Volumetric MRI in autism: can high-tech craniometry provide neurobiological insights?

Abstract

Autism describes a spectrum of developmental disorders characterized by deficits in social interaction and communication, with repetitive behavior patterns and a limited repertoire of interests. Pervasive developmental disorder (PDD) is the diagnostic umbrella term used in the Diagnostic and Statistical Manual of Mental Disorders, 4th ed. (DSM-IV) to refer to these disorders.1 PDDs also include Autistic disorder, Asperger’s syndrome, childhood disintegrative disorder, and PDD–not otherwise specified (PDD-NOS). Autistic disorder is the prototypical PDD, with abnormalities in all three spheres (social interaction, communication, and repetitive or restricted behavior patterns) beginning before age 3 years. Asperger’s syndrome is distinguished from autistic disorder by normal language development. Childhood disintegrative disorder is characterized by normal development for at least 2 years followed by loss of certain acquired skills and development of autistic features. PDD-NOS includes autistic syndromes that do not meet all criteria for the other defined PDDs. Despite specific diagnostic criteria for autistic disorder,1,2⇓ there remains substantial heterogeneity of clinical manifestations within the disorder. The cause of autism is unknown and there are no widely accepted hypotheses on its neurobiology. Clinical heterogeneity undoubtedly contributes to the lack of neurobiological consensus. …