Introduction: The Centre for Disease Control in the United States estimates 1.7-3.8 million sport concussions annually with twenty percent presenting persistent symptoms requiring targeted clinical assessment. Few studies examine manual therapy in concussions. Our purpose was to investigate cranial bone and upper cervical mobility restriction prevalence in post-concussion syndrome.  
Methods: Twenty-one adults with post-concussion syndrome (PCS), 11 with history of concussion (CHx) and 12 controls (Ctl) participated. An osteopath assessed cranial bones and C0-C1-C2 mobility using a standard protocol to determine number of restrictions (NR). An athletic therapist assessed participants on Post-Concussion-Symptom-Scale (PCSS), King-Devick (KD), Tandem Gait Test (TGT), Sensory Organisation Test (SOT), and Vestibulo-Oculo-Motor-Screening (VOMS). Assessments were blinded to group assignment. We used a one-way ANOVA to assess group differences and a Pearson Correlation to assess relationships between variables. 
Results: NR was statistically different between groups (F(2,41)= 6.231, p= .004). PCS (8.24±4.25) had a higher NR compared to the Ctl (2.92±3.8) (mean difference 5.321±1.512, p= .003). The NR demonstrated a relationship with PCSS symptom severity (r2=0.333, p= .027) and VOMS vestibular score (r2=0.305, p= .044). Although not significant, there was a trend with number of symptoms (r2=0.283, p= .062), visual (r2=0.267, p= .079) and total score (r2=0.293, p= .054). There was no relationship between NR and KD, TGT and SOT.
Conclusion: NR was significantly higher in the PCS group compared to the Ctl group. NR was associated with the PCSS and VOMS, but not the KD, TGT, SOT. Cervical and cranial mobility restrictions should be investigated in concussions with prolonged recovery.