**4. Reports of acupuncture as a therapy for headaches**

In patients with migraine without aura, the number of headache attacks and analgesic use among patients who received acupuncture were significantly decreased in comparison with those who were treated with flunarizine [11].

Kikuchi et al. reported the effects of acupuncture on headache. They examined the numbers of medication days and headache days using a headache diary and found that the number of days in patients who experienced migraines, chronic tension‐type headache, medication overuse headache, and chronic migraines decreased by 75, 50, 30, and 20%, respectively [12].

Thus, the effects of acupuncture differed according to the diagnosis. Yamaguchi et al. evaluated the effects of acupuncture in patients with tension‐type headache using plethysmography, electromyography, and thermography [13]. Acupuncture was found to be effective for treating headaches because it normalized the excess tension of the neck and upper shoulder muscles rather than the head muscles [13]. However, few articles have classified headaches in detail and examined the effectiveness of acupuncture. Thus, there is no clear evidence of the types of headache for which acupuncture is effective or whether acupuncture should be performed in the attack phase or intermittent phase. Acupuncture therapy is classified as a Grade B treatment in the Japanese clinical practice guideline for chronic headache, which was published by the Japanese Society of Neurology and Headache in 2013 [14].

A Cochrane review reported that there was no significant difference in the clinical effects of true acupuncture and sham acupuncture, but that the number of headache days was decreased by the intervention [15]. Acupuncture was reported to be more effective and to be associated with fewer side effects than preventive medications [9].

A large clinical study of acupuncture for headache was conducted in the European Union. The number of headache days at 3 months after acupuncture significantly decreased from 8.4 to 4.7 days in the acupuncture group, while it decreased from 8.1 to 7.5 days in controls. In the economic study, acupuncture improved the quality of life and was highly cost‐effective [16]. The placebo effect of acupuncture, however, is reported to be nearly 40% [17]. The accurate effect should be verified by a double‐blind controlled trial, but it is difficult to establish control groups in acupuncture studies.

Acupuncture studies are associated with another problem with regard to the reproducibility of the treatment. In most reports, acupuncture was performed by an experienced acupunctu‐ rist; however, many parts depend on the technique of operator.

The accurate effect should be verified by a double‐blind controlled trial, but it is difficult to establish control groups in acupuncture studies. So, some studies have used objective assess‐ ments. Chassot et al. reported a crossover trial regarding the effect of electro‐acupuncture (EA) on chronic tension‐type headache, including an assessment using a biological sample [17]. The visual analog scale score decreased more than 50% following EA in nine patients, but it also decreased in the sham period for five patients. The serum brain‐derived neurotrophic factor was inversely correlated with pain intensity and degree of depression.

Kinfe et al. recently reported that presurgical acupuncture predict the effect of surgical occipital nerve stimulation (ONS) [18]. Twelve patients with chronic refractory headache syndrome eligible for ONS were treated using EA (100 Hz, 30 min) before ONS. For EA, four needles were inserted subcutaneously at the level of C1, defined as 3 cm below the occipital protuberance, 1.5 cm bilateral from the midline (two needles), and 3.5 cm bilateral from the midline (two needles), to ensure that it reached the occipital afferent distribution area [18]. The results showed that surgically implanted ONS was effective in some patients who had previously been non‐responsive to acupuncture. Acupuncture may be a useful new tool for presurgical assessment.
