RESUMEN
BACKGROUND: Medication overuse headache (MOH) is a chronic pain syndrome that arises from the frequent use of acute antimigraine drugs. Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique with a possible therapeutic effect in this particular context. METHODS: This was a randomized, sham-controlled, cross-over study. Eighteen patients with MOH (17 women, age range: 20-38 years) received three sets of three consecutive daily sessions of tDCS: anodal tDCS over the prefrontal cortex, cathodal tDCS over the occipital cortex ipsilateral to the dominant side of migraine pain, and sham. The order in which the tDCS blocks were delivered was randomly defined based on a 1:1:1 ratio. Patients filled in a migraine diary that allowed recording of the pain intensity (visual analogue scale) and the daily consumption of analgesic pills from one week before to two weeks after each condition. RESULTS: Both prefrontal and occipital tDCS lowered the total number of migraine days and the number of severe migraine days per week at week 1, but only the effects of occipital tDCS on these two outcomes lasted until week 2. Only occipital tDCS decreased the daily analgesic pills consumption, at weeks 1 and 2. CONCLUSION: Three consecutive days of cathodal occipital tDCS appear to improve the clinical outcomes in patients with MOH.