IMPAIRED SENSORIMOTOR GATING IN PATIENTS WITH NONEPILEPTIC SEIZURES

The aim of the study was to identify possible disturbances of sensorim otor gating and habituation of the eye blink startle response, in pati ents with non-epileptic seizures (NES). Prepulse inhibition (PPI) of t he startle reflex, as an operational measure of sensorimotor gating an d habituation was studied in 21 patients with NES and in 22 healthy co ntrol subjects. Six NES patients were taking antiepileptic drugs at th e time of testing. PPI was significantly impaired in the NES group com pared to the control group, with deficits being greater in unmedicated patients. There was a trend for medicated NES patients to show higher PPI than unmedicated patients, but this was not significant. Habituat ion was intact in both medicated and unmedicated NES patients. It is p roposed that deficits of information processing related to sensorimoto r gating in patients with NES may be associated with abnormalities wit hin the limbic system-basal ganglia circuitry which has been shown to be the substrate of 'gating' assessed by PPI. It was also found that N ES patients had greater psychopathology than the control group when ra ted by the Traumatic Symptom Checklist (TSC-40). Overall, the anxiety subscale was the only element that was negatively correlated with PPI. It is suggested that anxiety may contribute to impairment of PPI in p atients with NES. (C) 1998 Elsevier Science B.V. All rights reserved.