Developmental sequence of postural control in prone position in children with spastic diplegia

The aim of this study was to assess the development of postural control in the prone position in children with spastic diplegia and triplegia, and determine the influence of clinical characteristics, visual acuity and cognitive performance on that development. We also analysed the relation between these early motor achievements in the prone position and the subsequent acquisition of motor competence in the sitting position. We followed 24 diplegic and triplegic children from before age 2 years (mean age 12 months) to mean age 41 months, videorecording motor behaviour every six months and abstracting acquisitions in alignment and balance using a standardised procedure. We confirm a developmental sequence of all the acquired movements in the prone position. 83.3% of the children completed the uprighting sequence in the sagittal plane, acquired good balance, and ability to rotate the head and trunk. 70.8% of the children (all but one of the diplegic children and none among triplegic children) acquired symmetric posture in the frontal plane and 83.3% reduced leg hyperextension. Development was not uniform, and at 12-18 months two groups began to emerge: diplegic children who rapidly achieved all or most of the steps in the sequence and had a favourable prognosis for subsequent motor development; and triplegic children who achieved these steps at a much slower rate or in some cases not at all and had a less favourable prognosis for future development. Diplegic children with normal visual acuity, and general quotient GQ>70 did better than triplegic children with compromised visual acuity and GQ<70. Acquisition of the full uprighting sequence in the prone position before the age of two related to the later acquisition of autonomous sitting.