The Investigation of Underlying Mechanism of Lumbar Multifidus Muscle Activation Deficits

Sponsor

Mahidol University (Other)

Overall Status

Recruiting

CT.gov ID

NCT05961774

Collaborator

National Research Council of Thailand (Other)

Enrollment

Location

Arms

15.5

Anticipated Duration (Months)

4.4

Patients Per Site Per Month

Study Details

Study Description

Brief Summary

The goal of this clinical trial is to investigate mechanism underlying lumbar multifidus muscle (LM) activation deficits in adults with chronic low back pain (CLBP). The main questions it aim to answer is whether motor cortex or muscular level is the underlying mechanism responsible for the LM activation deficits.

Participants will:

Undergo cortical excitability measurement using transcranial magnetic stimulation, LM activation measurement using ultrasound imaging, and force measurement using hand-held dynamometer.
Be randomly assigned to either repetitive magnetic stimulation (rTMS) or neuromuscular electrical stimulation (NMES)
Undergo all measurement at post-intervention Researchers will compare within and between groups to see changes in cortical excitability, LM activation, and force.

Condition or Disease	Intervention/Treatment	Phase
Low Back Pain	Device: Transcranial magnetic stimulation Device: Neuromuscular electrical stimulation	N/A

Detailed Description

Procedure The study will use a sample of convenience. The subject with CLBP will be recruited by the flyers posted at physical therapy clinic, as well as words of mouths. The participants who are interested in the study will undergo screening process for eligibility using the inclusion-exclusion criteria checklist. If the participants meet the eligibility criteria, participants will receive the brief information of the study and the consent process will be performed.

After receiving the informed consents, all participants will be requested to fill out the information sheet for demographic and clinical data. The participants will be asked to change the cloth of the top to be able to expose the lower back region. After collecting demographic and clinical data, 3-condition of LM thickness and cross-sectional area will be measured including 1) resting condition (Rest), maximum voluntary isometric contraction condition (MVIC), and maximum voluntary isometric contraction combined with neuromuscular electrical stimulation (COMB). The landmarks will be identified while the participants lay down in prone position. The landmarks include 1) lumbar spinous process of L2-L5 and 2) L4-5 facet joint (2 cm lateral to lower half of spinous process of L4). Rehabilitative ultrasound imaging (RUSI) will be used to measure LM activation and hand-held dynamometer will be used to measure force in this study across 3 conditions.

The participant will have 10 minutes rest before the transcranial magnetic stimulation (TMS). A pair of surface electrodes (Ag/AgCl, 10 mm) will be place according to SENIAM recommendation. The common ground electrode will be placed at the iliac crest. Two surface EMG electrodes will be placed relative to L4-5 along with the line joining from posterosuperior iliac spine and L1-L2 vertebral interspace (24) on the side of pain. The researcher will determine the hotspot of lumbar multifidus muscle area on the brain. The hotspot of the LM will be determined by least intensity of TMS which at least elicits 50 percent of measurable motor evoked potential (MEP) and this intensity will be the active motor threshold (AMT) of the participants. After the AMT is achieved, the 120% of AMT will be used as the intensity to induce the MEP. The MEP will be used to represent cortical excitability.

After the baseline RUSI and TMS data collection, the participants will be randomly assigned in to 2 groups include 1) NMES and high-frequency repetitive TMS (HF-rTMS) group. For HF-rTMS group, the participants will be in sitting position feet placed firmly on the floor. The stimulation point is the LM hot spot which is pre-determined by single pulse TMS as aforementioned. The HF-rTMS will be applied for participant individually. According to the theory, HF-rTMS results in facilitation of the targeted area; therefore, it will increase the excitability of the LM hot spot and potentially increase LM's neural drive and activation. The parameters will be set at frequency 10 Hz, 50 number of pulses, 40 train of stimulation (5 seconds stimulation and 25 seconds inter-stimulation interval) (34). The stimulation will approximately 20 minutes. The position of coil will be placed tangentially at 45 degrees on the LM hotspot. For the neuromuscular electrical stimulation (NMES) group, participants will be lying in prone position. The landmarks and electrodes placements are the same as mentioned in MVIC combined with NMES and LM thickness measurement. NMES parameters are interferential current 6000 Hz, amplitude 20-50 Hz with scanning mode, duration 20-minute, intensity to elicit the LM contraction (6). After the participants completed receiving the stimulation, the participant will undergo the collecting the LM thickness and force again using the same protocol.

Data will be used to 1) identify changes in cortical excitability, LM activation and force before and after stimulation at cortical level by HF-rTMS, 2) identify changes in cortical excitability, LM activation and force before and after stimulation at muscular level by NMES, and 3) compare the percent changes in cortical excitability, LM activation and force between stimulation at cortical (by HF-rTMS) and muscular (by NMES) levels.

Study Design

Study Type:

Interventional

Anticipated Enrollment :

68 participants

Allocation:

Randomized

Intervention Model:

Parallel Assignment

Masking:

Double (Investigator, Outcomes Assessor)

Primary Purpose:

Treatment

Official Title:

The Investigation of Underlying Mechanism of Lumbar Multifidus Muscle Activation Deficits in Adults With Chronic Low Back Pain

Actual Study Start Date :

Mar 15, 2023

Anticipated Primary Completion Date :

Mar 14, 2024

Anticipated Study Completion Date :

Jun 30, 2024

Arms and Interventions

Arm	Intervention/Treatment
Experimental: High frequency repetitive transcranial magnetic stimulation This group will receive high frequency repetitive transcranial magnetic stimulation.	Device: Transcranial magnetic stimulation The stimulation point is the lumbar multifidus hotspot. The parameters will be set at frequency 10 Hz, 50 number of pulses, 40 train of stimulation (5 seconds stimulation and 25 seconds inter-stimulation interval). The position of coil will be placed tangentially at 45 degrees on the LM hotspot. The stimulation will be 20 minutes.
Active Comparator: Neuromuscular electrical stimulation This group will receive neuromuscular electrical stimulation.	Device: Neuromuscular electrical stimulation The neuromuscular electrical stimulation will be set as interferential current 6000 Hz, amplitude 20-50 Hz with scanning mode, duration 20 minutes, intensity to elicit the LM contraction.

Arm

Intervention/Treatment

Experimental: High frequency repetitive transcranial magnetic stimulation

This group will receive high frequency repetitive transcranial magnetic stimulation.

Device: Transcranial magnetic stimulation

The stimulation point is the lumbar multifidus hotspot. The parameters will be set at frequency 10 Hz, 50 number of pulses, 40 train of stimulation (5 seconds stimulation and 25 seconds inter-stimulation interval). The position of coil will be placed tangentially at 45 degrees on the LM hotspot. The stimulation will be 20 minutes.

Active Comparator: Neuromuscular electrical stimulation

This group will receive neuromuscular electrical stimulation.

Device: Neuromuscular electrical stimulation

The neuromuscular electrical stimulation will be set as interferential current 6000 Hz, amplitude 20-50 Hz with scanning mode, duration 20 minutes, intensity to elicit the LM contraction.

Outcome Measures

Primary Outcome Measures

Resting motor threshold [Change from baseline after 1 session]
The stimulus intensity that causes a minimum motor response in a resting muscle during single transcranial magnetic stimulation (TMS) pulses applied over the motor hotspot.
Active motor threshold [Change from baseline after 1 session]
The lowest stimulus intensity to elicit a motor evoked potential ≥ 200μV in 5 out of 10 consecutive trials during an isometric contraction of 10% maximum voluntary contraction in the target muscle.
Motor evoked potential [Change from baseline after 1 session]
The electrical signals recorded from the descending motor pathways or from muscles following stimulation of motor pathways within the brain.
Cortical silent period [Change from baseline after 1 session]
The temporary interruption of electromyographic signal from a muscle following a motor evoked potential triggered by transcranial magnetic stimulation over the primary motor cortex.
Muscle thickness [Change from baseline after 1 session]
Muscle contractility.
Muscle cross-sectional area [Change from baseline after 1 session]
Cross-sectional area can be related to joint torque production and isokinetic strength in different muscle groups.
Muscle pennation angle [Change from baseline after 1 session]
Pennation angle can represent the maximum force developed by a muscle

Secondary Outcome Measures

Force generation [Change from baseline after 1 session]
Hand-held dynamometer will be used to measure muscle force.

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 40 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Inclusion Criteria:

Male and female age between 18 and 40 years.
Experience of low back pain at least 3 months, or recurrent of back pain for at least two episodes in 6 months that interferes with activities of daily living.

Exclusion Criteria:

Spondylolysis, spondylolisthesis, spine tumor and malignancy
Radiculopathy or myelopathy
History of lumbar or abdominal surgery
Pregnancy
Neurological Disease (e.g., stroke, Parkinson, traumatic brain injury, spinal cord injury)
Major cardiovascular diseases (e.g., heart failure, coronary artery diseases, angina pain)
Skin lesion (e.g., skin laceration) on site of stimulation.
Experience of lumbar motor control exercise more than or equal to 2 weeks
Metal implantation sensitive to magnetic field, or cardiac implantations
BMI greater or equal to 30 kg/m2
Taking any medications that would interfere with brain stimulation (e.g., Calcium channel blockers, Na+ channel blocker, NMDA antagonist, Glutamate receptor antagonist, nicotine uptake)