Abstract
In the previous questionnaire, we discovered that the children who had been born as extremely low birthweight infants (ELBIs) had significantly more problems with the sucking and masticatory function than the children who had been born as full term infants (FTIs). The purpose of the present study was further to investigate the difference in the nutritive sucking patterns between ELBIs and FTIs and to examine the change in those sucking patterns with maturation after birth.
We measured the sucking wave pattern of both 8 ELBIs aged between 25 weeks and 34 weeks (mean gestational age was 28.4 weeks at birth and mean birthweight was 1015.3 g) and 7 FTIs aged between 2 and 7 days (mean gestational age was 39.1 weeks at birth and mean birthweight was 3296g). Four of the ELBIs and 7 of the FTIs were continued to measure for 10 months to investigate the change in the sucking wave patterns.
While there was no significant difference in the positive phase of the sucking wave, there was a significant difference in the negative phase (p<0.01) between the ELBIs and the FTIs, eventually the sucking cycle time (the positive phase and the negative phase) was significantly shorter in the ELBIs. The intensity of the sucking pressure in the ELBIs was significantly smaller than that in the FTIs (p<0.01). There was significant correlation between the actual age or the modified age and the sucking pressure (r=0.699 or r=0.708) in both ELBIs and FTIs.
Sucking cycle time, however, did not vary with maturation. Shorter time in the negative phase of sucking and smaller intensity of sucking pressure in the ELBIs meant smaller amounts of milk intake at each sucking and shorter time for swallowing. These results might be caused by the weakness of the muscular function and immaturity of the sucking function itself in ELBIs. These results, furthermore, indicated that lower sucking pressure in ELBIs might last for a longer period, which might cause a deficit in the development of the oral muscular function and the training for sucking and swallowing. Finally, those deficits could bring about the possibility of the deficiency of masticatory function in ELBIs.
