Spectral analysis of visual potentials evoked by pattern-reversal checkerboard in juvenile patients with headache

Changes in visual evoked potentials, mainly affecting the amplitude of the major positive wave, are referred to by many authors and are related to the pathophysiological basis of primary headache. We performed both transient pattern-reversal visual evoked potentials and spectral analysis by means of fast Fourier transform of 8-Hz steady-state pattern-reversal visual evoked potentials in 34 children affected with migraine (14 with aura, 20 without aura), and compared them with 14 patients with tension-type headache and 10 healthy subjects. The amplitude of the response to the transient stimulation (P100) was higher and the latency shorter in the patients with headache compared with the controls, but the difference was not statistically significant. The absolute power of the first harmonic (1F) obtained by the spectral analysis of the steady-state stimulation was increased in all the patients with headache compared with the controls, and the increase was significant in patients with migraine. These data seem to confirm the hypothesis of abnormal processing of visual input in migraineurs and could be interpreted as neurophysiological support for the theory that different headache types are related conditions. Furthermore, the spectral analysis of steady-state pattern-reversal visual evoked potentials could be proposed as a test to diagnose migraine.