Neural mechanisms and functional correlates of altered postural responses to perturbed standing balance with chronic low back pain

Abstract

This study sought to determine the effects of chronic low back pain (LBP) on the cortical evoked potentials, muscle activation, and kinematics of postural responses to perturbations of standing balance. Thirteen subjects with chronic, recurrent, non-specific LBP and 13 subjects without LBP participated. The subjects responded to unpredictably timed postural perturbations while standing on a platform that randomly rotated either “toes up” or “toes down”. Electroencephalography (EEG) was used to calculate the negative peak (N1) and subsequent positive peak (P2) amplitudes of the perturbation evoked cortical potentials. Passive-marker motion capture was used to calculate joint and center-of-mass (CoM) displacements. Surface electromyography was used to record muscle onset latencies. Questionnaires assessed pain, interference with activity, fear of activity, and pain catastrophizing. Results demonstrated that subjects with LBP exhibited significantly larger P2 potentials, delayed erector spinae, rectus abdominae, and external oblique onset latencies, as well as smaller trunk extension yet larger trunk flexion, knee flexion, and ankle dorsiflexion displacements compared to subjects without LBP. For the subjects with LBP, CoM displacements significantly and positively correlated with knee displacements as well as activity interference and fear scores. The P2 potentials significantly and negatively correlated with CoM displacements as well as activity interference, catastrophizing, and fear scores. These results demonstrate that people with LBP exhibit altered late-phase cortical processing of postural perturbations concomitant with altered kinematic and muscle responses, and these cortical and postural response characteristics correlate with each other as well as with clinical reports of pain-related fears and activity interference.

Task-related and person-related variables influence the effect of low back pain on anticipatory postural adjustments

“…Thus, the lost statistical effect of group on pre-movement negativity amplitudes when including velocity as a covariate suggests that the group difference in cortical motor preparation may be at least partially mediated by cortical processing of the impending movement’s velocity. Regardless of the mechanism underlying the increased pre-movement cortical activity of subjects with LBP, our findings corroborate previous interpretations that LBP associates with enhanced activity, and perhaps influence, of the cerebral cortex on postural coordination (Jacobs, et al, 2010; Jacobs, et al, 2016; Masse-Alarie, et al, 2016b; Sadeghi, et al, 2016). …”

“…This initial position was intermittently verified during testing by visual inspection with a goniometer and taped outlines of the feet. A seated task was chosen in order to localize postural control to the trunk, because it is known that people with LBP compensate with distal lower-limb control during standing postural tasks (Claeys, Brumagne, Dankaerts, Kiers, & Janssens, 2011; Jacobs, Henry, Jones, Hitt, & Bunn, 2011; Jacobs, Roy, Hitt, Popov, & Henry, 2016; Sadeghi, et al, 2016). …”

Balance control during gait initiation: State-of-the-art and research perspectives

“…Jacobs et al[ 46 ] found that during gait initiation, knee trembling causes multiple APAs that are observable as a right-left leg loading-unloading cycles (cf. also[ 47 ]). Interestingly, the alternating unloading and loading of the legs was accompanied by similar alternating activation and deactivation of right-left tibialis anterior (Figure 2 in Jacobs et al[ 46 ]).…”

Immediate effects of kinesio taping on pain and postural stability in patients with chronic low back pain

“…Studies have shown changes in mobility and stability of spine, insufficiency of muscle strength, coordination, sensory-motor function, the ability to control body balance, proprioception, and orientation in relation to low back pain (Barrey et al, 2016;Jacobs et al, 2016;Ruhe et al, 2011;Truszczy nska et al, 2016;Tsigkanos et al, 2016). It was reported that these changes and insufficiencies of the musculoskeletal system affect the balance performance ability and limit the use of a proper exercise strategy in perturbation (Xia et al, 2008).…”

“…It was reported that these changes and insufficiencies of the musculoskeletal system affect the balance performance ability and limit the use of a proper exercise strategy in perturbation (Xia et al, 2008). Especially, patients with low back pain have a decreased balance ability compared to normal individuals (Jacobs et al, 2016;Truszczy nska et al, 2016;Tsigkanos et al, 2016). When the human body is exposed to an unexpected load, muscles have to respond quickly to maintain the body's balance and posture against the load.…”