Abstract
The influence of aging and the oral condition on the control of mandibular movements in correspond response to auditory signals have been studied. The subjects were 20 dentulous young adults and 10 edentulous aged persons with complete dentures. They were asked to perform tap-tap movement of mandible in synchronization to auditory signals, which were generated at regular intervals (0.6, 1.3, 2.0, 4.0 time/sec) and given in two ways:(1), Constant signals that were repeated sixty times at a given pace; and (2), Inconstant signals that were first paced slowly and then were gradually increased to a faster pace (0.6-1.3, 1.3-2.0, 2.0-4.0 time/sec). For each sequence, the signals were generated ten times.
The following results were noted:
1. A strong relationship was observed between the synchronized time of the tooth contact with the signal and both the range and the velocity of the mouth opening/closing movement. In each subject, the range of the mouth opening decreased according to the increase in the signal pace. Also, the range and the velocity of the mouth opening/closing movement of the aged were greater than that of the young subjects at each pacing.
2. With both the constant and inconstant signals, the time that the aged took to synchronize their movements was longer than that of the young subjects.
3. In the ability to control the range and the velocity of the mouth opening/closing movement, a significant difference between the aged and the young subjects was found.
