OBJECTIVE:
The aim of this study was to examine the effect of acupuncture-like electrical stimulation on chronic tension-type headache (TTH) in a randomized, double-blinded, placebo-controlled study.

METHODS:
Thirty-six patients (18 men, 18 women) with chronic TTH in accordance with the criteria of International Headache Society were investigated. The patients were randomly assigned into 2 groups: a treatment group and a placebo group. Pain duration, pain intensity on a 0 to 10 cm visual analog scale, number of headache attacks, and use of medication were recorded in a diary for 2 weeks before treatment (baseline), early stage of treatment (Treat-1; 2 wk), late stage of treatment (Treat-2; 4 wk), and after the end of treatment (Post-1, Post-2, Post-3 corresponding to 2, 4, and 6-wk follow-up). The patients also provided an overall evaluation of the treatment effect at each stage. Patients were taught how to use either an acupuncture-like electrical stimulator or a sham stimulator (identical but incapable of delivering an electric current) and then instructed to use the device at home. Six acupoints, bilateral EX-HN5, GB 20, LI 4, were selected to be stimulated 3 minutes for each point, twice a day. Friedman repeated measure analysis of variance on rank was used to test the data.

RESULTS:
The pain duration was shortened at Treat-1 and pain intensity was decreased at Treat-1 and Treat-2 compared with baseline. The overall evaluation of the 2 treatments indicated improvements in both the treatment and the placebo groups, but with no significant difference between the groups (P>0.061). Despite the apparent improvement in both the treatment and placebo groups, a decrease in analgesic use was only observed in the treatment group. There was also a significant positive correlation between the reported intensity of the stimulus-evoked sensation and the evaluation of the effect of either active or placebo treatments (P=0.039).

CONCLUSIONS:
The use of acupuncture-like electrical stimulation was not associated with significant adverse effects. These results indicate that acupuncture-like electrical stimulation is a safe and potentially analgesic-sparing therapy that may be considered as an adjunctive treatment for patients with chronic TTH although the clinical effect on pain seems to be marginal in the present set-up.