An oral appliance for the treatment of obstructive sleep apnea includes a mouthpiece configured for being received in an oral cavity of a user. The mouthpiece may include a pulse oximeter, a pressure sensor, an airflow sensor, an actigraphy sensor, a noise detector, and at least one stimulator for providing stimulation to a user's tongue in the event of decreased oxygen saturation levels, increased pressure applied to occlusal surfaces of the user's dentition, decreased actual airflow levels and/or increased noise levels. A microprocessor receives data from the oxygen sensor, pressure sensor, airflow sensor, actigraphy sensor and noise detector, and activates the at least one stimulator.