The researchers behind the new study assessed a group of older adults experiencing memory difficulties who practiced 12 minutes per day of music listening or simple yoga meditation for 12 weeks.
Samples of their blood from before and after the 3 months of therapy revealed changes in levels of certain markers with associations to cell aging and Alzheimer’s disease.
These changes also linked directly to improvements in subjective assessments of cognitive function, mood, sleep, and quality of life.
Dr. Kim Innes, a professor at West Virginia University School of Public Health in Morgantown, led the study and is first author of the study paper, which features in the Journal of Alzheimer’s Disease.
Blood markers as predictors of Alzheimer’s
The team chose to measure a number of blood markers that “have emerged as possible predictors of cognitive decline and dementia.” These included telomere length, telomerase activity, and levels of certain beta-amyloid peptides with links to Alzheimer’s disease.
Telomeres are “protective caps” that work to prevent the ends of chromosomes from deteriorating. Telomerase is an enzyme that helps preserve telomere length. Reduction in telomere length and telomerase activity are both “markers of cellular aging.”
Symptoms of Alzheimer’s disease, such as a gradual decline in the ability to remember, think, and make decisions, emerge long after the changes in the brain that cause them have already taken hold.
For this reason, and because of the difficulties of diagnosing this form of dementia from symptoms, researchers are pushing for a model that “defines Alzheimer’s by brain changes, not symptoms.”
They argue that this would help clinicians diagnose Alzheimer’s much earlier and give therapies a chance to make a real difference in delaying, if not averting, the debilitating symptoms.
One change that often occurs in the brains of people with Alzheimer’s disease is clumps of beta-amyloid protein. Whether these beta-amyloid clumps in the brain cause the disease or just accompany it, and how they relate to blood levels of the protein, is not entirely clear.
Scientists are, however, becoming increasingly confident that a blood test based on beta-amyloid markers will one day be able to predict Alzheimer’s long before symptoms such as memory loss and confusion emerge.
Changes in beta-amyloid and symptoms
In the new study, the scientists randomized 60 older adults to undertake a 12-minute daily practice of either a simple yoga meditation called Kirtan Kriya or a music-listening program for 12 weeks. All had undergone assessments that indicated that they had “subjective cognitive decline.”
The researchers assessed blood markers from samples drawn at the start and end of the 3 months of practice. At these times, and also after another 3 months, they also assessed memory, cognitive function, quality of life, sleep, stress, and mood.
After 12 weeks of practice, the yoga meditation group had higher levels of beta-amyloid 40 than the music-listening group.
Beta-amyloid 40 is one of the biomarkers that scientists are focusing on as the basis of a potential predictive blood test for Alzheimer’s disease.
This result does not mean that those with higher levels of beta-amyloid 40 have a higher risk of Alzheimer’s; the relationship between higher blood beta-amyloid 40 and amyloid clumps in the brain is not that straightforward.
Where scientists are working on a blood test for predicting the disease, for example, they are thinking about using a ratio between beta-amyloid 40 and another beta-amyloid.
What is significant about this result, however, is that a change in blood beta-amyloid occurred.
The analysis also revealed links between increasing levels of beta-amyloid and improvements in memory, cognitive function, quality of life, mood, and sleep for the 3- and 6-month measuring points. The links were much stronger, however, in the group that did the yoga meditation.
Changes in markers of cellular aging
Markers of cellular aging also changed in both groups as a result of practice. Telomerase activity went up in both groups, but the increase was only significant in those with lower telomerase activity at the start and who practiced more often. A similar pattern occurred with telomere length.
The results also showed links between increases in these two markers and improvements in some of the cognitive and “psychosocial” measures.
Stress, mood, sleep, quality of life, and other symptoms improved in both groups, but the biggest improvements occurred in the meditation group. These improvements lasted or even strengthened during the 3 months following the intervention.
The authors conclude:
“Biomarker increases were associated with improvements in cognitive function, sleep, mood, and [quality of life], suggesting potential functional relationships.”