The objective of the American Academy for Cerebral Palsy and Developmental Medicine (AACPDM) evidence reports is to provide the biomedical research and clinical practice communities with the current state of evidence about various interventions for the management of developmental disabilities. AACPDM evidence reports aggregate all that has been published about outcomes of an intervention for a medical condition, gauge the credibility (i.e. strength of the internal validity) of that evidence, and identify gaps in our scientific knowledge. The original version of this report was published in the ‘AACPDM Database of Evidence Reports’ on the internet (www.aacpdm.org) where evidence reports are regularly updated to include new research.