Persistent post-traumatic headache (PTH) after mild traumatic brain injury (TBI) is associated with diminished pain inhibitory capacity, as well as greater depression and pain catastrophizing, according to study results published in the Journal of Headache and Pain.
PTH is a common lasting symptom following mild TBI, but its pathology is not fully understood. Study researchers sought to assess whether pain modulatory profiles and psychological factors following mild TBI could predict the development of persistent PTH in this patient population.
This prospective study included 44 adults with mild TBI who were recruited from Level 1 emergency department trauma centers in Indianapolis. At 1 to 2 weeks, 1 month, and 4 months following the occurrence of the mild TBI, study researchers assessed conditioned pain modulation for endogenous pain inhibitory capacity, temporal summation of pain and pressure pain thresholds of the head, pain catastrophizing using the Pain Catastrophizing Scale, depressive symptoms using the Center for Epidemiological Studies (CES) – Depression Scale, and headache using a standardized headache survey.
Based on the 4-month data, participants were classified as having persistent PTH (n=21) or no persistent PTH (n=21). The mean ages in both groups were 29.5 and 32.9 years, respectively. A significantly greater proportion of patients with persistent PTH were female (66.7%) compared with patients who did not have persistent PTH (33.3%; P =.013).
The study researchers found that patients with mild TBI who developed persistent PTH had significantly diminished pain inhibitory capacity (mean CPM score, 5.6±6.8 vs 33.6±6.8, respectively), increased depression (mean CES-Depression scores, 24.1±2.7 vs 19.0±2.7, respectively), and greater pain catastrophizing (mean Pain Catastrophizing Scale Score, 24.6±2.3 vs 15.3±2.3, respectively) after injury relative to participants who did not develop post-TBI persistent PTH.
In the logistic regression analysis, predictors of persistent PTH at 4 months following mild TBI included headache pain intensity at 1 to 2 weeks (95% CI, 1.16-3.37; P =.013) and pain inhibitory capacity on the conditioned pain modulation test (95% CI, 0.933-0.995; P =.022).
Limitations of the study were the inclusion of only patients from the Emergency Department, the relatively short follow-up period, and the reliance on retrospective headache assessment via interview rather than diary.
Despite these limitations, the researchers concluded that their “study provides the first longitudinal human evidence for the contribution of deficient endogenous pain inhibition in the transition from acute to persistent PTH.”
Naugle KM, Carey C, Evans E, Saxe J, Overman R, White FA. The role of deficient pain modulatory systems in the development of persistent post-traumatic headaches following mild traumatic brain injury: an exploratory longitudinal study. J Headache Pain. 2020;21(1):138. doi:10.1186/s10194-020-01207-1