Low Back Pain: Unveiling the Contribution of Motor Control Adaption Using Biomechanical Modeling and Neuroimaging

Study Overview
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Brief Summary
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This project aims to reveal the potential sensorimotor reorganization of sensory input in low back pain patients and its association with different motor control strategies in LBP.

Detailed Description
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Background: Low back pain (LBP) is a major health issue. Treatment of chronic LBP is still a major challenge due to a lack of pathophysiological understanding. Thus, understanding LBP pathophysiology is a research priority. Adaptions of motor control likely play a significant role in chronic or recurrent LBP because motor control is crucial for spine posture, stability and movement. Different motor adaption strategies exist across individuals with LBP and two phenotypes representing the opposite ends of a spectrum have been suggested; i.e. tight control and loose control over trunk movement. The former would be associated with reduced trunk motor variability, the later with increased trunk motor variability. This conceptual framework is very useful to explain maintenance and aggravating of LBP because motor control adaptations are expected to have long-term consequences, such as increased spinal tissue loading, associated with degeneration of intervertebral discs and other tissues. Several knowledge gaps need to be addressed to test the validity of this framework: 1) Do loose/tight control phenotypes indeed exist and/or do other motor control adaption strategies exist? 2) Is reduced/altered paraspinal proprioceptive input associated with LBP related to neuroplastic cortical changes, thereby affecting the organizational structure in sensorimotor cortices and top-down trunk motor control? 3) Do psychological factors influence the organizational structure in sensorimotor cortices and motor control strategies? To address these knowledge gaps, the objectives of the current project are: I) To establish motor control phenotypes in LBP. Proprioceptive weighting and biomechanical assessment of dynamic movement tasks, including subject-specific spine kinematic variability and its relationship to pain duration, negative pain-related cognitions, segmental loadings and paraspinal muscle forces, will be performed. II) To test whether cortical proprioceptive maps differ between healthy subjects and patients with LBP. Brain activation in response to thoracolumbar vibrotactile stimulation will be interrogated using functional magnetic resonance imaging data and univariate and multivariate analysis based on machine learning. III) To test whether proprioceptive maps demonstrate a relationship to spine kinematic patterns, pain duration and negative pain-related cognitions in LBP patients.

Official Title
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Low Back Pain: Unveiling the Contribution of Motor Control Adaption Using Biomechanical Modeling and Neuroimaging

Conditions
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Low Back Pain

Intervention / Treatment
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* Other: mechanical stimulation
* Other: vibrotactile stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion criteria healthy subjects: Aged between 18 and 60 Written informed consent after being informed Inclusion criteria low back pain patients: Aged between 18 and 60 Low back pain for more than 1 week Exclusion criteria healthy subjects: Consumption of alcohol, drugs, analgesics within the last 24 h Pregnancy acute and/or low recurrent back pain within the last 3 months Prior spine surgery Other chronic pain condition history of psychiatric or neurological disorders MR-contraindications Body mass index (BMI) > 30 kg/m2 Exclusion criteria low back pain patients: Consumption of alcohol, drugs, analgesics within the last 24 h Pregnancy Specific causes for the back pain (ruled out by the clinician) Prior spine surgery History of psychiatric or neurological disorders MR-contraindications Body mass index (BMI) > 30 kg/m2

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Healthy subjects<br>Spine kinematics assessment during daily activities and brain responses to thoracolumbar mechanical and vibrotactile stimulation | Other: mechanical stimulation<br>* mechanical non-painful low- and high pressure stimuli to thoracolumbar segments of healthy subjects and low back pain patients<br>Other: vibrotactile stimulation<br>* non-painful vibrotactile stimulation within a frequency range between 20-150Hz to thoracolumbar segments of healthy subjects and low back pain patients<br>|
| Experimental: Low back pain patients<br>Spine kinematics assessment during daily activities and brain responses to thoracolumbar mechanical and vibrotactile stimulation | Other: mechanical stimulation<br>* mechanical non-painful low- and high pressure stimuli to thoracolumbar segments of healthy subjects and low back pain patients<br>Other: vibrotactile stimulation<br>* non-painful vibrotactile stimulation within a frequency range between 20-150Hz to thoracolumbar segments of healthy subjects and low back pain patients<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood oxygenation level dependent (BOLD) responses | supraspinal BOLD responses induced by mechanical and vibrotactile stimulations of the back recorded by means of functional magnetic resonance imaging (fMRI) | MR assessment, 30 minutes | 
| Spine kinematics | Sagittal and frontal plane lumbar and thoracic spinal curvature angles | Spinal kinematics assessment, 120 minutes | 
| Spine biomechanics: muscle forces | segmental muscle forces (N/mm) during dynamic tasks | Spinal kinematics assessment, 120 minutes | 
| Spine biomechanics: segmental loading | segmental loading (N) during dynamic tasks | Spinal kinematics assessment, 120 minutes | 
| Proprioceptive repositioning errors | Sagittal plane repositioning errors assessed through lumbar and thoracic spinal curvature angles | Proprioceptive assessment, 10 minutes | 
| Center of pressure displacements | Center of pressure displacements during vibrotactile stimulation while standing on a force plate | Postural stability assessment, 20 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Segmental movement | Displacement (intervertebral angles) of the stimulated and adjacent spinal segments during mechanical pressure using dynamic T2 scans | MR assessment, 20 minutes | 
| Fear of movement | score of the Tampa Scale of Kinesiphobia (TSK) questionnaire | Medical assessment, 5 minutes | 
| Fear Avoidance Beliefs | scores of the Fear Aovidance Beliefs questionnaire (FABQ) in low back pain patients | Medical assessment, 5 minutes | 
| Level of disability | scores of the Oswestry Disability Index (ODI) in low back pain patients | Medical assessment, 3 minutes | 
| Pain characteristics | Pain quality assessment using the PainDETECT questionnaire in low back pain patients | Medical assessment, 1 minutes | 
| Perception of the back | Assessment of self-perception of the back using the Fremantle Back Awareness Questionnaire | Medical assessment, 2 minutes | 
| State and Trait anxiety | scores of state and trait anxiety (STAI) questionnaire | Medical assessment, 2 minutes | 
| Perceived harmfulness of back stressing movements | Assessment of the perceived harmfulness of back stressing movements using the electronic version of the PHODA questionnaire | Medical assessment, 15 minutes |