The purpose of this study is to determine whether the use of anesthetic agents in infants and children have long term adverse effects on neurocognitive development. According to the National Hospital Discharge Survey, around 2.5 million children have surgical procedures requiring anesthesia each year in the US. Recent animal studies have suggested that the exposure of the immature organism to a variety of commonly used anesthetic agents may lead to neurobehavioral functional deficits in vivo and to neuronal apoptosis in vitro. While the relevance of these findings on children exposed to anesthetics remains to be determined, it is clearly critically important to public health that this issue is resolved quickly and clearly.

Hypothesis: Exposure to anesthetic agents within the first three years of life will not significantly impair cognitive functions at ages 8 yr, 0 mo to 15 yr, 0 mo.

The purpose of our study is to compare neurocognitive functions in sibling pairs: one of whom had exposure to anesthesia during surgery before 36 months of age (exposed sibling cohorts) and who would be from ages 8yr, 0 mo to15 yr, 0 mo at the time of the study; and the other who never had anesthesia or surgery less than 36 months of age, is from ages 8yr, 0mo to 15 yr, 0 mo at the time of the study, and is within 36 months of age range from the exposed sibling(unexposed sibling cohort).

Neuropsychological assessments are administered to the sibling cohorts prospectively and parents of the siblings will complete parental interviews/questionnaires. We assess individually neurocognitive, behavioral and emotional function for both exposed and unexposed siblings. Family function will also be evaluated. We will also obtain complete medical history for each participant, including significant perinatal events and social history. We also review medical records when appropriate.

All testing are performed during a one day site visit.

Inclusion Criteria:

Exposed cohort:

1. Subjects who had inguinal hernia surgery before 36 months of age
2. Ages 8 yr, 0 mo to 15 yr, 0 mo
3. Gestation age greater or equal to 36 weeks
4. Categorized as ASA I or ASA II
5. English speaking
6. Biologically related to the unexposed sibling

Unexposed cohort:

1. Sibling within 36 months of age of the exposed cohort
2. Never had surgery or exposure to anesthesia prior to 36 months of age
3. Ages 8 yr, 0 mo to 15 yr, 0 mo
4. Gestation age greater or equal to 36 weeks
5. Categorized as ASA I or ASA II

5. English speaking 6. Biologically related to the exposed sibling

Exclusion criteria:

Exposed cohort:

1. Gestational age less than 36 weeks at birth
2. No exposure to surgery or anesthesia prior to 36 months of age
3. Surgery/Anesthesia other than index hernia repair prior to 36 months of age
4. Not categorized as ASA I or ASA II
5. Not ages 8 yr, 0 mo to 15 yr, 0 mo
6. Not English speaking
7. Not biologically related to the unexposed sibling

Unexposed cohort:

1. Gestational age under 36 weeks at birth
2. Any exposure to surgery or anesthesia prior to 36 months of age
3. Not categorized as ASA I or ASA II
4. Not ages 8 yr, 0 mo to 15 yr, 0 mo
5. Not English speaking
6. Not biologically related to the unexposed sibling

The study will be a multi-center study based at Columbia University with the following participating centers: Boston Children's (Harvard University), Children's Hospital of Philadelphia (University of Pennsylvania), Monroe Carell Children's Hospital (Vanderbilt University), and Morgan Stanley Children's Hospital of New York (Columbia University). Children exposed to anesthesia prior to 36 months must be ages 8 yr, 0 mo to 15 yr, 0 mo and have a sibling with no history of surgery or anesthesia prior to 36 months of age.