Namaste: Yoga for the Aging Brain

(Editor’s note: This article from the Winter 2017 issue of Brain World magazineIf you enjoy this article, consider a print or digital subscription!)

For thousands of years, yoga has stood as one of the most important practices for spiritual discipline and transcendence of the ego. But today, yoga has made its way from out of the ashrams and into multiple neurological institutes and research centers throughout the world, being investigated as a new treatment approach to some of today’s most complicated neurophysiological conditions.

Already, this meditational exercise has been shown to help treat a broad spectrum of conditions — depression, anxiety, stress, post-traumatic stress disorder, and attention-deficit hyperactivity disorder. Yet one of the most exciting and new breakthroughs in the fields of contemplative neuroscience and aging is how yoga modulates the brains of Alzheimer’s patients and those at risk for developing it later in life.

As biomedicine and technology advance, people are living longer. Since 1840, the average lifespan has more than doubled and is increasing at the rate of about five hours per day. While some see this as biomedical progress, others see it as a warning. Dr. Gregory Petsko — an internationally renowned biochemist and member of the National Academy of Sciences — predicts that by 2050, there will be about 32 million people living in the United States over the age of 80 and about half of them will have Alzheimer’s. Today, the disease already stands as one of the most challenging public and global health concerns — the Alzheimer’s Association estimates that, as of 2016, 5.4 million Americans of all ages are afflicted.

Even though billions of dollars are being spent on Alzheimer’s medical care and clinical research, it still stands among the top 10 causes of death in America that cannot be effectively prevented, cured, or even slowed. Both the financial and emotional burden upon family members who act as caregivers for loved ones with Alzheimer’s disease can cause them to be six times more likely to develop dementia than a noncaregiver. The inadequacy of effective pharmaceuticals and severe stressors placed upon families, patients, and doctors have expanded Alzheimer’s research into the field of integrative care; a field which can utilize both mind-body practices and medications to optimize clinical care.

Yoga may be one of the most beneficial mind-body practices that can be administered to this patient group. In order to understand how the practice of yoga may be a successful complementary means for treating age-related cognitive decline and Alzheimer’s disease, one must look at the specific neural systems that may be targeted and nurtured during this practice. Even though the World Health Organization officially began promoting yoga in developing countries as early as 1978 as a therapeutic practice, neuroscience researchers remained unsure about whether yoga held any promises for treating some of the world’s most complicated neurological diseases.

A groundbreaking meta-analysis was published in 2012 by neurologist Dr. Shri Mishra and his fellow researchers. They gathered studies from numerous databases — PubMed, Ovid, MD Consult, and libraries of the University of Southern California and the University of California, Los Angeles — in order to determine whether yoga can be considered a valid rehabilitation treatment for disorders like epilepsy, stroke, multiple sclerosis, peripheral nervous-system disease, fibromyalgia, and Alzheimer’s. The analysis showed that yoga did in fact demonstrate statistically encouraging physiological and psychological improvements. Yet, due to certain inadequacies in the designs of the studies they analyzed, the researchers made a call for further research to be done.

The following year, the Advanced Centre for Yoga in Mental Health and Neurosciences in Bangalore, India, answered the call and published a study in the Indian Journal of Psychiatry — one of the first studies to investigate the neurobiological effects of yoga on cortical structures in the elderly. Previous studies published from this center discovered that three months of yogasana (physical movements) and pranayama (breathing techniques) yoga therapy in adults with depression elevated the brain-derived neurotrophic factor, a neuroprotective chemical strongly expressed in the hippocampus. The hippocampus, located in the medial temporal lobe of the brain, is a very vulnerable structure that undergoes a loss of gray matter with aging. If this volume reduction is significant enough, it could be an early indicator of Alzheimer’s. Therefore, researchers hoped to see whether yoga could in fact promote an increase in the hippocampus’ volume.

Led by Dr. V.R. Hariprasad, the researchers recruited seven elderly participants (between the ages of 69 and 81) and enrolled them in a yoga program comprised of yogasana (posture), pranayama (breath control) and om (chanting) — practices that were specifically selected to provide benefits against age-related cognitive loss. When the researchers compared functional MRI scans of the seven elderly participants before and after six months in the yoga training program, they found a significant increase in bilateral hippocampus volume (in the posterior region). This finding confirms the neuroplastic effect seen in other studies (which have shown how aerobic exercise and meditation produce an increase in hippocampus volume). If meditation and physical activity are commonly thought to stimulate brain regions associated with age-related neurodegeneration, as does yoga, should we accept yoga as a similar complimentary treatment intervention? If we decide to look deeper into the neural systems associated with physical activity, meditation, and yoga, we may find that they are not so similar after all.

Contrary to common belief, meditation and physical activity are associated with unique and contrasting structural differences in neural regions that do not quite overlap. A variety of studies shows that meditators were repeatedly shown to have greater hippocampal, insular volume, and left inferior temporal gyrus volume than controls. Greater cardiorespiratory fitness and physical activity were most consistently associated with larger hippocampal and prefrontal gray-matter volume. Given that yoga is a meditative practice embodied in physical postures, it may be likely that there are specific brain regions whose gray matter is more likely influenced by either postures, breath control, meditation, or a combination of these. A study that investigated such a conjecture was published last year in Frontiers in Human Neuroscience.

In this study, Chantal Villemure, along with others, used fMRI data from 14 experienced yoga practitioners and 14 physically active age-matched controls to investigate age-related gray-matter decline and the effect of increasing yoga experience and weekly practice on gray-matter volume. They also assessed which aspects of the weekly practice contributed most to brain size.

To their astonishment, the researchers found that the physically active age-matched controls displayed typical age-related reduction in gray-matter volume while the yogis did not. They also found that regular weekly yoga practice is associated with larger brain volume in areas involved in somatic representation, attention, self-relevant processing, visualization, and stress regulation. In particular, the number of years of yoga experience was positively correlated with gray-matter volume in clusters located in the left mid-insula, and left frontal operculum. The weekly amount of yoga practice was positively correlated with gray-matter volume in clusters located in the right primary somatosensory cortex, left hippocampus, and right primary visual cortex.

Furthermore, the three distinct subcomponents of the weekly yoga practice — which included postures, breathing exercises, and meditation — significantly predicted unique gray-matter volumes in particular areas of the brain that are associated with the processing of these three techniques. Yet one of the most fascinating findings of this study is that certain brain regions for the yoga practitioners located in the left hemisphere (insula, frontal operculum, and orbitofrontal cortex) continued to grow after several years of practice, suggesting that increasing practice tunes the brain toward a parasympathetically driven mode associated with relaxation, peace, and healing.

Since yoga can progressively grow and rewire certain regions of the brain that are prone to degeneration, it should be administered during the early signs of mild cognitive impairment and subjective cognitive impairment, both risk factors for developing Alzheimer’s disease. Dr. Dharma Singh Khalsa, of the Alzheimer’s Research and Prevention Foundation in Tucson, Arizona, conducted a series of three studies investigating the positive effects on memory in subjects with both mild and subjective cognitive impairment who took part in a simple 12-minute yoga meditation called Kirtan Kriya. For the first study, 14 subjects received single-photon emission computed tomography (a nuclear medicine tomographic imaging technique) and comprehensive memory testing before and after eight weeks of Kirtan Kriya practice. The second study added outcomes of common risk factors for Alzheimer’s disease, such as perceived stress, mood, sleep, blood pressure, and memory. The third study measured memory function, mental health, and cellular health in highly stressed dementia caregivers.

When compared to controls, the meditation group showed a significant increase in baseline cerebral blood flow in important brain areas related to Alzheimer’s disease, enhanced scores on memory tests, and improvement in mood and anxiety. Compared to controls, participants in Kirtan Kriya also demonstrated improvement in all major outcomes including perceived stress, mood, depression, sleep, blood pressure, and memory. This group had less depression, higher levels of well-being, and an astounding increase of 43 percent in cellular health (the largest increase ever recorded) along with a decrease in inflammatory markers.

Because chronic stress, memory loss, and cognitive impairment are being increasingly associated with the onset of Alzheimer’s disease, perhaps it is now time to administer yoga interventions as significant preventive treatment measures.

I can’t help but think of my grandmother, whom I call Nana, an 88-year-old woman suffering from the last stages of Alzheimer’s in a nursing home in Illinois. I could remember when our conversations would last for hours, discussing Miles Davis, fine wines, Picasso, and how she cooks a pizza. I also remember her stress and anxiety — something she would try to channel through her cooking and love of painting. But soon it all caught up with her and she started forgetting and not knowing why. None of us did. The doctors put her on a combination of antidepressants and tranquilizers and told her to relax, even when her husband, my grandfather Leo, passed away. Sometimes I think that if the signs of cognitive distress and impairment were caught earlier and that if she took part in a practice that integrated mind and body and nurtured those neurological systems that needed tending instead of buffering, she would still be able to call me on the phone and discuss Picasso a few more times.

(Editor’s note: This article from the Winter 2017 issue of Brain World magazineIf you enjoy this article, consider a print or digital subscription!)


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