Altered postural control in anticipation of postural instability in persons with recurrent low back pain

Comparisons of postural control, proprioception, muscle strength, pain and disability between individuals with acute, subacute and chronic low back pain

PURPOSE/AIM

Postural control, proprioception and lower extremity muscle strength are affected in individuals with low back pain (LBP). However, it is yet unknown whether these variables differentiate between acute, subacute and chronic stages of LBP. The aim was to investigate if there were any differences in postural control, proprioception, lower extremity muscle strength, pain intensity and disability between individuals in the different stages of LBP.

MATERIALS AND METHODS

In this cross-sectional study, 124 individuals with LBP were grouped as acute LBP (ALBP) (n = 38), subacute LBP (SLBP) (n = 30) and chronic LBP (CLBP) (n = 56) groups. Postural control was assessed via computerised technology. Lumbar proprioception, lower extremity muscle strength, pain intensity and disability were assessed using Joint Repositioning Error Test, hand-held dynamometer, Numeric Rating Scale and Oswestry Disability Index (ODI), respectively. Kruskal-Wallis Tests, ANCOVA and post hoc Mann-Whitney U-Test with Bonferroni correction were performed.

RESULTS

While there were no significant differences in terms of postural control, proprioception and pain intensity (p > 0.05), significant differences were found in terms of lower extremity muscle strength and ODI scores between groups when adjusted for age (p < 0.05). Individuals with CLBP demonstrated poorer lower extremity muscle strength than those with ALBP and SLBP, and higher disability than those with ALBP (p < 0.017).

CONCLUSIONS

Although postural control, proprioception and pain intensity were similar between individuals with acute, subacute and chronic LBP, muscle strength and disability seem to worsen stepwise as the pain becomes chronic. Muscle strength and disability should be taken into account while evaluating and/or managing individuals with acute and subacute stages of LBP.

Evaluation of balance in patients with systemic sclerosis

BACKGROUND

The aim was to examine static/dynamic balance and proprioception of Systemic Sclerosis by comparing healthy and relationship with demographic and disease-related data.

METHODS

21 Systemic Sclerosis and 19 healthy were included.Berg Balance Scale (functional balance), Sensamove Sensbalance Maxiboard Software (static, dynamic balance:reaction time and travel time and proprioception), Scleroderma Health Assessment Questionnaire/Health Assessment Questionnaire (health status), Medsger's Disease Severity Scale, Modified Rodnan Skin Score were used in evaluation.

FINDINGS

Comparing the groups, there was significant difference in Berg Balance Scale (p:0.036); Health Assessment Questionnaire/Scleroderma Health Assessment Questionnaire (p:0.001); Static balance-center (p:0.001), front (p:0.001), back (p:0.001), left (p:0.001), right (p:0.021); proprioception-front (p:0.025);Reaction Time-front (p:0.031) and left (p:0.010);Travel Time-front (p:0.041) and left (p:0.014) in favor of healthy group.In Systemic Sclerosis, disease severity had moderate correlation with static balance-back (r:-0.504,p:0.020).Skin thickness had low correlation with Reaction Time-front (r:-0.449,p:0.041).Age had low correlation with Travel time-front (r:0.458,p:0.037) and proprioception-left (r:0.450,p:0.041); moderate with Travel time-back (r:0.515;p:0.017) and proprioception-front (r:0.539,p:0.012).

INTERPRETATION

Compared to healthy, Systemic Sclerosis had worse health status, functional balance, static/dynamic balance and proprioception.This situation is related to disease severity, skin thickness and age. Evaluations made with objective methods may have the potential to determine the extent of the problem.Clinicians can guide the treatment of patients with SSc by evaluating their static/dynamic balance and proprioception.With early treatment, additional problems that may occur due to worsening of balance and proprioception can be prevented.Proprioception and dynamic balance evaluation can be performed for older patients, static balance when disease activity is high, and dynamic balance when skin thickness score is high.

Multifidus dysfunction and restorative neurostimulation: a scoping review

OBJECTIVE

Chronic low back pain (CLBP) is multifactorial in nature, with recent research highlighting the role of multifidus dysfunction in a subset of nonspecific CLBP. This review aimed to provide a foundational reference that elucidates the pathophysiological cascade of multifidus dysfunction, how it contrasts with other CLBP etiologies and the role of restorative neurostimulation.

METHODS

A scoping review of the literature.

RESULTS

In total, 194 articles were included, and findings were presented to highlight emerging principles related to multifidus dysfunction and restorative neurostimulation. Multifidus dysfunction is diagnosed by a history of mechanical, axial, nociceptive CLBP and exam demonstrating functional lumbar instability, which differs from other structural etiologies. Diagnostic images may be used to grade multifidus atrophy and assess other structural pathologies. While various treatments exist for CLBP, restorative neurostimulation distinguishes itself from traditional neurostimulation in a way that treats a different etiology, targets a different anatomical site, and has a distinctive mechanism of action.

CONCLUSIONS

Multifidus dysfunction has been proposed to result from loss of neuromuscular control, which may manifest clinically as muscle inhibition resulting in altered movement patterns. Over time, this cycle may result in potential atrophy, degeneration and CLBP. Restorative neurostimulation, a novel implantable neurostimulator system, stimulates the efferent lumbar medial branch nerve to elicit repetitive multifidus contractions. This intervention aims to interrupt the cycle of dysfunction and normalize multifidus activity incrementally, potentially restoring neuromuscular control. Restorative neurostimulation has been shown to reduce pain and disability in CLBP, improve quality of life and reduce health care expenditures.

Exploring the Interplay of Muscular Endurance, Functional Balance, and Limits of Stability: A Comparative Study in Individuals with Lumbar Spondylosis Using a Computerized Stabilometric Force Platform

Lumbar spondylosis, characterized by degenerative changes in the lumbar spine, often leads to pain, reduced spinal stability, and musculoskeletal dysfunction. Understanding the impact of lumbar spondylosis on musculoskeletal function, particularly lumbar extensor endurance, functional balance, and limits of stability, is crucial for improving the management and well-being of affected individuals. This study aimed to assess lumbar extensor endurance, functional balance, and limits of stability in individuals with lumbar spondylosis compared to age-matched healthy individuals and explore the correlations among these parameters within the lumbar spondylosis group. The lumbar spondylosis group consisted of 60 individuals initially screened by an orthopedician and referred to physical therapy. Age-matched healthy controls (n = 60) were recruited. Inclusion criteria encompassed adults aged 45-70 years for both groups. Lumbar extensor endurance was assessed using the Sorensen test, functional balance with the Berg Balance Scale, and limits of stability using a computerized stabilometric force platform. Lumbar extensor endurance was significantly lower in individuals with lumbar spondylosis compared to healthy controls (23.06 s vs. 52.45 s, p < 0.001). Functional balance, as assessed by the Berg Balance Scale, demonstrated a significant decrement in the lumbar spondylosis group (48.36 vs. 53.34, p < 0.001). Additionally, limits of stability variables, under both eyes-open and eyes-closed conditions, exhibited marked impairments in the lumbar spondylosis group (p < 0.001 for all variables). Within the lumbar spondylosis group, lumbar extensor endurance exhibited significant positive correlations with functional balance (0.46, p < 0.001) and negative correlations with limits of stability variables (r ranging from -0.38 to -0.49, p < 0.01 for all variables). This study underscores the significance of addressing lumbar extensor endurance, functional balance, and stability impairments in the comprehensive management of lumbar spondylosis.

Biological Responses to Local Vibratory Stimulation for the Lower Legs and Lower Back and Criterion Values Based on Sweep Frequencies of Healthy Individuals: An Observational Study

Declining proprioceptive function is associated with problems such as lower back pain and falls. Therefore, we developed a vibration device using sweep frequency to evaluate several proprioceptors with different response frequency ranges. This study aimed to elucidate the biological responses of healthy individuals to vibratory stimulation at different sites and frequency ranges and to propose cutoff values to determine the decline in proprioceptive function. Mechanical vibration was separately applied to the lower legs and lower back, and proprioceptive function was evaluated by defining the ratio of the center of pressure (CoP) in the anteroposterior direction during mechanical vibration to that during no vibration in the three frequency ranges. The cut-off value was defined as the mean value, with the standard deviation subtracted for each indicator. The cut-off values were higher in the lower legs than in the lower back at all frequency ranges and in the 30-53 Hz and 56-100 Hz frequency ranges for both the lower legs and lower back. In healthy individuals, 9.9% and 8.6% were below the cut-off values in the 30-53 Hz and 56-100 Hz frequency ranges for the lower legs, respectively.

Anticipatory postural adjustments mediate the changes in fear-related behaviors in individuals with chronic low back pain

OBJECTIVES

The role(s) of anticipatory postural adjustments (APAs) in changes in subsequent motor and postural controls in response to movement perturbations are unclear in individuals with chronic low back pain (CLBP). This study aimed to clarify the relationships among kinesiophobia, APAs, lumbar kinematic output, and postural control associated with lumbar movement in individuals with CLBP.

METHODS

CLBP participants (n=48) and healthy controls (HCs) without CLBP (n=22) performed a bend-forward task using their lumbar region on a force platform and returned upright. Each participant's lumbar movements were recorded using an electrogoniometer. We calculated the APA duration, the duration of lumbar direction changes from forward to backward, and the center of pressure (COP) position after lumbar movement tasks completion.

RESULTS

Compared with the HCs, the duration of direction changes in lumbar movement and the APA duration in CLBP participants were prolonged, and the COP position was shifted forward. The mediation analysis revealed that the duration of lumbar direction changes in the CLBP group was subjected to a significant indirect effect of APAs and a direct effect of kinesiophobia, and the COP position was subjected to a significant indirect effect of kinesiophobia through APAs.

CONCLUSIONS

APAs partially mediate the relationship between kinesiophobia and changes in lumbar motor control and mediate the relationship between kinesiophobia and postural control in response to movement perturbations. These findings expand our understanding of APAs in altered subsequent movement and postural controls due to kinesiophobia in individuals with CLBP.

Delayed response in rectus abdominis muscle following a step perturbation in subjects with and without recurrent low back pain

BACKGROUND

Delayed trunk and lower limb muscle activation is associated with balance loss and fall injuries in subjects with recurrent low back pain (LBP).

PURPOSE

This study was conducted to compare differences in the onset of muscle contractions of the trunk and lower limb muscles following a treadmill-induced step perturbation between subjects with and without LBP.

METHODS

Eighty-three right limb dominant individuals (43 subjects with LBP and 40 control subjects) were exposed to the perturbation (0.31 m/s velocity for 0.2 m). The electromyography (EMG) reaction times were analyzed during the first step following the perturbation. The EMG electrodes were placed on both sides of the trunk and lower limbs, including the rectus abdominis (RA), erector spinae (ES), tibialis anterior (TA), and gastrocnemius (GA) muscles.

RESULTS

The group x muscle interaction was statistically significant (F = 9.44, p = 0.003). The TA muscle activation was significantly delayed compared to the RA, ES, and GA. There was a significant interaction on side x muscle (F = 4.14, p = 0.04). The RA muscles were significantly delayed on the non-dominant (t = - 3.35, p = 0.001) and dominant (t = - 2.53, p = 0.01) sides in the LBP group.

CONCLUSION

The LBP group demonstrated a delayed reaction time on the RA muscles, which indicated poor trunk control relative to the lower limbs. The delayed bilateral RA muscle might indicate possible coordination problems relative to the ES and lower limb muscles, which may lead to potential fall hazards.

The immediate effects of iTBS on the muscle activation pattern under challenging balance conditions in the patients with chronic low back pain: A preliminary study

Background

The patients with chronic low back pain (CLBP) showed impaired postural control, especially in challenging postural task. The dorsolateral prefrontal cortex (DLPFC) is reported to involve in the complex balance task, which required considerable attentional control. The effect of intermittent theta burst stimulation (iTBS) over the DLPFC to the capacity of postural control of CLBP patients is still unknown.

Methods

Participants diagnosed with CLBP received a single-session iTBS over the left DLPFC. All the participants completed the postural control tasks of single-leg (left/right) standing before and after iTBS. The activation changes of the DLPFC and M1 before and after iTBS were recorded by functional near-infrared spectroscopy (fNIRS). The activation pattern of the trunk [transversus abdominis (TrA), superficial lumbar multifidus (SLM)] and leg [tibialis anterior (TA), gastrocnemius medialis (GM)] muscles including root mean square (RMS) and co-contraction index (CCI) during single-leg standing were measured by surface electromyography (sEMG) before and after the intervention. The paired t-test was used to test the difference before and after iTBS. Pearson correlation analyses were performed to test the relationship between the oxyhemoglobin concentration and sEMG outcome variables (RMS and CCI).

Results

Overall, 20 participants were recruited. In the right-leg standing condition, compared with before iTBS, the CCI of the right TrA/SLM was significantly decreased (t = −2.172, p = 0.043), and the RMS of the right GM was significantly increased (t = 4.024, p = 0.001) after iTBS. The activation of the left DLPFC (t = 2.783, p = 0.012) and left M1 (t = 2.752, p = 0.013) were significantly decreased and the relationship between the left DLPFC and M1 was significant after iTBS (r = 0.575, p = 0.014). Correlation analysis showed the hemoglobin concentration of M1 was negatively correlated with the RMS of the right GM (r = −0.659, p = 0.03) and positively correlated between CCI of the right TrA/SLM (r = 0.503, p = 0.047) after iTBS. There was no significant difference in the brain or muscle activation change in the left leg-standing condition between before and after iTBS.

Conclusion

Intermittent theta burst stimulation over the left DLPFC seems to be able to improve the muscle activation pattern during postural control ability in challenging postural task, which would provide a new approach to the treatment of CLBP.

Comparison of proprioceptive postural control strategies between prolonged standing induced low back pain developers and non-low back pain developers

BACKGROUND

Proprioception deficit has been suggested as a possible mechanism contributing for the impaired postural control in low back pain (LBP) patients. Whether proprioception deficit is a result of or a cause of LBP has not been investigated.

OBJECTIVE

The purpose of this study was to compare proprioceptive postural control strategies between prolonged standing induced low back pain developers (PDs) and non-pain developers (NPDs).

METHOD

Thirty-two healthy subjects performed 1-h prolonged standing and their ratings of perceived LBP have been recorded. Eight quiet standing trials for 60 s performed immediately before and after the prolonged standing. Postural control was challenged by muscle vibration and different postural conditions during quiet standing. Data were recorded using a force platform.

RESULTS

Forty percentage of participants is classified as PD. Before the prolonged standing, relative proprioceptive weighting was greater in the PD compared to NPD group (P = .029). Main effect of postural condition (F_1,24 = 5.21, P = .032) and interaction of time by group (F_1,24 = 8.08, P = .009) were significant for COP displacement in anteroposterior direction. Interaction of postural condition by group (F_1,26 = 7.82, P = .010) and time by group (F_1,26 = 9.71, P = .004) were significant for COP displacement in mediolateral direction. Main effect of postural condition (F_1,26 = 6.31, P = .018) and interaction of postural condition by group (F_1,26 = 7.07, P = .013) were significant for mean velocity in mediolateral direction.

CONCLUSION

The PD group has altered proprioceptive postural control strategies before and after prolonged standing. Proprioception deficit should not be considered to be solely an adaptive response and may be causal for LBP development.

A Comprehensive Review of Pain Interference on Postural Control: From Experimental to Chronic Pain

Motor control, movement impairment, and postural control recovery targeted in rehabilitation could be affected by pain. The main objective of this comprehensive review is to provide a synthesis of the effect of experimental and chronic pain on postural control throughout the available literature. After presenting the neurophysiological pathways of pain, we demonstrated that pain, preferentially localized in the lower back or in the leg induced postural control alteration. Although proprioceptive and cortical excitability seem modified with pain, spinal modulation assessment might provide a new understanding of the pain phenomenon related to postural control. The literature highlights that the motor control of trunk muscles in patient presenting with lower back pain could be dichotomized in two populations, where the first over-activates the trunk muscles, and the second under-activates the trunk muscles; both generate an increase in tissue loading. Taking all these findings into account will help clinician to provide adapted treatment for managing both pain and postural control.

Chronic low back pain is associated with impaired bed turning ability: Evaluation by a mobility detection system

BACKGROUND

We aimed to assess and compare kinetics and kinematic variables of bed turning ability using a mobility detection system in patients with and without chronic low back pain and to observe the impacts of the disease on bed turning kinetics and kinematics.

METHODS

Thirty-five patients with chronic low back pain were enrolled and compared to healthy controls (n = 34). Pain scores and disability level were assessed by Numeric Pain Rating Scale and the function questionnaires including Oswestry Disability Index and Roland Morris Disability Questionnaire. Bed turning ability was tested using the Mobile Detection System. Univariate and multivariate regression analysis were applied to compare the differences between groups.

FINDINGS

Patients with chronic low back pain had significantly lower turning over and back force/weight ratio (p < 0.001) than those healthy controls. Turning over time was significantly longer in patients with Numeric Rating Scale score 3 than in those with Numeric Rating Scale score 2 (p = 0.015). Turning over and back force were significantly higher in male patients and patients with higher BMI after adjusting BMI and sex, respectively (all p < 0.001). When turning back, chronic low back pain patients with Numeric Rating Scale scores of 3 had lower turning back force/weight ratio than those with Numeric Rating Scale scores of 2 (p = 0.014). Male patients had higher turning back force/weight ratio after adjusting pain score (p = 0.001).

INTERPRETATION

The novel Mobility Detection System can provide more objective assessments of bed turning kinetics and kinematics in patients with chronic low back pain.

Preferred Limb Reaction, Swing and Recovery Step Times between Subjects with and without Chronic Low Back Pain

A compensatory stepping strategy following repeated perturbations may compromise dynamic balance and postural stability. However, there is a lack of study on preferred limb reaction, swing, and step time adjustments. The purpose of this study was to investigate limb reaction, swing, and recovery step times following repeated trip perturbations in individuals with and without non-specific chronic low back pain (LBP). There were 30 subjects with LBP and 50 control subjects who participated in the study. The limb reaction, swing, and recovery step times (s) were measured following treadmill-induced random repeated perturbations (0.12 m/s velocity for 62.5 cm displacement), which caused subjects to move forward for 4.90 s. Both groups demonstrated a significant interaction of repetitions and times (F = 4.39, p = 0.03). Specifically, the recovery step time was significantly shorter in the LBP group during the first trip (t = 2.23, p = 0.03). There was a significant interaction on repetitions and times (F = 6.03, p = 0.02) in the LBP group, and the times were significantly different (F = 45.04, p = 0.001). The initial limb reaction time of the LBP group was significantly correlated with three repeated swing times to avoid falls. The novelty of the first trip tends to enhance a protective strategy implemented by the LBP group. Although limb preference did not demonstrate a significant difference between groups, the LBP group demonstrated shorter recovery step times on their preferred limb initially in order to implement an adaptive strategy to avoid fall injuries following repeated perturbations.

Effect of Sustained Natural Apophyseal Glides on Stiffness of Lumbar Stabilizer Muscles in Patients With Nonspecific Low Back Pain: Randomized Controlled Trial

OBJECTIVE

The aim of this study was to investigate the immediate effect of Mulligan sustained natural apophyseal glides (SNAGs) on muscular stiffness by using ultrasound shear wave elastography, pain, and function in patients with nonspecific low back pain.

METHODS

In a prospective, randomized, controlled, double-blinded study, 30 participants with nonspecific low back pain were randomly divided into 2 groups: a real SNAG group (aged 21.0 ± 1.7, 5 men, 10 women) and sham SNAG group (aged 20.4 ± 0.5, 4 men, 11 women). Muscular stiffness of the multifidus and erector spinal muscles with ultrasound shear wave elastography, visual analog scale, the sit and reach, flamingo balance, the functional reach, side bridge, and Biering-Sorensen tests were made before and immediately after intervention. The Oswestry Disability Index score was recorded only baseline.

RESULTS

After intervention, the change in visual analog scale, sit and reach, Biering-Sorensen, and side bridge tests scores were significantly different between real SNAG and sham SNAG groups (P < .05), but there was no significant difference in functional reach and flamingo balance test scores between the groups (P > .05). There was no significant difference for all measurements between pre- and post-intervention in sham SNAG group (P > .05). There was a significant reduction in muscular stiffness in the real SNAG group. But there was no change in muscular stiffness between pre- and postintervention in the sham group (P > .05).

CONCLUSIONS

This study demonstrated that the Mulligan SNAG technique had a positive effect on pain severity, flexibility, trunk muscle endurance, and muscle stiffness in patients with nonspecific LBP.

Translation, Cross-Cultural Adaptation, and Psychometric Validation of the English Version of the Postural Awareness Scale

PURPOSE

The Postural Awareness Scale (PAS) was developed among a sample of German speakers to measure self-reported awareness of body posture. The first aim of this study was to conduct an English translation and cross-cultural adaptation of the PAS. The second aim was to assess psychometric properties of the English version of the PAS.

METHODS

Forward and backward translations were conducted. The translated scale was then pretested in a small sample of English-speaking adults (n = 30), followed by cognitive interviews. Finally, consensus of the translated scale was achieved among an expert committee (n = 5), resulting in the Postural Awareness Scale-English Version (PAS-E). Psychometric properties of the PAS-E were investigated among a sample of individuals with chronic pain (n = 301) by evaluating factor structure, reliability, and construct validity. Analyses of variance were conducted to calculate differences in PAS-E scores between specific subgroups (pain conditions, sex, and history of mindfulness practice). Linear regression analyses investigated whether the scores on the PAS-E predicted levels of pain, stress, and mood.

RESULTS

The results obtained from an exploratory factor analysis showed a two-factor solution and were supported by a confirmatory factor analysis. The scale demonstrated good internal consistency and satisfactory construct validity. No significant differences related to sex at birth or pain duration were found.

CONCLUSION

PAS-E demonstrated good psychometric properties, and therefore, can and should be used both for research and clinical practice.

Diaphragm thickness, thickness change, and excursion in subjects with and without nonspecific low back pain using B-mode and M-mode ultrasonography

Background: Previous studies have demonstrated that respiratory dysfunction has a potential association with low back pain (LBP). Despite the role of the diaphragm for respiration and spinal stability, knowledge of the function of both sides of the diaphragm in subjects with LBP is still limited.Objective: This study aimed to compare the structural integrity and function of the right and left hemidiaphragm by ultrasonography (USG) in subjects with and without nonspecific chronic low back pain (NS-CLBP).Methods: A total of 37 subjects with NS-CLBP and 34 healthy subjects participated in this case-control study. The thickness, thickness change, and excursion of the right and left hemidiaphragm were compared within and between the groups during quiet breathing (QB) and deep breathing (DB) through B-mode and M-mode ultrasound imaging.Results: The LBP group had a significantly smaller degree of right hemidiaphragm thickness change (P = .001) compared with the healthy control group, with a strong effect size. Nevertheless, there was no significant change for diaphragm thickness and excursion between the two groups. The result showed that, in the healthy group, the right hemidiaphragm had a significantly smaller thickness at expiration and larger thickness change compared with the left hemidiaphragm, with a moderate effect size. Based on the multivariate prediction analysis, the right hemidiaphragm thickness change might significantly predict LBP.Conclusion: We found that participants with LBP had a smaller degree of right hemidiaphragm thickness change. Also, the right hemidiaphragm thickness change might significantly predict LBP.

Low back pain leads to a protective action of pain on dynamic postural stability

Low back pain (LBP) is a painful manifestation in the lower part of the spine which causes disabilities changing the sensitivity of sensory neurons resulting in weakness of postural muscles interfering with the balance. It is not already clear if LBP people's muscle changes affect the centre of pressure (CoP) recovery in challenging stance perturbations. The aim of this study was to identify differences in the muscle reactions of people with and without LBP to control CoP in challenging stance perturbations. We applied low (Vel1) and high (Vel2) magnitude stance perturbation by a movable platform and evaluated (a) the magnitude and latency time of trunk and lower limb muscle activation, (b) and the displacement and the latency time of the first CoP peak. The latency of trunk and hip muscle activation on Vel2 was lower for LBP group. The CoP latency and displacement did not change between groups and velocities indicating that the muscles took the same time to overcome the external forces. In conclusion, the maintenance of CoP latency at both velocities was not affected on Vel2, suggesting that such alterations have protective action and preservation of the pain on the LPB group in challenging stance perturbations.

Effects of back extensor and hip abductor fatigue on dynamic postural stability in patients with nonspecific chronic low back pain: A case-control study

INTRODUCTION

Patients with nonspecific chronic low back pain (NSCLBP) complain of pain and fatigue during functional activities. Poor back muscle endurance has been associated with recurrent pain and long-term disability. However, the relationship between proximal muscle fatigue and postural stability is not well understood.

PURPOSE

To investigate the effects of lumbar extensor and hip abductor fatigue on postural stability in NSCLBPs.

METHODS

To induce isolated fatigue, participants (24 LBPs, 24 controls) were asked to perform multiple back extension and hip abduction in the separate sessions until the muscle force reached 60% of pre-fatigued force. The overall (OSI), anteroposterior (APSI), and mediolateral (MLSI) stability indices were measured during single-leg stance using the Biodex dynamic platform.

RESULTS

The results revealed higher postural instability (APSI and OSI) following fatiguing lumbar extensor and hip abductor muscles (greater effect size for APSI than OSI) in LBPs than controls. Furthermore, significant and inverse relationships were found between the level of physical activity, pain, and post-fatigue postural instability (OSI) in NSCLBPs.

CONCLUSION

Fatigue of proximal muscles could differentiate postural stability primarily in the sagittal plane between NSCLBPs and controls. Therefore, reducing the fatigability of these muscles by endurance training in addition to balance training may improve physical activity.

The reaction times and symmetry indices in the bilateral trunk and limb muscles in control subjects and subjects with low back pain that persisted two months or longer

PURPOSE

This study was conducted to investigate the reaction times and symmetry index (SI) of the bilateral trunk and limb muscles between control subjects and subjects with low back pain (LBP) that persisted for two months or longer.

METHODS

Fifty-seven right limb dominant subjects (31 healthy control subjects and 26 subjects with LBP) participated in this study. The subjects were exposed to a slip perturbation (0.24 m/sec velocity for 1.20 cm), which caused them to move forward for 0.10 s in standing while holding a tray. The electromyography (EMG) electrodes were placed on the bilateral erector spinae (ES), rectus abdominis (RA), rectus femoris, hamstring, tibialis anterior, gastrocnemius, biceps brachii (BB), and triceps brachii muscles. The reaction times were analyzed, and the SI was used to compare the bilateral trunk and limb muscles for the degree of asymmetry between groups.

RESULTS

The ES reaction time was significantly delayed in the control group (0.33 ± 0.22 vs. 0.22 ± 0.17; t = 2.25, p = 0.03). The SI of reaction times was significantly different on the RA (t = -2.28, p = 0.03), ES (t = -2.36, p = 0.04), and BB (t = -2.15, p = 0.04) muscles between groups.

CONCLUSION

The delayed non-dominant ES reaction time might indicate a freedom of pain recurrence in the control group. Although the asymmetry increased on the RA and BB muscles in the LBP group, it decreased on the ES muscle. The asymmetries on the trunk and BB muscles were evident in the LBP group. The asymmetrical reactions in the arm-trunk muscles need to be considered for rehabilitation strategies.

Effects of a multimodal exercise intervention on physical and cognitive functions in patients with chronic low back pain (MultiMove): study protocol for a randomized controlled trial

BACKGROUND

Chronic low back pain (CLBP) is a common medical condition in adults over the age of 50. It is associated with severe disability, ranging from physical impairments to psychosocial distress. Since current treatments provide only small to moderate short-term effects, alternative interventions are required, whereby guidelines recommended multimodal approaches. Dancing can be considered as an inherently multimodal approach, as it requires a combination of physical and cognitive functions. Furthermore, it has already been applied effectively in neurorehabilitation. Therefore, it seems promising to merge a dance-therapeutic component together with motor-cognitive, strength and flexibility exercises in a novel multimodal treatment (MultiMove) to target the impaired everyday mobility and cognition of CLBP patients. The aim of this study is to analyse specific physical, cognitive and psychosocial effects of MultiMove in CLBP patients.

METHODS

A prospective, two-arm, single-blinded, randomized controlled trial will be conducted with an estimated sample size of 100 CLBP patients, assigned to either the MultiMove group or a control group. The intervention group will receive MultiMove twice a week for 60 min each over a period of 12 weeks. The primary outcome will be the mobility and function of the lower extremities assessed by the Timed Up-and-Go Test. Secondary outcomes comprise further physical and physiological functions (e.g. gait variability and haemodynamic response in the prefrontal cortex during motor-cognitive dual tasks), subjective health state (e.g. disability in daily life), executive functions (e.g. cognitive flexibility) and psychosocial aspects (e.g. kinesiophobia). Measures will be taken at baseline, after the intervention and at a 12-week follow-up. It is assumed that MultiMove improves the mentioned outcome parameters.

DISCUSSION

The combined assessment of changes in physical and cognitive functions as well as neuropsychological aspects in response to MultiMove will allow a better understanding of the motor-cognitive adaptations induced by multimodal exercises in CLBP patients. The specific conclusions will lead to recommendations for the conservative treatment approach in this clinically relevant patient group.

TRIAL REGISTRATION

German Clinical Trial Register (ID: DRKS00021696 / 10.07.2020), https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00021696.

Comparison of the reliance of the postural control system on the visual, vestibular and proprioceptive inputs in chronic low back pain patients and asymptomatic participants

BACKGROUND

Although proprioception deficits have been documented in chronic low back pain (CLBP) patients, little is known about adaptive strategies to provide postural control in these patients. Substitution of unreliable proprioceptive information with other afferents might be considered plausible.

RESEARCH QUESTION

Is the response of the postural control system dependent on the source of sensory afferents being manipulated in persons with and without CLBP?

METHODS

Sixty persons with and without CLBP participated in this cross-sectional study. Center of pressure (COP) displacement range, velocity, path length and area were calculated under four sensory conditions: 1) normal upright standing; 2) upright standing on a foam with eyes open and head in neutral position; 3) upright standing with eyes open and 60° cervical extension and 4) upright standing with eyes closed and 60° cervical extension. A two-way repeated measures analysis of variance was used to compare COP masseurs under different conditions and between the groups.

RESULTS

CLBP patients demonstrated fewer alterations to manipulation of both visual and vestibular afferents in terms of number of COP variables significantly altered. ML range and velocity in both groups and path length in the CLBP group were significantly different between conditions 2 and 4. In both groups, all COP variables except AP range increased significantly in condition 2 compared to conditions 1and 3 (p < 0.001). AP velocity was the only variable to be different between conditions 1 and 3 in both CLBP (p = 0.025) and control (p < 0.001) groups. Between group differences were significant on AP velocity (p = 0.019).

SIGNIFICANCE

No overweighting was observed in the vestibular or visual afferents in CLBP patients. Compensatory strategies seem to lie within proprioceptive system by reweighting afferents from different body segments. The postural control system behaved more robustly in CLBP patients while AP COP velocity was found as the most sensitive and discriminating parameter.

Revisiting the Instrumented Romberg Test: Can Today's Technology Offer a Risk-of-Fall Screening Device for Senior Citizens? An Experience-Based Approach

Risk of fall (ROF) is a worldwide major concern for its prevalence and consequent dramatic outcomes in the elderly population. The growing age-related risk appears to be associated with increasing motor, sensory, and cognitive problems in the elderly population. There is a consensus on the need to screen for these balance dysfunctions, but the available methods are largely based on subjectively assessed performances. The instrumented Romberg test using a force plate represents a validated assessment process for the evaluation of balance performances. The purpose of this study is to propose an innovative instrumental method to identify balance deficits, assess their severity, and give an automated indication of the most likely etiology. The proposed new method was applied to the instrumented Romberg test, using force plate data recorded in a cohort of 551 females aged >65 participating in adapted physical activity courses. The method allowed us to identify 145 dysfunctional subjects and to determine the likely origin of their deficit: 21 central, 5 vestibular, 9 visual, 59 proprioceptive (musculoskeletal etiology), and 51 functional. Based on the preliminary findings of the study, this test could be an efficient and cost-effective mass screening tool for identifying subjects at risk of fall, since the procedure proves to be rapid, non-invasive, and apparently devoid of any contraindications.

Postural Sway in Older Patients with Sagittal Imbalance and Young Adults during Local Vibratory Proprioceptive Stimulation

This study aimed to assess differences in somatosensory control strategies between older patients with sagittal imbalance and young adults during postural tasks. The center of pressure displacement in 27 older patients with sagittal imbalance and 27 young adults was determined upon standing blindfolded on a balance board. Vibratory stimulation at 56 to 100 Hz was applied bilaterally to the gastrocnemius and soleus muscles (GS) and lumbar multifidus to evaluate the contributions of proprioceptive signals to postural control. Data of older patients and young adults were compared using the Mann–Whitney U-test or independent sample t-tests. Compared with the young adults, the older patients were significantly more reliant on the GS (p < 0.005) for their postural control and showed a higher relative proprioceptive weighting ratio (RPW) (p = 0.038). The postural strategy adopted by the older patients depended on the level of proprioceptive stimulation applied to the GS, and the postural control strategy of the ankle correlated with RPW. Overall, this study identifies RPW as a novel measure of postural strategy in older patients with sagittal imbalance and provides an understanding of strategies used to maintain balance, which may assist in developing preventative measures to reduce the risk of falls.

Eight-Week Inspiratory Muscle Training Alters Electromyography Activity of the Ankle Muscles During Overhead and Single-Leg Squats: A Randomized Controlled Trial

This study was conducted to evaluate the effects of 8-week inspiratory muscle training on activity in the ankle muscles of athletes with chronic low-back pain. A randomized controlled trial involving 45 men and women with chronic low-back pain was carried out. Electromyography activity in the tibialis anterior, peroneus longus, gastrocnemius medialis, and gastrocnemius lateralis muscles of the dominant leg was recorded. Secondary outcomes included biopsychosocial indices, such as pain, disability, anxiety and depression, fear-avoidance beliefs, and fear of (re)injury. Static and dynamic overhead squat tests showed that inspiratory muscle training decreased activity in the tibialis anterior, peroneus longus, and gastrocnemius medialis muscles. In the static single-leg squat test and the descending phase of the dynamic equivalent, such a decrease was observed in all the 4 muscles. Inspiratory muscle training significantly reduced pain severity and activity in the tibialis anterior, peroneus longus, and gastrocnemius medialis muscles during the ascending phase of the dynamic single-leg squat test. On the basis of the findings, 8 weeks of inspiratory muscle training may constitute useful rehabilitation for reducing excessive activity in ankle joint muscles and aiding chronic low-back pain recovery.

Static Balance Modification during the Workday in Assembly Chain Workers with and without Current Low Back Pain

Background: Low back pain (LBP) is a common recurrent pathology among assembly chain workers. This population tends to spend most of the workday in a static standing posture and handling loads, with balance being essential for correct job performance. LBP is related to poorer postural control, so balance could be affected in this condition. Methods: The purpose of the present study is to analyze the deterioration of static balance generated by work activity in a prolonged standing position. We assess sway with a pressure platform at three moments of the workday (before, during, and after work), comparing the different balance parameters in 22 manufacturing plant workers with (17) and without (5) LBP. Results: In the pre-work capture, an independent t-test showed no significant differences between the pain and non-pain groups’ static balance parameters. Between the pre- and mid-workday captures, a two-way ANOVA with repeated measures showed a significant decrease in the medial-lateral center of pressure displacement with open eyes in workers with LBP. Conclusions: workers with low back pain do not show a greater deterioration in static balance than workers without pain during the workday.

Effects of Equine-Assisted Therapies or Horse-Riding Simulators on Chronic Pain: A Systematic Review and Meta-Analysis

Background and objectives: Chronic pain is a complex global public health problem that affects the health status, quality of life, activities of daily living, and different work-related variables. Riding a horse may lead to some benefits in chronic pain patients through the improvement of postural control and other biopsychosocial processes. Therefore, this systematic review and meta-analysis aimed to evaluate the effects of horse riding (with real or simulated horses) on chronic pain. Materials and methods: A systematic literature search was carried out in accordance with PRISMA guidelines in Web of Science (WOS) and PubMed (Medline) electronic databases. Eleven articles (seven randomized controlled trials) were selected to be included in the review. Due to some risk of bias concerns, two meta-analyses (using postintervention or change-from-baseline measures) were conducted utilizing Review Manager Software (RevMan 5.3). Results: Horse-riding simulators significantly reduced the pain levels of patients with low back pain (p = 0.03, with a SMD of -1.14 and a 95% CI from -2.16 to -0.11) using change-from-baseline measures. However, the p-value in the meta-analysis with the postintervention measures was 0.06. Regarding interventions with real horses, it was not possible to conduct a meta-analysis due to the low number of studies. Conclusion: Horse riding could be a useful exercise to reduce pain, but more studies are needed to make evidence-based recommendations and to compare the effects of horse-riding with real and simulated horses.

The effect of core stability training with ball and balloon exercise on respiratory variables in chronic non-specific low back pain: An experimental study

BACKGROUND

Studies have shown the involvement of respiratory characteristics and their relationship with impairments in non-specific low back pain (NS-LBP). The effects of core stability with a combined ball and balloon exercise (CBB) on respiratory variables had not been investigated.

OBJECTIVE

To evaluate the effectiveness of CBB on respiratory variables among NS-LBP patients.

STUDY DESIGN

pre- and post-experimental study.

PARTICIPANTS

Forty participants were assigned to an experimental group (EG) [n = 20] and control group (CG) [n = 20] based on the study criteria.

INTERVENTIONS

The EG received CBB together with routine physiotherapy and the CG received routine physiotherapy over a period of 8 weeks. Participants were instructed to carry out the exercises for 3 days per week. The training was evaluated once a week and the exercises progressed based on the level of pain.

OUTCOME MEASURES

Primary outcomes were maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP) and maximum voluntary ventilation (MVV). The secondary outcomes were measured in the numeric rating scale (NRS), total faulty breathing scale (TFBS), cloth tape measure (CTM) and lumbo-pelvic stability.

RESULTS

The MIP increased significantly among the EG when compared with that in the CG (p > 0.05).The EG showed a significant increase in MVV (p = 0.04) when compared to the CG (p = 0.0001). There was a significant reduction in pain for both groups. The MEP, TFBS, chest expansion and core stability showed no changes in either group.

CONCLUSION

CBB was effective in improving respiratory variables among NS-LBP patients.

Posturography Comparison and Discriminant Analysis Between Individuals With and Without Chronic Low Back Pain

OBJECTIVE

The aims of this study were to evaluate the center of pressure (CoP) in individuals with chronic low back pain (LBP) compared with matched controls and perform discriminant analysis to detect which CoP variables differentiate the groups.

METHODS

Thirty-two participants with LBP and 33 matched controls were evaluated on a force plate in a bipedal static position for 30 seconds in 2 conditions: eyes open (EO) and eyes closed (EC). Two discriminant analyzes were performed to detect which CoP variables could discriminate between groups.

RESULTS

Those with LBP had higher values (ie, poorer balance) for most variables compared with the control group. With EO, total displacement of sway (TDS) was as follows: LBP group (median [25%-75%]) 31.77 (26.39-41.79) cm, control group 27.21 (22.29-31.78) cm, P = .008 and area: LBP group 3.31 (2.33-4.68) cm², control group 1.77 (1.3-2.71) cm². With EC, TDS was as follows: LBP group 49.6 (39.65-68.15) cm, control group 38.77 (30.36; 45.65) cm, P = .003 and area: LBP group 4.68 (2.6-7.28) cm², control group 2.4 (2.1-3.34) cm². The discriminating variables in the EO condition were the TDS for the LBP group and the anteroposterior mean velocity for the control group, while in the EC condition they were mediolateral dispersion and area for the LBP group.

CONCLUSION

Individuals with chronic LBP had worse postural control performance than matched controls, and it is possible to characterize those with and without LBP with CoP variables.

Postural Sway during Local Vibratory Stimulation for Proprioception in Elderly Individuals with Pre-Sarcopenia

OBJECTIVE

Many studies have demonstrated that the loss of muscle mass (LMM) poses a risk of postural instability in the elderly; however, few studies have shown how LMM decreases proprioception. In this study, we investigated the changes in postural sway among older individuals with LMM induced by application of a local vibratory stimulus.

METHOD

We enrolled 64 older adults (mean age). Postural sway was measured while applying vibration stimuli of 30, 60, and 240 Hz to both the gastrocnemius and lumbar multifidus muscles. We also measured the relative proprioceptive weighting ratio (RPW) of postural sway. The patients were divided into LMM and non-LMM (NLMM) groups. The study subjects were compared in terms of their age, height, weight, body mass index (BMI), lower leg skeletal muscle mass index (LSMI), L4/5 lumbar multifidus cross-sectional area ratio, and RPW at 30, 60, and 240 Hz.

RESULTS

Subjects in the LMM group showed a significantly lower RPW at 60 Hz, LSMI, and BMI than did those in the NLMM group.

CONCLUSIONS

Decrease in RPW with 60-Hz stimulation concerning the lower leg proprioception is a risk factor for LMM-associated postural instability in the elderly. Consequently, with respect to the gastrocnemius muscles proprioception in LMM, it is necessary to perform assessments using muscle spindle stimuli.

Adaptive trunk sway velocities following repeated perturbations in subjects with and without low back pain

Faster trunk motions could be a strategy to prevent loss of balance and fall injuries due to unexpected perturbations. However, it is unclear how trunk sway velocities can be compensated during stepping in subjects with low back pain (LBP). The purpose of this study was to investigate lower limb reaction, swing, and step times, as well as trunk sway velocities at heel strike and toe-off, following repeated step perturbations between subjects with and without LBP. There were 30 subjects with LBP and 42 control subjects who were exposed to treadmill-induced perturbations at a velocity of 0.12 m/sec for 0.62 m. The treadmill-induced steps caused subjects to walk forward for 4.90 sec after the perturbation. The groups demonstrated significant interactions on the lower limb reaction times and on the number of repeated perturbations (F = 4.83, p = 0.03) due to a decreased step time at the first perturbation (t = 2.52, p = 0.01) in the LBP group. For the trunk sway velocities, the repeated perturbations demonstrated a significant interaction between groups (F = 4.65, p = 0.03). This adaptive trunk strategy for gait stability increased step times with repeated perturbations in the LBP group. The group interactions on the trunk sway velocities also indicated a possible somatosensory integration for step time adjustments to avoid potential fall hazards. This adaptive response with repeated step perturbations could result in compensatory trunk sway for gait stability.

Relationship between postural stability and fall risk in elderly people with lumbar spondylosis during local vibratory stimulation for proprioception: a retrospective study

Purpose: Reduced proprioception affects fall risks in elderly people with lumbar spondylosis. The decrease in proprioception in the trunk or lower legs may contribute to a decline in postural stability. We aimed to investigate the association between proprioceptive postural stability and fall risks in elderly individuals with lumbar spondylosis.Materials and Methods: In this retrospective study, the centre-of-pressure displacement was determined in elderly individuals with lumbar spondylosis during upright stance while standing on a Wii Balance Board with their eyes closed (fall-risk group, n = 55; non-fall-risk group, n = 60). Vibratory stimulations at 30 Hz were applied to the lumbar multifidus and gastrocnemius to evaluate the relative contributions of proprioceptive signals used in postural control (relative proprioceptive weighting ratio).Results: Compared with the non-fall-risk group, the fall-risk group displayed a high relative proprioceptive weighting ratio (p = 0.024). Relative proprioceptive weighting ratio (odds ratio, 1.1; 95% confidence interval: 1.004-1.109) was independently associated with fall risks after adjusting for confounding factors. Among variables related to fall risk, the relative proprioceptive weighting ratio was a significant factor (p < 0.035).Conclusion: The fall-risk group of elderly individuals with lumbar spondylosis was dependent on the ankle strategy. The fall risk in elderly people with lumbar spondylosis could be due to over-dependence on the input from muscle spindles in the gastrocnemius.

Association Between Back Muscle Strength and Proprioception or Mechanoreceptor Control Strategy in Postural Balance in Elderly Adults with Lumbar Spondylosis

This study aimed to investigate the relationship between back muscle strength and proprioception or mechanoreceptor control strategies used for postural balance in elderly adults with lumbar spondylosis. The displacement of the center of pressure (COP) excursion was determined in 24 elderly adults with lumbar spondylosis and 24 healthy young adults while the participants were standing upright on a balance board with their eyes closed. Vibratory stimulations of 30, 60, and 240 Hz were applied to the gastrocnemius (GS) and lumbar multifidus (LM) muscles to evaluate the effect of different proprioceptive signals on postural control. Back muscle strength was evaluated. Spearman’s rank correlation analysis was performed to determine the relationship between back muscle strength and significant COP excursion. Compared with young adults, elderly adults with lumbar spondylosis showed an increase in COP excursion displacement when a vibratory stimulation of 240 Hz was applied to the GS (P = 0.002) and LM muscles (P < 0.001). LM stimulation at 240 Hz was significantly associated with back muscle strength (P = 0.038). Postural control assessment with 240-Hz mechanoreceptor stimulation of the trunk could be a good indicator of postural instability due to over-dependence on mechanoreceptors and back muscle weakness in elderly adults with lumbar spondylosis.

The effects of familiarization with loading, weight and size of loading on neuromuscular responses during sudden upper limb loading in chronic low back pain patients

BACKGROUND

Changes in the motor control of the spine were found in patients with chronic low back pain (CLBP). Sudden loading of the spine is supposed to be the cause of about 12% of lower back injuries. However, some aspects of this problem, such as alterations in the sensory-motor control of the spine, remain questionable.

OBJECTIVE

To investigate the effects of familiarization with loading, weight and size of loading on neuromuscular responses during sudden upper limb loading in CLBP patients.

METHODS

In this quasi-experimental study surface electromyography of the erector spinae (ES) and transverses abdominis/internal oblique (TrA/IO) and external oblique (EOA) muscles were recorded in 7 men and 13 women with CLBP and 20 asymptomatic subjects (10 men and 10 women) aged 18-45 years from the general community familiarization. Moreover, investigating control of the posture measurements of the center of pressure (COP) and vertical ground reaction force (GRF) or Fz were recorded using a force plate. Data were analyzed using paired t-test and independent t-test with the significance level of 0.05.

RESULTS

Data analyses were performed using SPSS version 18. Some electromyography and force plate variables were significantly different for different conditions in each group and between the asymptomatic and low back pain groups (p⩽ 0.05).

CONCLUSION

Several motor control changes were observed in the CLBP patients. These patients showed decreased trunk muscle activity as well as too early and too delayed responses compared to asymptomatic subjects.

The effect of short foot exercise using visual feedback on the balance and accuracy of knee joint movement in subjects with flexible flatfoot

BACKGROUND

Flexible flatfoot is a condition characterized by the deformations of the foot where the calcaneus is pronated by weight support. Flat feet can affect balance and the entire chain of motion, causing indirect problems in adjacent joints. We investigated the effects of short foot exercise (SFE) using visual feedback on the static balance and function of proximal joints in subjects with flexible flat feet.

METHOD AND ANALYSIS

This study involved 30 participants who were assigned to either of the 2 groups: the flexible flatfoot group (n = 15, 8 men and 7 women, aged 22.00 ± 2.07 years) and normal foot group (n = 15, 7 men and 8 women, aged 22.13 ± 1.55 years). All subjects performed the SFE with visual feedback. SFE programs were performed 20 minutes a day, 5 times a week, for a total of 5 weeks. The static balance and accuracy of knee joint motions were compared before and after training.

RESULTS

There was a significant difference in static balance pre- and post-exercise in the flatfoot group but not in the normal foot group. Moreover, in the flatfoot group, the accuracy of knee joint motions was significantly different between pre- and post-exercise in the closed chain but not in the open chain.

CONCLUSION

This study examined the influence of SFE using visual feedback on the balance and accuracy of knee joint movements in subjects with flatfoot and demonstrated that this exercise, using visual feedback, improved the balance and accuracy of knee movement.

Perception of verticality is altered in people with severe chronic low back pain compared to healthy controls: A cross-sectional study

BACKGROUND

People with chronic low back pain (CLBP) have abnormal lumbar proprioception, which increases their reliance on visual input to maintain body verticality. Maintaining verticality is important for spatial orientation, balance and movement coordination. It is unknown if these patients also have altered perception of verticality.

OBJECTIVE

To compare whether the perception of verticality is different between people with and without CLBP.

DESIGN

Cross-sectional.

METHODS

Two comparisons of perception of verticality were done between a group of people with CLBP (n = 25) and healthy people (n = 25); and between a subgroup of people with severe CLBP (n = 14) and healthy people (n = 25). In a dark room, the subjective visual vertical test was performed under 3 conditions: rod, rod-and-frame, and rod-and-disc. In each condition, the rod was tilted 40° clockwise and counterclockwise, and the participants were asked to bring it back to vertical 0° position. The rod deviation from verticality was recorded in degrees.

RESULTS

When considering the CLBP group, analysis of variance showed that deviation from verticality had no significant group interaction with condition (p = 0.2), or group main effect (p = 0.2). However, deviation from verticality was significantly different between the conditions (p < 0.001). When considering the severe CLBP subgroup, the interaction effect was significant (p = 0.046). Simple main effects showed that the severe CLBP subgroup had larger deviations from verticality (7.5 ± 0.9 deg) compared to the healthy group (4.2 ± 0.7 deg) specifically on the rod-and-frame condition (p = 0.007).

CONCLUSION

People with severe CLBP appear to have larger deviations in judging verticality compared to the healthy group.

The Transverse Gravitational Deviation Index, a Novel Gravity Line-Related Spinal Parameter, Relates to Balance Control and Health-Related Quality of Life in Adults With Spinal Deformity

STUDY DESIGN

Prospective cross-sectional case-control study design.

OBJECTIVE

This study aims to analyze the relation between balance control as well as health-related quality of life (HRQOL) in patients with adult spinal deformity (ASD), with a novel gravity line (GL)-related 3D spinal alignment parameter, the transverse gravitational deviation index (TGDI), defined to quantify the transverse plane position of any vertebra with respect to the GL.

SUMMARY OF BACKGROUND DATA

Demographic data and balance control have both been identified as important determinants of HRQOL in ASD patients during a preoperative setting. Therefore, a better understanding of the relation between spinal alignment and balance is required.

METHODS

After informed consent, 15 asymptomatic healthy volunteers (mean age 60.1 ± 11.6 years old) and 55 ASD patients (mean age 63.5 ± 10.1 years old) were included. Relation between performance on BESTest as well as core outcome measures index (COMI) with spinopelvic alignment was explored using General Linear Modeling (GLM). A P-value ≤0.05 was considered statistically significant.

RESULTS

The L3 TGDI was identified to relate to balance control in the total ASD population after correction for confounding demographic factors (P = 0.001; adjusted R = 0.500) and explained 19% of the observed variance in balance performance. In addition, COMI is related to L3 TGDI in a subgroup of ASD patients with combined coronal and sagittal malalignment of L3 (P = 0.027; slope B = 0.047), despite significant influence of age (P = 0.020).

CONCLUSION

In ASD patients with a combined coronal and sagittal malalignment of the L3 vertebra, both the level of balance impairment as well as HRQOL are related to the distance component of the L3 TGDI, that is, the offset between the center of the L3 vertebral body and the GL in the transverse plane.

LEVEL OF EVIDENCE

2.

Computation of Intersegmental Moments during Standing Posture: Can We Neglect the Horizontal Ground Reaction Force? Results from an Experimental Study

Background

The development of postural analysis thanks to force and pressure platforms, in order to determine the center of pressure, can be valuable in the setting of spinal malalignment. The purpose of this study was to compare “pressure” and “force” platforms for the evaluation of the center of pressure. In other words, can we neglect the horizontal ground reaction force in the evaluation of intersegmental moments during standing posture? Methods. Postural data from two healthy adult volunteers were analyzed. Analysis of the posture was done according to a protocol providing sagittal intersegmental moments. A set of 36 markers was used to divide the body in 10 segments. Postacquisition calculations were done in order to obtain the sagittal net intersegmental moments. To evaluate the differences in intersegmental moments between force and pressure platforms, the postacquisition calculations were done with a simulated pressure platform. Mean intersegmental moments between each body segment for each volunteer were compared.

Findings

There were significant differences between the 2 platforms in intersegmental moments for the lumbo-sacral junction, hips, knees, and ankles (p < 0.005). All differences were inferior to intrasubject variability measured with the force platform (p < 0.001). Results from intra- and interobserver comparisons showed that differences measured with the pressure platform were all inferior to the standard error obtained with the force platform for every intersegmental moment (p < 0.001).

Interpretation

The use of a simulated pressure platform to determine intersegmental moments has the same clinical efficiency as force platforms. Moreover, the possibility to set the platform into the radiograph room will allow in a second time a correlation between radiographic parameters and biomechanical constraints applied to the spine.

Anticipatory postural control differs between low back pain and pelvic girdle pain patients in the absence of visual feedback

PURPOSE

The aim of this study was to examine the effect of vision on anticipatory postural control (APA) responses in two groups of clinically diagnosed chronic low back pain patients, those with Posterior Pelvic Girdle pain and those with Non-Specific Low Back Pain compared to a matched group of healthy controls during the modified Trendelenburg task.

METHODS

Seventy-eight volunteer participants (60 females and 18 males) gave informed consent to take part in this study. 39 with confirmed LBP or PGP lasting longer than 12 weeks and 39 healthy matched controls performed 40 single leg lift tasks (hip flexion to 90° as quickly as possible) with their non-dominant lower limb. A force plate was used to determine the medial-lateral displacement of the center of pressure, and the initiation of weight shift; kinematics was used to determine initiation of leg lift; and electromyography was used to determine onset times from the external oblique (EO), internal oblique (IO) and lumbar multifidus (MF), gluteus maximus (GM) and biceps femoris (BF).

RESULTS

The PGP group showed significantly longer muscle onset latencies in the BF, EO MF with visual occlusion (F_2,746 = 4.51, p < .0001).

CONCLUSION

The muscle onset delays identified between the two LBP sub-groups suggests that pain may not be the primary factor in alteration of APA response. The PGP group show a greater reliance on vision which may signal impairment in multiple feedback channels.

Factors Associated With the Ultrasound Characteristics of the Lumbar Multifidus: A Systematic Review

OBJECTIVE

The first aim of this review was to investigate the association between age, sex, height, weight, physical activity level, posture, lumbar level and body side, and structural characteristics (cross-sectional area [CSA], thickness, linear dimensions, and echo intensity) of the lumbar multifidus (LM) measured by ultrasound. Second, differences between healthy individuals and patients with chronic low back pain (CLBP) were investigated. TYPE: Systematic review.

LITERATURE SURVEY

PubMed, Embase and Web of Science were searched until September 2018.

METHODOLOGY

Studies were included if (a) full text was available in English, Dutch, or French; (b) participants were older than 18 years of age and were asymptomatic or had nonspecific CLBP; and (c) the relation between structural characteristics of the LM, measured by ultrasound, and at least one of the above-mentioned factors was described, and/or a comparison between a CLBP and control group was made. Data were extracted independently by two reviewers. Quality of studies was assessed using an adapted version of the Downs and Black checklist.

SYNTHESIS

Twenty-seven studies were included. Thickness and CSA of the LM do not correlate with age. Males have a larger LM size than females. Thickness and CSA of left and right LM are highly correlated in healthy subjects. More significant side-to-side differences are present in subjects with CLBP than in those without. Muscle size increases from proximal to caudal lumbar levels. The presence of CLBP is associated with muscle size and function.

CONCLUSIONS

The association between the factors age, sex, height, weight, physical activity level, posture, lumbar level, body side, and presence of CLBP, and the ultrasound characteristics of the LM is discussed. These factors should be taken into account in future research on structural muscle characteristics, or when correlating with functional behavior or investigating the effect of a targeted intervention.

LEVEL OF EVIDENCE

I.

The effect of pain on balancing behavior: Complexity analysis of mediolateral force trajectories

BACKGROUND

Postural instability is a prevalent and deleterious consequence of aging. It is unclear how the occurrence of chronic pain augments balance issues as age progresses.

RESEARCH QUESTION

We investigated how postural stability is influenced by aging and chronic pain.

METHODS

Fifty-five participants with and without recent chronic pain balanced on one foot while performing three tasks, a standard balancing task with no challenge, a mental task in which participants answered arithmetic questions while balancing on one foot, and a knot-tying task in which participants tied knots in a ribbon while balancing on one foot. General linear models were used to assess the relationship between age, sex, BMI, and pain category for the three different balancing tasks. In addition, a multivariate analysis of variance was used to test the effect of age and pain category on Hurst exponents from all of three different balancing tasks.

RESULTS

Our results show that aging changes the control strategy of balancing from less persistent to more repetitive. The strong feedback elements intrinsic to healthy stability ensure quick reactions and strong capacity to compensate for balance checks; this reactive state changes into a less reactive and more predictable balance strategy with age while balancing on one foot. Mental tasks during balancing also decreased the feedback in balancing strategy. Balance strategy during the knot-tying task was correlated with age, but unaffected by chronic pain. Overall, the chronic pain group had a worse balance strategy while performing the mental task in comparison with healthy people, but were not differentiable from controls in the standard or knot-tying tasks.

SIGNIFICANCE

Scores from balancing while engaging in cognitive tasks may provide evidence of health decline, and contribute to our knowledge about how pain affects feedback mechanisms.

Altered postural timing and abnormally low use of proprioception in lumbar spinal stenosis pre- and post- surgical decompression

Background

Lumbar spinal stenosis (LSS) is frequently associated with postural instability. Although several studies evaluated patients’ functional impairments, underlying sensorimotor mechanisms are still poorly understood. We aimed to assess the specific set of postural control deficits associated with LSS during spontaneous and externally perturbed stance and evaluated post-surgical changes in postural behavior.

Methods

We analyzed postural control in eleven LSS patients (age 69 ± 8 years) pre- and post-laminectomy, correlated experimental data with functional tests and patient-reported outcomes, and compared findings to 15 matched, healthy control subjects (age 70 ± 6 years). Postural control was characterized by spontaneous sway measures and measures of perturbed stance. Perturbations were induced by anterior-posterior pseudorandom tilts of the body support surface. We used an established postural control model to extract specific postural control parameters.

Results

Spontaneous sway amplitude, velocity and frequency were abnormally large in LSS patients. Furthermore, patients’ postural reactions to platform tilts, represented by GAIN and PHASE were significantly altered. Based on simple feedback model simulations, we found that patients rely less on proprioceptive cues for stance regulation than healthy subjects. Moreover, their postural reactions’ timing is altered. After surgery, patients’ spontaneous sway amplitude was significantly reduced and their postural timing approximated the behavior of healthy subjects.

Conclusion

The reduction in proprioceptive input for stance control due to stenosis-caused afferent dysfunction is a functional disadvantage for LSS patients – and may be the basis of increased spontaneous sway. This disadvantage may cause the timing of postural reactions to alter, with the intent of preventing rapid changes in stance regulation for safety reasons. After surgery, patients’ postural timing approximated those of healthy subjects, while the abnormally low use of proprioception remained unchanged. We suggest the post-surgery rehabilitation of proprioception, eg through balance exercises on unstable surfaces and reduced visual input.

Non-specific Low Back Pain and Postural Control During Quiet Standing-A Systematic Review

Background: There is a great number of people who require treatment for non-specific low back pain (LBP) yet the causes are still unclear. One proposed cause for LBP is impaired motor control and more specific an impaired postural control.

Objective: The purpose of this review is to provide an overview of postural control parameter differences in persons with and without non-specific LBP during quite standing.

Methods: A literature search in five databases from January 2000 until January 2018 was performed and was followed by a hand search. Twenty-one articles comparing healthy adults and adults with non-specific LBP in neuromuscular and/or biomechanical parameters during bipedal stance without external perturbation in lab studies were examined. Data extraction and quality assessment were independently performed by two persons. Factors such as study population, outcome measures, and results were extracted from the articles and included in this analysis.

Results: The results show that persons with and without non-specific LBP differed in several parameters of postural control such as the center of pressure displacement, postural control strategy, and muscle activation patterns.

Conclusion: While the results show that none of the parameters alone lead to significant effects, the combination of neuromuscular and biomechanical parameters was associated with the impairment of postural control in individuals with LBP during standing. Since the studies included in this analysis used different methodological procedures a replication of these studies with standardized procedures is imperative for the acquisition of more conclusive evidence on the differences in postural control during standing.

Quantifying Range of Motion and Stress Patterns at the Transitional Lumbosacral Junction: Pilot Study Using a Computational Model for Load-Bearing at Accessory L5-S1 Articulation

Background

Symptomatic or asymptomatic transitional anomalies at the lumbosacral junction are common occurrences in the population. Lumbosacral (L5-S1) accessory articulations are the most common presentations of transitional anomalies at this region. Such anatomical alterations are believed to be associated with biomechanical changes of load-bearing and movement restrictions leading to low back pain. This study attempts to use computational models of a normal and a lumbosacral transitional vertebrae (LSTV) accessory articulation to analyze and compare the range of motion and loading patterns at the lumbosacral articulations.

Methods

Three-dimensional Finite Element computational models of normal and accessory L5-S1 articulated sacrum were created. These models were tested for range of motion and stress patterns generated at the lumbosacral articulations using similar loading and motion simulation to elicit different moments/excursions at the lumbosacral junctions.

Results

Compared to the normal variant, the transitional model exhibited different range of motion and divergent patterns of stress generation at the lumbosacral and accessory articulations with equal and physiological magnitudes of loading applied to both the models.

Conclusions

The finite element modeling approach can be used for biomechanical investigations in LSTV variants. However, larger sample studies with different LSTV models may be required to statistically compare movement and loading patterns at LSTV-affected lumbosacral and sacroiliac junctions, and to recommend definitive treatment strategies in these situations.

Proprioceptive Weighting Ratio for Balance Control in Static Standing Is Reduced in Elderly Patients With Non-Specific Low Back Pain

MINI: Elderly patients older than 65 years were divided into non-specific low back pain (NSLBP) and non-LBP (NLBP) groups. The postural control study of the relative contributions of different proprioceptive signals (relative proprioceptive weighting ratio [RPW]) revealed lower leg proprioceptive decreases (RPW 240 Hz) in NSLBP compared to NLBP.

STUDY DESIGN

A cross-sectional, observational study.

OBJECTIVE

The aim of this study was to determine a specific proprioceptive control strategy during postural balance in elderly patients with non-specific low back pain (NSLBP) and non-LBP (NLBP).

SUMMARY OF BACKGROUND DATA

Proprioceptive decline is an important risk factor for decreased balance control in elderly patients with NSLBP. The resulting reduction in proprioception in the trunk or lower legs may contribute to a reduction in postural sway. This study aims to determine the specific proprioceptive control strategy used during postural balance in elderly patients with NSLBP and NLBP and to assess whether this strategy is related to proprioceptive decline in NSLBP.

METHODS

Pressure displacement centers were determined in 28 elderly patients with NSLBP and 46 elderly patients with NLBP during upright stances on a balance board without the benefit of vision. Gastrocnemius and lumbar multifidus muscle vibratory stimulations at 30, 60, and 240 Hz, respectively, were applied to evaluate the relative contributions of the different proprioceptive signals (relative proprioceptive weighting ratio, RPW) used in postural control.

RESULTS

Compared to elderly patients with NLBP, those with NSLBP had a lower RPW at 240 Hz and significantly higher RPW at 30 Hz. A logistic regression analysis showed that RPW at 240 Hz was independently associated with NSLBP after controlling for confounding factors.

CONCLUSION

Elderly patients with NSLBP decreased their reliance on ankle strategy (RPW at 240 Hz) and hip strategy (RPW at 30 Hz) proprioceptive signals during balance control. The inability to control hip and ankle strategies indicates a deficit of postural control and is hypothesized to result from proprioceptive impairment. Moreover, elderly patients with NSLBP are at higher risk for lower leg proprioceptive decrease (240 Hz) through the NSLBP exacerbation.

LEVEL OF EVIDENCE

4.

Compensatory strategy between trunk-hip kinematics and reaction time following slip perturbation between subjects with and without chronic low back pain

Compensatory trunk and hip motions following slip perturbations may compromise the control of lumbopelvic movement. However, it is unclear how postural integration of the trunk and hips can be transferred to treadmill-induced slip perturbations in subjects with chronic low back pain (LBP). The purpose of this study was to investigate trunk reaction times and three-dimensional trunk-hip angle changes following a slip perturbation (duration: 0.12 sec, velocity: 1.37 m/sec, displacement: 8.22 cm) with a handheld task between subjects with and without chronic LBP. There were 23 subjects with LBP and 33 control subjects who participated in the study. The trunk reaction time was not significantly different between groups. However, the three-dimensional trunk-hip angle changes were significantly different following the perturbation. There were significant interactions between the body regions and three-dimensional angles between groups. There was a negative correlation between reaction time and trunk flexion in the LBP group. Overall, the LBP group demonstrated significantly reduced trunk flexion, which might be associated with reduced adaptability or a possible fear of avoidance strategy. Clinicians need to consider compensatory strategies to improve trunk flexibility following slip perturbations in subjects with chronic LBP. Mini abstract: Trunk reaction time and three-dimensional trunk-hip motions were compared between subjects with and without chronic low back pain (LBP). The control group demonstrated greater trunk flexion; however, the LBP group reduced trunk flexion to protect against further injuries following the novelty of the slip perturbation.

Altered postural sway during quiet standing in women with clinical lumbar instability

[Purpose] The current study aimed to investigate the center of pressure, as an indicator of postural sway, to determine any differences between women with clinical lumbar instability and asymptomatic low back pain. [Participants and Methods] Thirty healthy and fifteen clinical lumbar instability participants were measured for their postural sway in the anterior-posterior and medial-lateral directions. The women were tested for postural sway on a force plate in quiet standing and eyes closed. Center of pressure path length and mean velocity in the anterior-posterior and medial-lateral directions and total area of excursion were measured and analyzed for 30 seconds. [Results] Clinical lumbar instability participants showed a significantly increase when compared with healthy participants, in path length and mean velocity in both directions and total area of excursion. [Conclusion] The findings suggest that chronic low back pain patients with clinical lumbar instability have increased postural sway when vision is deprived. The clinical significance of this has not yet been determined but may provide an opportunity for therapy directed at improving balance control in this patient group.