Electrical Stimulation of Paralyzed Orbicularis Oculi

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DESCRIPTION (provided by applicant): Paralysis of the orbicularis oculi muscle results in incomplete eyelid closure during both voluntary and reflex movement. Since eyelid closure is the means by which the cornea is lubricated, functional deficits in the ability to close the eyelid can lead to damage to the cornea and permanent vision impairment. Current methods for ensuring eye closure include gold weights attached to the eyelid, artificial tears, and tarsorrhaphy (suturing the eye closed). All these methods aid in the preservation of the cornea, but often are not fully effective, are inconvenient, and can limit vision. Functional electrical stimulation has been proven effective for activating muscle and nerve over many years. Other studies have demonstrated that electrical stimulation of the orbicularis muscle can restore the ability to close the eye in animal models for a limited period of time. However, the previous research in this area is minimal and has not investigated the electrical response characteristics of the orbicularis muscle in great detail. Also, the longest term of continuous stimulation of any published account is 30 days. To prove safety and effectiveness of a stimulating device, it will be necessary to increase the length of time of implantation and stimulation. In addition, the effectiveness as related to the length of paralysis should be studied. The hypothesis guiding this research is that functional electrical stimulation can effectively restore the function of the orbicularis oculi muscle for up to six months in animal models of seventh nerve paralysis. To investigate this hypothesis, experiments will be conducted to determine the effects of stimulating electrode position and stimulus waveform on the muscle response and the effects of length of paralysis on the muscle response. The results of these initial experiments will lead to the design and implementation of a chronic stimulating electrode. The stimulator will be chronically implanted and activated for six months.