What does Electroglottoscopy (EGG) measure?

Electroglottoscopy (EGG) primarily measures electrical impedance changes associated with the vibrations of the vocal folds during phonation. It involves placing electrodes on the surface of the neck over the thyroid cartilage, which allows the detection of variations in the electrical signal as the vocal folds open and close during speaking or singing. These impedance changes provide valuable insights into the function and health of the vocal folds; for example, it can show patterns of vocal fold closure, which is critical in assessing vocal quality and diagnosing voice disorders. This method is particularly useful because it is non-invasive and provides real-time data about vocal fold movement, contributing significantly to voice research and clinical practice.

The other options, such as measuring vocal fold length, air pressure in the larynx, or sound frequency of speech, pertain to different aspects of vocal function and cannot be assessed directly by Electroglottoscopy. Thus, focusing on electrical impedance changes is what defines this technique and highlights its relevance in the study of voice and speech science.