Studies with Dancing, Computer Training, Show Ways to Maintain a Healthy Brain in Old Age
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NR-11-05 (11/15/05). For more information, please contact Sara Harris at (202) 462-6688 email@example.com.
STUDIES WITH DANCING, COMPUTER TRAINING, SHOW WAYS TO MAINTAIN A HEALTHY BRAIN IN OLD AGE
WASHINGTON, DC, November 15, 2005 — Scientists are unraveling the mysteries of how the brain ages—and none too soon. The number of people living past age 65 has increased dramatically during the last century, from slightly over 4 percent in 1900 to 13 percent in 2000. It’s estimated that by 2050, when the baby boomer generation is fully ensconced in its elderly years, 20 percent of Americans will be 65 or older. Indeed, the fastest-growing segment is people over age 85.
As the population ages, the incidence of neurodegenerative disorders associated with old age, such as Parkinson’s disease, Alzheimer’s disease, and other forms of dementia, will rise significantly, placing an emotional and economic burden on an increasing number of individuals and families as well as on the public health system. Fortunately, most people do not develop such diseases as they age, but they do experience age-related memory and other cognitive declines. By better understanding how and why those declines occur, scientists hope to find preventive and therapeutic treatments that will help the growing population of the elderly retain active, productive lives throughout their lives.
According to new research, two effective treatments for maintaining a healthy brain include tango dancing and a specialized computer training program.
“Just as the aging of a bottle of wine is a function of the grape and vineyard that the wine came from and how it’s treated during its life, so is the aging of the human body and brain,” says Paul Coleman, PhD, professor of neurobiology and anatomy at the University of Rochester Medical Center. “So people need to treat the brain properly and take care of it and do things to it that will increase its longevity.”
There’s plenty of good news about the aging brain. Recent neurobiological studies have found that healthy individuals lose far fewer nerve cells (neurons) in the brain as they age than previously thought, says Marilyn Albert, PhD, a neuroscientist at Johns Hopkins University.
And there’s more: Scientists have also found that not everybody experiences age-related changes in cognition. “Some older adults perform much more poorly on tests of mental ability than younger individuals, which tends to make the average for the group decline,” notes Albert. “But other older individuals perform in the same range as people many decades younger than themselves. This variability suggests that there must be factors that influence brain aging, even among healthy individuals.”
Genetics certainly plays a role, but so does, according to growing evidence, environmental and lifestyle factors. Epidemiological studies conducted in many countries and across many cultural and socioeconomic backgrounds have found that three important factors help predict how well healthy adults maintain cognitive function as they age: mental activity, physical activity, and social engagement.
“Much work remains to be done to understand the mechanisms by which lifestyle factors affect brain aging and thereby permit specific recommendations for individuals,” says Albert. “The findings to date, however, suggest that as the 21st century unfolds, we will learn much more about ways in which we can maintain brain function at an optimal level into old age.”
Some scientists are examining the nature of age-related changes in the brain. Using a new statistical technique to analyze the results of structural magnetic resonance imaging (MRI) of the brain, researchers at Columbia University were recently able to identify, for the first time, brain “patterns” or “networks” implicated in the normal aging process and to assess the impact of these interrelated patterns on changes in cognition. Previous MRI studies of the aging brain tended to use analytic techniques that considered each region of the brain independently.
For the study, researchers recruited 113 subjects who tested negative for medical, neurological, psychiatric or cognitive impairment. The subjects were divided into a younger group (average age =24) and an older group (average age = 73). The brains of all the subjects were scanned with high-resolution MRI and evaluated with a brief series of neuropsychological tests. The MR images were segmented so that grey and white matter of the brain could be examined separately. A multivariate technique based on a subprofile scaling model was then used to identify age-associated patterns of grey and white matter. The degree to which individuals expressed this pattern was compared to their performance on the neuropsychological tests.
“Our results suggest that there are identifiable networks of grey and white matter regions that systematically decline with age,” says Adam M. Brickman, PhD. Many areas of the brain appear to be involved in these networks. For grey matter, the network includes areas along the surface of the brain (cortical) and deep within the brain (subcortical). For white matter, the network includes deep frontal regions, areas surrounding the ventricles (cavities within the brain that that contain cerebrospinal fluid), and the large fiber tracts that connect the various parts of the brain.
“We also found that the expression of both grey and white patterns is associated with performance on cognitive tests, particularly tests that measure memory, attention, and executive function,” adds Brickman. “That is, the more each individual’s images resembled older brains, the poorer the performance on the tests of cognition.”
Brickman and his colleagues will next attempt to determine what factors might mediate the relationship between age and these structural and functional changes in the brain—studies that may help scientists develop treatments to halt or perhaps even reverse the effects of age on the brain.
Most research into the aging brain has focused on gray matter, the darker-colored tissue of the brain composed mainly of the bodies of nerve cells (neurons). Gray matter includes such structures as the cerebral cortex, the thalamus, and the basal ganglia, and is believed to be the “thinking” center of the brain where memory, among other cognitive functions, is processed. As we age, some neurons shrink and others die, resulting in a loss of gray matter.
Although less studied, white matter—the fibers (axons) that connect neurons within and between brain regions—also shrinks with age. Axons transmit messages among neurons, and are encased in a sheath of fat called myelin. With aging, the thickness of the myelin decreases, resulting in reduced white matter density—a change that can be seen under a microscope, particularly around the brain’s ventricles (cavities containing cerebrospinal fluid) and in deep white matter. If this shrinkage or deterioration in the brain’s “telephone wires” is significant, it may cause interference in communication between areas of gray matter. In turn, this disrupted communication could impact a person’s ability to perform complex, coordinated daily tasks, such as remembering to pay the bills on time or doing complicated mathematical calculations in one’s head.
At the Massachusetts Institute of Technology, David A. Ziegler and his colleagues used a fairly new MRI-based brain imaging technique, diffusion tensor imaging (DTI), to study white matter changes in healthy aging brains and how these changes are linked to cognitive performance. DTI measures the ease with which water molecules move in a particular direction through different types of tissue. Because bundles of myelinated axons create barriers that restrict the movement of water non-randomly, DTI can be used as an indirect measure of the integrity of white matter—and, thus, of whether regions of white matter are particularly susceptible to the adverse effects of aging.
The cognitive tasks chosen for the study were designed to assess episodic memory (the ability to remember specific events and their contexts), semantic memory (the ability to remember facts), and frontal lobe cognitive control processes (the ability to coordinate one’s thoughts and actions). “We found that white matter integrity was particularly reduced in the frontal-most parts of the brain—areas such as the prefrontal cortex and the anterior portion of the corpus callosum,” says Ziegler. “We were also able to demonstrate that this decline in integrity is associated with a decreased ability to perform tasks that require cognitive control—precisely those functions traditionally assigned to the frontal lobes.” In contrast, performance on semantic and episodic memory tasks appears to relate more to integrity of white matter in other parts of the brain, such as regions underlying the parietal and temporal lobes.
Next, Ziegler and his colleagues intend to determine the extent to which age-related functional declines are dependent upon white matter versus gray matter and when in the course of aging these patterns first emerge. In other words, is it the neurons themselves or the connections between them that are the critical factor in age-related function decline? Or do gray matter and white matter each play a distinct role? One way to address this issue would be to see whether increasing white matter integrity would improve cognition and in what way. Until now, therapeutic attempts have focused largely on specific neurotransmitter systems (such as the cholinergic system) or on pathological entities in the brain (such as neuritic plaques).
“An unexplored target for drug development is the brain’s white matter,” says Ziegler. “Because the cellular components of white matter show a remarkable capacity for plasticity through the lifespan, it may be possible to enhance white matter integrity in older individuals pharmacologically or even through changes in diet or cardiovascular fitness. If it is possible to harness white matter plasticity, this approach might prove a very effective means of countering some of the cognitive declines that are typical of advanced age.”
While some scientists examine how the brain ages, others are exploring what can be done to prevent or possibly even reverse age-related cognitive decline. At McGill University in Montreal, Canada, researchers have found that the sultry moves of Argentine tango dancing can help the aging brain. “Our findings suggest that tango may be better than walking for improving the execution of complex tasks and the ability to move within a restricted area without losing one’s footing,” says Patricia McKinley, PhD.
More than one-third of the elderly population in the United States experiences a fall each year, and, for older adults, falls are a leading cause of death. In addition, 71 percent of seniors over the age of 65 live alone, and many spend more than seven hours a day without any social contact. This isolation, coupled with the normal aging process, can lead to cognitive decline.
Tango dancing is beneficial to the elderly, says McKinley, because it incorporates elements found in standard neurological rehabilitation programs: forward, backward and side-to-side weight shift; one-legged stance; walking on a straight line both backwards and forwards; increasing step length in all directions; and turning within a narrow space.
“An added benefit of tango is that its movements are performed to music, which is known to facilitate performance of ambulatory activities,” says McKinley.
For the study, which was funded by the Drummond Foundation, the researchers recruited 30 seniors, aged 62 to 90. All were healthy individuals who had experienced a fall within the last year and had developed a fear of falling. They were randomly assigned to either a walking group or a tango dancing group. Both groups met for two hours twice a week for ten weeks.
Both the dancers and the walkers had their motor and cognitive skills evaluated before and after the program. The evaluations included spatial and numerical memory tests, complex and simple walking tasks, clinical measurements of balance, and self-efficacy for balance.
The tango group showed improvement in balance, posture and motor coordination, as well as cognitive gains. Specifically, the tango group performed significantly better than the walking group at performing a complex cognitive task while walking, at standing on one foot, and at turning in confined spaces. Memory testing, however, was inconclusive, perhaps because the sample size was not large enough, says McKinley.
The drop-out rate for the tango group was smaller than that for the walking group (one versus four), and 66 percent of the tango group continued to participate in the activity a year later.
“Tango dancing is an ideal leisure activity for this population,” says McKinley, “because it satisfies three basic requirements for exercise adherence: it’s fun, it’s a group activity, and it has a tangible goal that can be perceived not only by the dancer, but by his or her family and friends.”
Another new study has demonstrated that an eight-week computer-based training program that exercises the brain’s auditory and language systems can significantly improve neuropsychological measures of memory in older adults. These findings open up new therapeutic possibilities for enhancing memory and reversing the cognitive function decline associated with the aging brain. Perhaps more importantly, they underscore the premise that the brain is capable of adapting and improving at any age. While the “use it or lose it” slogan has recently become closely associated with mental fitness, this study is one of the first to demonstrate how to “use it” to achieve measurable results.
The training program used in the study was designed based on extensive research into the brain’s inherent plasticity, or ability to adapt at any age, and represents a departure from conventional approaches by treating underlying causes of cognitive decline rather than just the symptoms.
The study involved 95 participants (ages 63 to 94) who were randomly assigned to one of three groups: a brain plasticity-based training program group, a control group using a computer, and a no-contact control group. The training group completed an hour of computer exercises daily. The program included six exercises that rotated on a daily basis with each participant performing four of the six exercises on a given day. A trainer was present if any participants had difficulty with the program. Using a computer-based program permitted the researchers to deliver stimuli accurately and consistently, to change the difficulty of the tasks as people improved, and to track performance gains.
Before and after the training period, all participants were administered standardized assessments of memory and cognition, including the Repeatable Battery for Assessment of Neuropsychological Status (RBANS), which evaluates five cognitive areas: immediate memory, delayed memory, attention, spoken language, and visuospatial perception. In addition, participants received a standardized assessment of working memory. Those participants who completed more difficult levels of exercises showed the greatest improvements.
“We found that the group who completed the training program experienced significant improvement in measurable memory scores,” says Michael Merzenich, PhD, chief scientific officer at Posit Science and the Francis A. Sooy Professor at the Keck Center for Integrative Neurosciences at the University of California-San Francisco. “In fact, by using RBANS age norming data, we concluded that the majority of the participants in the training program group improved 10 or more years in neurocognitive status. Beyond measurable results, participants in the study reported a range of benefits from feeling more engaged in conversation to having more control over their lives.”
The next step in this research, Merzenich says, is to evaluate the effects of computer training on people’s ability to process and understand speech. The researchers also intend to use brain imaging techniques to map how the training program changes brain function.
“While it seems each year brings new scientific advances that increase the physical lifespan in humans, our program shows that brain plasticity-based applications can positively affect cognitive performance,” says Merzenich. “In doing so, we hope to improve overall quality of life as we age, helping our ‘brainspan’ match our ever-growing lifespan.”
The authors of this study are employed by Posit Science Corporation, which is developing brain plasticity-based training programs for commercial release.