Photoparoxysmal response elicited by flickering dot pattern stimulation and its optimal spatial frequency of provocation.

We studied 21 photosensitive persons aged 9-40 years (mean +/- SD: 20.9 +/- 9.3 years), producing a flickering dot pattern stimulation with a strobo-filter with 22 nits luminance. Five dot patterns (spatial frequencies of 0.5-4.9 c/deg) were used. Using 6 flicker frequencies from 5 to 30 Hz, we gave flickering dot pattern stimuli with each dot pattern, for 5 s each, to subjects with eyes open. Spatial frequency of 2.1-1.5 c/deg, and flicker frequency of 20-15 Hz were most effective in eliciting generalized photoparoxysmal response (PPR). Results indicate that low-luminosity 20-15 Hz flickering 2.1-1.5 c/deg dot pattern stimulation is necessary to increase PPR screening sensitivity.