The central hypothesis of this Phase IIb trial is that early identification of electroencephalography (EEG) biomarkers and early treatment versus delayed treatment with vigabatrin in infants with tuberous sclerosis complex (TSC) will have a positive impact on developmental outcomes at 24 months of age. It would also prevent or lower the risk of developing infantile spasms and refractory seizures. This preventative approach would be expected to result in more favorable long-term cognitive, behavioral, developmental and psychiatric outcomes and significantly improve overall quality of life. It is a randomized, double-blind, placebo-controlled clinical trial design. Successful completion of this trial will also advance the field by demonstrating the value of systematic surveillance with EEG in asymptomatic infants with TSC.