P300 auditory event related potential in children with attention deficit hyperactivity disorder [ADHD]

ABSTRACT

The overall purpose of this research was to evaluate children with attention deficit hyperactivity disorder [ADHD], investigate P300 auditory evoked potentials in those children and to compare between medicated and non-medicated children. The study included twenty children aged between 7 and 12 years, with primary diagnosis of ADHD, who participated in this study. All subjects had normal hearing, and they were divided into two groups non medicated group [10 subjects], and medicated group [10 subjects] under methylphenidate treatment [10mg/day]. They underwent detailed history, psychometric assessment, Otoscopic examination, and basic audiological evaluation and P300 evaluation. The twenty children who participated in the study were free from any gross neurological signs. Majority of the children [14 children - 70%] have had normal age appropriate psychomotor development Sixty per cent came from consanguineous families. Seventy five per cent have had smooth past medical history. Half of the included children have had normal scholastic achievement. The mean general intelligence quotient [IQ] among the studied children was 85.35 [S. 0. 9.65]. The mean percentage score of ADHD was 90.95 [5. D. 10.74]. Among 40 ears [20 right and 20 left] 60% of the subjects did not have any P300, 20% from the medicated group and 40% from non-medicated group. From meditated group 8 ears out of 20 ears [40%] did not show P300, right ears [37.5%] and left ear [62.5%]. For non medicated group 16 ears out of 20 ears [80%] did not showed P300, right ears [44%] and left ear [56%]. There were significantly reduced in P300 latency and increased amplitude in medicated group compared with non-medicated. Multivariate analysis between different variables revealed the following statistically significant correlations verbal reasoning and P300 latency in medicated group, quantitative reasoning and P300 latency in medicated group, general IQ and P300 latency in non-medicated group and quantitative reasoning and P300 latency in non-medicated group. Children with ADHD need to have thorough and comprehensive psychometric assessment because on general psychological examinations, they may function normally. Also, the medicated subjects have more persistence of P300, which showed reduced latency and increased amplitude than non - medicated group. So, auditory cognitive evoked potential [P300] topography may be able to predict robust response to the stimulant medications in children with ADHD