Event-related brain potentials in depressed patients treated with electroconvulsive therapy

1. As impairment of attention has long been recognized as a clinical feature of depression, we undertook to evaluate in depressed subjects and controls a feature of the event-related brain potentials (ERP) the N100 wave which has been linked to attentional processes. 2. This study involved collection of EEG data in an "auditory oddball" ERP paradigm in 9 depressed subjects prior to and following a course of 6 electroconvulsive therapy (ECT) treatments, as well as 11 controls. Concurrent Hamilton depression rating scales provided a measure of symptomatic severity. 3. Pretreatment N100 amplitude was significantly lower in the depressed group while N100 latency was greater than among controls, with treatment differences from control values disappeared. Further a robust correlation (r = 0.85 p less than or equal to .0038) emerged between N100 amplitude (increased amplitude being lower) and severity of depression. 4. Those results provide evidence for a physiological attentional disturbance in depression and suggest that certain features of this disturbance relate directly to symptom severity.