Relationships Among Stimulability Testing, Patient Factors, and Voice Therapy Compliance

Objective: Voice stimulability testing to determine voice therapy efficacy and prognosis is commonly used during the voice evaluation, but little is known about how patient factors (eg, voice diagnosis, dysphonia severity) can influence stimulability outcomes. The predictability of voice therapy success with different stimulability facilitating techniques (eg, hums, pitch glides) is also unknown. The goals of this study were to identify relationships between patient factors, voice therapy compliance, and stimulability testing. Methods: A retrospective chart review was conducted on 50 patients who were seen for their initial voice therapy evaluation at the UT Southwestern Clinical Center for Voice Care. Chart review included documentation of the stimulability tasks that yielded/did not yield voice changes, level of stimulability, voice diagnosis, clinician-rated auditory-perceptual analysis of vocal quality, therapy attendance, and compliance with voice therapy recommendations. Statistical analysis was conducted to determine whether the types of facilitating techniques, voice diagnosis, and dysphonia severity could predict how stimulable patients were and whether any stimulability techniques could predict voice therapy attendance and compliance. Results: Patients diagnosed with functional voice disorders (eg, muscle tension dysphonia) were 11 times more likely to be stimulable for voice improvements than patients with neurological voice disorders (eg, vocal fold paralysis). Patients with lower dysphonia severity were more likely to be stimulable than patients with high dysphonia severity. Specific facilitating voice tasks did not predict the level of stimulability. Stimulability level was not predictive of therapy attendance or compliance with therapy recommendations. Conclusions: Voice diagnosis and severity of dysphonia influenced stimulability levels. However, voice stimulability was not predictive of voice therapy attendance or compliance, and no specific facilitative task predicted the level of stimulability. Future investigations should focus on other means of measuring a patient's motivation for change and on the predictive power of stimulability testing on voice therapy outcomes.