Allen M C, Capute A J
Pediatr Res. 1986 Dec;20(12):1284-9. doi: 10.1203/00006450-198612000-00018.
A longitudinal study describes the pattern of appearance of eight primitive reflexes in a population of 47 viable extremely premature infants, beginning as early as 25 wk postconceptional age (PCA). Infants were examined weekly, from 1 wk of age until discharge from the neonatal intensive care unit. Primitive reflexes were graded as to completeness and intensity of response. Three patterns emerged: the upper and lower extremity grasp reflexes were present in all premature infants, from 25 wk and beyond, the Moro, asymmetric tonic neck reflex and Galant (lateral trunk incurvature reflex) were present in some premature infants as early as 25 wk PCA, and in the majority by 30 wk PCA, and the lower extremity placing, positive support, and stepping were occasionally present prior to 30 wk PCA, yet were not uniformly present and/or complete even at term. In each case, the primitive reflex became stronger, more complete, more consistently elicited and more prevalent with increasing postconceptional age. The pattern of primitive reflexes in the premature infant at term (40 wk PCA) is similar to that of full-term newborns. Sequential assessment of the primitive reflexes may be a useful method of evaluating extremely premature infants prior to term.
一项纵向研究描述了47名存活的极早产儿群体中8种原始反射的出现模式，最早从孕龄25周开始。婴儿从1周龄起每周接受检查，直至从新生儿重症监护病房出院。原始反射根据反应的完整性和强度进行分级。出现了三种模式：所有早产儿从25周及以后都存在上肢和下肢抓握反射；早在孕龄25周时，一些早产儿就出现了莫罗反射、不对称性紧张性颈反射和加兰特反射（侧躯干内弯反射），到孕龄30周时，大多数早产儿都出现了这些反射；下肢放置反射、阳性支持反射和踏步反射在孕龄30周之前偶尔出现，但即使在足月时也并非都存在和/或完整。在每种情况下，随着孕龄增加，原始反射变得更强、更完整、更易于引出且更普遍。足月时（孕龄40周）早产儿的原始反射模式与足月儿相似。对原始反射进行连续评估可能是一种在足月前评估极早产儿的有用方法。
