No change in interictal plasma and salivary CGRP levels in individuals with vestibular migraine corresponding to episodic migraine

Background: Few studies have examined plasma calcitonin gene-related peptide (CGRP) levels in individuals with vestibular migraine (VM), with inconsistent findings. Additionally, salivary CGRP levels in VM have not been reported. Methods: Interictal plasma and salivary CGRP levels were measured using an enzyme-linked immunosorbent assay in participants with VM corresponding to episodic migraine (VM, n = 81), chronic migraine without vestibular symptoms (CM, n = 73) and healthy controls (HC, n = 59). Results: Plasma CGRP levels in VM with episodic migraine participants were significantly lower than those in participants with CM (median = 37.1 pg/mL, interquartile range (IQR) = 22.4–60.4 pg/mL vs. median = 74.6 pg/mL, IQR = 49.6–101.6 pg/mL; p < 0.001) but did not significantly differ from levels in HC. Similarly, salivary CGRP levels were also significantly lower in VM compared to CM (median = 54.5 pg/mL, IQR = 37.0–83.4 pg/mL vs. median = 72.0 pg/mL, IQR = 56.5–96.2 pg/mL; p = 0.036), with no significant difference observed between VM and HC. Receiver operating characteristic analysis showed that plasma CGRP levels effectively differentiated CM from VM corresponding to episodic migraine, achieving an area under the curve of 0.88. No significant correlations were found between plasma or salivary CGRP levels and clinical features of CM and VM. Conclusions: Interictal plasma and salivary CGRP levels are unlikely to serve a biomarkers for VM.