The PMHNP is evaluating a 6-year-old boy with suspected ADHD. Which of the following biological findings should she expect to find that might help confirm diagnosis?

Choice A reason: Neuroimaging studies have demonstrated that children with ADHD often exhibit reductions in total brain volume, particularly in frontal cortical and subcortical regions. These structural differences correlate with deficits in attention, executive functioning, and impulse control. Choice B reason: Decreased slow-wave activity on EEG is not a consistent biomarker for ADHD. EEG abnormalities in ADHD may vary and are not diagnostic. Choice C reason: Reduced thalamic volume is not a typical finding in ADHD. While subcortical structures may be affected, thalamic volume reduction is not a consistent diagnostic marker. Choice D reason: Early posterior-to-anterior cortical maturation is a normal developmental pattern, not specific to ADHD. Delayed cortical maturation, particularly in the prefrontal cortex, is more commonly associated with ADHD.