Changes in the electroencephalogram accompanying the use of stimulant drugs (methylphenidate and dextroamphetamine) in hyperactive children.

Fifteen hyperactive boys aged 5.6-10.6 years had their electroencephalograms (EEG) recorded during performance of a simple reaction task while on stimulant medication (methylphenidate or d-amphetamine) and after being free of medication for at least 48 hr. Interval histograms were formed from measurements of the duration of 780 half waves taken from predetermined portions of the EEG'S recorded from the left parietal-occipital derivation for both treatment conditions, and the histograms were subjected to a central-moments analysis. Previous evidence showed that, in normal children, smaller-valued 2nd, 3rd, and 4th central moments were associated with greater maturity. The EEG histograms obtained while the hyperactive children were taking stimulant medication had significantly (p less than 0.005) smaller 2nd, 3rd, and 4th central moments than the histograms of the same children obtained when off medication. Age of the group predicted from the means of the 2nd, 3rd, and 4th central moments of the EEG interval histograms was 91 months when the children were off medication--9 months less than the group's actual mean age. Age predicted in the same way when the children were on medication was 97 months. Findings support the concept of a neurophysiological maturational lag in hyperactivity and suggest that this lag is overcome, in part, by the use of stimulant drugs.