EMG as a Method to Predict 5-FU Injection Efficacy

Vocal fold (VF) scarring is one of the primary causes of dysphonia, which is a condition that affects as many as 1 in 11 Americans and can reduce quality of life by impeding the ability to communicate. In normal VF function, the superficial and deep layers of the VF move independently of one another. VF scarring can couple these layers, impeding VF movement and manifesting as dysphonia. It is therefore worthwhile to investigate treatments that can improve vocal fold scarring, thus helping to alleviate symptoms of dysphonia and improve quality of life.

Dexamethasone injection has been the standard VF scar treatment, however this treatment has a high rate of failure. More recently, 5-Fluorouracil (5-FU) injections have shown promise in improving vocal fold scarring at a higher rate than dexamethasone. Despite this, the failure rate is still significant. Therefore, finding markers to predict an individual’s reception to 5-FU treatment is worthwhile.

Electromyogram (EMG) can be used to assess thyroarytenoid muscle function and is performed as a baseline diagnostic procedure in the clinic at which the research is being conducted. Because increased muscle function would be expected to generate more movement of the surrounding mucosa, we expect that muscle function could be used as a predictor of the amount of VF scarring. Our research therefore seeks to identify a link between EMG results and 5-FU injection effectiveness, which would help clinicians predict whether a patient is a good candidate for 5-FU treatment. We predict that there will be a positive correlation between a patient’s baseline EMG and their response to 5-FU treatment.

In this study, data will be collected from patients who have received 5-FU treatment for vocal fold scarring. Data collected will include baseline EMG results, improvement in vocal fold vibratory function (measured via mucosal wave), VF scar size, VF stiffness, and glottic gap.