Speech-evoked auditory potentials in attention deficit hyperactivity disorder

Abstract Objective: To explore the processing of auditory information through auditory brainstem and higher cortical regions in a sample of children with attention deficit hyperactivity disorder (ADHD) of the combined inattention and hyperactivity subtype (ADHD/C) using auditory evoked potentials. Study Design: Fifteen Arabic speaking ADHD/C children were compared to 15 age-matched normal controls, aged between five and ten years. A Mini-International Neuropsychiatric Interview for Children and Adolescents (Arabic version) was performed to confirm the diagnosis, subtype of ADHD and to exclude comorbid conditions. All children were subjected to Auditory Brainstem Evoked Response (ABR) to click, speech ABR and cortical Mis-Match Negativity (MMN) to speech stimuli. Results: Thirty-three percent of the ADHD/C group showed prolongation of absolute and/or inter-peak wave latencies of the click ABR beyond two standard deviations. The peak latency of the onset waves for speech ABR was abnormal in 87% of the study group. Only three ADHD/C children gave normal MMN. Conclusion: This study demonstrated that abnormal auditory brainstem timing with reduced cortical functions was a characteristic in the studied ADHD/C children. Speech ABR can serve as a biological marker for brainstem neural asynchrony in children with ADHD/C. It might help to organize the highly heterogeneous population of ADHD into more homogeneous subgroups, at least on a particular biological indicator, specifically in individuals who cannot perform the behavioural measures. Further research is needed to determine whether individuals within these subgroups share a similar auditory perceptual profile.