Objectives: Greater occipital nerve block (GONb) is widely used in the treatment of migraine; however, its effects on brainstem excitability remain unclear. This study aimed to assess whether GONb alters brainstem excitability in patients with migraine by evaluating blink reflex (BR) and masseter inhibitory reflex (MIR) parameters.
Materials and methods: This randomized, placebo-controlled, double-blind study included 34 patients with migraine who received either GONb (n = 17) or placebo (n = 17). BR and MIR responses were recorded before and after treatment. The primary outcome was the change in BR R2 response latency, whereas secondary outcomes included BR inhibition, MIR parameters, and pain reduction (visual analog scale [VAS] scores).
Results: GONb significantly reduced BR R2 response latency (p = 0.002), indicating altered brainstem excitability. However, no significant changes were observed in BR inhibition (p > 0.05) or MIR parameters (p > 0.05). GONb led to a significant reduction in migraine frequency (-84.6%, p < 0.0001) and pain severity (VAS: 7.2 ± 1.1 to 2.3 ± 1.6, p < 0.0001), but these improvements did not correlate with neurophysiologic findings.
Conclusions: This study reveals that GONb modifies brainstem excitability by affecting BR R2 latency but does not significantly affect BR inhibition or MIR responses. The findings suggest that GONb selectively influences trigeminal nociceptive pathways rather than global brainstem inhibitory circuits. Further studies with larger cohorts and longer follow-up are needed to elucidate the broader neurophysiologic effects of GONb in migraine.
Keywords: Blink reflex; brainstem excitability; greater occipital nerve block; masseter inhibitory reflex; migraine.
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