Cerebral metabolism before and after external trigeminal nerve stimulation in episodic migraine

Abstract

Background and aimA recent sham-controlled trial showed that external trigeminal nerve stimulation (eTNS) is effective in episodic migraine (MO) prevention. However, its mechanism of action remains unknown. We performed 18-fluorodeoxyglucose positron emission tomography (FDG-PET) to evaluate brain metabolic changes before and after eTNS in episodic migraineurs.MethodsTwenty-eight individuals were recruited: 14 with MO and 20 healthy volunteers (HVs). HVs underwent a single FDG-PET, whereas patients were scanned at baseline, directly after a first prolonged session of eTNS (Cefaly®) and after three months of treatment (uncontrolled study).ResultsThe frequency of migraine attacks significantly decreased in compliant patients (N = 10). Baseline FDG-PET revealed a significant hypometabolism in fronto-temporal areas, especially in the orbitofrontal (OFC) and rostral anterior cingulate cortices (rACC) in MO patients. This hypometabolism was reduced after three months of eTNS treatment.ConclusionOur study shows that metabolic activity of OFC and rACC, which are pivotal areas in central pain and behaviour control, is decreased in migraine. This hypometabolism is reduced after three months of eTNS. eTNS might thus exert its beneficial effects via slow neuromodulation of central pain-controlling areas, a mechanism also previously reported in chronic migraine and cluster headache after percutaneous occipital nerve stimulation. However, this finding needs to be confirmed by further studies using a sham condition.

Neuromodulation for the treatment of primary headache syndromes

“…The maximum stimulation intensity for both treatment types is 16 mA. The precise mode of action is unknown but data from imaging studies based on FDG-PET and fMRI suggest functional changes in the orbitofrontal cortex and the rostral anterior cingulate cortex (20,21). the inherent shortcomings of a study without a sham group.…”

Migraine treatment with external trigeminal nerve stimulation: current knowledge on mechanisms

“…We have recently published the results of a fluoro-deoxyglucose (FDG)-PET study that analysed brain metabolism in 14 patients suffering from episodic migraine without aura before, immediately after one 20-min session and after a 3-months treatment period of daily 20-min sessions of supraorbital eTNS with the Cefaly ® (60Hz, 16mA) (44). Baseline FDG-PET revealed a significant hypometabolism of orbitofrontal (OFC), rostral anterior cingulate cortices (rACC) and middle temporal lobe, compared to a control group of healthy volunteers.…”

Therapeutic strategies that act on the peripheral nervous system in primary headache disorders

“…A fluorodeoxyglucose positron emission tomography (FDG-PET) study revealed that SONS by Cefaly® device increased the activity of the limbic system, and the orbitofrontal and anterior cingulate cortices in EM without aura patients. These results indicate that the proposed mechanism of Cefaly® might be the modulation of the descending pain control system of the trigeminovascular nociceptor in the trigemino-cervical complex [11,12]. This type of trigeminal nerve stimulation was the first to obtain the Food and Drug Administration's (FDA) approval for migraine therapy [12] (Table 3).…”