The Effects of Methylphenidate on the EEG of Children with Attention-Deficit/Hyperactivity Disorder

AimsAttention-Deficit/Hyperactivity Disorder (AD/HD) is a neurodevelopmental disorder, with the symptom profile consisting of hyperactivity, impulsivity and inattention. Currently methylphenidate is the most widely used treatment for AD/HD. Studies on mixed stimulant use have found that stimulants result in normalisation of electroencephalogram (EEG) activity during an eyes-closed resting condition. The aim of this study was to investigate the effects of Methylphenidate alone on the EEG of children with AD/HD and to extend the investigation into the gamma band.MethodFifty children with AD/HD and 50 typically developing children, between the ages of 8 and 12 years, participated in this study. Clinical participants were assessed for AD/HD at an initial session at which an EEG was performed. They returned within 1 week for a medication assessment, and a second EEG was recorded 1.5 h after ingestion of 10 mg of methylphenidate. EEG was recorded during an eyes-closed resting condition, and Fourier transformed to provide absolute and relative power estimates in delta, theta, alpha, beta and gamma bands.ResultsUnmedicated, the AD/HD group had elevated global absolute and relative delta, elevated posterior absolute theta, elevated posterior relative theta, reduced global relative alpha, and reduced global absolute and relative gamma activity compared to the control group. Methylphenidate ingestion was associated with a global increase in absolute and relative beta, and in relative gamma activity.ConclusionsSignificant increases in fast wave activity were observed with methylphenidate use. However, unlike past research, it is not clear that this should be considered as normalisation of the EEG.