Have a diagnosis of spastic CP Be able to stand for at least 2 minutes without support. Be seizure free and have no other neurological or musculoskeletal diagnoses (i.e. dystonia, severe scoliosis). Have no marked visual or hearing deficits. This study is conducted at the Shriners Hospital for Children®– Philadelphia and at the Temple University Virtual Environment and Postural Orientation (VEPO) Laboratory. Indoor on-site parking and lodging can be provided at no cost. Sung-Jae Hwang, PhD at 215.204.0448 or sungjae.hwang@temple.edu Samuel CK Lee, PT, PhD at 302.831.2450 or sclee@shrinenet.org Anastasia Zarkou, PT, MSc at 302.831.4646 or azarkou@udel.edu This research study has been approved by Temple University IRB and is assigned IRB Protocol # 22173