Correlation between self-report measures of function and lower limb motor performance in patients with and without imaging evidence of unilateral lumbar nerve root compression
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Date
2019
Authors
Sargent, Shelley
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Abstract
Lumbar radiculopathy is defined as compression of a lumbar nerve root, resulting in motor, sensory and, or reflex changes, correlating with the effected segment. Magnetic resonance imaging (MRI) investigations remain the gold standard for diagnosis of this condition. However, research studies provide evidence for the limitations of imaging to define the functional impact of various spinal conditions. The present study considered the impact of lumbar nerve compression on motor performance during a Fitts’ lower limb reaching task. Participants were stratified into three groups based on lumbar imaging and clinical presentation. Group 1 included subjects with imaging indicating lumbar nerve root compression, who presented with neurological deficit. Group 2 subjects demonstrated imaging evidence of nerve compression, without motor, sensory or reflex change. Group 3 were neurologically intact, and possessed degenerative changes on lumbar imaging films.
Movement time (MT), reaction time (RT), peak acceleration (PA), peak velocity (PV), time to peak acceleration (ttPA), time to peak velocity (ttPV), constant error (CE), absolute error (AE) and variable error (VE) were analyzed using 3 Group (1,2,3) by 4 ID (3,4a,4b,5) ANOVA models. The sole main effect for group was AE, where subjects in group 1 tended to land further from the target, compared to those in group 3.
A 2 Group (effected, non-effected limb) by 4 ID (3,4a,4b,5) ANOVA model revealed longer MTs and lower PVs for the effected limb in group 2. Between limb comparisons determined lower PAs and longer ttPAs for the non-dominant limb in group 3. There were no main effects for group, or group by ID interactions found between limbs for group 1. However, a tendency to undershoot the target at larger amplitudes of movement was a characteristic shared by group 1 and 2 participants.
Sub-analysis of between limb differences, using limb dominance to stratify subjects yielded main effects for PA and PV for group 2, when the dominant leg was the effected leg. The effected, dominant limb exhibited lower values for PA and PV, compared to the non-dominant, non-effected limb. Alterations in accuracy were noted for groups 1 and 2 when the non-dominant limb was impacted. The results align with the serial hybrid control theory regarding lateralization.
Pearson’s Correlation analysis revealed many significant correlations for groups 2 and 3 between self-report measures and motor performance variables. There was a lack of association between subjective and objective measures in group 1, which suggests that the presence of neurological deficit may impede evaluation of functional capability.
Overall, imaging did not predict most aspects of functional performance, when legs were collapsed for analysis. However, the Fitts’ task was able to differentiate groups, by way of accuracy evaluation and within group, between limb comparisons.
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Keywords
Motor performance, Lumbar nerve root compression