People with superior thinking skills into their 90s are resilient to some memory loss disorders, a UCI-led study shows

May 24, 2023
Older woman takes timed cognition test as part of the UC Irvine 90+ Study
A participant in the UC Irvine 90+ Study research project takes a
timed cognition test. The study's latest finding shows that older
adults with high cognitive skills are less likely to have brain
pathology changes found in Lewy body and other dementias.
Photo courtesy of the UCI School of Medicine

Irvine, Calif. — A University of California, Irvine-led team of researchers has discovered that the oldest-old, those who live to be 90-plus and have superior cognitive skills, have similar levels of brain pathology as Alzheimer’s disease patients.

However, they have less brain pathology for other neurodegenerative diseases that cause memory and thinking problems.

Their report, “Superior Global Cognition in Oldest-Old is Associated with Resistance to Neurodegenerative Pathologies: Results from the 90+ Study,” was published last week in the Journal of Alzheimer’s Disease.

“People who are 90-plus and still have good memory and thinking abilities tend to have similar levels of Alzheimer’s pathology in their brains,” said Roshni Biswas, a post-doctoral scholar with the 90+ Study.

“Our findings indicate that while Alzheimer's disease, neuropathological and vascular changes are common in their brains, these individuals are less susceptible to other types of neurodegenerative changes, such as Lewy body dementia.”

Risk factor for memory loss

Age is the primary risk factor for cognitive disorders such as Alzheimer’s disease, Lewy body and related dementias. Over the last 30 years, the number of Americans ages 90 and older has nearly tripled. That number is projected to quadruple in the next four decades.

As people age, many experience increased problems with memory and brain function. But little data is available on how the brain changes in people who maintain superior cognitive abilities despite being 90 and older.

The new study’s objective was to examine the brain features of people without cognitive impairment and their relation to superior cognitive skills and reasoning in those who are 90 and older.

“There are some individuals who can maintain high levels of cognitive function well into advanced age,” said María M. Corrada, ScD, the study's co-principal investigator and professor of neurology at the UCI School of Medicine.

“Further research into the factors that enable these individuals to maintain their cognitive function could provide insights into how to preserve cognitive health despite advanced age.”

Analyzing pathology and cognitive test scores

The study results were derived by analyzing autopsy data from 102 cognitively normal individuals who died at a mean age of 97.6 years. They also used cognitive test scores from people taken between two to 12 months before death. The average age of study participants at the time of their last visit was 97.1 years.

“In our future research, we will examine how lifestyle habits and health conditions are associated with superior cognition in individuals who are 90-plus and the factors that contribute to maintaining stable cognitive function over time,” Biswas said.

The 90+ Study is a longitudinal research project on aging and dementia initiated in 2003 to study the oldest-old population, which is the fastest growing U.S. age group.

With more than 2,000 participants now enrolled, it is one of the largest studies of its kind in the world. The project has produced several significant findings regarding cognitive function, health and lifestyle habits in the oldest-old population, information obtained during participants’ life.

This work is supported by the National Institutes of Health.

Media contact
Anne Warde
Director, Communications and Public Relations
UCI School of Medicine

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