Functional Electrical Stimulation of the Larynx with a Flexible Ribbon Electrode Array

Abstract

Objectives:

This study explored the selectivity of epimysial stimulation of the larynx using multi-channel electrode arrays. Recruitment curves from electrode channels within the array were compared, focusing on differences between location of the electrode and specific muscle activation.

Methods:

This was a prospective, nonrandomized acute animal study. Four cats underwent surgical implantation of electrode arrays into the posterior cricoarytenoid muscle. The airway was secured with a tracheostomy, and the glottis was visualized with a 0° 4-mm telescope while individual and combinations of electrodes within the array were stimulated with varying current. Digitized recordings of stimulated vocal folds were analyzed using imageJ and the degree of vocal fold abduction was measured to create recruitment curves.

Results:

Electrodes implanted along the medial aspect of the posterior cricoarytenoid stimulated graded physiologic degrees of abduction depending on the amplitude of stimulation current. Electrodes implanted laterally along the posterior cricoarytenoid stimulated greater degrees of simultaneous adduction with abduction. The electrode array allowed mapping of most useful electrode position, so that only one implantation procedure was required to yield good results, thus limiting trauma to the larynx. Electrode arrays with more electrodes were more likely to contain electrodes that were appropriately positioned for optimal abduction.

Conclusions:

Acute studies of implanted electrode arrays into the posterior cricoarytenoid produce graded physiologic degrees of abduction necessary for respiration. Further chronic studies are warranted to investigate long term feasibility and durability of this electrode design.