In a novel study, researchers stimulated certain areas of older adults’ brains with a low-level current that matched the brain’s own electrical signals, to aid in restoration of working memory.
The researchers wanted to learn if there are ways to restore working memory in older adults that don’t involve medication. They tested a technique known as transcranial alternating-current stimulation (tACS) to help the brain perform more like it does in younger adults. As people age, the connections between different regions of the brain begin to weaken, and this is thought to be one of the reasons for declines in working memory. In this study, researchers used tACS on older adults as a way to boost communication between the frontal and sensory areas of the brain.
Forty-two older adults (age 60 to 76) and 42 younger adults (age 20 to 29) performed a 75-minute working memory task while their brain activity was recorded with electroencephalography. In this task, participants were shown an image, then three seconds later were asked if a second image was either the same or slightly different from the first. This was repeated until the end of the experiment. Older adults did this task one day with tACS for the first 25 minutes and another day without, while younger adults performed the task without tACS.
On the days older adults did not receive tACS, they performed significantly worse on the task than younger adults and showed reduced activity between regions of the brain. On days when tACS was used, however, there were no differences between older and younger adults in task performance. Another interesting finding was that while tACS was only used during the first 25 minutes of the 75-minute experiment, the improvements in performance lasted for the rest of the experiment, and connectivity between brain regions followed similar patterns as in younger adults.
These findings not only provide more insight into why working memory tends to decline with age, but also show that technologies such as this may be able to help restore working memory in older adults, at least for a short time.
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