Objective
To clarify the relationship of primitive reflexes and motor development during second six months of age.

Method
All infants were referred to Inha University Hospital Cerebral Palsy Clinic from January 1, 1996 to March 30, 1997. Identical evaluations were performed on 49 risk infants at eight months of age. Their primitive reflexes were graded on a 0∼2 scale; 0 being inability to elicit the reponses passively, 1 being intermediate degree, 2 being obligatory. The following primitive reflexes were studied; asymmetric tonic neck reflex (ATNR), tonic labyrinthine reflex on supine (TLS), Moro reflex (Moro). The presence of some voluntary activities (rolling prone to supine, rolling supine to prone, and sitting unsupported) were observed. The Mantal-Haenszel chi-square for trend test was used in order to study the association of primitive reflex and motor development in infants with delayed development.

Results
Inability of rolling prone to supine was most significantly associated with presence of ATNR and TLS but not with that of Moro reflex. Inability of rolling supine to prone was significantly associated with presence of TLS and then Moro reflex, ATNR. Inability to Sit independently without support was associated with the presence of TLS, but not with that of ATNR and Moro reflexes.

Conclusion
This study suggests that the presence of primitive reflexes at second half of age are negatively influenced on motor development of infants.