The Low Mandible Maneuver: Preliminary Study of Its Effects on Aerodynamic and Acoustic Measures.

Objectives: The purpose of this preliminary study was to determine the aerodynamic and acoustic effects of the low mandible maneuver (LMM) as compared to normal voice production.

Methods: Ten participants with normal voice characteristics who were nonsingers produced sustained vowel and repeated syllable utterances during two different speaking conditions: using the LMM and using normal phonation posture. The LMM involves a wider vocal tract configuration with a lowered and relaxed jaw position. Acoustic recordings and analyses were performed to determine formants 1 and 2 (F1 and F2) and sound pressure level. Aerodynamic data were collected and analyzed to investigate the effects of the LMM on mean peak pressure, mean airflow, aerodynamic power, aerodynamic efficiency, and aerodynamic resistance.

Results: Participants showed greater aerodynamic efficiency, mean peak pressure, and sound pressure level during the LMM condition as compared to normal phonation. The LMM vocal tract configuration changes were also associated with a lowering of F1 and F2 relative to normal voice production.

Conclusions: The lowering of the mandible and increased oral area that occurred during the LMM increased vocal efficiency and sound output without significant change to parameters that can be associated with increased vocal effort. These changes in filter configuration were associated with changes in vocal tract resonances. The LMM was readily learned and implemented by healthy participants in this study, and may have utility for singers in training as well as people with hyperfunctional voice disorders.