Hannah Kazis-Taylor

A new Yale study suggests that negative perceptions of the elderly may be more harmful than some expected.

Researchers at Yale, along with a team from the National Institute of Aging, have found that individuals who hold negative stereotypes of aging are more likely to develop brain abnormalities characteristic of Alzheimer’s disease. The longitudinal study used imaging of subjects’ brains to identify neurological biomarkers and correlated these results with initial measurements of attitudes toward the elderly.

“I’ve been interested in the question of whether cultural beliefs, or how a culture conceptualizes an older member, affect individuals’ health,” said Becca Levy, study co-author and professor of epidemiology at the Yale School of Public Health. “We thought there might be a direct impact, but the degree to which we saw change was surprising.”

Levy said the study was inspired by two separate theories. First, past studies had shown that people with more negativity experience more stress-related health events. Secondly, stress, in turn, affects the brain — specifically, the hippocampus, which is related to memory.

The researchers designed a pair of studies to determine whether negative age stereotypes would cause measurable changes in the brain, specifically a decrease in hippocampal volume and an increased accumulation of amyloid plaques — a buildup of toxic proteins — and neurofibrillary tangles, which are twisted protein fibers. These changes are all symptomatic of Alzheimer’s disease, according to a December press release that accompanied the study.

Subjects were selected from the Baltimore Longitudinal Study of Aging. Their initial negative age stereotypes were scored based on their agreement with a series of statements, such as “Old people are absent-minded.” Hippocampal volume was measured with annual MRIs. Corinna Loeckenhoff, professor of human development at Cornell University and gerontology at Weill Cornell Medical College, said the MRI data was a strength of the study, as it allowed researchers to actually observe pathological brain changes related to developing dementia.

Researchers found that hippocampal volume decreased three times more quickly in subjects with initial negative age stereotypes. Brain samples taken from subjects who donated their brains to science after their death were analyzed to identify amyloid plaques and neurofibrillary tangles. Subjects with more negative age stereotypes had higher levels of plaques and tangles.

In order to demonstrate causation, the initial negative perceptions were measured over 20 years before the plaques and tangles were measured, and all subjects were originally dementia-free.

Levy said she hopes that future studies can elucidate the mechanism by which stress causes these brain changes, which the researchers were not able to directly study, since it might offer important insight into potential interventions. Past studies have shown that age stereotypes can be shifted — negative stereotypes can be reduced, and positive stereotypes can be bolstered, Levy said, adding that with proper intervention to modify this risk factor, there could be a beneficial impact on quality of life.

According to Loeckenhoff, this will be a challenge. Levy and Loeckenhoff both noted that beliefs about aging develop at a young age, so any intervention would have to be continuous, rather than a one-time effort, Loeckenhoff said.

“It’s non-trivial,” Loeckenhoff said. “Trying to change expectations of aging requires changing expectations built up over a lifetime.”

Alzheimer’s disease affects as many as 5 million people in the United States, according to the Centers for Disease Control and Prevention.