Methods: Unexposed, singly exposed, and multiply exposed children born in Olmsted County, Minnesota, from 1994 to 2007 were sampled using a propensity-guided approach and underwent neuropsychological testing at ages 8 to 12 or 15 to 20 yr. The primary outcome was the Full-Scale intelligence quotient standard score of the Wechsler Abbreviated Scale of Intelligence. Secondary outcomes included individual domains from a comprehensive neuropsychological assessment and parent reports.
Results: In total, 997 children completed testing (411, 380, and 206 unexposed, singly exposed, and multiply exposed, respectively). The primary outcome of intelligence quotient did not differ significantly according to exposure status; multiply exposed and singly exposed children scoring 1.3 points (95% CI, −3.8 to 1.2; P = 0.32) and 0.5 points (95% CI, −2.8 to 1.9; P = 0.70) lower than unexposed children, respectively. For secondary outcomes, processing speed and fine motor abilities were decreased in multiply but not singly exposed children; other domains did not differ. The parents of multiply exposed children reported increased problems related to executive function, behavior, and reading.
Conclusions: Anesthesia exposure before age 3 yr was not associated with deficits in the primary outcome of general intelligence. Although secondary outcomes must be interpreted cautiously, they suggest the hypothesis that multiple, but not single, exposures are associated with a pattern of changes in specific neuropsychological domains that is associated with behavioral and learning difficulties.
There is strong evidence from preclinical studies that most general anesthetics modulate brain development. There is mixed evidence in humans that anesthesia exposure in early life is associated with changes in neurodevelopmental outcomes. The association may be stronger after multiple exposures.
This matched cohort study found that anesthesia exposure before age 3 yr was not associated with deficits in the primary outcome of general intelligence.
Single exposures were not associated with deficits in other neuropsychological domains (assessed as secondary out comes). However, multiple exposures were found to be associated with modest decreases in processing speed and fine motor coordination. Parents also reported that multiply exposed children have more difficulties with behavior and reading.