EFFECTS OF INTRAVENOUS DIAZEPAM (VALIUM) UPON EVOKED POTENTIALS OF PHOTOSENSITIVE EPILEPTIC AND NORMAL SUBJECTS

The effects of 7.5-10.0 mg of i.v. diazepam were studied in seven patients with photo-sensitive epilepsy and in nine normal controls. Minimal side effects (drowsiness, dizziness and slurred speech) occurred in three controls, but not in the epileptic subjects. Diazepam very rapidly blocked the photoconvulsive and photomyoclonic responses of epileptic subjects, as well as reducing the blinking and autonomic or vegetative changes induced by photic stimulation. Spontaneous epileptic discharges were also abolished. In both epileptic and normal subjects, beta activity appeared in the EEG maximally in anterior head regions, and marked hypotania and subjective relaxation were induced. Visual and somato-sensory evoked potentials (VEP and SEP) and the electroretinogram (ERG) were modified. In epileptics, early occipital VEP components were somewhat decreased in amplitude and increased in latency, and later components underwent variable effects, the most consistent being reduction in amplitude of negative components IV and VI. The VEP after-rhythm was abolished; and apparent midline central responses were greatly attenuated, as was the anterior spread of occipital components. Similar but less marked effects were observed in controls. The SEP in epileptics underwent a consistent reduction in amplitude and became more localized to the central region. The ERG a wave decreased in amplitude and b wave increased in peak latency and duration. All evoked potential changes appeared to be directly related to the action of the drug. The effects of i.v. diazepam on the evoked potentials of photosensitive epileptics in large part appeared to represent a normalization of cerebral reactivity. © 1969.