Electrical current from a cochlear implant has guided corrective genetic material into inner ear cells and stimulated nerve regeneration in deaf guinea pigs. The treatment improved the animals’ hearing sensitivity and range, researchers report April 24 in Science Translational Medicine. The gene therapy technique, which does not use viruses that could induce immune reactions, holds promise for improving the hearing of people with cochlear implants. It may also have applications in deep brain stimulation, the scientists say.