Sub-occipital muscle pressure pain thresholds correlate to direction of symptomatic active comfortable sustained neck rotation testing in post-concussive headache: a retrospective observational cross-sectional study

To compare sub-occipital muscle pressure sub pain thresholds (PPTs) in individuals with persistent-post-traumatic-headache (PPTH) in relation to the presence or not of cranial nerve and/or autonomic symptoms reported during sustained neck rotation (SNR).

Previously 81% of military service members with PPTH demonstrated symptoms with SNR up to 60 seconds. Of these, 54% reported symptoms in one (Uni-Symp) and 46% in both directions of rotation (Bi-Symp). Sub-occipital PPTs, in relation to SNR direction, were of interest.

Retrospective review of records of 77 individuals, with PPTH with both SNR and PPTs. Average suboccipital and scalene PPTs were compared between Asymptomatic (n = 13), upon SNR testing, or Symptomatic (Uni-Symp, n = 32, Bi-Symp, n = 32), groups.

The Bi-Symp group had significantly reduced sub-occipital PPTs relative to the Asymptomatic group on both sides [p < 0.009] with no side-to-side differences in either group. The Uni-Symp group had significantly lower sub-occipital PPTs on the symptomatic SNR test direction compared to the asymptomatic side [t(31) = 3.37, p = 0.002]. There were no differences within or between groups in the scalene PPTs(p's > 0.08).

An upper cervical mechanical trigger of symptoms during SNR tests in some individuals with PPTH is possible. The direction of symptomatic SNR tests may indicate direction of guarded hypermobile dysfunction and direct treatment.