Transcranial Magnetic Stimulation Improves Memory in Older Adults
A painless and noninvasive brain stimulation technique may help improve some types of memory in older adults, investigators reported.
One possible explanation for age-related memory loss is degradation of the neural connections between the hippocampus and the cortex. Weakening of these connections may lead to difficulties in creating new memories of specific events and the locations of objects. Scientists hypothesized that strengthening the connections between the hippocampus and cortex through repetitive transcranial magnetic stimulation (TMS) may help the storage of new memories. TMS delivers painless magnetic pulses to a particular region of the brain, changing the activity of the neurons within the targeted area.
To determine whether TMS could improve memory, 15 healthy adults over the age of 64 received TMS to a part of the cortex that communicates with the hippocampus. Treatment lasted for five days. During a separate week, each participant received five days of sham treatment, in which the setup was the same, but the stimulation was too low to influence the neural connections. Before and after each five-day session, participants were asked to remember pictures of everyday objects and pictures of outdoor scenes associated with each one. The adults’ ability to recall the scenes associated with the objects improved after receiving TMS, but not after the sham treatment.
“Our study demonstrates that TMS could potentially be used as a way to improve memory for older adults experiencing age-related memory impairments,” said John A. Walker, PhD, postdoctorate fellow at Northwestern University in Evanston, Illinois. “TMS can be used to probe the relationship between brain networks and memory experimentally, opening new doors to understanding the network basis of cognitive decline in aging.”
Heading the Ball Hurts Women More Than Men
Intentionally hitting a soccer ball with the head, or “heading,” may have more adverse brain consequences for women than men, said researchers.
Heading does not typically result in a concussion, yet growing evidence links the move to CNS damage. Previous studies using diffusion tensor imaging (DTI) have revealed that heading damages the integrity of the axons. Women appear to be more vulnerable than men to problems associated with heading, as they report more symptoms that last longer, but the reason for these gender differences remains unknown.
To assess possible gender differences in the effects of heading, researchers used DTI to examine 49 male and 49 female amateur soccer players who were matched on age and frequency of heading. Higher levels of heading were associated with decreased axonal integrity in three brain regions for men and eight brain regions for women. In seven of the areas identified in women, the association between axonal integrity and heading was significantly stronger than it was in men.
“Given similar amounts of exposure to heading, women show a greater volume of abnormality that is significantly different from what is seen in men,” said lead author Todd G. Rubin, MD, a doctoral student at Albert Einstein College of Medicine in Bronx, New York. “Identifying and understanding the basis for differences in susceptibility to injury represent key steps in determining better treatments and guidelines for safer play.”
DBS Can Individualize Treatment for Parkinson’s Disease
A new approach to deep brain stimulation (DBS) adjusts itself to deliver the appropriate amount of stimulation in patients with Parkinson’s disease, according to new research. The approach could improve symptom management and reduce side effects.
DBS has been a valuable treatment for Parkinson’s disease by helping to quell the abnormal movements that are characteristic of the disease. Traditional DBS delivers a constant level of stimulation and cannot adapt if a patient’s symptoms vary over the course of a day. As a result, a patient may sometimes receive too little stimulation, which fails to control symptoms, or too much, which causes side effects such as dyskinesia.
To match stimulation to variations in patient symptoms throughout the day, researchers and engineers developed a novel implantable device that provides DBS and records activity from the surface of the brain. Similar to a cardiac pacemaker, this adaptive device can autoadjust its level of stimulation based on a physiologic signal—in this case, brain activity related to dyskinesia. A high dyskinesia signal indicated greater likelihood of unwanted side effects and caused the device to reduce the stimulation level. A low signal indicated a higher chance of symptoms returning and triggered an increase in stimulation.
The device was tested in two patients inside and outside of the laboratory. Neither patient reported discomfort, adverse events, or worsening symptoms. In addition, the battery used as much as 45% less energy than traditional DBS, which is an important advantage, since battery replacement requires surgery.
“Our study showed that totally implanted, adaptive DBS is feasible and can be used at home in patients,” said lead author Nicole C. Swann, PhD, Assistant Professor of Human Physiology at the University of Oregon in Eugene. “Adaptive stimulation represents one of the first major advances in DBS technology since this technique was first introduced for the treatment of Parkinson’s disease 25 years ago.”