Silent periods in dysfunction patients: a preliminary study using a novel approach

Strong peri-oral stimulation is known to elicit a transient inhibition in the activity of the jaw-closing muscles. Several reports have claimed that this 'silent period' (SP) is prolonged in patients with temporomandibular joint dysfunction syndromes. In the present preliminary study, the biphasic SP evoked by electrical lip stimulation was tested in single motor units in the masseter muscles of dysfunction patients. In comparison with normal subjects, the pattern of the SP was different in the patients in that the shorter-latency phase predominated over the later phase, whereas the converse is true for normals.