Psychosomatic Medicine 15:66-83 (1953)
© 1953 American Psychosomatic Society

Photically-Activated Electroencephalogram: Research Tool in Psychiatry

Preliminary Observations

¹ National Institute of Mental Health of the National Institutes of Health, United States Public Health Service

Electroencephalography used in conjunction with intermittent photic stimulation seems a promising tool for psychiatric research. The results of a preliminary investigation on 20 psychiatric patients and 45 control subjects is reported.

Brief psychiatric and psychological screening examinations revealed that 26 of the 45 "normal controls" showed some evidence of maladjustment. This group was found to have an increased response to photic stimulation at frequencies of 20 to 30 c.p.s. and showed some tendency to greater second harmonic response than 19 subjects who had little or no evidence of personality maladjustment.

Rhythmic photic stimulation can, in susceptible subjects, induce subjective sensations, frequently of a dysphoric nature. In psychiatric patients, such sensations may take the form of previously experienced symptoms.

A lowered convulsive threshold has been demonstrated by the production of seizures by photic stimulation alone in 4 patients with psychiatric disorder whose symptoms included "attacks" with motor manifestations. Myoclonic reactions or generalized seizures were also produced in five control subjects with no personal history of convulsive disorder, all of whom had either some personality disturbance, a personal history of syncope, a family history of convulsive disease, or some combination of these. In individuals in whom seizures were produced, certain frequencies seemed critical, whereas adjacent frequencies could produce a less severe reaction or only subjective dysphoria.

These findings indicate that a tendency to paroxysmal response may be found in subjects other than those with manifest convulsive disorder and that such a tendency may occur in subjects who present primarily psychiatric disorders.