Electrical Stimulation Makes Old Brains Act Young Again
According to a recent study, a short session of brain zapping can reverse some of the effects of aging in older adults. The technique is not ready to be used out of clinical studies yet, and it is not clear how long the benefits last. But the study authors said they hope their findings will set the stage for improving cognition in both healthy adults and in people experiencing Alzheimer’s and other types of dementia.
This study focused on an aspect of cognition called working memory. This is the sketch pad of the brain, a study author cites. Working memory allows people to hold information in active use for a few seconds at a time, allowing for all sorts of critical tasks, from calculating mental math to reading to having a conversation. Research has shown that working memory is a key part of intelligence.
But unfortunately, working memory declines over adulthood. The even though the decline is gradual, it is enough that older adults generally perform worst, on working memory tasks than young adults.
The researchers recruited 42 adults ages 20-29 and 42 older adults ages 60-76. The scientists asked the participants to complete a working-memory task while their brain activity was being monitored by electroencephalogram. The task was a “spot the difference” game, in which participants saw two similar images on the screen in a short time frame and had to identify what was the differences were. All the participants were healthy, without any kind of cognitive issues.
According to the study, in some sessions, participants did the task while their brain was lightly stimulated with a non-invasive electrical method called transcranial alternating-current stimulation. Using electrodes on the scalp, the researchers pulsed rhythmic electrical stimulation. Using electrodes on the scalp, the researchers pulsed rhythmic electrical stimulation into prefrontal and temporal brain areas. Communication between these regions, at the front and sides of the brain, is thought to be important for working memory.
The experiment was double-blind, so neither participants nor researchers knew when the participants were receiving brain stimulation. Other than an initial tingling sensation on the scalp, the stimulation does not feel a thing. They gave participants 30 seconds of light electric current through the electrodes to mimic the sensation. Participants come in for different days for their sham for real sessions, the simulation lasted 25 minutes.
Prior to any stimulation, older adults performed less well on the working memory task than their younger peers. Accuracy in younger adults averaged about 90%, with scores ranging from high 80s to nearly 100% correct. In older adults, the average was a bit closer at 80%, with scores ranging from the low 70s to the mid 80s.
Stimulation closed this perceived gap. Within around 12 minutes of the start of brain stimulation, older adults began to perform as well as the younger group. This improvement was consistent for as long as the experiment lasted, 50 minutes after the stimulation stopped.
In follow-up experiments to verify findings with another 49 older and younger adults, the researchers also tested the effects of brain stimulation on young adults who had the lowest working memory scores. Those young people also got a boost, researchers discovered.
Ultimately, this approach of boosting brain power could potentially have positive effects on cognitive disorders. It does rise the question that these brains that saw a boost might have just had reduced electrical activity between synapses and this electrical stimulation prompted more effective synaptic communication. I think any of us who have had a loved one that has faced challenges with cognitive disorders would be excited to see even more research in this field in the future.