High-amplitude photic driving response and occipital lobe epilepsy

We demonstrated high-amplitude (> 50 mu V) photic driving response (PDR) elicited by low-luminance (20 cd/m(2)) 5-Hz flickering dot pattern stimulation in two adult male occipital lobe epilepsy patients. We made a 5-Hz frequency topographic mapping analysis on each PDR elicited by regional stimulation to the center, periphery and center plus periphery (full field); the highest amplitudes were obtained with a 0.8 c/degrees dot pattern stimulus to the center in a 33-year-old patient and with a 0.5 c/degrees dot pattern one to the periphery in a 48-year-old patient. It was suggested that high-amplitude PDR is diagnostically useful evidence in an occipital lobe epilepsy patient, in whom neither photoparoxysmal response nor other paroxysmal discharge can be found.