Electroencephalographic Alpha Measures Predict Therapeutic Response to a Selective Serotonin Reuptake Inhibitor Antidepressant: Pre- and Post-Treatment Findings

Abstract

Background-There is growing evidence that individual differences among depressed patients on electrophysiologic (EEG), neuroimaging, and neurocognitive measures are predictive of therapeutic response to antidepressants. This study replicates prior findings of pretreatment differences between SSRI responders and nonresponders in EEG alpha power or asymmetry, and examines whether these differences normalize or are stable following treatment.

Electrophysiological predictors of clinical response to antidepressants

“…Moreover, the early studies reviewed above suggest that alpha is not be specific for predicting response to a SSRI but also predicts response to a tricyclic antidepressant. In contrast to our prior study (Bruder et al, 2008), treatment response was not related to hemispheric asymmetry of alpha. Although the reason for this lack of replication is unknown, alpha asymmetry is less reliable than alpha power and may be more influenced by a number of moderator variables.…”

“…We confirmed the value of alpha power in predicting clinical response to an SSRI and also found a difference in posterior alpha asymmetry between responders and nonresponders (Bruder et al, 2008). Resting EEG scalp potentials were measured from 28 electrodes (nose reference) in 18 depressed patients before and after about 12 weeks of treatment with fluoxetine, and 18 matched healthy controls were also tested.…”

“…(Smit et al, 2005) and depressed patients (Allen et al, 2004;Bruder et al, 2008). Auditory evoked potentials likewise have high reliability in healthy adults and depressed patients.…”

Biological Alterations in Depression

“…Several groups have demonstrated the usefulness of cordance in characterizing antidepressant response (Bares et al, 2008;Cook et al, 2002). Responders and non-responders differ in QEEG measurements at rest and during taskoriented activities (Bruder et al, 2008). LORETA, which assesses activity of deeper cortical regions like ACC and orbitofrontal cortex (Pizzagalli et al, 2001), identifies cortical alterations in relation to depression and antidepressant response (Anderer et al, 2002;Saletu et al, 2010).…”

The Antidepressant Treatment Response Index as a Predictor of Reboxetine Treatment Outcome in Major Depressive Disorder

“…21,22 In addition, studies have examined the predictive value of absolute and relative power, using various methods and with different results. Bruder et al 23 examined absolute alpha and theta power in frontal, central, parietal, and occipital regions at baseline and after 12 weeks of fluoxetine treatment. They found a trend for increased absolute alpha power in occipital regions of responders versus nonresponders to fluoxetine, and also observed an effect of laterality, with responders showing significantly greater alpha power on the right than the left.…”