You searched for: “electrolaryngograph
electrolaryngograph, laryngograph, glottograph
1. An instrument for making a tracing of the movements of the vocal folds.
2. An instrument for recording the activity of the vocal cords during respiration and phonation or the rapid, periodic opening and closing of the glottis through separation and apposition of the vocal cords that, accompanied by breath under lung pressure, constitutes a source of vocal sounds.

The electrolaryngograph consists of a pair of electrodes, one for application to either side of the neck adjacent to the larynx, a generator, an amplifier, and an oscilloscope.