Jitter is the cycle-to-cycle variability of the period duration of the acoustic signal coming from voice production. It is used as one way to assess the micro-instability of vocal cord vibrations, and is one of the acoustic measures often used by adherents of the technology-driven diagnostic model.
However, given that it can vary dramatically with changes of voice production within the same voice, and also that a given jitter measurement is non-specific to any particular voice disorder, it is considered superfluous to the integrative diagnostic model and is not used routinely at our practice.