ANTERIOR DIGASTRIC MUSCLE RESPONSES TO SUDDEN UNLOADING OF THE MANDIBULAR ELEVATOR MUSCLES IN YOUNGER AND OLDER ADULTS

The digastric motor responses in the unloading reflex were investigate d in a sample of 10 younger and eight older dentate subjects. The occu rrence of the pre-collapse digastric activity (PDA) and the reflex eve nts (burst of activity) following the mandibular unloading (DB) were s tudied separately. PDA was nearly consistent in half of the subjects o f both groups. DB was clearly identified in 60% of the younger subject s, but in 54.2% of the older subjects. The mean latency of DB found in the younger subjects was 32.4 +/- 9.5 ms but 34.5 +/- 8.8 ms in the o lder subjects. For the latencies found we can infer that they are rela ted to polysynaptic pathways. Also a slight tendency for decreased fre quency of occurrence and increased latencies of DB is observed in the older age group.