The cause or causes of DAS are not yet known. Some scientists believe that DAS is a disorder related to a child’s overall language development. Others believe it is a neurological disorder that affects the brain’s ability to send the proper signals to move the muscles involved in speech. However, brain imaging and other studies have not found evidence of specific brain lesions or differences in brain structure in children with DAS. Children with DAS often have family members who have a history of communication disorders or learning disabilities. This observation and recent research findings suggest that genetic factors may play a role in the disorder.