Selective Improvement in Neck and Limb Motor Control Outcomes Following Treatment of the Upper Neck and Spine: A Repeated Measures Cohort Study

Background: Sensory feedback from the upper cervical regions is used by the central nervous system to stabilize the occipito-atlantal (C0-C1) joint for leveled vision and to assess head position, which is used in sensorimotor integration (SMI) of neck and upper limb motor control. However, few studies have specifically investigated the impact of C0-C1 dysfunction and/or its rectification on SMI related outcomes. This study sought to determine the impact of restricted C0-C1 mobility and musculoskeletal pain on neck and upper limb motor control, whether these motor control deficits persist without treatment, and whether motor control improves following treatment designed to improve C0-C1 mobility. Methods: Twenty-two participants with restricted C0-C1 mobility attended three data collection sessions (baseline, control (2 to 5 days later), and post-treatment) at a private clinic. The One-to Zero (OTZ) system which treats the C0-C1 first followed by other spinal regions if clinically indicated, was administered twice weekly until participants reached 80% improvement from baseline symptoms. Shoulder range of motion, peak force and electromyography during maximal resisted scapular elevation (upper trapezius) and neck flexion (sternocleidomastoid), peak grip, and quadricep strength were measured before and after treatment. Repeated measures ANOVAs with pre-planned contrasts (e.g., control to baseline, and post-treatment to baseline) were conducted. Results: Neck and limb control impairments persisted without treatment, with no changes between the double baseline (p > 0.05). Shoulder abduction and extension, and peak force output of the sternocleidomastoid, upper trapezius, and quadriceps improved post-intervention (all p < 0.05). Conclusions: Selective improvement in neck and limb motor control outcomes post-treatment suggests that increased corticospinal drive/motor neuron excitability from normalized afferent input may impact gross motor output first. Clinical Registration Number: ACTRN12625000627459. https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=389394&isReview=true.