The electrically elicited startle blink reflex in patients with schizophrenia: A threshold study of different reflex components.

The electrically elicited blink reflex consists of three components (R1, R2, R3). In humans the excitability of these components is influenced by attentional states. In particular, distraction from the stimulus leads to facilitation of the bilateral R2 and R3. The present study was performed in order to investigate the excitability of the different components of the electrically evoked blink reflex in 13 patients with schizophrenia and 13 normal controls under standard conditions. Therefore, the thresholds of the distinct components were determined without any inhibitory or facilitatory procedure. There was no significant difference in R1 and R2 thresholds between patients and controls. In contrast, the R3 threshold was significantly reduced in schizophrenic patients (R3 threshold = 17.5 mA in normal subjects, 10.5 mA in patients, p = 0. 0001). In recent studies the R3 magnitude was found to be highly susceptible to changes in the attentional state of normal subjects. The lower threshold of R3 in patients with schizophrenia might therefore be a neurophysiological marker of attentional dysfunctions in schizophrenia.