An electrical brain-stimulation technique used to treat Parkinson’s disease and chronic pain appears to enhance human memory as well, according to a tiny but intriguing new study that bolsters hope for one day developing a nondrug treatment for memory problems, including ailments like Alzheimer’s disease.
The new study, published in the New England Journal of Medicine, focused on seven patients with severe epilepsy whose memory abilities ranged from normal to severely impaired. They had electrodes implanted through a hole in the skull in order to detect the source of their seizures. This gave researchers the chance to send an undetected burst of current to different brain regions, known as deep-brain stimulation, and observe changes in memory.
The participants completed a task where they pretended to be taxi drivers who needed to drop off passengers at stores on different blocks. Researchers stimulated the brains of participants when they were learning the location of half the stores but not the others. Participants were tested for how well they remembered the location of the stores.
All patients, regardless of how good their memory was, saw improvement in their memory after stimulation in a particular brain region known as the entorhinal area. Stimulating areas just millimeters away showed no benefit.
The entorhinal cortex is an area of the brain that is one of the first to be damaged by Alzheimer’s. Fibers from that region transmit the sensory information to the hippocampus, a brain region critical to learning and memory. The thinking is that the stimulation enhanced learning or the encoding of memories, perhaps by resetting the electric rhythm of brain cells within the hippocampus, according to Itzhak Fried, a study author and professor of neurosurgery at the University of California, Los Angeles, and Tel Aviv University in Israel.
The work is preliminary, and extensive follow-up is needed. But, “the hope would be that this type of approach—deep-brain stimulation—can be used to help people with memory problems,” Dr. Fried said.