Which instrument is best used for measuring vocal fold vibration indirectly?

The correct instrument for measuring vocal fold vibration indirectly is electroglottography. This technique involves placing electrodes on the surface of the neck, which allows for the measurement of the electrical impedance of the vocal folds during speech or phonation. As the vocal folds vibrate, the impedance changes due to the alternating contact and separation of the folds, enabling the calculation of the frequency and amplitude of their movement.

Electroglottography provides valuable insights into vocal fold function without needing to visualize them directly, making it a non-invasive tool widely used in both clinical and research settings. By capturing the changes in electrical conductance as the vocal folds open and close, clinicians and researchers can evaluate voice quality, identify vocal disorders, and monitor the effects of various treatments.

In contrast, electromagnetic articulography is used to track the movements of articulators like the tongue and lips, which do not provide direct information about vocal fold vibration. A pneumotachograph assesses airflow and provides information on respiratory function but does not measure vocal fold activity itself. A strain belt is used to monitor changes in neck circumference or other physical parameters rather than directly measuring vocal fold vibration.