Altered Intra-Network Functional Connectivity Predicts the 6-Month Prognosis in Patients With Medication Overuse Headache: A Case-Control Study.

Background: Previous studies suggested that changes in functional connectivity (FC) within intrinsic resting-state networks (RSNs) might be associated with treatment responses during withdrawal in patients experiencing medication overuse headache (MOH). This study examined alterations in intra- and internetwork FC in intrinsic RSNs among MOH patients and explored the relationship between neuroimage changes and six-month prognoses.

Methods: This case-control study enrolled healthy controls and MOH patients. Six months after implementing a withdrawal and preventive strategy, patients who had successfully discontinued overusing acute medications and reduced headache days by at least 50% from baseline were classified as having 'good outcome' and those not reaching this outcome were classified as having a 'poor outcome'. Changes in intra- and inter-network FC in intrinsic RSNs across groups at baseline were evaluated. Univariate and multivariate logistic regression analyses were conducted to identify independent alterations associated with good outcomes.

Results: In the MOH group, 16 patients had poor outcomes and 17 patients had good outcomes. Compared to 24 healthy controls, all patients showed significantly increased FC in the left middle temporal gyrus of the left frontoparietal network (FPN). Furthermore, those with good outcomes had significantly decreased FC in the left orbital inferior frontal gyrus (IFG) of the left FPN compared to both poor outcome patients and healthy controls. Altered FC in the left orbital IFG of the left FPN was significantly associated with good outcomes and positively correlated with baseline headache intensity.

Conclusions: The altered FC in the left orbital IFG of the left FPN may be associated with MOH treatment prognosis.

Significance: The present study provides evidence of the association between alterations of intra-network functional connectivity in intrinsic resting-state networks and six-month prognoses in patients with medication overuse headache. Our results imply potential neuroimaging biomarkers associated with the prognosis of medication overuse headache.