Electrolaryngography in laryngeal disorders

Abstract

This study was designed to analyse recordings of vocal fold vibrations using the laryngograph, a machine which measures the change in electrical impedance across the larynx. Recordings were made of each patient reading a standard text. The output was analysed in two ways: by study of waveform, and by production of a frequency distribution curve, this last being performed by a PDP 12 computer. Analysis shows an increase in the low frequencies and irregular curve associated with hoarseness but no pattern specific for different diseases. After operation and speech therapy an objective measure of success or failure is provided. But for practical use other than in research a less time consuming method of analysis is necessary. Production of this is being considered.