Effect of Short-Term Neurofeedback on the Neural Correlates of Attention Control and Impulsivity in Adult Attention-Deficit/Hyperactivity Disorder

Attention-deficit/hyperactivity disorder (ADHD) is characterized by deficits in attention and inappropriate levels of hyperactivity and/or impulsivity. Neurofeedback (NF) uses electroencephalogram (EEG) brain-computer interface to give participants a real-time feedback about their brain functioning, and represents a promising non-pharmacological treatment enhancing self-regulation skills in ADHD patients. However, the neural mechanisms involved in NF therapeutic outcomes still remain poorly understood. Our study investigated the effect of short-term NF on the neurophysiological indices associated with attention control and impulsivity in adult ADHD. Because low amplitude alpha rhythm (8-12 Hz) is mainly correlated with an active attentional state, the NF target state was set at reducing alpha amplitude (alpha desynchronization). High-density EEG was first acquired at rest and during a continuous performance task (CPT). Then a 30-min alpha-desynchronizing NF session was performed using each subject’s individual alpha frequency extracted from resting state EEG. Immediately after NF training a post-testing EEG recording at rest and during the CPT was performed again. Specific effects of NF were assessed by comparing behavioral and EEG measures pre-to-post NF. Preliminary results in ADHD patients revealed two main patterns: 1) post-NF alpha desynchronization associated with improvement in attention performance; 2) post-NF alpha synchronization, likely due to cumulative fatigue, associated with deteriorating performance. Our data suggest that successful NF regulation in adult ADHD patients may induce short-term brain plasticity demonstrated by greater reductions in spontaneous alpha amplitude and behavioral errors pre-to-post NF. Inversely, failure to reduce spontaneous alpha amplitude is accompanied by increased behavioral errors.