Effects of acute low back pain on postural control

Low Back Pain: The Potential Contribution of Supraspinal Motor Control and Proprioception

Motor control, which relies on constant communication between motor and sensory systems, is crucial for spine posture, stability and movement. Adaptions of motor control occur in low back pain (LBP) while different motor adaption strategies exist across individuals, probably to reduce LBP and risk of injury. However, in some individuals with LBP, adapted motor control strategies might have long-term consequences, such as increased spinal loading that has been linked with degeneration of intervertebral discs and other tissues, potentially maintaining recurrent or chronic LBP. Factors contributing to motor control adaptations in LBP have been extensively studied on the motor output side, but less attention has been paid to changes in sensory input, specifically proprioception. Furthermore, motor cortex reorganization has been linked with chronic and recurrent LBP, but underlying factors are poorly understood. Here, we review current research on behavioral and neural effects of motor control adaptions in LBP. We conclude that back pain-induced disrupted or reduced proprioceptive signaling likely plays a pivotal role in driving long-term changes in the top-down control of the motor system via motor and sensory cortical reorganization. In the outlook of this review, we explore whether motor control adaptations are also important for other (musculoskeletal) pain conditions.

Association Between Clinical Tests Related to Motor Control Dysfunction and Changes in Pain and Disability After Lumbar Stabilization Exercises in Individuals With Chronic Low Back Pain

OBJECTIVE

To investigate whether clinical tests used to detect motor control dysfunction can predict improvements in pain and disability in patients with chronic nonspecific low back pain (LBP) who have undergone an 8-week lumbar stabilization exercise program.

STUDY DESIGN

A prospective cohort study.

SETTING

Outpatient physical therapy university clinic.

PARTICIPANTS

Seventy people with chronic nonspecific LBP were recruited, and 64 completed the exercise program (N=64).

INTERVENTIONS

The lumbar stabilization program was provided twice a week for 8 weeks.

MAIN OUTCOME MEASURES

Pain intensity (11-point numerical rating scale) and disability (Roland Morris Disability Questionnaire) and clinical tests, such as the Deep Muscle Contraction (DMC) scale, Clinical Test of Thoracolumbar Dissociation (CTTD), and Passive Lumbar Extension (PLE) test. Univariate and multivariate linear regression models were used in the prediction analysis.

RESULTS

Mean changes in pain intensity and disability following the 8-week stabilization program were -3.8 (95% confidence interval [CI], -3.2 to -4.4) and -7.4 (95% CI, -6.3 to -8.5), respectively. Clinical test scores taken at baseline did not predict changes in pain and disability at 8-week follow-up.

CONCLUSION

Our findings revealed that the DMC scale, CTTD, PLE test, clinical tests used to assess motor control dysfunction, do not predict improvements in pain and disability in patients with chronic nonspecific LBP following an 8-week lumbar stabilization exercise program.

Effect of Whole Body Horizontal Vibration Exercise in Chronic Low Back Pain Patients: Vertical Versus Horizontal Vibration Exercise

OBJECTIVE

To elucidate the effect of a 12-week horizontal vibration exercise (HVE) in chronic low back pain (CLBP) patients as compared to vertical vibration exercise (VVE).

METHODS

Twenty-eight CLBP patients were randomly assigned to either the HVE or VVE group. All participants performed the exercise for 30 minutes each day, three times a week, for a total of 12 weeks. Altered pain and functional ability were evaluated using the visual analog scale (VAS) and Oswestry Disability Index (ODI), respectively. Changes in lumbar muscle strength, transverse abdominis (TrA) and multifidus muscle thicknesses, and standing balance were measured using an isokinetic dynamometer, ultrasonography, and balance parameters, respectively. These assessments were evaluated prior to treatment, 6 weeks and 12 weeks after the first treatment, and 4 weeks after the end of treatment (that is, 16 weeks after the first treatment).

RESULTS

According to the repeated-measures analysis of variance, there were significant improvements with time on VAS, ODI, standing balance score, lumbar flexor, and extensor muscle strength (all p<0.001 in both groups) without any significant changes in TrA (p=0.153 in HVE, p=0.561 in VVE group) or multifidus (p=0.737 in HVE, p=0.380 in VVE group) muscle thickness. Further, there were no significant differences between groups according to time in any of the assessments. No adverse events were noticed during treatment in either group.

CONCLUSION

HVE is as effective as VVE in reducing pain, strengthening the lumbar muscle, and improving the balance and functional abilities of CLBP patients. Vibrational exercise increases muscle strength without inducing muscle hypertrophy.

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

BACKGROUND

Automatic and voluntary body position control is essential for postural stability; however, little is known about individual factors that impair the sensorimotor system associated with low back pain (LBP).

OBJECTIVE

To evaluate automatic and voluntary motor control impairments causing postural instability in patients with LBP.

METHODS

Motor control impairments associated with poor movement and balance control were analyzed prospectively in 32 patients with LBP. Numeric Rating Scale (NRS) for pain assessment, Oswestry Disability Index (ODI) for disability measurement, and computerized dynamic posturography (CDP) for analysis of postural responses were used to measure outcomes of all patients. Computerized dynamic posturography tests including Sensory organization test (SOT), limits of stability test (movement velocity, directional control, endpoint, and maximum excursion), rhythmic weight shift (rhythmic movement speed and directional control), and adaptation test (toes-up and toes-down tests) were performed and the results compared with NeuroCom normative data.

RESULTS

The mean age of the patients was 40.50 ± 12.28 years. Lower equilibrium scores were observed in SOT (p < 0.05). There was a significant increase in reaction time and decrease in movement velocity, directional control, and endpoint excursion (p < 0.05). Speed of rhythmic movement along the anteroposterior direction decreased, while speed increased along the lateral direction (p < 0.05). Poor directional control was recorded in the anteroposterior direction (p < 0.05). Toes-down test showed an increased COG sway in patients compared with that in the controls (p < 0.05).

CONCLUSIONS

LBP causes poor voluntary control of body positioning, a reduction in movement control, delays in movement initiation, and a difficulty to adapt to sudden surface changes.

The Effects of Shoulder Slings on Balance in Patients With Hemiplegic Stroke

Objective

To investigate the effects of a shoulder sling on balance in patients with hemiplegia.

Methods

Twenty-seven hemiplegic stroke patients (right 13, left 14) were enrolled in this study. The subjects' movement in their centers of gravity (COGs) during their static and dynamic balance tests was measured with their eyes open in each sling condition-without a sling, with Bobath's axillary support (Bobath sling), and with a simple arm sling. The percent times in quadrant, overall, anterior/posterior, and medial/lateral stability indexes were measured using a posturography platform (Biodex Balance System SD). Functional balance was evaluated using the Berg Balance Scale and the Trunk Impairment Scale. All balance tests were performed with each sling in random order.

Results

The COGs of right hemiplegic stroke patients and all hemiplegic stroke patients shifted to, respectively, the right and posterior quadrants during the static balance test without a sling (p<0.05). This weight asymmetry pattern did not improve with either the Bobath or the simple arm sling. There was no significant improvement in any stability index during either the static or the dynamic balance tests in any sling condition.

Conclusion

The right and posterior deviations of the hemiplegic stroke patients' COGs were maintained during the application of the shoulder slings, and there were no significant effects of the shoulder slings on the patients' balance in the standing still position.

Does wearing unstable shoes reduce low back pain and disability in nurses? A randomized controlled pilot study

OBJECTIVE

To evaluate if wearing unstable shoes reduces low back pain and disability in nurses.

DESIGN

A randomized controlled trial.

SETTING

Hospitals and homecare.

SUBJECTS

A total of 20 matched female registered nurses with low back pain. The mean (standard deviation) age was 31 years (5) for the control and 34 years (6) for the intervention group; height was 161 cm (5) and 165 cm (7), respectively.

INTERVENTIONS

The intervention group received unstable shoes at Week 2 to wear for at least 36 h/week for a month.

MAIN MEASURES

The Oswestry Low Back Pain Disability Questionnaire and a visual analogue pain scale.

RESULTS

The mean (standard deviation) pain level was 6 (1) at baseline vs. 6 (2) at Week 6 for the control group, and 5 (1) vs. 1 (1) for the intervention group. The mean (standard deviation) disability level was 31% (9) at baseline vs. 28% (7) at Week 6 for the control, and 27% (12) vs. 13% (5) for the intervention group. There were no significant changes over time on pain or disability levels for the control group. The intervention group reported lower levels of pain on Weeks 4 (mean difference ⩾-1.4, p ⩽ 0.009) and 6 (mean difference ⩾-3.1, p < 0.001). Disability levels were also lower on Weeks 4 (mean difference = -4.5%, p NS) and 6 (mean difference = -14.1%, p = 0.020).

CONCLUSIONS

Wearing unstable shoes reduced low back pain and disability in nurses and might be helpful as part of the back pain rehabilitation process.