Our memory tends to get worse as we age, and with a global population that’s rapidly skewing older, that’s something that scientists are trying to address – to keep us fully functioning for longer and to ward off dementia and diseases such as Alzheimer’s.
A new study suggests that mild, non-invasive electrical stimulation, applied through a cap with electrodes attached, could be enough to combat the effects of getting older and keep our memory circuits in a better and more robust shape.
Technically, it’s known as transcranial alternating current stimulation, or tACS, and it is thought to work by synchronizing our brain waves.
In experiments conducted by researchers at Boston University, just 20 minutes of stimulation a day was enough to produce noticeable improvements in 2 types of memory function that lasted for at least a month.
With more research, this could open up methods for keeping our minds sharp as we get older, as well as treating problems with memory.
“Our findings demonstrate that the plasticity of the aging brain can be selectively and sustainably exploited using repetitive and highly focalized neuromodulation,” write the researchers in their published paper.
Here’s what the team did: in a series of experiments, 150 individuals between 65 and 88 years old were given 20 minutes of electrical brain stimulation a day for 4 consecutive days. At the same time, they were asked to listen to and recall 5 lists of 20 words each.
Based on earlier research, two specific areas of the brain were targeted with distinct frequencies.
Stimulating the brain’s inferior parietal lobule at a frequency of 4 Hz was shown to improve the recall of words at the end of the lists – that’s working memory in action, being able to remember something in the short term (like the platform number your train is leaving from).
Stimulating the brain’s dorsolateral prefrontal cortex at a frequency of 60 Hz was shown to help the participants remember words from the beginning of the lists, an indication of an improvement in long-term memory. An example of long-term memory would be being able to remember where you parked your car at the airport after a week’s vacation.
Those who showed the worst levels of cognitive performance before the stimulation treatment were the ones who had the larger and longer improvements in memory recall.
“This is promising work, and it shows how amazingly flexible and adaptable the brain is,” neuroscientist Tara Spires-Jones at the University of Edinburgh told The Guardian.
However, Spires-Jones noted that the specific word-list task given to participants may not be so representative of everyday activities.
What we also don’t yet know, and what wasn’t covered in this study, is whether or not those with impaired memory capabilities due to a brain disorder can be helped through this kind of stimulation and brain training.
That’s something that researchers can look into next, as well as potentially analyzing how the treatment might work for those at risk of dementia – a syndrome that currently affects around 55 million people worldwide and sees the brain deteriorate further than would be expected from normal biological aging.
While it’s still early days, this is a promising start: the technology is non-invasive, can be applied quickly, and lasts for a least a month, as well as working on both short-term and long-term types of memory recall.
“We’re hoping that we can extend upon this work in meaningful ways and contribute more information about how the brain works,” Boston University cognitive neuroscientist Shrey Grover told Nature.
The research has been published in Nature Neuroscience.