The goal of this program is to create an implantable stimulator device to restore functional eye blink in patients with unilateral facial nerve paralysis. The system will electrically stimulate the paretic eyelid when EMG electrodes detect normal blink from the contralateral eye to produce a synchronous blink. The implant will consist of a thin, ceramic package placed subcutaneously above the hairline with an EMG electrode pair for detecting contralateral blink and a thin-film stimulating array implanted on the paretic orbicularis oculi muscle (OOM). We have designed this system to include a polyimide flex circuit thin-film stimulation array, which is implanted along the length of the palpebral component of the paretic orbicularis oculi muscle. Multiple stimulation sites will allow clinicians the ability to selectively activate all necessary muscle tissue to evoke spontaneous blink via a diffuse injection of low levels of current across the array. The system will include a pair of EMG recording electrodes implanted into the contralateral intact orbicularis oculi muscle to detect normal reflexive blink. This detected blink single will be relayed to implanted circuitry inserted above the hairline in the scalp, which will trigger stimulation causing a synchronous blink. The device will be powered by a small, external module worn behind the ear, which activates the implanted with a wireless reflected impedance signal and provides a user interface to control stimulation intensity. The implant will be inductively powered from an external system consisting of a battery, stimulation control, and a low frequency RF inductive coil placed near the patient's implant. This external power configuration has the advantages of decreasing the size of the implanted device and increasing the lifetime of the device by avoiding an implanted battery. The market for these devices is relatively small with annual patient populations on the order of a few thousand per year. For these patients, however, the availability of this technology will provide a profound improvement in quality of life and reduction of total care costs due to complications related to exposure of the affected eye.
The implantable blink prosthesis system produced in this program will provide a fundamental improvement in the treatment of facial paralysis. These improvements will apply to both the aesthetic and functional use of the paralyzed eyelid preventing painful ocular ulceration and profound facial disfiguration.
