Amplitude and frequency spectrum of temporomandibular joint sounds from subjects with and without other signs/symptoms of temporomandibular disorders

Temporomandibular joint (TMJ) sound is one of the most commonly recognized signs in patients with temporomandibular disorders (TMD) but is also freque ntly seen in asymptomatic individuals. Sound recording is therefore only me aningful if the sounds from a normal healthy joint can be differentiated fr om those in patients. In this study, the amplitude and power spectrum of th e TMJ sounds from symptomatic patients and asymptomatic individuals were re corded and compared. The result showed that TMJ sounds from symptomatic pat ients had a larger amplitude than sounds from asymptomatic subjects. A sign ificant proportion of sounds had frequencies between 2000 and 3000 Hz. It w as concluded that the characteristic amplitude is worthy of further study a s a sign of possible diagnostic value. Secondly, the bandwidth of the senso rs used at electronic TMJ sound recording should not be less than 3000 Hz.