Design of surface electrode array for electromyography in the genioglossus muscle.

The patency of the upper airway is dependent on the sustained activity of upper airway muscles, in particular the genioglossus (GG) muscles which act to protrude the tongue. Obstructive sleep apnea syndrome (OSAS) is a common and serious disorder in which this mechanism fails, resulting in frequent collapse of the airway during sleep. The properties of the upper airway muscles are therefore of interest in both normal and OSAS subjects, so that their role in the pathogenesis of OSAS can be better understood. Electromyography (EMG) is an important tool for assessing muscle activity and has been used in many GG studies. We have designed a new appliance incorporating a surface electrode array for GG EMG recording. The electrode configuration enables estimation of muscle fibre conduction velocity (CV), an important parameter for monitoring muscle fatigue, which has not been studied before in the GG. The appliance is also designed to provide accurate and repeatable placement of electrodes. Preliminary results presented demonstrate the performance of our appliance, which will now be used to measure GG CV in a range of fatiguing conditions.