Migraine is a typical neurological condition characterized by recurrent bouts of unilateral, throbbing headaches often accompanied by nausea, photophobia, and phonophobia [1]. Approximately 14% of people worldwide suffer from migraines, which are the second greatest cause of disability [2]. For pharmacological management, an analgesic is administered during the acute stage to relieve pain, and prophylaxis is administered during remission to reduce the length, frequency, and intensity of headaches. Both are effective; however, each has its set of adverse effects [3]. Acupuncture is a simple, effective, convenient, clinical treatment that is beneficial for pain management in acute and chronic forms [4]. According to somatic reflexology theory, auricular therapy incorporates the connections between the ear, energy lines (channels and meridians), and muscle regions making up the entire body. According to this hypothesis, when a sickness or symptom manifests itself in the body, it is projected onto the ear at a predictable and quantifiable zone [5,6]. According to Traditional Chinese Medicine, the root cause of all diseases is an imbalance in ‘qi’ or energy. Auricular acupuncture regulates ‘qi’, activates the meridians and collateral networks, and balances ‘yin’ and ‘yang’. Auricular acupuncture is effective in treating several health issues including pain [6]. In a previous study, a combination of ear points was used for the management of migraine [7]. However, no studies have evaluated the efficacy of a single auricular point, i.e., a sympathetic point in patients with migraine. Hence, this study aimed to evaluate pain intensity and depression levels in patients with migraine.

1. Study design and settings

This randomized controlled study was conducted at the Government Yoga and Naturopathy Medical College and Hospital (GYNMCH) in Chennai, India. In total, 100 participants were divided into either the auricular acupuncture group (AAG) (n = 50) or placebo control group (PCG) (n = 50). The AAG underwent needling at the sympathetic point (an auricular acupuncture point) and the PCG underwent needling at a non-acupuncture point for 20 minutes daily for 7 days. Assessments were performed before and after the intervention (Fig. 1).

Figure 1. Trial profile.

2. Participants

One hundred patients with migraine were recruited from the GYNMCH. Participants who were 18–45 years old, were not taking medications, and with or without aura were included in this study. Participants with other primary and secondary types of headache, cerebral hemorrhage and vascular malformation, stroke, tumors, pregnancy, lactation, severe pain syndromes of the cervical spine, and focal neurological symptoms were excluded from this study. Participants were free to withdraw from the study at any time for any reason with or without prior permission from investigators.

Institutional Ethics Committee clearance was obtained from GYNMCH (RES/IEC-GYNMC/2021/129) before the recruitment of the first participant. The study protocol was explained to the participants and written informed consent was obtained from each participant.

3. Intervention

1) Auricular acupuncture group

Participants underwent bilateral needling in the sitting position at a sympathetic point, an auricular acupuncture point located inside the helix following the path of the lower part of the antihelix crus.

2) Placebo control group

Participants underwent bilateral needling in the sitting position at a non-acupuncture point located at the tip of the concha of the ear.

3) Note

For both groups, needling was performed using a press needle (0.22 × 1.5 mm). All patients were informed about the needling procedure and felt the needling sensation. The needle was maintained for 20 minutes daily for 7 days.

4. Outcome measures

Pain intensity was measured before and after 7 days of the intervention using a 6-item headache impact test (HIT-6) scale. The HIT-6 consists of six questions, each with five verbal response categories, and examines the effect of headaches on the capacity to work effectively in daily life. The following values are used to score responses, according to the HIT-6 user’s manual: never = 6, rarely = 8, sometimes = 10, very often = 11, and always = 13 [8]. Scores of 60–49 points indicated severe, 56–59 indicated significant, 50–55 indicated moderate, and 49 indicated little to no life effect [9].

Depression was assessed using the Beck depression inventory (BDI). BDI is a 21-item self-report test that evaluates major depressive symptoms, which has a range of 0–63 [10]. The total scores obtained from the participants can be divided into groups based on how severe their depressive symptoms are using the following ranges: minimum, 0–13; mild, 14–19; moderate, 20–28; severe, > 28 [11].

5. Sample size

One hundred patients with migraine were recruited. Sample size calculation was not performed, which is one of the limitations of the study.

6. Randomization

Participants were randomly divided (1:1 ratio) into the AAG or PCG by a simple random method using computerized randomization. Allocation concealment was performed by using sequentially numbered opaque sealed envelopes. Randomization was performed by an author who was not involved in the data collection.

7. Blinding

Patients were blinded to the AAG and PCG. However, outcome assessors were not blinded in this study.

8. Statistical analysis

Data were checked for normality using the Kolmogorov–Smirnov test. Baseline demographic and clinical characteristics of the AAG and PCG were compared using the independent samples t-test and Mann–Whitney U-test based on the data distribution. As the demographic and baseline values between the groups differed significantly for a few variables, univariate analysis of covariance (ANCOVA) and post-hoc analysis with Bonferroni adjustment were performed to compare both groups for those variables. Along with between-group analysis, within-group analysis was performed using the paired sample t-test and Wilcoxon signed-rank test based on data distribution. Statistical analysis was performed using SPSS version 16.0 (SPSS Inc.).

The study was conducted between January 2022 and March 2023. A total of 120 participants were screened and 100 eligible participants were randomly divided into two groups. Of the 100 participants, 7 (AAG, n = 3; PCG, n = 4) did not complete the study for personal reasons. Thus, 93 participants (AAG, n = 47; PCG, n = 46) completed the study. No significant differences in the baseline and demographic variables (except age, body mass index, HIT-6, and BDI score; p-value < 0.05 for all) were found between the AAG and PCG at baseline assessments (Table 1).

Table 1 . Baseline and demographic details of the study and control groups.

Variable	Auricular acupuncture group (n = 47)	Placebo control group (n = 46)	p-value
Age (y)	30.13 ± 7.98	24.15 ± 5.05	< 0.001
Gender	Female (n = 33), male (n = 14)	Female (n = 36), male (n = 10)
Height (m)	1.58 ± 0.08	1.90 ± 2.20	0.609
Weight (kg)	61.87 ± 10.29	58.39 ± 11.21	0.122
Body mass index (kg/m2)	24.73 ± 4.25	23.66 ± 9.25	0.038
HIT-6	65.00 ± 5.42	62.04 ± 5.03	0.008
BDI	19.43 ± 11.42	33.26 ± 7.87	< 0.001

Values are presented as mean ± standard deviation..

HIT-6, 6-item headache impact test; BDI, Beck depression inventory..

Needling at a sympathetic point produced greater reduction in the pain intensity level (p < 0.001) but a lesser reduction in the depression level (p < 0.001) compared to needling at a non-acupuncture point in patients with migraine. The within-group analysis showed a significant reduction in pain intensity (p < 0.001) and depression level (p < 0.001) in the AAG, whereas a significant increase in pain intensity (p < 0.001) and a significant reduction in depression level (p < 0.001) were noted in the PCG in the post-test assessments compared to their respective pre-test assessments (Table 2). None of the participants reported adverse effects during the study period.

Table 2 . Baseline and post-test assessments of the auricular acupuncture and placebo control groups.

Variable	Assessment	Auricular acupuncture group (n = 47)			Placebo control group (n = 46)			Between groups analyses
								t/z-value	p-value
HIT-6	Baseline	65.00 ± 5.42			62.04 ± 5.03			t = 2.725	0.008
	Post test	49.51 ± 7.66			67.15 ± 7.61			F = 79.756	< 0.001
	Within group analysis	z = 5.003	p < 0.001	d = 2.271	z = 3.533	p < 0.001	d = 0.762
BDI	Baseline	19.43 ± 11.42			33.26 ± 7.87			z = 5.544	< 0.001
	Post test	13.32 ± 8.44			27.52 ± 9.66			F = 11.674	< 0.001
	Within group analysis	t = 5.551	p < 0.001	d = 0.596	z = 4.359	p < 0.001	d = 0.645

Values are presented as mean ± standard deviation..

In within-group analysis: t = paired samples t-test, z = Wilcoxon signed rank test, d = Cohens’ d for effect size..

Between-groups analyses: F = analysis of covariance, t = independent sample test, z = Mann–Whitney U-test..

HIT-6, 6-item headache impact test; BDI, Beck depression inventory..

This study aimed to determine the efficacy of needling at a sympathetic point (auricular acupuncture point) on pain intensity and depression levels in patients with migraine. In this study, AAG produced a larger effect (effect size: 2.271) in reducing HIT-6, whereas PCG produced a moderate effect (effect size: 0.762) in increasing HIT-6. Moreover, the redcution in the HIT-6 was significant in the AAG compared to that in the PCG. In contrast, though both AAG and PCG produced a moderate effect (effect size: AAG, 0.596; PCG, 0.645) in reducing BDI, the reduction was significant in the PCG compared to that in the AAG. It indicates that needling at sympathetic point produces a greater reduction in the pain intensity level but lesser reduction in the depression level compared to needling at a non-acupuncture point in patients with migraine.

Needling at a sympathetic point balances the autonomic nervous system, and the trigeminal nerve may be responsible for the modulation of pain input structures including the rostral ventromedial medulla, ventrolateral periaqueductal gray, locus coeruleus, and nucleus raphe [12]. Cholinergic and adrenergic fibers present in the ear may be responsible for the release of neurotransmitters such as acetylcholine and noradrenaline [13]. The analgesic effects of auricular acupuncture might be attributed to the activation of the descending pain inhibitory pathway of the brain stem and inhibition of the ascending pain pathway. Pain relief may be produced by suppressing the dorsolateral funiculus in the spinal cord [14]. Stress is a major causative factor in migraine [15]. Auricular acupuncture regulates the hypothalamo-pituitary-adrenal axis and helps patients cope with stress by regulating cortisol levels. Acupuncture also increases the secretion of serotonin, dopamine, and endorphins, thus providing relaxation and pain relief [16]. Thus, needling at a sympathetic point may greatly reduce the pain intensity level compared to that at a non-acupuncture point. The results showed an increase in the pain intensity level, but reduced depression level in the PGG. Moreover, the reduction in depression was greater in PCG than that in the AAG. The reduction in the depression level even after increase in the pian intensity level in PCG is unclear; thus, more studies are warranted to identify the underlying reasons.

Previous studies have suggested that auricular acupuncture is effective in reducing migraine attacks by stimulating sensory nerves of the skin and body muscles, causing significant release of β-endorphins or by acting as a nonpainful sensory stimulus that competitively inhibits nociceptive pathways [17]. The auricular branches of the trigeminal and vagus nerves are responsible for 80% and 20% of the sensory innervations of the anterior part of the helix, respectively [18]. The sensory stimulus provided by needle insertion can modulate the trigeminovascular system (the pathway involved in migraine headaches) by acting on the nociceptive input [19]. These results reveal that stimulation of a sympathetic point reduces pain intensity in migraines by regulating neuroinflammation and neuronal sensitization.

1. Strength of the study

To our knowledge, this is the first randomized controlled study to investigate the effect of a single auricular acupuncture (sympathetic point) in patients with migraine. A press needle was used in this study, which is cost effective. The participants did not report any adverse effects during the study period.

2. Limitation of the study

The sample size was not calculated based on previous studies, and limited subjective parameters were analyzed.

3. Future directions of the study

Further studies with a larger sample size, longer duration, and more objective variables are warranted to determine the effects of interventions at sympathetic points and the mechanisms underlying these effects.

The results suggest that needling at a sympathetic point produces a greater reduction in the pain intensity level and lesser reduction in the depression level compared to needling at a non-acupuncture point in patients with migraine. However, further studies are required to confirm the results of this study.

Conceptualization: OD, AM, N. Mangaiarkarasi, N. Manavalan. Data curation: OD. Formal analysis: AM. Investigation: OD. Methodology: OD, AM. Project administration: AM, N. Mangaiarkarasi, N. Manavalan. Resources: N. Mangaiarkarasi, N. Manavalan. Software: AM. Supervision: AM, N. Mangaiarkarasi, N. Manavalan. Validation: AM. Visualization: AM, N. Mangaiarkarasi, N. Manavalan. Writing – original draft: OD, AM. Writing – review & editing: All authors.

The authors have no conflicts of interest to declare.

None.

Institutional Ethics Committee clearance was obtained from GYNMCH (RES/IEC-GYNMC/2021/129), and written informed consent was obtained from each participant.