Background: Posttraumatic Headaches (PTH) are common symptoms from mild traumatic brain injury (mTBI) that typically resolve within 3 months post-mTBI. However, in a sub-group of patients’ symptoms persist beyond the three-month period. It remains unclear if brain functional networks contribute to the lingering symptoms in patient’s experiencing persistent PTH symptoms. The objective of this investigation was to evaluate the extent to which resting state functional network (RSN) connectivity is altered between a group of patients with resolved versus persistent PTH symptoms relative to healthy controls. It was predicted that persons with persistent symptoms would show distinct functional network abnormalities relative to healthy controls compared to the resolved symptom group. 

Methods: Patients diagnosed with PTH fulfilled the ICD-9 criteria for mTBI and reported to have developed a headache within 8 days after mTBI. Subjects were placed into two cohorts according to headache status R-PTH <3 months or P-PTH >3 Month. All subjects were ages 12-21 at the time of participation (12=Healthy, 15=Persistent, 13=Resolved). Rivermead Post Concussion symptom survey and RSN scans were obtained from all mTBI subjects at the 3-month study visit. RSNs were identified using FSL melodic tool restricted to 27 components. The group maps were dual regressed in-order to determine alterations between study cohorts (Healthy, P-PTH, R-PTH).

Results:  The mean score for the Rivermead survey was significantly elevated in the P-PTH relative to R-PTH. Ten resting state networks were positively identified in the data set. Six networks showed significant group differences (p<0.05). Changes were observed in Brodmann area 6, the anterior cingulate cortex, and the right hippocampus. 

Conclusion: Network functional changes are observed in both mTBI cohorts with resolved and persistent PTH symptoms. Changes in the same RSNs but distinct anatomical regions may underlie functional network alterations and why symptoms may resolve in some, but not other patients. Increased functional connectivity within the Right Hippocampus-Frontal Pole has been report in the literature. By understanding the Functional connectivity alterations in Persistent and Resolved PTH, findings may supplement clinical diagnostics or treatment efforts and may inform return-to-play/return-to-sport protocols.

Evaluating Post-Traumatic Headaches in patients with mTBI in the acute and chronic settings: Resting-State fMRI identifies unique network changes