Current Source Density Measures of EEG Alpha Predict Antidepressant Treatment Response
Craig E. Tenke1,2, Jürgen Kayser1,2, Carlye G. Manna1, Shiva Fekri1, Christopher J. Kroppmann1, Jennifer D. Schaller1, Daniel M. Alschuler1, Jonathan W. Stewart2,3, Patrick J. McGrath2,3, Gerard E. Bruder1,2
1Division of Cognitive Neuroscience, New York State Psychiatric Institute, New York, NY, USA; 2Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA; 3Depression Evaluation Service, New York State Psychiatric Institute, New York, NY, USA
Received 18 November 2010; revised 7 February 2011; accepted 11 February 2011; available online 20 April 2011.
Abstract
Background: Despite recent success in pharmacologic treatment of depression, the inability to predict individual treatment response remains a liability. This study replicates and extends findings relating pretreatment EEG alpha to treatment outcomes for serotonergic medications. Methods: Resting EEG (eyes-open and eyes-closed) was recorded from a 67-electrode montage in 41 unmedicated depressed patients and 41 healthy controls. Patients were tested prior to receiving antidepressants including a serotonergic mode of action (SSRI, SNRI, or SSRI plus NDRI). EEG was quantified by frequency principal components analysis (fPCA) of spectra derived from reference-free current source density (CSD) waveforms, which sharpens and simplifies EEG topographies, disentangles them from artifact, and yields measures that more closely represent underlying neuronal current generators. Results: Patients who did not respond to treatment had significantly less alpha current source density compared with responders or healthy control subjects, localizable to well-defined posterior generators. The alpha difference between responders and nonresponders was greater for eyes-closed than eyes-open conditions and was present across alpha subbands. A classification criterion based on the median alpha for healthy controls showed good positive predictive value (93.3) and specificity (92.3). There was no evidence of differential value for predicting response to an SSRI alone or dual treatment targeting serotonergic plus other monoamine neurotransmitters. Conclusions: Findings confirm the value of EEG alpha amplitude as a viable predictor of antidepressant response, and suggest that personalized treatments for depression may be identified using simple electrophysiologic CSD measures.
Key Words: depression; antidepressant treatment response; alpha rhythm; quantitative EEG (qEEG); current source density (CSD); principal components analysis (PCA)