O1-E-11. Correlation between scalp-recorded and subdural slow cortical potentials: Direct comparison during neuro-feedback training

Abstract

Recently, neuro-feedback (NFB) training by self-regulation of slow cortical potentials (SCPs) recorded at scalp vertex has been applied for seizure suppression in patients with refractory epilepsy. However, it is not clear whether the whole cortices or parts of the cortices contribute to the scalp-recorded SCPs. It is also uncertain whether scalp-recorded SCPs may contain slow component of galvanic-skin response. To clarify the two questions, we evaluated the correlation of SCPs between scalp and subdural recording by means of the coherence analysis. In 5 patients with refractory partial epilepsy while invasive recording was done before epilepsy surgery, scalp and subdural SCPs were recorded simultaneously during NFB training by means of DC-EEG machine (IRB#C533). SCPs in C1 or C2 (contralateral to the subdural electrodes) was employed as a reference to the coherence analysis. As a result, for scalp-recorded SCPs, SCPs on the primary sensorimotor cortices had the highest correlation, than those of lateral ( P = 0.02) and basal temporal ( P = 0.01) cortices. It is most likely that scalp-recorded SCPs from the scalp vertex area exclusively could reflect SCPs of the cortices of the lateral convexity close to the vertex, and thus that scalp-recorded SCPs do not contain the galvanic skin response.