Common developmental delays that should be screened for (with approximate prevalence %) include: - Speech and language impairment (6%) - Learning disabilities (8%) - Attention deficit disorder (ADD) (7%) Less common conditions include: - Mental retardation (1%–2%) - Cerebral palsy (0.2%) - Autism and autism spectrum disorders (0.5%) According to the US Department of Education, just over 13% of school-age children are in special education. Most of these children are diagnosed with learning disabilities or mental retardation.