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.

Tactile Perception of Pressure and Volitional Thrust Intensity Modulate Spinal Manipulation Dose Characteristics.

OBJECTIVE: The purpose of this study was to examine clinicians' ability to modulate spinal manipulation (SM) thrust characteristics based on their tactile perception of pressure and volitional intensity. METHODS: In a cross-sectional, within-participants design, 13 doctors of chiropractic delivered SM thrusts of perceived least, appropriate, or greatest intensity of their perceived safe output level for an SM thrust on low-fidelity thoracic spine models of 4 different pressure levels. The participants performed SM over the course of 96 trials in a randomized order on combinations of thrust intensity and pressure. Dependent variables included normalized preload force, thrust force, thrust duration, peak acceleration, time to peak acceleration, and displacement. For all dependent measures, 2-factor within-participants analysis of variance models with repeated measures on both factors were performed. RESULTS: Preload force increased with intensity (F2,24 = 9.72; P < .001) and model pressure (F3,36 = 4.27; P = .011). Participants modulated thrust force and displacement as each also increased with intensity escalation (F2,24 = 22.53, P < .001; F2,18 = 45.20, P < .001). The highest accelerations were observed during the greatest intensity. Increased thrust force was delivered at higher model pressures (F3,36 = 6.43; P < .001). A significant interaction demonstrated that as volitional thrust intensity increased, greater displacement was attained, particularly on low pressure models (F6,54 = 11.06; P < .001). Thrust duration and time to peak acceleration yielded no significant differences. CONCLUSION: Spinal manipulation thrust dosage was modulated by the chiropractors' tactile perception of pressure and volitional intensity.

Acceleration of clinician hand movements during spinal manipulative therapy.

This study used an observational design to examine the kinematics of spinal manipulative therapy (SMT) by determining the acceleration characteristics of the manipulative input at the cervical, thoracic, and lumbar spinal regions. Studies of SMT have been restricted to measuring the forces that result from the manipulative input. Several studies have indicated the rate of force development is a key parameter of clinically delivered SMT. Despite this, the movement strategies employed during SMT, including acceleration, have not been directly measured. Participants (n = 29) were recruited from a private practice chiropractic clinic. A wireless accelerometer attached to the clinician's hand was used to characterize the thrust phase of the SMT treatments. Significant differences were found across each spinal region for acceleration amplitude parameters (p < 0.0001). Post-hoc analysis indicated that amplitudes significantly increased in order from thoracic to cervical to lumbar regions (p < 0.0001). Spinal level was also a significant factor in determining the temporal parameters of hand acceleration during SMT (p < 0.0005). This study provides a description of the acceleration properties of clinically delivered SMT. Consistent with that reported for SMT forces, acceleration amplitudes varied significantly across spinal regions with relatively little differences in acceleration latencies. Notably, acceleration amplitudes and latencies were not associated with each other within spinal regions. These findings indicate that changes in acceleration amplitude, rather than latency, are used to tailor SMT to individuals.