Characterization of Nociception Phenotype in Individuals With Intellectual Disability

* INCLUSION CRITERIA: In order to be eligible to participate in this study, an individual must meet all of the following criteria: For All Participants * Provision of signed and dated informed consent form by participant or parent / Legally Authorized Representative (LAR) of patient. * Stated willingness to comply with all study procedures and availability for the duration of the study. * Male or female, aged 8-30 years of age. * Agreement to avoid use of analgesics, NSAIDs, caffeine (24 hours before procedures), illicit substances and alcohol within 2 days prior to enrollment and during study participation. Healthy Adult Controls * IQ 85 OR General Adaptive Composite ABAS-3 score above 85 * Must be fluent in the English Language. Healthy Children * OR ABAS-3 score above 85. * Must be fluent in the English Language. Patients -Diagnosis of Intellectual Disability. EXCLUSION CRITERIA: An individual who meets any of the following criteria will be excluded from participation in this study: All participants * NIH employees or children of NIH employee who subordinate to an investigator in this study will be excluded. This will ensure that participation or refusal to participate cannot be perceived as having any beneficial or adverse effects on their employment. There will be no direct solicitation of employees or of employees' children by the employee's supervisor. * Allergic reactions to EEG water based gel. * History of concussions in individuals with an IQ\>85. * Uncontrolled seizures. * Pregnancy (verbal confirmation). Pregnant women will be excluded as there is no data on the effects of nociception in pregnancy. * For healthy volunteers only - known history of neurological, psychiatric or pain disorders. * History of head injury resulting in prolonged loss of consciousness in individuals with an IQ\>85. Healthy Children -Children who have been diagnosed with neurodevelopmental disorders or treated in early intervention programs. Patients -Subjects who are on opioids, NSAID, gabapentin, or pregabalin chronically.