Steady-state visual evoked potentials in photosensitive patients with idiopathic generalized epilepsy

Abstract

To assess the visual system excitability of photosensitive patients with idiopathic generalized epilepsy (IGE) with the steady-state flash visual evoked potential (SS-FVEP) technique. We studied 13 adult patients with IGE showing a photoparoxysmal electroencephalographic response (PPR). Twenty normal subjects of similar age and sex acted as controls. We recorded FVEPs from occipital electrodes (1–1000\u202fHz; 10\u202fkHz) with eyes closed. Stimuli were 3 s trains of flashes delivered at 8 and 16\u202fHz. Eighty sweeps were collected for any stimulus type and averaged off-line. SS-FVEPs were analyzed in the frequency domain with a discrete Fourier transformation and the amplitude of the first (1H) and second harmonic (2H) were measured. In patients, at 16\u202fHz, a significant (p