Regional Sensorimotor Effects of Chiropractic Spinal Manipulation: Preliminary Results From an Experimental Study

Abstract

Objective: The purpose of this study was to assess the effects of different spinal manipulation (SM) techniques and target segments on a specific dermatome and myotome, when compared with a remote spinal cord segment that served as a control location. Methods: Twenty-nine healthy volunteers were randomized to receive instrumental (Activator IV, Activator Methods International Ltd) or manual SM at the C6, C1, and T4 vertebral segments in 3 independent sessions. Pressure pain thresholds (PPTs) and muscle strength were examined at the C6 (test) and L4 (control) dermatomes and myotomes, at baseline and after intervention. Linear mixed-effects models were used to analyze changes over time and interindividual variability. Results: Pressure pain thresholds significantly increased at both proximal and distal C6 dermatome locations (P.2). No significant changes were observed at the L4 dermatome. Muscle strength remained unchanged throughout the study. Multilevel modeling revealed significant associations between increased PPTs along the C6 dermatome (P