Location-Specific Disruption of the Body Schema in Chronic Low Back Pain.

OBJECTIVES: To investigate whether chronic low back pain (CLBP) involves location-specific or more general body schema alterations, thereby helping to determine whether location-specific tasks may improve assessment of sensorimotor alterations and/or rehabilitation strategies for CLBP patients. And, secondarily, to examine whether pain intensity is associated with the extent of body schema alterations. DESIGN: Between-subject comparative study with age- and sex-matched groups. SETTING: This study was conducted at a University Hospital. PARTICIPANTS: Nineteen patients with CLBP and 19 healthy control participants matched for age and sex. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Body schema alterations were assessed using response time and accuracy of implicit motor imagery (IMI; ie, laterality judgment tasks) involving the painful location (low back) and a nonpainful location (hand). In CLBP patients, average pain intensity was assessed using numerical rating scales. RESULTS: Compared with healthy adults, CLBP patients showed longer response time in the task involving the painful location (low back) but no difference in the task involving a nonpainful location (hand). No significant correlation was found between pain intensity and response time or accuracy. CONCLUSIONS: CLBP seems associated with location-specific alterations of the body schema rather than being a generalized sensorimotor impairment. Consequently, this study highlights the value of location-specific tasks as tools for objectively identifying pain-related sensorimotor alterations and their potential to improve rehabilitation.