Abstract
The purpose of the study was to investigate the muscle activities of the perioral muscles during the sucking movement of infants and the differences in sucking movements during breast and bottle feedings.
Electromyographic recordings were performed on 17 healthy infants during breast feeding (9 infants, BRF group) and bottle feeding (8 infants, BOF group). Muscle activities were examined by surface electromyography from the anterior belly of the unilateral temporalis, masseter, orbicularis oris, and suprahyoid muscles. The parameters evaluated were the total feeding time (s), resting time rate (%), sucking cycle (ms), and sucking rate (times/s). The sucking force was evaluated by measuring the maximum muscle activity (μV) at the burst in 10consecutive waves of each muscle in the early, middle, and late feeding periods.
The following results were obtained:
1) In sucking movements, suprahyoid muscles (BRF,99.3: BOF 85.2 μV) and the orbicular oris muscle(BRF,75.9; BOF 54.2μV)showed a higher level of activity than the temporal muscle(BRF,27.9; BOF 34.6μV)or masseter muscles(BRF,24.1; BOF,29.2μV).
2) No significant difference was observed between the BRF and BOF groups in the total feeding time (BRF,658; BOF,610 s), the sucking cycle (BRF,607; BOF,641 ms), or the sucking rate (BRF,1.7; BOF 1.6 times/s). Howe v er, the resting time (BRF,86.7; BOF,44.4 s), resting time rate (BRF,13.7; BOF,7.3%), and the number of interruptions (BRF,18.8; BOF,10.0 times) were significantly greater in the BRF group.
3) The activities of the orbicular oris muscle of and suprahyoid muscles tended to be higher in the BRF group although the differences were not signi ficant.
The findings suggest that the orbicular oris muscles and suprahyoi d muscles may be considered to play primary roles in sucking, and greater muscle activity appeared to be needed for breast feeding than for bottle feeding.
