The Loudness Dependence of Auditory Evoked Potentials is associated with the Symptom Severity and Treatment in Boys with Attention Deficit Hyperactivity Disorder

OBJECTIVE: The loudness dependence of the auditory evoked potential (LDAEP) is associated with central serotonergic neurotransmission. Recent studies have proposed that LDAEP is also influenced by dopaminergic activity. Evidence shows attention deficit hyperactivity disorder (ADHD) symptoms are associated with dopamine dysfunction. This study aimed to evaluate the relation between ADHD symptoms and LDAEP, as well as medication-mediated changes of LDAEP. METHODS: A total of 38 male children (6−12 years old) with ADHD were analyzed in this study. Symptom severity was assessed using the ADHD rating scale (ARS) and the continuous performance test. To determine LDAEP, the auditory event-related potential was evaluated before medication. Changes in LDAEP were measured after 12 weeks of treatment with methylphenidate. RESULTS: The subjects had a mean age of 9.24 ± 1.74 years with an average IQ of 109.4 ± 13.8. Before pharmacological treatment with methylphenidate, LDAEP was positively associated with the ARS score after adjusting for age and IQ (r = 0.592, p = 0.005). LDAEP was correlated with inattention (r = 0.522, p = 0.015) and hyperactivity-impulsivity (r = 0.6, p = 0.004). However, the LDAEP of 15 subjects decreased following methylphenidate treatment (Z = −1.988, p = 0.047). CONCLUSION: In boys with ADHD, LDAEP appears to be associated with symptom severity. LDAEP showed a significant association with impulsivity and inattention. Importantly, LDAEP was shown to decrease after drug treatment. Our findings support the utility of LDAEP as a noninvasive and clinically useful method to assess symptom severity in children with ADHD.