Occipital nerve stimulation (ONS) can directly counteract a central sensitization mediated by the trigeminal nerve in patients with chronic migraine (CM), which could have a protective effect to reduce aversive peripheral irritation, according to a study in pain therapy.
This study included 8 patients with refractory CM who received ONS. During the ON phase of the study with active ONS, the researchers quantitatively recorded the orbicularis oculi reflex with active ONS. In contrast, the researchers measured the orbicularis oculi reflex with the ONS disabled during the OFF phase of the study.
Participants were randomly assigned to the ON phase measurement and, after a one-hour break, to the OFF phase of the study. The other group started with the OFF phase measurement and ended with the ON phase measurement, both of which were also separated by a one-hour break.
At the start of the study, the blinking frequency, measured without stimulation of the occipital nerve, was 20.63 (± 17.55) eyelid closures per minute. The baseline blink rate with active ONS was 22.63 (± 15.96) eyelid closures per minute. These frequency rates did not differ significantly from one another.
The researchers activated the orbicularis oculi reflex with a standardized flow of air directed at the cornea, increasing the blinking frequency to 39.38 (± 21.85) eyelid closures per minute without ONS.
Active ONS was associated with an increase in blinking frequency to only 30.00 (± 17.22) eyelid closures per minute (active vs. inactive ONS: P = 0.035). The orbicularis oculi reflex showed a significantly lower flashing frequency with active ONS (7.38 ± 20.14 eyelid closures / min) compared to inactive ONS (18.73 ± 14.30 eyelid closures / min; P = 0.021).
A primary limitation of this study was the small sample size. Larger studies are needed in the future.
Since this study shows that active ONS can ultimately reduce aversive peripheral irritation, the researchers suggest that “the effects of trigger factors in migraines may be weakened and central nervous system awareness may be reduced”.
Göbel CH, Heinze A., Karstedt S., Clasen S., Göbel H. Effect of stimulation of the occipital nerve (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
This article originally appeared on Clinical Pain Advisor