The aim of the study was to examine whether the change of quantitative EEG (QEEG) theta prefrontal cordance after one week of various antidepressive interventions predicts response to a 4-week treatment in patients with bipolar depression. We investigated 20 inpatients who completed a 4-week treatment.
EEG data were monitored at baseline and after 1 week of treatment. QEEG cordance was computed at 3 frontal electrodes (Fp1, Fp2, Fz) in theta frequency band.
Depressive symptoms and clinical status were assessed using Montgomery-Åsberg Depression Rating Scale (MADRS), Clinical Global Impression (CGI) and Young Mania Rating Scale (YMRS). Seven of 8 responders (reduction of MADRS GREATER-THAN OR EQUAL TO50%) and only 2 of 12 non-responders had decreased prefrontal theta cordance value after the first week of treatment (p = 0.02).
The positive and negative predictive values of cordance reduction for response were 0.78 and 0.91, respectively. We also found significant differences in cordance value reductions between responders and non-responders after week 1 and higher baseline cordance in responders.
The change in prefrontal theta cordance was associated with subsequent change in depressive symptoms and potentially might be a useful tool in the early detection of acute response to antidepressive interventions in bipolar depressed patients.