Inclusion Criteria

Participants must have:

AS PER AMENDMENT 10/24/96:

• Signed, informed consent from a parent or legal guardian for patients under 18 years of age.

HIV-Infected Group: Documentation of HIV infection from a state-licensed lab as follows: Children > one month of age:

• Documentation of current or prior enrollment in an investigational drug therapy or other research protocol in which the protocol inclusion criteria specify HIV infection OR laboratory evidence of vertically transmitted HIV infection as demonstrated on two separate peripheral blood samples by either a positive viral culture (blood or cerebrospinal fluid) OR detectably serum p24 antigen OR positive HIV-DNA PCR.

Children >= 18 months of age:

• Fulfillment of above criteria OR >= 2 positive tests for HIV antibody (two different specimens) determined by a federally-licensed test kit for detection of antibody, confirmed by an independent supplemental test.
• Documentation of presumption of maternal HIV infection at or prior to the birth of the child.

HIV-Exposed, Uninfected Group: Children < 18 months of age:

• At least two negative tests for direct detection of HIV (viral culture and/or antigen detection and/or PCR assay and normal immunologic function.

Children >= 18 months of age:

• Negative serological test by an FDA-licensed test kit for detection of HIV antibody performed on a specimen obtained at >= 18 months of age.
• Documentation of presence of maternal HIV infection at or prior to the birth of the child.

Exclusion Criteria

Co-existing Condition:

Patients with the following conditions are excluded:

AS PER AMENDMENT 10/24/96:

• Central nervous system (CNS) disorders including poorly controlled seizure disorder while on anticonvulsant therapy, evidence of neuroimaging abnormality resulting from a traumatic brain injury or major congenital malformations associated with CNS dysfunction.
• Genetic diseases including:
• inborn errors of metabolism, inherited genetic diseases that would compromise CNS function, chromosomal disorder that would compromise CNS function, cystic fibrosis, muscular dystrophy, sickle cell anemia.
• Juvenile onset diabetes.
• Organ transplant recipients.
• Deafness or blindness.

Concurrent Medication:

Excluded:

• Intrathecal or intraventricular chemotherapy.

Concurrent Treatment:

Excluded:

• Cranial or spinal radiation therapy.

Patients with the following prior conditions are excluded:

• Traumatic brain injury with loss of consciousness of > 24 hours and/or skull fracture.
• Prematurity including:
• intraventricular hemorrhage > grade 2, requirement for mechanical ventilation for > 28 days, seizures or another perinatal brain injury history including history of hydrocephaly.

Prior Medication:

Excluded:

• Intrathecal or intraventricular chemotherapy.

Prior Treatment:

Excluded:

• Cranial or spinal radiation therapy.