Contact pressure distribution features in Down syndrome infants in supine and prone positions, analyzed by photoelastic methods

BACKGROUND: Local force distribution supporting the bodyweight of infants with Down syndrome (DS) appears to be different from that of healthy controls. The purpose of the present study was to establish methods to assess this force distribution and to allow therapeutic evaluation of neurological development in DS infants prior to walking. METHODS: Contact pressure distribution patterns in supine and prone positions were measured by photoelastic methods and were compared between DS infants and healthy controls. The DS group included eight subjects, seven with regular trisomy 21, and one with a Robertson translocation. The controls consisted of 14 neonates, four 4-month-old infants and eight 7-month-old infants. RESULTS: In both groups, head loading ratio decreased as age advanced but the decrement was less in the test group than in the control group. When the bodyweight loading ratios were measured in two different lying positions, that is, prone and supine, the ratios for prone generally tended to be smaller than those for supine in the controls. This kind of difference between prone and supine was not seen in the DS group. The bodyweight is somewhat sustained with limbs and the limbs loading ratios in the DS group were always significantly lower than in the controls. CONCLUSION: Coordinated development of weight-supporting limbs seems to be poor in the DS group.