Date of Award

Spring 2018

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Biomedical Engineering - (Ph.D.)

Department

Biomedical Engineering

First Advisor

Sahin, Mesut

Second Advisor

Adamovich, Sergei

Third Advisor

Deutsch, Judy

Fourth Advisor

Foulds, Richard A.

Fifth Advisor

Ihlefeld, Antje

Abstract

The extrinsic tongue muscles are activated in coordination with pharyngeal muscles to keep a patent airway during respiration in wakefulness and sleep. The activity of genioglossus, the primary tongue-protruding muscle playing an important role in this coordination, is known to be modulated by several reflex pathways mediated through the mechanoreceptors of the upper airways. The main objective is to investigate the effectiveness of activating these reflex pathways with mechanical stimulations, for the long-term goal of improving the upper airway patency during disordered breathing in sleep. The genioglossus response is examined during mandibular and sub-mandibular mechanical stimulations in healthy subjects during wakefulness. The genioglossus activity is recorded with custom-made sublingual EMG electrode molded out of silicone. Mechanical vibrations are applied to the lower jaw at 8 and 12 Hz with an amplitude of 5 mm in the first experiment, and to the sub-mandibular area at three different intensities (0.2-0.9 mm, 21-33 Hz) in the second experiment. The effects of sub-mandibular mechanical vibrations are also investigated in severe obstructive sleep apnea patients during a whole night sleep study. The major findings of this study are that the genioglossus reflexively responds to the mechanical vibrations applied to the mandible and the sub-mandibular skin surface in healthy subjects during wakefulness and the sub-mandibular stimulations during sleep terminate the apnea earlier and decrease the level of hypoxia with smaller micro arousals.

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