Alzheimer’s disease (AD) is a brain disorder that destroys memory and thinking skills over time. It is the most common form of dementia in older adults. There is presently no cure for the condition, though treatment options are available. Today, some 5.3 million Americans live with AD, and it is now the sixth leading cause of death in the United States. The number of older adults who will develop AD is expected to more than triple by 2050.
Geriatrics experts have suggested that exercising can improve brain health in older adults. The World Health Organization (WHO) has recommendations for how much older adults should exercise. They suggest that older adults perform 150 minutes a week of moderate exercise (such as brisk walking), 75 minutes a week of vigorous aerobic training, or a combination of the two types. The WHO also recommends older adults perform muscle-strengthening exercises on at least two or more days a week.
However, not all studies of exercise and older adults have proven the benefits of exercise. We don’t know for sure whether exercise slows mental decline or improves older adults’ ability to think and make decisions.
A team of researchers designed a study to learn whether exercise could delay or improve AD symptoms. They reviewed 19 studies that examined the effect of an exercise training program on cognitive function in older adults who were at risk for or diagnosed with AD. The studies included 1,145 older adults, most of whom were in their mid-to late 70s. Of the participants, 65 percent were at risk for AD and 35 percent had been diagnosed with AD.
The researchers published their findings in the Journal of the American Geriatrics Society.
As the researchers examined the studies, they discovered that older adults who did aerobic exercise by itself experienced a three times greater level of improvement in cognitive function than those who participated in combined aerobic training and strength training exercises. The researchers also confirmed that the amount of exercise WHO recommends for older adults was reinforced by the studies they examined.
High-intensity exercise three times a week is safe for individuals with early-stage Parkinson’s disease and decreases worsening of motor symptoms, according to a new phase 2, multi-site trial led by Northwestern Medicine and University of Colorado School of Medicine scientists.
This is the first time scientists have tested the effects of high-intensity exercise on patients with Parkinson’s disease, the second most common neurodegenerative disorder and the most common movement disorder, affecting more than a million people in the United States.
It previously had been thought high-intensity exercise was too physically stressful for individuals with Parkinson’s disease.
The paper will be published in JAMA Neurology Dec. 11, 2017.
Parkinson’s symptoms include progressive loss of muscle control, trembling, stiffness, slowness and impaired balance. As the disease progresses, it may become difficult to walk, talk and complete simple tasks. Most people who develop Parkinson’s are 60 and older.
“If you have Parkinson’s disease and you want to delay the progression of your symptoms, you should exercise three times a week with your heart rate between 80 to 85 percent maximum. It is that simple,” said co-lead author Daniel Corcos, professor of physical therapy and human movement sciences at Northwestern University Feinberg School of Medicine.
Researchers have developed new single-cell sequencing methods that could be used to map the cell origins of various brain disorders, including Alzheimer’s, Parkinson’s, schizophrenia and bipolar disorder.
By analyzing individual nuclei of cells from adult human brains, researchers at the University of California San Diego, Harvard Medical School and Sanford Burnham Prebys Medical Discovery Institute have identified 35 different subtypes of neurons and glial cells and discovered which of these subtypes are most susceptible to common risk factors for different brain diseases.
“There are multiple theories regarding the roots of various brain diseases. Our findings enable us to narrow down and rank which types of cells in the brain carry the most genetic risk for developing these diseases, which can help drug developers pick better targets in the future,” said Kun Zhang, a professor of bioengineering at the UC San Diego Jacobs School of Engineering and co-senior author of the study.
This work builds off of a previous study published in Science, which Zhang also co-led, in which researchers identified 16 subtypes of neurons in the cerebral cortex. That study was the first large-scale mapping of gene activity in the human brain and provided a basis for understanding the diversity of individual brain cells.
“Our ultimate goal is to produce a complete cell atlas of the human brain,” Zhang said. “Here, we’ve created a fuller and more detailed map than what we’ve done in our previous work.”
In the new study, researchers developed a new generation of single-cell sequencing methods that enabled them to identify additional neuronal subtypes in the cerebral cortex as well as the cerebellum, and even further divide previously identified neuronal subtypes into different classes. The new methods also enabled researchers to identify different subtypes of glial cells, which wasn’t possible in the previous study due to the smaller size of glial cells.
The advance was made possible by combining next-generation RNA sequencing with chromatin mapping–mapping of DNA and proteins in the nucleus that combine to form chromosomes–for more than 60,000 individual neurons and glial cells. The work was published Dec. 11 in Nature Biotechnology.
Scientists have identified brain networks involved in a baby’s learning to walk — a discovery that eventually may help predict whether infants are at risk for autism.
The findings build on previous research that has shown that babies who have delays in developing skills involved in coordination and movement are more likely to be diagnosed subsequently with autism spectrum disorder.
The new study by researchers at Washington University School of Medicine in St. Louis and other scientists is available online in the journal Cerebral Cortex.
In brain scans and motor skills evaluations of nearly 200 babies, the researchers unexpectedly found that part of a brain network that operates in adults when the brain seems to be doing nothing is involved in learning to walk and control motor functions. This network — called the default-mode network — is active during sleep and daydreaming and when a person is thinking about one’s self and one’s environment, including that individual’s social ability, which is disrupted in people with autism spectrum disorder.
Previous research has shown that people with Alzheimer’s disease and autism often have disruptions in the default-mode network.
“Walking is a huge gross motor milestone, and it’s associated with a child’s understanding of his or her own body in relation to the environment,” said first author Natasha Marrus, MD, PhD, an assistant professor of child psychiatry at Washington University. “That the default-mode network is involved is important because that network is thought to be very involved in developing one’s own sense of self. Our findings may allow us to identify the brain regions and networks that can predict aspects of autism before it’s possible to make a clinical diagnosis.”
Marrus worked with colleagues from the multicenter Infant Brain Imaging Study (IBIS) network, performing functional brain scans on 187 young children while they were sleeping. They scanned the children near their first birthdays and again about a year later and evaluated gross motor skills at those same times.
“Understanding the early development of functional brain networks underlying walking and motor function in infancy adds critically important information to our understanding not only of typical development but also of a key deficit that appears early in the development of a number of neurodevelopmental disorders, such as autism,” said Joseph Piven, MD, one of the study’s co-senior authors and a professor of psychiatry, pediatrics and psychology at the University of North Carolina.
Some toddlers in the study had an elevated risk for autism because they have siblings with an autism diagnosis. Autism spectrum disorder is, in part, a genetic condition that runs in families. In the general population, about one in 68 children is affected, but the odds rise to one in five when a sibling has an autism diagnosis.