These epilepsy patients were being assessed for a future operation, meaning that electrodes were already being slipped into their brain to see what type of probing can cause or prevent seizures. As plenty are placed in the memory centers of the brain, this provided the team with a good chance to test out their new device.
Rather than send continuous pulses of electricity into the brain, it operated when it detected a lull in the brain’s memory storage abilities, and shut off when it registered when it was working well. The patients couldn’t feel when the device was on or not; it caused no pain or any physical sensation at all.
Using word recall tests – reading through a list of words and trying to remember them a bit later – they found that patients did around 15 percent better at the tests when the implant was active.
The ability of the device to respond to specific brain states is known as a “closed-loop design.” Other papers attempting the same memory-boosting feat tended to use open-loop designs, those that use continuous, high-frequency stimulation.
The team’s Department of Defense-funded paper explains that the “literature shows that direct open-loop stimulation of the hippocampus and medial temporal lobes is unlikely to reliably improve memory.” They state that their closed-loop device, which targets the left lateral temporal cortex, has “provided proof of concept for the therapeutic treatment of memory dysfunction.”
Again, it’s early days. Far more data is required before any firm conclusions are made, and remember, this trial only involved people with epilepsy.
Although agreeing that this work still involved a small sample size, Dr Mark Dallas, Lecturer in Cellular and Molecular Neuroscience, University of Reading, told IFLScience that “this is a more robust study than the previous [Alzheimer’s] study.”
He added, however, that “without the relevant controls, this could be a placebo effect.”