P50 sensory gating deficit in children with centrotemporal spikes and sharp waves in the EEG.

Sensory gating refers to the ability of the brain to inhibit irrelevant sensory input. In several studies, a pathogenic role of the CHRNA7 gene and the CHRNA7-like gene, respectively, is suggested. In linkage analysis concerning familial centrotemporal spikes and sharp waves (CTS) and benign rolandic epilepsy, evidence for linkage was found to a region on chromosome 15q14, close to the alpha-7 subunit gene of the neuronal nicotinic acetylcholine receptor (CHRNA7). According to these findings, P50 evoked potentials to paired click stimuli were studied in 13 children with CTS in the EEG to determine whether they had normal sensory gating. The control group consisted of 13 healthy probands matched for gender and age. Children with CTS showed a significant sensory gating deficit (p=0.001). These results (1) suggest an inhibitory deficit in early pre-attentive auditory sensory processing in children with CTS and (2) confirm the assumption of a cholinergic pathology in CTS.