Vector Laryngeal Electromyography

Principal Investigator: Rick Roark, Ph.D.

Enrollment: Open 

Objective: Electromyography is a procedure that records the electrical activity of muscle fibers, which depolarize each time they receive action potentials from the neural drive. EMG of laryngeal muscles has been used extensively by many investigators to determine the specific motor behavior of the larynx during phonation, including the control of loudness and pitch, and the critical roles performed by the larynx during respiration and swallowing. Researchers in the Department of Otolaryngology have worked with the NeuroMuscular Research Center of Boston University to develop a new EMG technology for laryngeal muscles, vector laryngeal electromyography, which provides a wealth of additional information about the upstream neural mechanism that controls the muscle. The technology is being applied to study various classes of disease, such as vocal fold paralysis/paresis, spasmodic dysphonia, and to identify "pattern signatures" within processed signals that indicate certain neurological diseases such as Parkinsons, for the purpose of improving early diagnosis.

Overview: The Department is co-recipient of a Bioengineering Research Partnership (Program Project) with Boston University to develop and implement a new clinical instrument to perform functional neural imaging via electromyography. Our Department will be applying the new technology to a clinical population having unilateral vocal fold paresis for the purpose of improving prediction of recovery (prognosis), which has historically proven difficult for this clinical condition. The study is funded by the National Institutes of Health. Dr. Rick Roark is a Co-Principal Investigator of the project.

Other Co-Principal Investigators of the five-year study include Dr. Mario Manto of the Free University of Brussels, applying the neural imaging technology to patients with cerebellar stroke; Dr. Zeynep Erim at the Rehabilitation Institute of Chicago, studying neural control changes in the aged population; and Principal Investigator Dr. Carlo De Luca of the NeuroMuscular Research Center at Boston University, examining neural control during muscle fatigue. Departmental Co-Investigators are Steven Schaefer, MD, James CL Li, MD, Lucian Sulica, MD and Craig Zalvan, MD.

Eligibility: Research subjects are being recruited for this study. If you are a physician treating unilateral vocal fold paresis of known etiology, please contact Dr. Roark for participation details.

Contact Information: Rick Roark, Ph.D., (212) 979-4200

Funding: The National Institutes of Health     [Read the abstract]

Selected Publications & Presentations:

Roark RM, Li JC-L, Schaefer SD, Adam A, De Luca CJ. Multiple Motor Unit Recordings of Laryngeal Muscles: The Technique of Vector Laryngeal EMG. Laryngoscope 2002, 112:2196-2201. [Abstract]

De Luca CJ, Nawab S, Adam A, Roark R, Manto M. Precision decomposition II for EMG signals: An NIH bioengineering research project. XIVth Congress of the International Society of Electrophysiology and Kinesiology, Vienna, Austria, June 2002.

Roark, RM., Dowling EM, DeGroat RD, Watson BC, Schaefer SD. Time-Frequency analysis of thyroarytenoid myoelectric activity in normal and spasmodic dysphonia subjects, Journal of Speech and Hearing Research 1995, 38:289-303. [Abstract]

Roark RM, De Luca CJ, Schaefer SD, Li JCL, Adam A, Wong H. Multiple motor unit recordings of laryngeal myoelectric signals, 29th Annual Symposium: Care of the Professional Voice, The Voice Foundation, Philadelphia, June 2000.

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Preliminary Results:

In A, the firing time plot of five active motor units (MU) of thyroarytenoid muscle during a high-pitched glissando /i:/ task for a 26-year old female normal subject, accompanied by the pseudo-force (PF) and acoustic signals. In B, the mean firing rate (MFR) plot. These data were obtained using the technique of Vector Laryngeal EMG and provide a functional image of lower neuron activity. It is hypothesized that features of motoneuron firing rate may help to predict recovery of laryngeal neural function.

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