Self-reported Measures of Function Compared to Lower Limb Motor Performance in People With and Without Imaging Evidence of Unilateral Lumbar Nerve Root Compression: A Cross-sectional Study

Objective: The primary objective of the present study was to determine if imaging findings of unilateral lumbar nerve root compression (ULNRC) impact performance on a coordinated motor performance task and to determine if there were correlations between motor performance and self-reported clinical measures.

Methods: People with back pain (N = 45) were stratified into 3 groups based on combinations of: lumbar imaging; and clinical presentation for ULNRC. Group 1 included people with imaging of lumbar nerve root compression, who presented with neurological deficit. Group 2 people demonstrated imaging evidence of nerve compression, without motor, sensory or reflex change. Group 3 participants possessed only degenerative changes on lumbar imaging films, and were neurologically intact. Performance measures included behavioral and kinematic variables from an established lower limb Fitts' Task requiring movements to targets of different difficulties. Self-reported measures of disability, function and pain were collected. Analysis of variance for between and within group variables were conducted, and Pearson correlation compared performance with self-reported measures.

Results: All groups yielded main effects for movement time with increasing task difficulty as predicted by Fitts' Law. A main effect revealed Group 1 participants performed less accurately than Group 3 participants. Positive correlations were predominantly found between self-report measures and motor performance for Group 2 and Group 3.

Conclusion: Imaging, and self-reported measures alone did not predict function, however, Fitts' task performance accuracy effectively differentiated groups.