  Poor laryngeal muscle coordination that results in abnormal glottal posturing
is believed to be a primary etiologic factor in common voice disorders such as
non-phonotraumatic vocal hyperfunction. Abnormal activity of antagonistic
laryngeal muscles is hypothesized to play a key role in the alteration of
normal vocal fold biomechanics that results in the dysphonia associated with
such disorders. Current low-order models of the vocal folds are unsatisfactory
to test this hypothesis since they do not capture the co-contraction of
antagonist laryngeal muscle pairs. To address this limitation, a self-sustained
triangular body-cover model with full intrinsic muscle control is introduced.
The proposed scheme shows good agreement with prior studies using finite
element models, excised larynges, and clinical studies in sustained and
time-varying vocal gestures. Simulations of vocal fold posturing obtained with
distinct antagonistic muscle activation yield clear differences in kinematic,
aerodynamic and acoustic measures. The proposed tool is deemed sufficiently
accurate and flexible for future comprehensive investigations of
non-phonotraumatic vocal hyperfunction and other laryngeal motor control
disorders.
