The first results are promising for the two types of memory performance. But experts see the extent of medical use.
On which conveyor belt can one still pick up a suitcase? It was just announced. And on which parking deck did you park the car before the two-week vacation? On the one hand, the so-called “working memory” provides the answer – to stuff information that has just been taken for granted. Long-term memory, on the other hand, stores information in your own car for the drive home.
This brain performance develops very differently in people and tends to decline with age. A recent study with healthy older people suggests that both types of non-invasive electrical brain stimulation can improve memory performance.
A research team led by Boston University’s Shrey Grover and Robert Reinhart says it could make everyday activities easier for people in many countries, given the aging of the population. Electrical brain stimulation for four consecutive days was able to improve memory performance for up to one month in people aged 65 and older, Report researchers in the journal “Nature Neuroscience”,
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a tickling sensation on the scalp
For the study, electrical currents were conducted through electrodes into a cap worn by 150 participants between the ages of 65 and 88. Test individuals unanimously reported a tickling sensation on the scalp at the onset of stimulation. The method is known as transcranial alternating current stimulation, which stimulates brain oscillations and is said to be known as neuroplasticity. These are experiential changes in the brain that form the basis of learning and memory.
During the 20-minute session, subjects listened to lists of 20 words to remember. The researchers targeted two brain regions with two different stimulation frequencies: Stimulating the inferior parietal lobe at a frequency of four hertz improved the recall of words at the end of the list — a sign of storage in working memory. Stimulating the dorsolateral prefrontal cortex at 60 Hz supported the recall of words at the top of the list, indicating long-term memory retention.
The participants with the lowest cognitive performance at the start of the study benefited the most from brain stimulation. Further investigation should show whether the recorded effects last for more than a month. The authors suggest exploring implications for people with neuropsychiatric and neurodegenerative disorders, in addition to potential benefits for healthy older adults.
“little practical use for the clinic”
“The experimental approach is not complicated,” said neurologist Wolf-Julian Neumann of the Berlin Charité The Science Media Center Germany (SMC). In the future, such techniques could potentially be used at home as well. “However, no direct therapeutic approach can currently be obtained from this study, as the effect shown is very specific and small.” They limit themselves to repeating words that have been read aloud. And the effect has only been proven for learning during electrical stimulation.
Johannes Lewin of the German Center for Neurodegenerative Diseases questions the point of treating cognitively healthy people with electrical brain stimulation. Although the study authors found remarkable results in the area of language memory performance, it “looks like brain performance adaptation rather than actual therapy in this setting,” Levine told SMC. The authors also did not examine whether the subjects’ quality of life improved.
“In my opinion, this is not of much practical use for the clinic,” says Paul Lingor, a neurologist at the Technical University of Munich. One might ask whether traditional cognitive training is not as effective or better and would have other positive effects as well.
