Giving mild electric shocks to the brain could protect older people from short-term and long-term memory loss, research suggests.
It remains unclear as to whether the approach could help people with dementia. Robert Reinhart, an assistant professor at Boston University and a co-author of the study, said memory loss was a normal symptom of cognitive decline experienced as we age, and that forgetfulness could affect decision-making, planning and learning, for example.
Reinhart and his team found that targeting specific areas of the brain with a noninvasive weak electrical current in repeated 20-minute sessions over four days could help prevent memory decline for at least a month.
“Based on the spatial location and the frequency of the electrical stimulation, we could improve either short-term memory or long-term memory separately,” Reinhart said.
However, others said the study was limited to healthy participants and word recall, meaning the results would not necessarily apply to those living with dementia.
The team recruited 150 people aged 65 to 88. On four consecutive days, the researchers asked participants to recall five lists of 20 words while electrical signals were delivered to parts of the brain involved in short-term and long-term memory.
The researchers tracked the participants’ performance over the four days, as well as one month after the experiment. “We watched the memory improvements accumulate over time with each passing day, so that the memory enhancement in short-term memory and long-term memory were observable at the one-month timepoint,” Reinhart said.
The participants who were the most forgetful at the beginning of the study displayed the greatest gains a month after the treatment, said the researchers.
“Older people with poor general cognitive functioning at baseline – coming into the experiment – showed the largest improvements during the intervention and the one-month timepoint,” said Reinhart. This meant that electrical brain stimulation could help patients with more severe memory impairment, such as those with Alzheimer’s disease, he said.
“The effects on memory were of the order of remembering three to four more words out of a list of 20, but this improvement in memory ability was detectable one month after stimulation which is quite remarkable,” said Prof Masud Husain from the University of Oxford, who was not involved in the study.
Dr Susan Kohlhaas, the director of research at Alzheimer’s Research UK, who was not involved in the study, said: “This is a small early-stage study that showed some memory benefits for older people who received a type of noninvasive brain stimulation involving specialised equipment and very specific procedures.
“It is important to note that these participants did not have memory problems, and this research doesn’t tell us anything about the potential to slow cognitive decline caused by diseases such as Alzheimer’s. Many people experience changes in their memory skills as they get older and it’s not necessarily a sign of dementia. Anyone with concerns about their memory should speak to their GP.”
Prof Tara Spires-Jones, from the UK Dementia Research Institute at the University of Edinburgh, who was also not involved in the study, said: “This is promising work, and it shows how amazingly flexible and adaptable the brain is. However, the participants were given really specific word-list tasks, which might not be so representative of everyday activities.”
Regular exercise and lifelong learning are effective ways to slow memory decline, Spires-Jones said. “Keeping fit and healthy is very protective against cognitive decline and dementia. Taking good care of your body and mind is taking good care of your brain.”
