A trans mucosal neuromuscular electrical stimulation device (103) comprises a mouthpiece (103), electrode means (133a) associated with the mouthpiece (103) and electrical circuitry operatively connected to the electrode means (133a), characterised in that the mouthpiece (3, 103) comprises a pair of arms (131) joined together at one end and diverging from one another with at least one flange (133) extending inwardly from at least one arm, the at least one flange (133) being shaped to cooperate or approximate or accommodate a sublingual tongue surface, the at least one flange (133) includes the electrode means (133a) associated therewith for providing, in use, via the electrode means (133a) electrical stimulation to one or more palate and/or tongue muscles via the sublingual tongue surface to increase resting muscle tone and/or muscle tone during sleep.