Pilot Trial Finds Transcranial Direct Stimulation to be Safe, Effective in Treatment of Cervicogenic Headaches

Chantel Debert, MD, MSc, an associate professor at the University of Calgary

A recently published randomized pilot study showed that a combination of transcranial direct stimulation (tDCS) with exercise therapy (ET) was safe and feasible in patients with cervicogenic headaches, as treated patients demonstrated superior headache intensity, frequency, maximal intensity, and neck pain intensity over sham tDCS + ET. Overall, the findings were encouraging and support a larger clinical trial.

Led by Chantel Debert, MD, MSc, an associate professor at the University of Calgary, the sham-controlled, double-blinded study featured 32 recruited patients between the ages of 18 and 65 years that met the International Classification of Headache Disorders third edition criteria for cervicogenic headache. In total, 16 were randomized to either tDCS + ET or sham tDCS + ET, and 14 completed the treatment protocol in both groups. Within each group, 12 (active) and 9 (sham) completed treatment within the proposed 6 weeks (3 sessions per week), other received 18 sessions but took longer.

tDCS was administered to the primary motor cortex (M1) ipsilateral to worse pain anodally with the cathode placed over the supraorbital region. Patients received tDCS via two 35 cm2 sponges at 2 mA in the active group for 20 minutes with a 30 s fade in and fade out period. In the sham group, tDCS was administered during the 30 s fade in period to give the individual the impression they may be receiving the stimulation; however, for the remaining 20 min the machine was turned off.

In terms of safety and adherence, retention was 88%, with four participants dropping out (two per group). Dropout reasons included time commitment (one per group), a minor adverse event (active group), and transportation issues (sham group). Of the 28 participants who completed the intervention, 21 finished all 18 tDCS sessions within 6 weeks, with an overall completion rate of 96%. Participants reported completing the ET program on 87% of days. Missed sessions were mostly due to symptom fluctuations, transportation challenges, or competing commitments. Recruitment, retention, and adherence were similar between groups.

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Secondary outcomes, which focused on efficacy of active vs sham tDCS + ET, revealed a significant group x time interaction for average headache intensity from pre- to post-treatment (ß = –1.01; 95% CI, –1.75 to –0.27; P = .008), 6-weeks (ß = –1.37; 95% CI, –2.11 to –0.63; P <.001), and 12-weeks (ß = –1.84; 95% CI, –2.60 to –1.09; P <.001) post-treatment favoring the active tDCS + ET group. In addition, significant group × time interactions favored the active tDCS + ET group for headache frequency at 6 weeks (β = −0.15, 95% CI −0.29 to −0.01; P = 0.038) and 12 weeks (β = −0.19, 95% CI −0.33 to −0.05; P = 0.010), as well as for maximal headache intensity at 6 weeks (β = −1.01, 95% CI −1.93 to −0.10; P = 0.031) and 12 weeks (β = −1.65, 95% CI −2.59 to −0.71; P < 0.001).

In terms of longitudinal improvements, significant reductions in headache intensity were observed at 6 weeks (β = −1.51, 95% CI −3.02 to −0.01; P = 0.049) and 12 weeks (β = −1.87, 95% CI −3.41 to −0.33; P = 0.018) post-treatment with active tDCS + ET. Headache frequency (β = −0.22, 95% CI −0.45 to 0.00; P = 0.047) and maximal headache intensity (β = −1.69, 95% CI −3.27 to −0.10; P = 0.038) also significantly decreased at 12 weeks, though headache duration showed no changes. Neck pain (NPRS)(β = −1.56, 95% CI −3.12 to 0.00; P = 0.049) and pain interference (PROMIS-PI) (β = −3.84, 95% CI −7.30 to −0.38; P = 0.031) improved significantly post-treatment.

Functional impacts of headaches (HIT-6) decreased significantly in the active group from pre-treatment to post-treatment (β = −5.12, 95% CI −9.18 to −1.07; P = 0.014), 6 weeks (β = −7.26, 95% CI −11.32 to −3.21; P < 0.001), and 12 weeks (β = −6.11, 95% CI −10.24 to −1.97; P = 0.005). The sham group also showed improvement in HIT-6 from pre-treatment to post-treatment (β = −5.09, 95% CI −9.86 to −0.32; P = 0.037). No significant differences were found for HDI, PCS, RPQ, EQ-5D, GAD-7, or PHQ-9 in either group at any follow-up.

According to the study authors, this was the first study to consider the safety and feasibility of a tDCS + ET program for the treatment of cervicogenic headaches. “While findings regarding efficacy should be interpreted with caution, this study has demonstrated the safety and feasibility for tDCS + ET providing strong support to proceed with a larger, adequately powered, clinical trial," Debert el al concluded.

REFERENCE
1. Jobin K, Smith A, Campbell C, et al. The safety and feasibility of transcranial direct current stimulation and exercise therapy for the treatment of cervicogenic headaches: A randomized pilot trial. Headache. Published online January 17, 2025. doi:10.1111/head.14887