Active trigger points are common but not universal with tension-type headache: Pain features rather than musculoskeletal function may explain why.

BACKGROUND

Active trigger points (ATrPs) are common and considered a peripheral nociceptive source in tension-type headache (TTH). Understanding differences in features between individuals with TTH who have few or more ATrPs is needed.

OBJECTIVES

i) To determine sub-groups by the number of ATrPs present in TTH; ii) to compare headache and participant characteristics, psychological and behavioural features, number of painful areas, quantitative sensory testing (QST), tenderness scores, cervical musculoskeletal function and symptoms on cervical testing between subgroups.

METHODS

This secondary analysis of a cross-sectional study involved 80 participants with TTH. Participants were assessed with multiple cervical musculoskeletal tests, pressure and cold pain thresholds, wind-up ratio, pericranial tenderness and ATrPs.

RESULTS

Two clusters were formed. Cluster 1 (n = 48) with few or nil ATrPs (median 2, range 0-5) and Cluster 2 (n = 32) with multiple ATrPs (median 8, range 5-13). Individuals in Cluster 2 reported a longer headache history (p = 0.026, r = 0.25), more reporting neck pain (p = 0.012, Phi = 0.30), more painful body areas (p = 0.001, d = 0.82), higher tenderness scores (all p < 0.001, all d > 1.00) and more pain on cervical musculoskeletal testing (p < 0.001 to p = 0.036, Phi = 0.18-0.85). They had less cervical joint dysfunction (p = 0.044, w = 0.24) but no differences in psychological and behavioural features and QST.

CONCLUSIONS

Few features differentiated individuals with multiple ATrPs from those with only a few ATrPs. ATPs were not related to musculoskeletal function but possibly an element of pain hypersensitivity. Further research is needed to better understand ATrPs in TTH.