Autonomic nervous system and endocrine system response to upper or lower cervical spine mobilization in males with persistent post-concussion symptoms: a proof-of-concept trial.

Nineteen participants with no a priori power calculation; the authors acknowledge this risks missing real differences (type II error). No sham or control group, so it is impossible to separate a true cervical-level effect from the non-specific effects of lying still, being touched, or the passage of time. Males only, aged 19 to 35, recruited from one university community; the authors note females sustain higher concussion rates and must be included in future work. The treating clinician was not blinded and participants were unlikely to be blinded to which level was mobilized. Data were non-normally distributed, forcing non-parametric tests and preventing a formal group-by-time interaction test. 15.8% of symptom-questionnaire responses were missing despite reminder texts. A single session was tested; no information about repeated treatment or longer-term effects.

Funded by the Stanley Paris PhD OMT scholarship, the University of Otago Doctoral scholarship, and the University of Otago School of Physiotherapy PhD fund. No industry sponsorship or conflicts of interest were declared.

Do not read the within-group changes as proof that one cervical level is superior to the other. Every between-group comparison (cortisol, heart-rate variability, symptom scores) failed to reach significance, and the primary outcome (overnight cortisol) was null. This is a single-session proof-of-concept in 19 young males with no sham control, not evidence that cervical mobilization treats post-concussion symptoms or that you should preferentially mobilize one level over another.