- A new study led by researchers from the University of California, Irvine, has discovered that individuals aged 90 and older, who exhibit superior cognition, display brain pathology comparable to that of Alzheimer’s patients.
- These findings prompted researchers to investigate the connection between lifestyle habits, health conditions and superior cognition in the 90+ age group.
- Autopsy data and cognitive test scores were examined to understand the participants’ cognitive function and brain health, finding similar levels of Alzheimer’s pathology.
In the United States, the number of individuals aged 90 and above has nearly tripled in the past three decades, and it is projected to quadruple in the next 40 years.
As people age, there is a higher likelihood of experiencing memory and brain function issues. However, there is limited available data on the brain changes that occur in individuals aged 90 and above who maintain excellent cognitive abilities, despite their age.
Now, new research, published in the Journal of Alzheimer’s Disease, shows that although the “oldest old” individuals, those who live to be 90 years or older, may possess superior cognitive abilities, these individuals exhibit brain pathology comparable to Alzheimer’s patients.
The 90+ Study, commenced in 2003, is a longitudinal research project that investigates aging and dementia. Its primary objective is studying the oldest-old population, which is the age group experiencing the fastest growth in the United States.
With over 1,600 participants enrolled, it has become one of the largest studies of its kind worldwide.
Throughout the project, significant findings have been obtained, shedding light on cognitive function, health, and lifestyle habits in the oldest-old population, based on information collected during their lifetimes.
According to the researchers of this new study, individuals who are 90 years or older and still maintain good memory and thinking abilities yet tend to have similar levels of Alzheimer’s pathology in their brains.
The researchers set out to understand why some people who are very old can still think clearly and have good memory skills.
With that in mind, they focused on a group of individuals who were very old and had excellent cognitive abilities because they wanted to see if there were any changes in their brains that could explain this.
Specifically, they looked at the connection between Alzheimer’s disease — a common cause of memory problems — and other brain changes that are not related to Alzheimer’s.
The research suggests that although Alzheimer’s disease-related changes and vascular changes are common in their brains, these individuals are less vulnerable to other forms of neurodegenerative changes like Lewy body disease.
The study findings were obtained by analyzing autopsy data from 102 cognitively normal individuals who passed away at an average age of 97.6 years.
Cognitive test scores taken between 2 to 12 months prior to their deaths were also included and the average age of the study participants during their last visit was 97.1 years.
The researchers found that older individuals with excellent cognitive abilities were able to withstand the negative effects of Alzheimer’s disease-related brain changes and low levels of damage from vascular problems.
These individuals were also resistant to other types of brain changes that are not related to Alzheimer’s disease and multiple additional brain health problems.
By understanding what factors allow these individuals to resist these changes, we can gain valuable insights into how to maintain good cognitive abilities despite getting older.
Dr. Roshni Biswas, from the Department of Neurology at the University of California, one of the co-authors of the study, explained the key findings to Medical News Today, saying that “individuals who live to be 90 and older with excellent memory and thinking abilities tend to have similar levels of Alzheimer’s disease pathology in their brains, but have lower levels of pathologies from other diseases that cause memory and thinking problems.”
Dr. Biswas pointed out how these participants also have fewer co-existing brain pathologies:
“Over the past 30 years the number of people aged 90 and older in the U.S. has nearly tripled and this number is projected to quadruple in the next four decades. Given this significant increase in the number of oldest-old individuals, it is crucial to prioritize research into understanding the factors that promote both quality and quantity of life for those who reach their 90th birthday.”
Dr. Biswas highlighted that this research “provides evidence that it is possible to maintain excellent memory and thinking abilities even after age 90 and in the presence of age-related abnormal brain changes.”
However, “further research into the factors that enable these individuals to maintain intact cognitive abilities could provide insights into how to preserve cognitive health despite advanced age,” Dr. Biswas explained.
Dr. Ari D. Kalechstein, president and CEO of Executive Mental Health, not involved in this research, told MNT that “the assertion intuitively makes sense.”
“Cognition is a proxy for brain integrity. To the degree that the brain is compromised by neurodegenerative disease, including, but not limited to, conditions such as Alzheimer’s disease and stroke, then cognition will be adversely affected.”
Dr. Kalechstein highlighted that “there are several important takeaways from this and similar studies.”
“First, it is important to refrain from the use of sweeping generalizations vis-à-vis increased age and the functional capacity, e.g., whether an individual can perform the usual and customary job duties related to serving as a United States senator. That does not negate a well-established finding that older individuals are at-risk to experience a decline in cognition; rather, it means that such an outcome should not be assumed,” he explained.
“Additionally, it will be interesting to see whether this study serves as the catalyst for future investigations that might seek to identify factors that protect cognition in the ‘oldest-old’,” he noted.
“Yes, there are many studies that have examined this important issue and there exist theories that focus on this specific issue, e.g., brain reserve capacity; nonetheless, it may be that future studies enhance what is known and/or serve as the cornerstone for a new theory that better explains why it is that a subset of adults are more resilient than others regarding the adverse effects of age on cognition.”
– Dr. Ari D. Kalechstein