After conducting initial experiments in monkeys, Rubinstein and a collaborator, James Phillips, received approval for a 10-person clinical trial of the device, which is manufactured by the Australian company Cochlear. So far, the Yakima patient is the only one who’s received the device; the team has funding to implant devices in two additional patients. Rubinstein says it may take some time to evaluate the effectiveness, because the timing of Meniere’s attacks is unpredictable.
Daniel Merfeld, a balance researcher at Massachusetts Eye and Ear Infirmary who was not involved in the work, says that this device represents “a first step toward the long-term goal of sensory replacement via a vestibular implant.” A handful of groups in the United States and Europe, including Merfeld’s, have been working on a prosthetic device that would help people with balance disorders of the inner ear, similar to the way a cochlear implant allows deaf people to hear sounds. A cochlear implant picks up sounds from the environment and translates them into electrical signals that stimulate the auditory nerves.
In simple terms, a vestibular implant would replace the microphones of an auditory implant with motion sensors, and adapt the electrical signals for the vestibular nerves. The devices would sense motion of the head and translate that sensory information into electrical impulses. Merfeld says that each team has had good results in animals, and that the goal of replacing the sense of balance seems technically feasible in the next several years. “What’s needed is a lot of research and some successful clinical trials,” he says.
In the meantime, the current device is an intermediate step in that process, as it does not sense or adapt its signals to head motion and does not replace the body’s own balance system, but is merely designed to override the function of the ear as it recovers from an attack. Rubinstein says that such a device is an attractive first foray into vestibular implants because it does not destroy existing function and does not require regulatory approval of a totally novel device.