Envoy Medical Corporation has received FDA approval for Esteem, an implanted hearing system used to treat moderate to severe sensorineural hearing loss, a type of permanent hearing loss.

As a condition of FDA approval, Envoy Medical must conduct two post-approval studies. In one study, the company 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.

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.

Envoy Medical said that the system is designed to alleviate the effects of hearing loss in patients of 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.

Envoy Medical said that in a multicenter clinical study of Esteem versus pre-implant hearing aids, 93% 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% scored better than with their pre-implant hearing aids.

Seven percent of participants experienced facial paralysis, and 42% 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.

Jeffrey Shuren, director of the center for devices and radiological health at FDA, said: “The approval of Esteem provides patients with an option to alleviate their hearing loss by using a device with no readily visible external components.”