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

Publication date: January 2019

Source: Clinical Neurophysiology, Volume 130, Issue 1

Author(s): G. Strigaro, C. Pizzamiglio, A. Vinassa, G. Vaghi, B. Gori, C. Varrasi, R. Cantello

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 Hz; 10 kHz) with eyes closed. Stimuli were 3 s trains of flashes delivered at 8 and 16 Hz. 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 Hz, a significant (p < 0.05) increase in the first and second harmonic amplitude (i.e. 16 and 32 Hz) was found compared to controls. No significant changes at 8 Hz were detected. The SS-FVEP technique documents significant changes in the visual system of photosensitive patients with IGE, whose features likely underlie the PPR development.

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