Near Infrared Spectroscopy in Children With Autism and ADHD

* INCLUSION CRITERIA: Children will be between 4 to 8 years of age (4 years, 0 months to 8 years, 11 months). English speakers only will be recruited for the study, because the language measures/tests and stimuli being used are in English and were developed and standardized on English-only samples. Typically Developing Group: -Development in nonverbal and verbal areas within age expectations (per scores onthe Differential Ability Scales, Second Edition or the Wechsler Preschool and Primary Scale of Intelligence Fourth Edition , no more than 1.5 standard deviation below the mean) ASD Group: -Diagnosis of Autistic Disorder, Asperger s disorder, or Pervasive Developmental Disorder - Not Otherwise Specified (PDD NOS), based on diagnostic evaluation conducted through a separate screening protocol ADHD Group: -Diagnosis of ADHD based on diagnostic evaluation conducted through a separate screening protocol Minimum Nonverbal IQ of 80; Minimum Verbal IQ score of 60 EXCLUSION CRITERIA: All children who meet the following criteria: * Primary language spoken at home is other than English * Any skin disease that affects the scalp * Past or present vascular disease, such as lupus, ankylosing spondylitis or scleroderma. * Known adverse reaction to latex * Presence or history of medical conditions known to affect cerebral anatomy, such as known cysts, arterivenous malformations or cortical tubers. * Head trauma with loss of consciousness lasting longer than 5 seconds in the last year or any evidence of functional impairment due to and persisting after head trauma * Motor movement disorder which may cause sudden excessive movement, such as Tourette s disorder * Birth before 32 weeks of gestation. Premature birth can have a profound effect on brain function and structure * A known neurological or neurogenetic condition affecting the central nervous system, such as epilepsy, cerebral palsy, neurofibromatosis, velo-cardiofacial syndrome. * Color blindness Typically Developing Group: * Cognitive impairment, defined as Nonverbal IQ below 80, or signs of ASD or ADHD * Confirmed diagnosis of any DSM-IV-TR Axis I disorder * Taking medications for neuropsychiatric disorders such as antidepressants, antipsychotics, mood stabilizers, anxiolytics or any medication used to treat ADHD (psychostimulants, atomoxetine (Strattera ), bupropion (Wellbutrin ), tricyclic antidepressants (like impramine), clonidine, guanfacine, or modafinil (Provigil ). ASD Group: * Taking medications for neuropsychiatric disorders: such as antidepressants, antipsychotics, mood stabilizers, or anxiolytics. Some medications used to treatment for ADHD are also exclusionary for all children - including atomoxetine (Strattera ), bupropion (Wellbutrin ), tricyclic antidepressants (like impramine), clonidine, guanfacine, or modafinil (Provigil ). Children with ASD who take stimulants (like Ritalin, adderall, concerta and vyvanse) may be able to participate if they are willing and able to stop stimulant medications for 2 days on 1 occasion for the study * A known neurological or neurogenetic condition affecting the central nervous system, such as epilepsy, cerebral palsy, neurofibromatosis, velo-cardiofacial syndrome. ADHD Group: * Taking medications for neuropsychiatric disorders: such as antidepressants, antipsychotics, mood stabilizers, or anxiolytics. Some medications used to treatment for ADHD are also exclusionary for all children - including atomoxetine (Strattera ), bupropion (Wellbutrin ), tricyclic antidepressants (like impramine), clonidine, guanfacine, or modafinil (Provigil ). Children with ASD who take stimulants (like Ritalin, adderall, concerta and vyvanse) may be able to participate if they are willing and able to stop stimulant medications for 2 days on 1 occasion for the study * Other psychiatric diagnoses (including ASD, anxiety and depression), except for comorbid oppostional defiant disorder