TASK-SPECIFIC ORGANIZATION OF ACTIVITY IN HUMAN JAW MUSCLES (EMG, SPEECH, COORDINATION, MANDIBLE)
Abstract
The activity of human jaw muscles was observed during the performance of a range of tasks, including mastication, voluntary oscillation, discrete movements, isolated speech utterances, and continuous speech production. Electromyographic recordings of masseter, temporalis, medial pterygoid, and anterior belly of digastric muscles were subjected to two analyses: a cross-correlation analysis that indicated the degree of co-activation present between pairs of muscles and an analysis in which the amount of time all muscle groups were co-activated were computed. The relative timing of activation in these muscles was shown to be task-specific. These results and physiological properties of the jaw muscles were taken as support for the suggestion that the coordinative organization of the jaw system can range from reciprocal activation to co- activation of jaw-opening and closing muscles in order to optimize the mechanical state of the system for changing task demands.
Degree
Ph.D.
Subject Area
Speech therapy
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