Persistent post-traumatic headache vs. migraine: an MRI study demonstrating differences in brain structure

DOI: https://doi.org/10.1186/s10194- 017- 0796- 0

Abstract-Summary The objective of this study was to compare brain structure in individuals with per- sistent post-traumatic headache (i.e. headache lasting at least 3 months following a traumatic brain injury) attributed to mild traumatic brain injury to that of individuals with migraine.

Twenty-eight individuals with persistent post-traumatic headache attributed to mild traumatic brain injury and 28 individuals with migraine underwent brain mag- netic resonance imaging on a 3 T scanner.

MRI data from 28 healthy control subjects were used to interpret the differences

in brain structure between migraine and persistent post-traumatic headache.

Differences in regional volumes, cortical thickness, surface area and brain curva- ture were identified when comparing the group of individuals with persistent post- traumatic headache to the group with migraine.

Considering these regions only, there were differences between individuals with persistent post-traumatic headache and healthy controls within the right lateral orbi- tofrontal lobe, right supramarginal gyrus, and left superior frontal lobe and no dif- ferences when comparing the migraine cohort to healthy controls.

Persistent post-traumatic headache and migraine are associated with differences their underlying

in brain structure, perhaps suggesting differences pathophysiology.

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Extended: The objective of this study was to compare measures of brain regional volume, cortical thickness, surface area, and brain curvature in a cohort of patients with PPTH attributed to mild traumatic brain injury (mTBI) to a cohort of patients with migraine.

Additional studies are planned to confirm these imaging findings and to deter-

mine their specificity.

Background The majority of individuals with post-traumatic headache (PTH) have headache characteristics that are consistent with a migraine phenotype [40, 183–185].

The ICHD criteria do not include any headache characteristics that differentiate

PTH from other headache types such as migraine or tension-type headache.

For the patient without a history of migraine who has head trauma and develops headache immediately following the trauma, the diagnosis of PTH is rather straightforward.

Even in such a situation, it is not clear if the head trauma caused a unique head- ache type (i.e. PTH) with a unique underlying pathophysiology or if the trauma unmasked an underlying propensity toward the development of migraine.

Identification of differences in the pathophysiology of migraine and PTH would

support the notion that migraine and PTH are truly distinct headache types.

Methods An independent samples t-test was performed on each MRI brain metric (i.e. regional volumes, cortical thicknesses, area, curvature) to identify significant differ- ences between PPTH and migraine cohorts.

For the PPTH vs. migraine analysis, ANCOVA controlled for sex, age, depres- sion scores, state and trait anxiety scores, and the number of years a subject had been having headaches, since these were parameters for which there were differ- ences between the PPTH and migraine groups.

For brain regions in which a structural measure differed between PPTH and migraine cohorts after controlling for nuisance variables in the initial ANCOVA: (1) correlations between the measurement with the number of years with PTH and with the number of total lifetime TBIs were calculated; (2) ANCOVA was performed to determine if there were differences in brain structure of these regions between PPTH and healthy controls; and (3) ANCOVA was performed to determine if there were differences in brain structure of these regions between migraine and healthy controls.

Results Compared to the PPTH cohort, the healthy control cohort had similar age (p = 0.97), fewer females (p = 0.02), and lower depression (p < 0.001), state anxiety (p < 0.001), and trait anxiety scores (p < 0.001).

Compared to the migraine cohort, the healthy control cohort had similar age (p = 0.33), the same number of females, and lower depression (p < 0.001), state anxiety (p < 0.001), and trait anxiety scores (p < 0.001).

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To better interpret the differences in brain structure identified between PPTH and migraine, the seven regional structural measures that differed between the PPTH and migraine cohorts were compared between the PPTH group to a group of healthy controls and between the migraine group and the healthy controls.

Discussion There were no significant correlations between the structural measurements of regions that differed when comparing PPTH to migraine with the number of years that individuals had PPTH.

Studies of mTBI have also demonstrated abnormalities of brain structure in sev- eral of the regions that we identified to have different structure in PPTH compared to migraine [186–188].

The brain regions that differed in structure when comparing individuals with PPTH to those with migraine in this study have all been previously demonstrated to participate in pain processing.

Although there are sufficient data to support a role for these brain regions in pain processing and headache, the explanation as to why the structure of these regions differs in individuals with PPTH compared to those with migraine is yet to be elucidated.

Conclusions Although there was substantial overlap in symptoms between individuals with PPTH and those with migraine, the structure of several brain regions differed in individuals with PPTH compared to those with migraine.

These structural differences suggest that the pathophysiology of PPTH might be different than that of migraine and support the classification of PPTH and migraine as distinct headache types.

Acknowledgement A machine generated summary based on the work of Schwedt, Todd J.; Chong, Catherine D.; Peplinski, Jacob; Ross, Katherine; Berisha, Visar 2017 in The Journal of Headache and Pain.

Decreased grey matter volume in mTBI patients with post- traumatic headache compared to headache-free mTBI patients and healthy controls: a longitudinal MRI study