Motor Outcomes in Premature Infants

Maureen Connors Lenke, BS, OTR/L


NAINR. 2003;3(3) 

In This Article

Impact of Prematurity on Motor Development

There are certain factors to consider during the assessment and follow-up of premature infants. Most significantly, the development of a preterm infant will follow expectations for their "corrected age," or age adjusted for prematurity, rather than their chronological age.[5] Thus, an infant born at 32 weeks, with a chronological age of 6 months will probably be performing motor skills closer to a 4-month level. Extremely premature infants may not achieve the same developmental level compared with their full-term counterparts until closer to 2 years of age.[6]

Most NICU Follow-Up Clinics will continue to adjust for prematurity to 2 years of chronological age. Even compared with other children of their corrected age, most infants born more than a few weeks prematurely will demonstrate additional developmental differences associated with prematurity. Muscle tone, or the resistance of a muscle to stretch, is generally much lower actively and passively in the preterm infant compared with the full-term infant.[5] In the first few months, the preterm infant demonstrates more extension and difficulty moving against gravity than the predominantly flexed full-term infant. At 40 weeks gestational age, the preterm infant is similar in muscle tone compared with the full-term infant, but generally never achieves the full degree of flexor tonus that is present in the full-term infant. There is a relative predominance of extensor tonus in the preterm infant that is demonstrated by a tendency for neck hyperextension, decreased antigravity movement, and decreased midline movements.

Primitive reflexes, including the Moro and palmar grasp, may either be absent or persist longer than in the full-term infant.[5] In addition, the rate of development in the preterm infant is often less predictable than in the full-term infant, with developmental lags and catch-up periods occurring.[6] An isolated delay or single abnormal sign does not always indicate that a child has a significant problem, because these infants grow and develop at different rates. The preterm infant may also demonstrate a jittery quality to their movement patterns in the early recovery period. These early differences may not always be indicative of an emerging deficit and may resolve, although some are associated with long-term problems and should be closely monitored.[6] Most mild motor abnormalities detected in the first few months will improve and may completely resolve over time.[6]

The length of hospitalization secondary to medical complications and decreased opportunities for movement may in itself interfere with the acquisition of early motor skills. Gross motor delays in head and trunk control may be present in the infant who required lengthy immobilization caused by medical complications or in those infants with compromised respiratory or cardiac status. Medically fragile premature infants will initially demonstrate hypotonia. This initial hypotonia may reflect an infant's poor medical status rather than a neurological deficit. These early delays may resolve as the infants medical condition improves in the first year.


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