Pre-Treatment EEG and It's Relationship to Depression Severity and Paroxetine Treatment Outcome

Abstract

An array of variables have been assessed as potential early predictors of antidepressant response in depressed patients. This exploratory study examined the relationship of clinical outcome, following pharmacotherapeutic treatment, with quantitative electroencephalographic (EEG) features assessed prior to treatment onset. In 70 major affective disorder patients, pre-treatment spectrum-analysed topographic EEG indices (absolute power, relative power, mean frequency, inter-hemispheric power asymmetry and coherence for 4 frequency bands) were assessed in relation to baseline HAM-D ratings and HAM-D rating changes following 6 weeks of open-label paroxetine treatment. EEG slow wave (theta) activities were positively correlated with depression ratings prior to treatment. Of the patients (n = 51) completing treatment, 80% evidenced a >50% reduction in HAM-D ratings. Improved rating changes in general were found to be negatively related to slow (delta and theta) wave activity and positively related to fast (beta) activity at frontal recording sites. Findings are discussed in relation to the neurochemistry and neurobiology of depressive disorders.

Brain arousal regulation as response predictor for antidepressant therapy in major depression

“…Responders and non-responders did not differ concerning sub-stage B2/3 which is characterized by dominant theta band activity. In line with that, other research groups found no differences in absolute or relative theta power38 or a decreased theta power in responders to antidepressants3940. Owing to the fact that another study found decreased theta activity to be associated with non-response41, the heterogeneity in results was recently explained with the origins of the measured theta activities14: the reduced widespread frontal activity within the responders3839 was ‘considered most likely’ as a sign of reduced drowsiness which may not be the case in the study investigating frontal midline theta activity41.…”

“…In line with that, other research groups found no differences in absolute or relative theta power38 or a decreased theta power in responders to antidepressants3940. Owing to the fact that another study found decreased theta activity to be associated with non-response41, the heterogeneity in results was recently explained with the origins of the measured theta activities14: the reduced widespread frontal activity within the responders3839 was ‘considered most likely’ as a sign of reduced drowsiness which may not be the case in the study investigating frontal midline theta activity41. For theta activity specifically assessed within the anterior cingulate cortex, results are again contradictory with both decreased and increased activity to be favourable for treatment outcome111213.…”

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“…The observed increased theta in the ACC may reflect increased metabolism in the ACC in response to effective treatment [78]. An increase in alpha wave activity has also been reported in depressed patients who are not on medication [75,79], and those who respond to SSRI treatment have detectable differences in alpha wave characteristics when compared to non-responders [80–82]. These observations support the idea that EEG measures may be informative for tracking treatment response.…”

Review on EEG and ERP predictive biomarkers for major depressive disorder

“…The MDD patients with greater theta and lower beta band activities were R compared to NR [98]. Furthermore, an increase in the left frontal theta activity compared to baseline was reported after electroconvulsive therapy (ECT) [100].…”

“…In contrast, a study reported increased alpha power associated with R with 29 MDD patients who were treated with imipramine for 6 weeks [42]; however, the study did not provide any statistical support. In addition, an increase in the alpha power accompanied with a decrease in the theta power among R compared with NR was reported, including paroxetine administration for 50 MDD patients for 6 weeks [98].…”