Mid-Latency Auditory-Evoked Responses and Sensory Gating in Focal Epilepsy: A Preliminary Exploration

Abstract

The relationship between epilepsy and psychosis is not well defined. Sensory gating is a possible endophenotype for psychosis, and has not been fully examined in epileptic patients. The authors examined 29 patients with focal epilepsy who were on antiepileptic medications, and 29 age-matched healthy comparison subjects, using a paired-stimulus (S1-S2) paradigm. P50 and N100 amplitudes or gating did not differ between the groups. The P200 was significantly smaller and did not gate as well in epileptic patients. Though alteration of sensory gating can be demonstrated in epileptic patients, it seems to be qualitatively different from alterations reported in association with schizophrenia.

Generators of the intracranial P50 response in auditory sensory gating

“…Variability of individual brain shapes and positions of electrodes makes it difficult to perform any type of group data analyses. A previous study from our group indicates that epileptogenic processes did not significantly affect P50 gating (Boutros et al, 2006). Similarly, Weate et al (1995) found normal scalp-recorded P50 sensory gating in patients with frontal lobe epilepsy.…”

Mapping Repetition Suppression of the N100 Evoked Response to the Human Cerebral Cortex

“…However, our prior investigation of this possibility did not yield any major findings (50). Also, psychopathology was minimally represented in this group (51). Another limitation of the employed methodology is that the sampling of brain areas is not based on hypotheses by dictated by the clinical situation of the individual subjects.…”

Test–retest reliability of P50, N100 and P200 auditory sensory gating in healthy subjects

“…P50 ratio-gating 16-50% (Adler et al, 1985;Boutros et al, 2004;Clementz et al, 1998a;Freedman et al, 1996;Kathmann and Engel, 1990;Olincy et al, 2000); N100 ratiogating 24-58% (Adler et al, 1990b;Boutros et al, 1999bBoutros et al, , 2006Kisley et al, 2003;Waldo et al, 1988;Yee et al, 1998); and P200 ratio-gating 15-57% (Hetrick et al, 1996;Boutros et al, 2004Boutros et al, , 2006. This may be related to additional differences in stimulus design, filter settings and amplitude-measurement methods.…”