Preterm and High Risk Infant

Neuromotor maturation process of the preterm, fragile or sick infant covers the infant’s active movement, resting posture, muscle tone, reflexes and/or behavioral responses. There are certain known variables that can affect the above mentioned factors of the infant. These include:

 

1) Infant’s gestational age (G.A.) at birth
2) Infant’s current gestational age
3) Timing of evaluation
4) Events prior to or leading up to assessment
5) Current and any significant past medical issues
6) Current medications

 

The sick newborn, the premature infant and the fragile infant move very differently than the healthy, full-term infant. All infants who are born prematurely will miss an important inter-uterine motor milestone: the development of flexor tone. This critical component of muscle development occurs throughout the third trimester of pregnancy.

 

26 to 28 weeks Gestational Age- Extension

 

34 to 36 Weeks Gestational Age – Flexion

 

During the first two trimesters, extensor tone becomes well established as an infant develops his extensor muscles along the back of his body. As the fetus grows larger and more cramped during months 7, 8, and 9, the muscles used for flexion, (muscles along the front of the body) develop. When born with the disadvantage of missing this crucial milestone, a premature infant will have differences in both their muscle tone and posture once born.

 

Normal motor development occurs in a sequential pattern. Prior to 40 weeks gestation, whether in utero or outside the womb, an infant’s muscle tone development progresses in a caudo-cephalic (toe to head) and centripetal (distal to proximal) direction. At 40 weeks Post- Conceptual Age (PCA), the infant’s actual due date, an infant’s motor development reverses and begins to progress in the opposite direction in a cephalo-caudal (head to toe) and proximal to distal (from the middle of the body out) direction. The same development pattern found in a normal term infant.