Sequential comparison of frequency modulations is more difficult for children and adolescents with ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by difficulties with attention, hyperactivity and impulsivity. A large number of children with ADHD also suffer from auditory processing deficits. Possible causes are abnormal lateralization of auditory processing and impaired hemispheric interaction. Children and adolescents (age 9-16 years) with and without ADHD (n = 53) performed two tasks for which the lateralization and amount of hemispheric interaction have been established in previous studies: (1) categorization of the direction of frequency modulation, mainly involving the right auditory cortex (AC), and (2) sequential comparison of frequency direction, involving both auditory cortices and therefore requiring stronger hemispheric interaction. The tones were presented binaurally, and monaurally with and without contralateral white noise. Basic assessment of low-level auditory abilities did not show significant differences between groups. We found no significant difference in task accuracy between the groups in the categorization task, but observed impaired accuracy in the ADHD group in the comparison task during monaural tone presentation without noise. Contralateral noise negatively affected performance only in the control group. The poorer performance of the ADHD group in the comparison task requiring stronger hemispheric interaction supports the assumption that deficits in auditory processing in ADHD may be caused by impaired hemispheric interaction.