Vocal fold paralysis affects approximately 7.5 million Americans. Paralysis can be caused by numerous conditions, including head, neck or surgical trauma, endotracheal intubation, neurological conditions, cancer, tumors, just to mention a few. Currently, vocal fold paralysis treatment involves surgery and voice therapy. The vocal folds are composed of a three part material stretched along the larynx, which enables frequency change. Intrinsic laryngeal muscles coordinate the motion of vocal folds during respiration, vocalization, and aid in airway protection. Sensory information is carried by the Superior Laryngeal Nerve (SLN) and the Recurrent Laryngeal Nerve (RLN). Injury to the RLN results in paralysis of all laryngeal muscles excluding the cricothyroid muscle [1]. Although optimal larynx reinnervation has been extensively researched and implemented to improve voice paralysis [2], voice electrotherapy offers an alternative to effectively stimulate the larynx muscles for voice production, breathing and airway protection. One of the main causes of voice disorders is neurological in nature and causes abnormal vocal fold vibration. Of particular importance to this research is paralysis due to RLN injury, which causes acute temporary paralysis [3]. Currently, invasive electrical stimulus is used to activate muscle function; however, abnormal activation of muscle patterns causes muscles to function out of synchronization resulting in low vocal output [4]. For this reason, our work focuses on the development of an effective electromagnetic stimulation system to aid patients with unilateral vocal fold paralysis by stimulating the RLN and in turn reinnervating the adequate laryngeal muscles involved in the vocal fold motion for the purposes of sound vocalization, respiration, and airway protection. So far, a proof of principle has been developed and evaluated to assess the system’s feasibility. The preliminary experiments have been conducted using BioMetal Fibers (BMF) (Toki Corporation, Japan), which are fiber-like solid state actuators designed to contract and extend similar to muscles. BMF contracts when stimulated through a current generated in this case through an electromagnetic field.

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