Rick M. Roark

Observations of recurrent laryngeal nerve injury and recovery using a rat model.

To evaluate standardized recurrent laryngeal nerve (RLN) injuries using a rat model via minimally invasive transoral electromyography (ToL EMG) and histologic studies.

Electromyographic and histologic evolution of the recurrent laryngeal nerve from transection and anastomosis to mature reinnervation.

To describe the natural evolution of recurrent laryngeal nerve (RLN) reinnervation in an animal model.

Evaluation of Functional Recovery of Recurrent Laryngeal Nerve Using Transoral Laryngeal Bipolar Electromyography : A Rat Model

Objectives: We developed a standardized method of minimally invasive transoral laryngeal (ToL) bipolar electromyography (EMG) for evaluation of recurrent laryngeal nerve (RLN) recovery after a controlled crush injury in a rat model. Methods: Ten 200- to 250-g Sprague-Dawley rats underwent a controlled crush injury to the left RLN performed with 60 seconds of use of a calibrated aneurysm clamp with a closing force of 0.61 N. Serial ToL bipolar EMG was performed on adductor muscles and the posterior criocoarytenoid muscle during spontaneous vocal fold motion under anesthesia. Each animal underwent ToL EMG immediately after surgery and 1, 3, and 6 weeks after surgery. Results: The EMG signals showed normal motor unit potentials and recruitment patterns 3 weeks after crush injury. Endoscopic evaluation of vocal fold mobility yielded consistently normal findings 6 weeks after crush injury. Conclusions: We have developed a standardized method of crush injury to the rat RLN model and a minimally invasive transoral bipolar spontaneous EMG technique to serially evaluate and follow nerve injury and recovery in rats. This model is intended to simulate intraoperative RLN injury, to elucidate the electrophysiological events that occur during nerve recovery, and to form the basis for studying agents to enhance such recovery.

Assessing and Documenting General Competencies in Otolaryngology Resident Training Programs

Objectives: The objectives of this study were to: 1) implement web‐based instruments for assessing and documenting the general competencies of otolaryngology resident education, as outlined by the Accreditation Council of Graduate Medical Education (ACGME); and 2) examine the benefit and validity of this online system for measuring educational outcomes and for identifying insufficiencies in the training program as they occur.

Systems Architecture for Quantification of Dynamic Myoelectric and Kinematic Activity of the Human Vocal Tract

This paper describes a systems architecture useful for scientific investigations that require the acquisition and analysis of multiple, time-synchronous signals in large volume. The architecture has recently been developed by this group to enhance our capability to research and quantify central nervous system function in the production of normal and pathologic speech. The architecture utilizes modern advances in desktop microcomputers and has been designed so that vocal motor control laboratories (or similar settings) with modest funding can more fully participate in comprehensive investigations of speech production. Research experiments organized with this architecture may involve many more subjects and measures than previously possible without significant increases in time and personnel resources. This paper will demonstrate the technique and practicality of this architecture as it is being used to successfully guide research to map hierarchic central nervous system regions of involvement in two speech disorders: Spasmodic dysphonia and stuttering. The architecture has broad usefulness to many areas of otolaryngology and health science.

Spectral myoelectric analysis of thyroarytenoid activity in normal and spasmodic dysphonia subjects

Time‐synchronous digital recordings of thyroarytenoid (TA) myoelectric activity (via percutaneous hooked‐wire electrodes) were obtained for 10 normal control and 11 spasmodic dysphonia subjects during performance of five vocal tract tasks of increasing motoric complexity: (1) quiet breathing, (2) Valsalva maneuver, (3) whispered ‖i‖, (4) voiced ‖i‖, and (5) Beep beep went the heap. Three‐dimensional power spectral density functions, PSD(f,t), were determined for a selected segment of the signals, and measures of median frequency, mean frequency, bandwidth, and center frequency of PSD(f,t) were derived for each sample point. Statistical median, mean, standard deviation, maximum, minimum, and mode of the PSD measures were computed to compose feature vectors for each signal. Discriminate analysis and maximum likelihood classification tests were applied to obtain global discrimination measures for the two subject populations as a function of task performance. Results of the analysis are reported that reveal a...

Quantitative analyses of thyroarytenoid activity in spasmodic dysphonia

Perceptual ratings of vocal abnormality in spasmodic dysphonia (SD) are confounded by high variability in the severity, quality (strain‐strangle versus aspirate), and task sensitivity of symptoms. Perceptual ratings are also relatively distant from the physiologic source of vocal disruption. Investigations at the neuromuscular level are closer to the source of disruption and may be informative. Thyroarytenoid myoelectric activity was recorded while SD and normal control subjects produced multiple tokens of sustained vowel, word repetition, and sentence tasks. Quantitative amplitude measures were submitted to several principal components analyses to develop models of neuromotor abnormality in SD. Analyses yielded quantitative indices of the magnitude and task‐sensitivity of thyroarytenoid activity. A between‐group model that included one measure across the three tasks achieved 100% discrimination of normal control and SD subjects on one component. The within‐group model failed to separate perceptually diff...