Comparison of visual and auditory evoked cortical potentials in migraine patients between attacks

Objective: As both habituation of pattern reversal visual evoked potentials (PR-VEP) (Schoenen J, Wang W, Albert A, Delwaide PJ. Potentiation instead of habituation characterizes visual evoked potentials in migraine patients between attacks. fur J Neurol 1995;2:115-122) and intensity dependence of a uditory evoked cortical potentials (IDAP) (Wang W, Timsit-Berthier M, Schoe nen J. intensity dependence of auditory evoked potentials in migraine: an i ndication of cortical potentiation and low serotonergic neurotransmission? Neurology 1996;46:1401-1409) were found abnormal in migraine between attack s, we have searched for intraindividual correlations between both tests in 59 migraine patients (22 with aura [MA], 37 without aura [MO]) and in 23 he althy volunteers (HV). Methods: Amplitude change of the PR-VEP N1-P1 was measured between the 1st and 5th block of 50 sequential averagings during continuous stimulation at 3.1 Hz. IDAP was computed from N1-P2 amplitudes of 100 averagings during st imulations at 40, 50, 60 and 70 dB SL. Amplitude-stimulus intensity functio n (ASF) slopes and amplitude changes between 40 and 70 dB were calculated. MO and MA differed from HV in PR-VEP amplitude change (P = 0.007) and IDAP slope (P = 0.0004). Results: There was no significant correlation between VEP amplitude changes and IDAP slopes, nor between the latter two and attack frequency or diseas e duration. A negative correlation was found between the amplitude of the f irst block of averaged responses and potentiation of VEP in all subject gro ups (P = 0.03) as well as between the amplitude of the auditory evoked pote ntial, at 40 dB, and the percentage of amplitude increase between 40 and 70 dB in MO (P = 0.004) and MA (P = 0.007). ASF slopes and 40 dB amplitudes w ere significantly correlated only in the MA group (P = 0.002). These result s confirm the interictal deficit of habituation in cortical processing of r epetitive Visual and auditory information in migraine. Since there is no in traindividual correlation between the cortical responses to these sensory m odalities they are complementary tools for the study of migraine and may he lp to identify subgroups of patients with distinct pathlophysiological mech anisms. Conclusions: The strong negative correlation between the initial amplitude of evoked potentials and their amplitude increase during subsequent averagi ng confirms that the response potentiation in migraine is likely to be due to a reduced preactivation level of sensory cortices. (C) 2000 Elsevier Sci ence ireland Ltd. All rights reserved.