A 9-year-old male adopted from foster care at age 3 is brought for psychiatric evaluation by his adoptive parents due to behavioral difficulties at school including impulsivity, difficulty following multi-step instructions, poor social judgment, and frequent disciplinary referrals. He was previously diagnosed with ADHD at age 6 and treated with methylphenidate, which provided minimal improvement. His adoptive parents report that he is 'friendly to everyone' including strangers, has difficulty understanding consequences of his actions, and struggles with abstract concepts despite adequate concrete reasoning abilities. His biological mother's history includes polysubstance use during pregnancy, though specific substances are unknown. On examination, he is below the 10th percentile for height and head circumference, has a smooth philtrum, thin upper lip vermilion, and short palpebral fissures. His IQ testing reveals a full-scale IQ of 82 with significant discrepancy between verbal comprehension and working memory indices. Which assessment finding pattern most strongly supports fetal alcohol spectrum disorder over ADHD as the primary diagnosis?