Auditory processing of sine tones before, during and after ECT in depressed patients by fMRI.

Our goal was to assess treatment effects of electroconvulsive therapy (ECT) on acoustic processing in major depression. We hypothesized that (1) depression is related to functional alterations in auditory networks, and that (2) pre-treatment alterations in auditory networks are reversible through treatment with ECT. Acoustic perception of 20 severely depressed and 20 age and gender matched healthy controls was investigated by 3 T functional magnetic resonance imaging employing repeated stimulation by sine tones. Prior to ECT, depressed patients presented a multimodal recruitment of additional brain areas including regions of the secondary visual system (cuneus, lingualis) and the medial frontal cortex. During ECT, signal intensities were reduced compared to pre-ECT values and controls. Activation of several regions increased after ECT. Our data suggest that depression is accompanied by cortical dysfunction including impaired auditory processing of non-speech stimuli. This might be based on overall alterations of brain metabolism indicating functional impairment.