Our aim in this study was to affirm or negate (quantitatively) our subjective impression of altered hands and knees crawling (H&K crawling) among children with Autism Spectrum Disorder (ASD). Through parental questionnaires and children's health records, we retrospectively compared early motor skills, including the frequency of H&K crawling in 79 children with Autistic Disorder or Asperger Syndrome versus 100 children with typical development (TD). We found H&K crawling to be significantly less frequent among children with ASD (44.2%) versus children with TD (69%). Children with ASD also showed a decreased frequency of acquiring a seating position without help and a later mean walking age compared to the TD children. These data suggest that early motor development delays may be a useful sign for detecting ASD at early ages.
Keywords: autism spectrum disorders; crawling on all fours; early diagnosis; hands and knees crawling; motor development.