CAREER: Functional Electrical Stimulation to Aid Phonation in the Presence of Unilateral Vocal Fold Paralysis

Virginia Polytechnic Institute And State University, Blacksburg VA

Investigators

Abstract

Leonessa 1055315 The objective of the proposed CAREER program is to engage and educate undergraduate and graduate students in the multidisciplinary field of bioengineering with particular focus on the understanding and control of muscle behavior using functional electrical stimulation. The proposed plan includes theoretical analysis, experimental investigation, and course development. The proposed research component aims to develop and validate a framework that will help to implement an efficient Functional electrical stimulation (FES) controller for human vocalization purposes. This framework will enable control of paralyzed vocal folds improving the ability of patients affected by unilateral vocal fold paralysis to communicate effectively. In a longer term, the PI?s plan is to considerably improve the quality of life of patients with unilateral and bilateral vocal fold paralysis. The principle of FES is to use surface or implantable electrodes to generate pulses of current in intact motor neurons, thereby inducing contraction of these muscles and corresponding movement. Several challenges hinder the application of closed-loop FES outside of research labs, such as the highly nonlinear and time-varying characteristics of muscles. Furthermore, a stimulated muscle changes when fatigue occurs and individual muscle models are different. Even more challenging is the fact that there is a significant delay between stimulation and muscle contraction, adding to the processing and transmission delays in the electrical stimulation system. The PI proposes to address the closed-loop FES problem using an Output-Based Reference Control approach. The development of a robust control strategy in cooperation with voice-driven data acquisition and a novel electrode array for stimulation purposes will provide a framework for guiding rehabilitation strategies for specific impairments. Through the collaboration with rehabilitation clinicians at Wake Forest, the PI will apply the techniques developed in this proposal to specific patient populations as a proof of concept. Intellectual Merit. The proposed activity will extend current nonlinear control techniques, such as backstepping, extremum seeking, Kalman filtering, and model reference control, to account for time delays, actuator amplitude and rate saturation limitations, and partial and noisy measurements, thereby substantially increasing the practical applicability of such algorithms. The real-time implementation and the requirements that the FES equipment is easy to setup and simple to use by therapists and patients add additional constraints to the control structure, which needs to be robust yet not overly complicated. The intellectual merit of this effort also lies in the opportunity to use these tools to advance understanding of the dynamic behavior of muscles and to investigate the possibility of controlling this behavior using feedback control techniques. The proposed activity will explore creative, original, and potentially transformative concepts by considering an active, minimally invasive, closed loop control system for vocalization purposes. Breathing and swallowing have received a lot of attention for patients with vocal fold paralysis, but vocalization is still considered an open problem with unresolved issued due to the complexity of the larynx and the difficulties in stimulating the relevant muscles, without invasive surgeries, given their depth in the neck. The proposed development of a robust control strategy in cooperation with voice-driven data acquisition and a novel electrode array for stimulation purposes will provide a solution to these issues. Broader Impact. The proposed research offers many potential benefits to society, including the possibility of improving the quality of life for patients with paralysis, as well as individuals with other neuromuscular disability including traumatic brain injury, multiple sclerosis, cerebral palsy, and Parkinson?s disease. Development of a robust control strategy in cooperation with muscle-driven simulations of movement will provide a framework for guiding rehabilitation strategies for specific impairments. Through potential future collaborations with rehabilitation researchers and clinicians, the PI plans to apply the techniques developed in this proposal to specific patient populations. The proposed activity will advance discovery and understanding of muscle dynamics while promoting teaching, training, and learning through the development of new courses as well as several camps and workshops targeting both youths and teachers. The participation of underrepresented groups is guaranteed by specifically addressing summer camps for female students as well as organizing a new summer camp dedicated to students with disabilities. The proposed effort will enhance the infrastructure for research by establishing partnerships with the medical community at Wake Forest University. From an educational point of view, the partnership and training of K12 teachers and implementation of state of the art teaching techniques (such the Universal Design for Instruction) will enhance the PI's ability to expose younger students and minorities to the field of bioengineering and several other activities. The results obtained through the proposed effort will be disseminated through the standard channels, such as conference and journal papers, but will also be made available using dedicated websites such as Connexions and the National Science Digital Library.