Individuals with episodic migraine may have stronger connectivity in the pain matrix compared with individuals with chronic migraine, according to a study published in The Journal of Headache and Pain.

A total of 44 and 18 adults with episodic and chronic migraine, respectively, age 18 to 60 who visited the headache clinic of the Samsung Medical Center in Seoul, Korea, between July 2016 and December 2017 were enrolled in this study. Participants underwent 3 T functional magnetic resonance imaging (fMRI) using identical scanners and were classified as interictal if they did not have a migraine headache the day of and ±1 day of fMRI acquisition.

The researchers performed connectivity analysis with a weighted and undirected network model using the group-independent component analysis and used 5000 permutation tests corrected with false discovery rate to assess between-group differences in degree centrality values.

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A total of 7 functionally interpretable spatially independent components were identified. Of these, only one, interpreted as the pain matrix, showed a significant between-group difference in degree centrality (with a higher degree centrality in chronic vs episodic migraine; P =.046). After adjusting for age, sex, migraine with aura, allodynia, depression, and anxiety, the association remained significant (P =.038).

The pain matrix was found to be functionally correlated with the hypothalamus, with a greater correlation in individuals with episodic vs chronic migraine (P =.040) and with the dorsal raphe nucleus, with a greater correlation in individuals with chronic vs episodic migraine (P =.039).

“Chronic migraine has an enhanced functional connectivity of the pain matrix which has a different functional connection to hypothalamus and [dorsal raphe nucleus] compared [with patients with episodic migraine],” the researchers wrote.

Reference

Lee MJ,Park B, Cho S, et al. Increased connectivity of pain matric in chronic migraine: a resting-state functional MRI study. [published online March 25, 2019]. J Headache Pain. doi:10.1186/s10194-019-0986-z

This article originally appeared on Clinical Pain Advisor