The U.S. Food and Drug Administration today announced the approval of the Esteem - an implanted hearing system used to treat moderate to severe sensorineural hearing loss, a type of permanent hearing loss.
Sensorineural hearing loss is usually caused by genetic factors or damage to the inner ear resulting from noise, viral infections, or aging. The results are reductions in perception of sounds and in the ability to understand speech.
This differs from conductive hearing loss, which occurs when sound waves cannot transmit well through the outer or middle ear or both. Medical or surgical treatment can often restore hearing in people with a conductive hearing loss, which can be caused by earwax, fluid in the middle ear space, or a punctured eardrum.
The Esteem system consists of external testing and programming instruments and three implantable components: a sound processor, sensor, and driver. The sensor senses vibrations from the eardrum and middle ear bones and converts these mechanical vibrations into electrical signals, which are then sent to the sound processor, which amplifies and filters the signal to compensate for the individual patient's hearing loss. The driver converts the enhanced electrical signal back to vibrations, which are then transmitted into the inner ear where they are perceived as sound.
"The approval of Esteem provides patients with an option to alleviate their hearing loss by using a device with no readily visible external components," said Jeffrey Shuren, M.D., J.D., director of the FDA's Center for Devices and Radiological Health.
The system is designed to alleviate the effects of hearing loss in patients ages 18 years and older. Other criteria for the device include: stable bilateral sensorineural hearing loss, a normally functioning Eustachian tube, and normal middle ear anatomy. A patient's ability to understand speech using Esteem should be similar to that of conventional hearing aids.
In a multi-center clinical study of Esteem versus pre-implant hearing aids, 93 percent of Esteem recipients scored equal to or better than their pre-implant hearing aids on a speech intelligibility test. Seven percent scored less than with their pre-implant hearing aids, and 56 percent scored better than with their pre-implant hearing aids.
Seven percent of participants experienced facial paralysis, and 42 percent experienced taste disturbance, both of which are results of the surgical procedure necessary to implant the device. The majority of these adverse events resolved during the one-year study period.
As a condition of FDA approval, Esteem manufacturer, Envoy Medical Corporation of St. Paul, Minn., must conduct two post-approval studies. In one study, Envoy must continue to follow-up on 61 subjects from the original study for five years to study safety and effectiveness. Another study of 120 newly enrolled subjects will include an evaluation of the incidence of facial paralysis at one month after implantation, and evaluate the effectiveness of Esteem five years after implantation.