Quantitative contributions of the muscles of the tongue, floor-of-mouth, jaw, and velum to tongue-to-palate pressure generation.

Purpose: The purpose of this investigation was to evaluate the relationship between tongue-to-palate pressure and the electromyography (EMG) measured from the mylohyoid, anterior belly of the digastric, geniohyoid, medial pterygoid, velum, genioglossus, and intrinsic tongue muscles. Methods Seven healthy adults performed tongue-to-palate pressure tasks at known percentages of their maximum pressure while intramuscular EMG was recorded from the muscles stated above. Multiple regression analysis was performed.

Patterns of laryngeal electromyography and the activity of the respiratory system during spontaneous laughter.

Laryngeal muscle electromyography (EMG) and measures of the behavior of the respiratory system have been made during spontaneous laughter in two groups of subjects. The smaller group also had a direct measure of tracheal pressure during this behavior. Laryngeal adductors such as the thyroarytenoid (TA) and lateral cricoarytenoid (LCA) exhibited brief high-amplitude bursts of activity, at a rate of approximately 5 Hz, which were usually associated on a 1 : 1 basis with the sound bursts (ha ha ha) of laughter.

Synchrony of laryngeal muscle activity in persons with vocal tremor.

Objective: To determine if the tremor activity in laryngeal muscles is synchronous, which would indicate a single central source of tremor.

Design: Six persons with vocal tremor participated in this study. Laryngeal muscle activity was recorded from 2 intrinsic and 2 extrinsic laryngeal muscles during production of a sustained \i\ sound.

Effect of substance P injection into the nucleus tractus solitarius of rats on cricothyroid and thyroarytenoid motor activity and cardiovascular and respiratory systems.

Identification of central neurotransmitters that mediate laryngeal adductor and/or tensor activity may prove useful in managing pathological laryngeal adduction as occurs in laryngospasm or apparent life-threatening events. The putative transmitter substance P (SP) is found in the nucleus tractus solitarius (NTS), in which laryngeal afferents terminate. Therefore, we studied the laryngeal, cardiovascular, and respiratory effects of SP injected into the NTS of rats.

Sustaining a constant effort by the tongue and hand: effects of acute fatigue.

A constant-effort task was used previously as a potential assessment technique for fatigue. Participants sustained submaximal target effort levels with the tongue and hand against soft air-filled bulbs. For 80% of all trials, pressure decreased exponentially to a positive asymptote.