Neuromodulation in primary headaches: current evidence and integration into clinical practice

Efficacy of cranial electrotherapy stimulation in patients with burning mouth syndrome: a randomized, controlled, double-blind pilot study

Background

The Burning mouth syndrome (BMS) is a chronic pain syndrome characterized by a burning sensation in the oral mucous membranes. The etiology and pathophysiology of BMS is largely unexplained. To date, there is no evidence-based treatment strategy for BMS. Cranial electrical stimulation (CES) represents a non-invasive treatment option with a low side effect profile that is approved for the treatment of pain, depression, anxiety disorder and insomnia. It has shown efficacy in studies for chronic pain such as fibromyalgia and neuropathic pain after spinal cord injury. This study aimed to investigate the therapeutic effectiveness of CES in combination with local transcutaneous electrical nerve stimulation (TENS) as an adjunct therapy in patients with BMS compared to sham stimulation.

Methods

This randomized, double-blind, sham-controlled pilot study enrolled 22 patients, aged 18 years and over, with the diagnosis of BMS meeting the ICHD-3 criteria from August 2020 to June 2021. The study duration was 4 weeks (28 days) per participant. After randomization, the active group participants (n = 11) received a 100 μA CES treatment for 60 min a day whereas the devices in the Sham group did not emit electricity. Simple linear regression was used to determine whether the interventions promoted significant differences in pain intensity.

Results

The linear regression showed that the period of stimulation significantly predicted decrease in the intensity of pain in the active group [β = -0.036; t(26) = -7.219; p < 0.001] as in the sham group [β = -0.026; t(26) = -2.56; p < 0.017]. With the applied cutoff of 30% pain reduction within the stimulation period, both the active and sham groups had 36% responders (n = 4) (Fisher's exact test, p = 1.00). In both groups (active stimulation and sham group), a significant decrease in the intensity of pain, somatic symptoms and an improvement in sleep quality over the study period was observed. Subjects reported no adverse events during the study.

Conclusion

Although CES is an easily applicable and safe therapeutic option for chronic facial pain, active stimulation was not superior to sham stimulation. Among other reasons, this could be due to the short double-blinded treatment period, duration of the daily stimulation session or the small sample size.

Medication adherence in patients with cluster headache and migraine: an online survey

To examine factors for adherent and non-adherent behavior in patients with cluster headache and migraine. Adults with cluster headache or migraine were included in this anonymous online survey using a questionnaire accessed via homepages of headache support groups. Medication adherence in preventive treatment was measured with the Medication Adherence Report Scale (MARS-D). Factors for non-adherent behavior were examined (subjective socioeconomic status, psychological comorbidities, self-efficacy, coping, side effects, expectations of treatment, information on medical treatment, and trust in the physician/treatment concept). 200 participants (n = 58 with cluster headache, n = 142 with migraine) were included. The rate of medication adherence in preventive treatment was 32.8% for participants with cluster headache and 20.4% for migraine. The most common reasons for low adherence in participants with cluster headache were altering the prescribed medication dose (34%) or taking less than instructed (14%), which was mostly due to insufficient benefit from the medication or side effects. Positive expectations of medical treatment (p ≤ 0.05) correlated significantly with adherent behavior in cluster headache. Furthermore, the adherence-promoting factors coping and self-efficacy were more pronounced in patients with cluster headache than in those with migraine (p < 0.05). This study is the first to comprehensively investigate medication adherence and factors influencing adherent/non-adherent behavior in patients with cluster headache. Patients with cluster headache had similar adherence levels to patients with migraine, but had higher resources of adherence-promoting factors.

Toward Diverse or Standardized: A Systematic Review Identifying Transcutaneous Stimulation of Auricular Branch of the Vagus Nerve in Nomenclature

OBJECTIVES

After 20 years of development, there is confusion in the nomenclature of transcutaneous stimulation of the auricular branch of the vagus nerve (ABVN). We performed a systematic review of transcutaneous stimulation of ABVN in nomenclature.

MATERIALS AND METHODS

A systematic search of the literature was carried out, using the bibliographic search engine PubMed. The search covered articles published up until June 11, 2020. We recorded the full nomenclature and abbreviated nomenclature same or similar to transcutaneous stimulation of ABVN in the selected eligible studies, as well as the time and author information of this nomenclature.

RESULTS

From 261 studies, 67 full nomenclatures and 27 abbreviated nomenclatures were finally screened out, transcutaneous vagus nerve stimulation and tVNS are the most common nomenclature, accounting for 38.38% and 42.06%, respectively. In a total of 97 combinations of full nomenclatures and abbreviations, the most commonly used nomenclature for the combination of transcutaneous vagus nerve stimulation and tVNS, accounting for 30.28%. Interestingly, the combination of full nomenclatures and abbreviations is not always a one-to-one relationship, there are ten abbreviated nomenclatures corresponding to transcutaneous vagus nerve stimulation, and five full nomenclatures corresponding to tVNS. In addition, based on the analysis of the usage habits of nomenclature in 21 teams, it is found that only three teams have fixed habits, while other different teams or the same team do not always use the same nomenclature in their paper.

CONCLUSIONS

The phenomenon of confusion in the nomenclature of transcutaneous stimulation of ABVN is obvious and shows a trend of diversity. The nomenclature of transcutaneous stimulation of ABVN needs to become more standardized in the future.

Preventive Migraine Treatment

PURPOSE OF REVIEW

This article provides an overview of preventive interventions for migraine, including when to start and how to choose a treatment, pharmacologic options (both older oral treatments and new monoclonal antibodies to calcitonin gene-related peptide [CGRP] or its receptor), nonpharmacologic treatment such as neuromodulation, and preventive treatment of refractory migraine.

RECENT FINDINGS

The migraine preventive treatment landscape has been transformed by the development of monoclonal antibodies targeting CGRP or its receptor. These treatments, which are given subcutaneously or intravenously monthly or quarterly, have high efficacy and were well tolerated in clinical trials. Emerging real-world studies have found higher rates of adverse events than were seen in clinical trials. They are currently recommended for use if two traditional preventive therapies have proven inadequate. Since the commonly cited 2012 American Headache Society/American Academy of Neurology migraine prevention guidelines were released, clinical trials supporting the preventive use of lisinopril, candesartan, and memantine have been published. Neuromodulation devices, including external trigeminal nerve stimulation and single-pulse transcranial magnetic stimulation devices, have modest evidence to support preventive use. The American Headache Society/American Academy of Neurology guidelines for the preventive treatment of migraine are currently being updated. A new class of oral CGRP receptor antagonists (gepants) is being tested for migraine prevention.

SUMMARY

Successful preventive treatment of migraine reduces disease burden and improves quality of life. Many pharmacologic and nonpharmacologic treatment options are available for the prevention of migraine, including newer therapies aimed at the CGRP pathway as well as older treatments with good evidence for efficacy. Multiple treatment trials may be required to find the best preventive for an individual patient.

Transcutaneous Auricular Vagus Nerve Stimulation: From Concept to Application

Whether in the West or the East, the connection between the ear and the rest of the body has been explored for a long time. Especially in the past century or more, the relevant theoretical and applied research on the ear has greatly promoted the development of ear therapy, and finally the concept of transcutaneous auricular vagus nerve stimulation (taVNS) has been proposed. The purpose of taVNS is to treat a disease non-invasively by applying electrical current to the cutaneous receptive field formed by the auricular branch of the vagus nerve in the outer ear. In the past two decades, taVNS has been a topic of basic, clinical, and transformation research. It has been applied as an alternative to drug treatment for a variety of diseases. Based on the rapid understanding of the application of taVNS to human health and disease, some limitations in the development of this field have also been gradually exposed. Here, we comprehensively review the origin and research status of the field.