EEG correlates of startle reflex with reactivity to eye opening in psychiatric disorders: preliminary results.

Previous studies have shown alterations of eyeblink reflex in patients with various psychiatric disorders. It has previously been demonstrated by our group that EEG measures of the reactivity to eye opening could effectively predict patient-reported startle response in patients with acute stress reaction. In our present study, EEG spectral power analysis and eyeblink electrical startle responses were acquired from a total of 39 patients diagnosed with various psychiatric disorders: 7 patients with schizophrenia, 10 patients with major depressive disorder (MDD), 10 patients with panic disorder, 5 patients with posttraumatic stress disorder (PTSD) and 7 patients with generalized anxiety disorder (GAD). EEG percent power data of each frequency band (delta, theta, alpha, beta) obtained from the 19 leads under open or closed eyelid conditions were used to calculate the arithmetical difference between eyes-open and eyes-closed states as representative of "EEG reactivity to eye opening". Data was analyzed separately for each diagnostic group. For all of the disorders, right-sided R2c (contralateral secondary component) latency was the single eyeblink startle measure that was found to be significantly correlated with EEG reactivity to eye opening. The correlation was most significant for right temporal theta frequency in schizophrenia, right temporal theta frequency in MDD, left central beta frequency in panic disorder, left parietotemporal delta frequency in PTSD and right occipital alpha frequency in GAD. Findings showed a newly identified pattern that has potential scientific and clinical value with respect to psychiatric medicine.