Vigilance regulation as predictor for response to psychostimulants in ADHD

Introduction: A consistent result of EEG-studies in ADHD is elevated theta activity (1), which is a characteristic feature of lower vigilance stages. A recently proposed concept (2) interprets some ADHD symptoms (e.g. hyperactivity) as reflections of an autostabilisation process counteracting an instable vigilance regulation. Since vigilance enhancing psychostimulants are effective in ADHD (3) and EEG-normalisation is found in stimulant responders (1), we investigated, whether assessment of vigilance regulation could be useful for prediction of treatment outcome. Method: We reanalyzed 2 minute resting EEG recordings of 49 unmedicated ADHD patients and 49 age-matched controls. Vigilance was determined using an classification algorithm. Treatment outcome was measured as changes in CPT performance from baseline after at least 4 weeks of medication. Results: Compared to healthy controls, ADHD patients spend less time in higher vigilance stages (A1: ADHD=66% KG=81%, p=.016). Patients, who made less mistakes in the post medication testing (Responders), showed more low vigilance stages (B23: Resp=31%, Non-Resp=11%, p=.008). Diskussion: We found signs of a vigilance labilisation in ADHD patients compared to controls. Those patients with a higher degree of vigilance labilisation did benefit more from stimulant medication. 1 Barry RJ et al, Clin Neurophysiol 2003; 114: 171–183 2 Hegerl et al, Pharmacopsychiatry, in press 3 Pliszka SR et al, Neruopsychol Rev 2007; 17: 61–72