Hypoechogenicity of brainstem raphe nuclei is associated with increased attack frequency in episodic migraine

Introduction Reduced echogenicity of the brainstem raphe nuclei (BRN) was demonstrated in major depression, possibly indicating serotonergic dysfunction. Postulating that migraine may constitute a “chronic low serotonin syndrome,” we aimed to evaluate the echogenicity of midbrain structures, including serotonergic BRN in episodic migraine. Methods Transcranial sonography was performed in 39 patients with episodic migraine (median age 35, interquartile range (IQR): 27–47 years; 27 women) and 35 controls (median age 31, IQR: 29–47 years; 19 women). Individuals with concomitant depression were excluded. Echogenicity of BRN, substantia nigra (SN) and third ventricle width was evaluated according to an internationally established examination protocol. Results Hypoechogenicity of BRN was depicted in 23.1% of migraine patients and 20% of controls, showing no significant difference. Migraine patients with hypoechogenic BRN had significantly higher attack frequency (median 3, IQR 2–5 vs. 1.5, IQR 1–2 days/month; p = 0.029) and a trend toward earlier disease manifestation. The rate of hyperechogenic SN and width of the third ventricle were similar between both groups. We did not observe any differences between migraine patients with and without aura. Conclusion Sonographic findings did not differ between migraine patients and controls. Hypoechogenic BRN correlated to a higher migraine attack frequency, probably indicating more severe disease activity.