Technology provides new understanding of voice, swallowing physiology

A current study is enrolling both healthy human patients and those with one immobile vocal fold — a condition that can occur due to a stroke or virus or after a surgery. Patients with an immobile vocal fold often report having a hoarse voice or difficulty drinking from a cup.

In addition to determining whether the process is tolerable for patients through this pilot research, the team is using the new data to more fully describe the physiology of voice and swallowing. Howell said the new knowledge will change how the field understands the intersection of voice and swallowing, providing new approaches for voice box and swallowing surgeries.

“There’s an anatomic area of the voice box that just is not appreciated, and you just can’t visualize it with what we currently use,” she said. “We’ll have a better understanding of the physiology, and then you can actually make more sense of the surgeries that you’re doing and the things that you’re doing for anatomic variance.”

Howell is also collaborating with Liran Oren and Charles Farbos de Luzan’s Laryngeal Biomechanics Laboratory to learn more about vocal fold vibration and stiffness. Aerospace engineers by training, Oren, PhD, and Farbos de Luzan, PhD, use airflow and aerospace principles to understand voice production. Just like a plane needs airflow to hit its wings in a streamlined fashion to keep the ride smooth, streamlined air flowing over the vocal cords leads to a strong voice.

The same surgical techniques and vocal cord implants employed to restore voice function that were pioneered in the 1940s are still often used today, and patients improve, but they do not get back to their normal voicing. 

In the lab, the team uses an artificial lung to blow air through animal model larynges and various implants to create a sound. After Howell prepares each model with an implant or surgical technique she wants to test, high-speed cameras, lasers and microphones capture a wide variety of data.

Tangible hard data can help remove the anecdotal or subjective perception of vocal cord surgeries’ outcomes, said Farbos de Luzan, assistant professor in the UC College of Medicine’s Department of Otolaryngology and the UC College of Engineering and Applied Science’s Department of Biomedical Engineering.

“Surgeons rely mostly on acoustic feedback during surgery of patients with unilateral vocal fold paralysis to assess voice improvement,” said Farbos de Luzan. “The long-term goal of this research is to educate laryngologists on the mechanisms of voice production from a physical standpoint.”

As the research progresses, the team will use the current data gathered to develop and validate computational models that can be used as diagnosis tools, and eventually virtual surgery predictors, to help surgeons choose the best treatment for patients.

“The part that’s really fun working with this lab is that they understand the physics in a way that I don’t, but I can tell them this is what we actually do in surgery,” Howell said. “It’s a really fun collaboration to be able to think of things in a very different way.”

The research is part of an NIH grant R01DC009435-12 from the National Institute of Deafness and Communication Disorders, with Oren serving as principal investigator, with Gregory Dion, MD, and Jacob Michaud-Dorko also on the team. Additional collaborators on the high-speed videoendoscopy research include Amna Mira, PhD, and Andres Llicos, PhD.

Read recently published research in the European Archives of Oto-Rhino-Laryngology.

Featured photo at top of Charles Farbos de Luzan and Jacob Michaud-Dorko in the lab. Photo/Andrew Higley/UC Marketing + Brand.