[1] McGill Univ, Fac Med & Hlth Sci, Montreal, PQ, Canada
[2] Res Inst McGill Univ Hlth Ctr, Canadian Cerebral Palsy Registry, Montreal, PQ, Canada
[3] Univ Toronto, Dept Pediat, Toronto, ON, Canada
[4] Univ Alberta, Dept Pediat, Edmonton, AB, Canada
[5] McGill Univ, Dept Neurol & Neurosurg, Montreal, PQ, Canada
[6] McGill Univ, Dept Pediat, Montreal, PQ, Canada
[7] McGill Univ, Fac Med & Hlth Sci, 3605 Montagne, Montreal, PQ H3G 2M1, Canada