Which disorder is characterized by normal language and cognitive development before symptoms appear?

Asperger's Disorder, which falls under the autism spectrum disorders, is characterized by normal language and cognitive development in early childhood before the onset of symptoms. Children diagnosed with Asperger's often exhibit socially awkward behaviors and may have restricted interests or repetitive behaviors. However, these children typically develop speech and cognitive skills at a normal rate initially, distinguishing them from other disorders on the spectrum like Rett's Disorder or Childhood Disintegrative Disorder, where significant language or cognitive regression occurs after typical developmental milestones.

Rett's Disorder involves a period of normal development followed by loss of purposeful hand skills and other cognitive abilities, often leading to more profound disabilities. Childhood Disintegrative Disorder shows a significant loss of skills in multiple areas, including language and social skills, after a period of normal development, making it quite different from Asperger's Disorder. Conversion Disorder, while it may present with psychological symptoms translating into physical manifestations, is unrelated to the developmental trajectory seen in autism spectrum disorders. Understanding these distinctions clarifies why Asperger's Disorder is the most appropriate answer here.