Functional contributors to poor movement and balance control in patients with low back pain: A descriptive analysis

Voluntary postural sway control and mobility in adults with low back pain

Introduction

Low back pain (LBP) is associated with altered somatosensory perception, which is involved in both involuntary and voluntary control of posture. Currently, there is a lack of methods and tools for assessing somatosensory acuity in patients with LBP. The purpose of this study was (1) to assess the reliability of the sway discrimination apparatus (SwayDA) (2) to evaluate the differences in somatosensory acuity between patients with LBP and pain-free individuals, and (3) to examine relationships between somatosensory acuity, severity of LBP, and mobility in patients with LBP.

Methods

Twenty participants (10 patients with LBP and 10 matched asymptomatic controls) were recruited in a test-retest reliability test. Another 56 participants were recruited for this study with 28 individuals presenting with LBP and a further twenty-eight being asymptomatic. The SwayDA was custom-built to measure somatosensory perception during voluntary anterior-posterior (SwayDA-AP), medial-lateral to the dominant side (SwayDA-ML-D), and non-dominant side (SwayDA-ML-ND) postural sway control. Participants also completed mobility tests, including 10 times and 1-min sit-to-stand tests (10-STS, 1 m-STS). The area under the receiver operating characteristic curve (AUC) was calculated to quantify somatosensory acuity in discriminating different voluntary postural sway extents.

Results

The ICC (2.1) for the SwayDA-AP, SwayDA-ML-D, and SwayDA-ML-ND were 0.741, 0.717, and 0.805 with MDC95 0.071, 0.043, and 0.050. Patients with LBP demonstrated significantly lower SwayDA scores (tSwayDA-AP = -2.142, p = 0.037; tSwayDA-ML-D = -2.266, p = 0.027) than asymptomatic controls. The AUC values of the SwayDA-AP test were significantly correlated with ODI (rSwayDA-AP-ODI = -0.391, p = 0.039). Performances on the 1 m-STS and the 10-STS were significantly correlated with the AUC scores from all the SwayDA tests (-0.513 ≤ r ≤ 0.441, all p < 0.05).

Discussion

The SwayDA tests evaluated showed acceptable reliability in assessing somatosensory acuity during voluntary postural sway. Somatosensory acuity was diminished in patients with LBP compared to asymptomatic controls. In patients with LBP, lower somatosensory acuity was associated with increased LBP-related disability. Future research could focus on investigating the factors contributing to the decreased somatosensory perception and mobility in individuals with LBP.

Tai Chi for spatiotemporal gait features and dynamic balancing capacity in elderly female patients with non-specific low back pain: A six-week randomized controlled trial

BACKGROUND

Non-specific low back pain (NS-LBP) is a serious public health problem. Tai Chi is promising in reducing the risk of falls and alleviating symptoms in this population.

OBJECTIVE

To investigate the effect of Tai Chi on gait and dynamic balance in elderly women with NS-LBP.

METHODS

20 women (age > 65 yr.) with NS-LBP were randomly assigned to a Tai Chi group (n= 10) or a control group (n= 10). The Tai Chi group practiced Tai Chi exercise 3 times a week for 6 weeks. Each session lasted 60 minutes. Pain, spatiotemporal gait features and dynamic balancing capacity were assessed at 0 and 6 weeks.

RESULTS

Compared to the control group at 6 weeks, the Tai Chi group had a significant decrease in VAS (p= 0.027) and stride width (p= 0.019), significant improvement in gait velocity, stride length (p< 0.001). Regarding dynamic balance capacity, the Tai Chi group had significant improvements in anterior (Left: p= 0.001; Right: p= 0.038), postero-lateral (Left: p< 0.001; Right: p= 0.038), and postero-medial (Left: p= 0.015; Right: p= 0.018).

CONCLUSION

6-week Tai Chi can relieve pain and improve gait and dynamic balance in elderly women with NS-LBP, which suggests Tai Chi could be a promising rehabilitation intervention to reduce the risk of falls in this population.

Physical Abilities in Low Back Pain Patients: A Cross-Sectional Study with Exploratory Comparison of Patient Subgroups

An abundance of literature has investigated the association between low back pain (LBP) and physical ability or function. It has been shown that LBP patients display reduced range of motion, decreased balance ability, impaired proprioception, and lower strength compared to asymptomatic persons. The aim of this study was to investigate the differences between LBP patients and healthy controls in terms of several physical abilities. Based on the premised that different biomechanical and physiological causes and consequences could be related to different types of LBP, a secondary exploratory attempt of the study was to examine the differences between LBP subgroups based on the pain location (local or referred) or type of pathology (discogenic or degenerative) on the level of impairment of function and ability. Participants performed range of motion tests, trunk maximal voluntary contraction force tests, a sitting balance assessment, the timed up-and-go test, the chair rise test, and the trunk reposition error test. Compared to the control group, symptomatic patients on average showed 45.7% lower trunk extension (p < 0.001, η² = 0.33) and 27.7 % lower trunk flexion force (p < 0.001, η² = 0.37) during maximal voluntary contraction. LBP patients exhibited decreased sitting balance ability and lower scores in mobility tests (all p < 0.001). There were no differences between groups in Schober’s test and trunk repositioning error (p > 0.05). No differences were observed among the LBP subgroups. The exploratory analyses are limited by the sample size and uncertain validity of the diagnostic procedures within this study. Further studies with appropriate diagnostic procedures and perhaps a different subgrouping of the LBP patients are needed to elucidate if different types of LBP are related to altered biomechanics, physiology, and function.

Contribution of the sensory innervation of the spine in low back pain: review and clinical commentary

Few validated tests allow a precise aetiological diagnosis of Low Back Pain (LBP), and the difficulty of clinical evaluations could be one of the reasons to explain the lack of effectiveness in the therapeutic management of chronic LBP. However, an implication of a sensory impairment in the control of sensorimotor circuits could be suggested. Interactive and specific responses between nociceptive nerve fibres and the paraspinal musculature motor control could have clinical implications, in particular through kinematic evaluation. Following an introduction to the link between the sensory innervation of the spine and pain, we then summarise the maladaptive movement in LBP at the kinematic and neuropathological level. A clinical objectification of these kinematic adaptations at the lumbar spine level, would clarify the aetiological diagnosis causes of chronic LBP, and so help optimising therapeutic strategies by proposing a relevant and precise clinical model of this painful condition.

Reliability and validity of a force-instrumented treadmill for evaluating balance: A preliminary study of feasibility in healthy young adults

Background:

With the development of computer technology, computerized dynamic posturography provides objective assessments of balance and posture control under static and dynamic conditions. Although a force-instrumented treadmill-based balance assessment is feasible for balance evaluations, currently no data exists.

Objective:

This study was undertaken to assess the reliability and validity of balance evaluations using a force-instrumented treadmill.

Methods:

Ten healthy adults participated in evaluations using both the treadmill and the EquiTest. Four balance evaluations were conducted: Modified Clinical Test of Sensory Interaction on Balance, Unilateral Stance, Weight Bearing Squat, and Motor Control Test.

Results:

All balance evaluations using the force-instrumented treadmill method shared good reliability (intraclass correlation coefficient ≥0.6). The Modified Clinical Test of Sensory Interaction on Balance, Unilateral Stance, and Weight Bearing Squat evaluations had a correlation of r < 0.5 with EquiTest, whereas the Motor Control Test balance evaluation had moderate correlations (r > 0.5) with the EquiTest.

Conclusion:

The results demonstrated that all balance evaluations using the force-instrumented treadmill were reliable, and that the Motor Control Test evaluation was moderately correlated with the EquiTest. Therefore, the use of a force-instrumented treadmill in balance evaluations might provide a certain level of value to clinical practice.

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

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.