Occipital nerve stimulation (ONS) may directly counteract trigeminal nerve-mediated central sensitization in patients with chronic migraine (CM), which could serve a protective action for reducing aversive peripheral irritation effects, a study in Pain Therapy suggests.
This study included 8 patients with treatment-refractory CM who had received ONS. During the ON phase of the study with active ONS, investigators recorded quantitatively the orbicularis oculi reflex with active ONS. In contrast, researchers measured the orbicularis oculi reflex with deactivated ONS during the OFF phase of the study.
Participants were randomly assigned to the ON phase measurement and, following a 1-hour break, to the OFF phase of the study. The other group started with the OFF phase measurement and concluded with the ON phase measurement, both of which were also separated by a 1-hour break.
At baseline, the blink frequency, as measured without occipital nerve stimulation, was 20.63 (±17.55) eyelid closures per minute. The baseline blink frequency with active ONS was 22.63 (±15.96) eyelid closures per minute. These frequency rates were not significantly different from each other.
The investigators activated the orbicularis oculi reflex with standardized air flow directed to the cornea, resulting in an increase in blink frequency to 39.38 (±21.85) eyelid closures per minute without ONS.
Active ONS was associated with an increase in blink frequency to only 30.00 (±17.22) eyelid closures per minute (active vs inactive ONS: P =.035). The orbicularis oculi reflex featured a significantly lower blink frequency on active ONS (7.38±20.14 eyelid closures/min) compared with inactive ONS (18.73±14.30 eyelid closures/min; P =.021).
A primary limitation of this study was the small sample size. Larger studies are warranted in the future.
Because this study shows active ONS may ultimately reduce aversive peripheral irritation, the researchers suggest “the effect of trigger factors in migraines could thus be weakened and the sensitization in the central nervous system reduced.”
Göbel CH, Heinze A, Karstedt S, Clasen S, Göbel H. Effect of occipital nerve stimulation (ONS) on the orbicularis oculi reflex triggered by a standardized air flow in patients with chronic migraine — a prospective, randomized, interventional study. Published online February 25, 2021. Pain Ther. doi:10.1007/s40122-021-00242-3