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

The electrically elicited blink reflex consists of th ree components (R1, R 2, R3). In humans the excitability of these components is influenced by att entional states. In particular, distraction from the stimulus leads to faci litation of the bilateral R2 and R3. The present study was performed in ord er to investigate the excitability of the different components of the elect rically evoked blink reflex in 13 patients with schizophrenia and 13 normal controls under standard conditions. Therefore, the thresholds of the disti nct components were determined without any inhibitory or facilitatory proce dure. There was no significant difference in R1 and R2 thresholds between p atients and controls. In contrast, the R3 threshold was significantly reduc ed 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 foun d to be highly susceptible to changes in the attentional state of normal su bjects. The lower threshold of R3 in patients with schizophrenia might ther efore be a neurophysiological marker of attentional dysfunctions in schizop hrenia.