RESUMO
OBJECTIVE: To determine whether visual evoked potentials (VEP) change, and to what degree, in different types of headache (migraine with or without aura, or tension headache). PATIENTS AND METHODS: We made a transversal study of 78 children (aged 3-14 years) studied between March 1997 and August 1998, classified into three groups according to HIS diagnostic criteria of 1988 and HIS-R 1997. A VEP of geometric pattern was done using the recording technique recommended by the International Society in their standards for VEP and the reference values were used for an amplitude of less than 5 microV and a latency of P100 +/- 15 ms. The qualitative variable was frequency, and the quantitative variables were the mean and the standard deviation. We studied the association between qualitative variables using the chi-squared test and the differences in means between the groups with ANOVA. All differences were considered to be statistically significant when p < 0.05. RESULTS: Girls made up 55%, with an average age of 8.84 years and a standard deviation of 3 years. There were no statistically significant differences in the mean of the VEP findings between the different types of headache with regard to amplitude (p = 0.975) and latency (p = 0.941). Neither were there any significant differences in the response to VEP in the different types of headache as far as sex and age were concerned, with p = 0.268 and p = 0.147 respectively. CONCLUSION: Our results show no statistically significant differences and do not support the idea of using VEP as a neurophysiological method for studying headaches and differentiating the various types.