Peripheral pulsed electromagnetic fields may reduce the placebo effect in migraine patients that do not respond to the sham intervention in a randomized, placebo-controlled, double-blind, cross-over clinical trial

Abstract

Objective: The purpose of the study was to evaluate the effect of the pulsed electromagnetic fields (PEMF) and its possible modulation of the placebo effect in migraine.

Design: Placebo-controlled, randomized, double-blind, cross-over clinical trial.

Setting: Government third level hospital.

Interventions: Patients with migraine were included. PEMF were applied to the wrist with a bracelet.

Main outcome measures: Frequency and intensity of the migraine attacks at baseline and during treatment were recorded. Also, we valuated the possible influence of gender and the presence of aura in the PEMF and placebo responses.

Results: Eighteen patients (fifteen women, 30±2 years old) were included. Migraine frequency and intensity was reduced with both PEMF and placebo to a similar extent in the whole population. However, in responders to placebo, migraine intensity was reduced to a median of 100% with the placebo and to 60% with the PEMF, while in non-responders there was only a slight effect of both treatments. Our results do not suggest an influence of gender or presence of aura in the outcomes.

Conclusions: Treatment with PEMF may not alter either migraine intensity or frequency compared to baseline, but may reduce the response to placebo in migraine patients.

Trial registration: ClinicalTrials.gov NCT00901862.