[Analysis of the EGG waveform of vocal polyps]

To study the effect of vocal polyps on vocal vibration, the authors analysed the EGG waveform of 201 cases of vocal polyps of various location and shape. The results showed that the EGG waveform in opening phase appeared a notch for vocal polyps with pedicle, and appeared steep for vocal polyps with a wide base. Among the polyps whose waveform appearing a notch in closing phase, most of their base located below vocal cord. Whether the polyps were located in the anterior, middle or posterior of the vocal cord and whether the polyps were unilateral or bilateral there are no effect on the EGG waveform. EGG was the potential technique for studying vocal function.