Measuring Stutterers’ Dynamical Vocal Tract Characteristics by X-ray Microbeam Pallet Tracking

Abstract

Stuttering is generally considered to be a disorder of motor timing, yet neither the nature of the spatiotemporal interruptions of speech movements nor the physiological level(s) at which they occur is sufficiently understood. In particular, two critical questions that bear on the nature and treatment of stuttering, and by extension, the role of timing in various aspects of normal speech production remain unanswered. The first question concerns the anatomical locus of disordered motor timing. To what extent is the aberrant neuromuscular and kinematic activity that is associated with moments of stuttering specific to a single anatomical structure rather than spread throughout the speech production system? An aberrant state associated with a single structure, the larynx for example, might trigger abnormal activity in the respiratory and/or supralaryngeal systems. In this example, where laryngeal dysfunction precedes respiratory and supralaryngeal dysfunction, the activity of the latter systems might be viewed as compensatory rather than as an integral part of the stuttering breakdown. That is, the respiratory and supralaryngeal systems might be functioning to maintain appropriate temporal relationships with the abnormal laryngeal gestures.