AN ELECTROENCEPHALOGRAPHIC STUDY COMPARING MAXIMUM BLINK RATES IN SCHIZOPHRENIC AND NONSCHIZOPHRENIC PSYCHIATRIC-PATIENTS AND NONPSYCHIATRIC CONTROL SUBJECTS

Background: Fire did a retrospective electroencephalographic (EEG) ana lysis of blink rates in patients with psychiati ic disorders and contr ol subjects to determine whether maximum blink rates under different c onditions were higher in patients with psychiatric disorders, Methods: Maximum blink rates in those with schizophrenia (n = 23), those with nonschizophrenic psychiatric illnesses (n = 21), and nonpsychiatric co ntrol subjects (n = 35) were obtained from patients' EEGs and compared with one-way analysis of variance and post hoc tests. In addition, co rrelation analysis was performed to determine if patients' medications affected maximum blink rates. Results: Patients with schizophrenic an d nonschizophrenic psychiatric disorders had twofold higher maximum re sting blink rates compared to controls (p < .05 respectively). No diff erence was found between those with schizophrenic and nonschizophrenic psychiatric disorders. The maximum blink rate during cognitive testin g was also twofold higher in those with nonschizophrenic psychiatric d isorders (n = 11) compared to controls (n = 16; p < .05). Within each group, maximum blink rates during quiet rest and cognitive testing did not differ, nor were there differences between groups in the duration of high-frequency blinking (greater than 40 blinks per minute) during quiet rest. In psychiatric patients, none of the medications taken at the time of EEG recording correlated with maximum blink rates. Conclu sions: High maximum blink rates recorded by EEG may suggest the presen ce of a psychiatric disorder. Published Society of Biological Psychiat ry 1998.