to dementia?” James added.

One positive life change during a pandemic may protect against cognitive symptoms
Investigators from countries across Central and South America and the United States have examined whether sociodemographic factors and changes in life associated with the epidemic are associated with experiencing cognitive symptoms, including problems with memory, attention, and other thinking skills, during the early stages of the epidemic.

In the study reported at the AAIC, 2,382 Spanish-speaking adults aged 55 to 95 (median 65.3 years, 62.3% female) from nine Latin American countries completed an online or telephone survey, and had a test Electronic cognitive, and they filled out a list assessing the positive and negative effects of the epidemic between May and December 2020. Of the total study population, 145 (6.09%) experienced symptoms of COVID-19.

Participants were from: Uruguay (1,423, 59.7%), Mexico (311, 13.1%), Peru (153, 6.4%), Chile (152, 6.4%), Dominican Republic (117, 4.9%), Argentina (106 , 4.5%), Colombia (50, 2.1%), Ecuador (39, 1.6%), Puerto Rico (19, 0.8%) and others (12, 0.5%)

Main results:

  • Female gender, not currently working and lower socioeconomic status were all independently associated with greater cognitive symptoms during the first part of the pandemic.
  • Negative life changes during the pandemic, such as economic hardship and limited social activities, were significantly associated with more cognitive symptoms. However, this association was weaker among study participants who reported at least one positive life change during the pandemic, including spending more time with friends and family or spending more time outside of nature.

Maria Markin, PhD, associate professor of medicine and psychiatry, and director of disparities research in the department of geriatrics, gerontology and palliative care at the University of California, San Diego. “Experiencing positive life changes during a pandemic may mitigate the detrimental effect of negative life changes on cognitive symptoms.”

“This study is an example of how researchers from different countries in Latin America and the United States, many of whom had never worked together and had limited resources, came together under difficult circumstances but with a common goal to advance scientific understanding of Alzheimer’s disease, and the important contributions it could make Such partnerships are multicultural.

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