Eeg Brain Wave Case Study

EEG brain wave activity at rest and during evoked attention in children with attention-deficit/hyperactivity disorder and effects of methylphenidate

*Bianca Lee Thomas (neé Negrao) (MSc)

**Margaretha Viljoen (PhD, PhD)

* Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg

**Department of Psychiatry, School of Medicine, Faculty of Health Sciences, University of Pretoria

Short title / running head: EEG brain waves in children with attention-deficit/hyperactivity disorder

Corresponding author: Mrs BL Thomas

Department of Human Anatomy and Physiology

Faculty of Health Sciences

University of Johannesburg

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Suite 149

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Exclusion criteria included children with co-morbidities such as conduct disorder, children on medication other than methylphenidate (including other stimulant mediation as well as medication known to affect the autonomic nervous system), overtly malnourished children, children with mental retardation and children with the inability to understand and give informed assent. Children were also excluded if informed consent was not obtained from their parent or guardian. The children with ADHD were regarded as being on stimulant medication if they had been taking methylphenidate (Ritalin) consistently for at least 10 days at the dosage prescribed specifically for them by their psychiatrist. Eighteen of the children with ADHD tested in our study were taking short-acting methylphenidate at a dosage of 10 mg, while one child was on long-acting methylphenidate at a dosage of 20 mg. These same children were tested after they had refrained from taking methylphenidate for a period of approximately three weeks during their school holidays and were then considered to be stimulant-free. The practise of taking children with ADHD off their stimulant medication during their school holidays is normal and was not

Interestingly though, when these same children were compared to control subjects while they were on stimulant medication then statistically significant differences in low alpha (p=0.0418) and high alpha (p=0.0164) power were found, with low alpha power found to be significantly lower and high alpha power found to be significantly higher in children with ADHD on stimulant medication. This suggests that methylphenidate has the ability to influence alpha power activity during focussed attention in these individuals. In the final analysis, alpha power during focussed attention was compared between children with ADHD while they were on stimulant medication and while they were stimulant-free. In this comparison a statistically significant difference in high alpha power (p=0.0486) was found, with high alpha power found to be significantly greater in children with ADHD while on stimulant medication. This finding therefore suggests that methylphenidate has the ability to increase high alpha power during focussed attention in children with