Neuromuscular Electrical Stimulation and Motor Control
Condition: Instability; Back
Study type: Interventional

Summary: 
      Phase I, this study aims to:-

        1. Establish intra- and inter-rater reliability and minimal detectable change of ultrasound
           imaging measurement

        2. Determine appropriate mode and dose for neuromuscular electrical stimulation on lumbar
           multifidus muscle

        3. Determine feasibility of proposed protocol and physical therapy intervention

      Phase II, this study aims to:-

        1. Determine the difference lumbar multifidus muscle activation based on arthrogenic muscle
           inhibition model between individuals with and without impaired lumbopelvic control

        2. Determine the effect of combined neuromuscular electrical stimulation and motor control
           training in individual with impaired lumbopelvic control
    

Detailed description: 
      Phase I: Preliminary study Subjects aged between 20 and 40 with and without history of low
      back pain will be recruited. Subjects who are interested in participation will undergo a
      screening process using inclusion-exclusion criteria checklist and receive brief information
      regarding the study. If they meet all inclusion criteria, the consent process will be
      performed.

      After obtaining the written informed consent, all subjects will fill out the information
      sheet for demographic data. The body landmarks will be identified. These landmarks include 1)
      lumbar spinous process of L2-L5, 2) L4-5 facet joint (2 cm lateral to inferior one half of
      spinous process of L4), and 3) lumbar multifidus muscle (2 cm lateral to L5 spinous process
      and 3 cm lateral to L2 spinous process). Bilateral L4-5 facet joints will be used to place
      ultrasound transducer for capturing lumbar multifidus muscle, while location of lumbar
      multifidus muscle will be used to place NMES electrodes. Then, subjects will undergo clinical
      outcome measures including clinical observation of aberrant movement pattern during
      functional movements, passive SLR, hamstrings muscle length test, modified Thomas's and
      Ober's tests, abdominal and back muscle strength.

      The subjects will be in prone position on treatment table with thorax (T3 level) and pelvis
      (S2 level) securely fastened to the bed. Hand-held dynamometer will be placed at the thorax
      to measure back extension force. Then, ultrasound transducer will be placed at right L4-5
      facet joint by rater-A. Right lumbar multifidus muscle activation at rest will be recorded.
      Then, rater-A will move the transducer to left L4-5 facet joint to measure left lumbar
      multifidus muscle activation. After that, the subject will be asked to perform 2 repetitions
      of maximum voluntary isometric contraction (MVIC) of back extensor muscle with 1 minute rest
      between repetitions. Rater-A will measure right and left lumbar multifidus muscle activation
      during MVIC and record back extension force from hand-held dynamometer for both repetitions.
      The data from repetition 1 and 2 will be used to establish intra-rater reliability of
      ultrasound imaging measurement and calculate minimal detectable change, while data from right
      and left lumbar multifidus muscles will be used to determine the difference between right and
      left sides. Subject will be asked to rate the rating of perceived exertion (RPE) and take 5
      minute rest to prevent muscle fatigue. After rest period, rater-B will perform exact process
      as rater-A. These data will be used to establish inter-rater reliability of ultrasound
      imaging measurement. Rater-A and rater-B are blinded to the subject's group.

      The NMES electrodes will be placed on bilateral lumbar multifidus muscles (positive electrode
      at L3 and negative electrode at L5). Ultrasound transducer will be placed at L4-5 facet joint
      to capture lumbar multifidus muscle activation. The NMES will be first set at faradic mode
      (20 Hz, 1 ms). The investigator will increase the intensity at 1 mA increment. Ultrasound
      imaging data will be recorded, while subject will be asked to rate the 0-10 level of
      discomfort every 5 mA increment. Rater-A and rater-B will record the intensity used to elicit
      observable lumbar multifidus muscle contraction. The NMES intensity will increase until
      maximum level of discomfort (10 out of 10). Subject will be asked to rate the RPE and take a
      rest period for 10 minutes to prevent muscle fatigue. After rest period, the NMES will be set
      at interferential mode (6000 Hz, beat frequency 20-50 Hz, scanning effect). The investigator
      will repeat the entire data collection process. Data from two modes of stimulation will be
      used to determine the appropriate mode and dose to activate lumbar multifidus muscles.

      To determine the feasibility of proposed protocol, the NMES will be set at interferential
      mode. The investigator will increase NMES intensity until lumbar multifidus muscle 10%
      increase in thickness. Then, subject will be asked to perform MVIC of back extensor muscle.
      Rater-A will measure right and left lumbar multifidus muscle activation during MVIC and
      record back extension force from hand-held dynamometer attached to the thorax. The
      investigator will decrease NMES intensity to zero. Subject will rest for 10 minutes. After
      that, the subject will be asked to perform another MVIC of lumbar multifidus muscle without
      NMES. Rater-A will measure lumbar multifidus muscle activation and record back extension
      force. The NMES electrodes will be removed and subject's skin will be cleaned. The data (MVIC
      and MVIC+NMES) will be used to preliminarily determine the existence of arthrogenic muscle
      inhibition of lumbar multifidus muscle. In addition, the MVIC data without NMES between pre-
      and post-NMES will be used to determine the existence of retention effect of NMES.

      To determine the feasibility of proposed intervention, the NMES will be applied using
      interferential mode on bilateral lumbar multifidus muscles. The investigator will increase
      the intensity up to the subject's maximum tolerance. Stimulation will be set at 10 seconds on
      and 60 seconds off to minimize muscle fatigue. The total NMES time is 15 minutes. This
      intervention dose is based on previous studies by Hicks et al. Quadruped rocking exercise
      will be used as a motor control training in this study. This exercise is based on movement
      system impairment concept. Subject will be asked to perform quadruped position with spine in
      neutral position, shoulder and hip in 90 degrees, hips centered over knees, and feet pointing
      away from body with the dorsum of the feet on the support surface. Then, the subject will be
      asked to perform rocking back by pushing back with both hands. This verbal instruction will
      be given to the subject as "Keep your back straight throughout the movement. Think about
      moving in your hips and not your back. Move in the hips equally". Subject performs rocking
      back to the position that cause observable and/or palpable posterior pelvic rotation. The
      subject will be asked to perform rocking back to this target point supervised by the
      investigator for 10 repetitions followed by 1 minute resting period to minimize muscle
      fatigue. Subject will be asked to rate the RPE after completion of 10 repetitions. Then, the
      investigator will re-evaluate the target point again for the next 10 repetitions. This
      process will be continuously performed for 15 minutes.

      After completion of intervention, subject will undergo post-intervention data collection
      using the same protocol, except only rater-A will perform the post-intervention data
      collection. The NMES electrodes will be re-applied to bilateral lumbar multifidus muscles.
      Ultrasound transducer will be re-placed at L4-5 facet joint, and hand-held dynamometer will
      be re-placed at the thorax. Subject will be asked to perform 2 repetitions of MVIC of back
      extensor muscle with 1 minute rest between repetitions. Rater-A will measure right and left
      lumbar multifidus muscle activation during MVIC and record back extension force from
      hand-held dynamometer for both repetitions. The investigator will increase NMES intensity
      until lumbar multifidus muscle 10% increase in thickness. Then, subject will be asked to
      perform MVIC of back extensor muscle. Rater-A will measure right and left lumbar multifidus
      muscle activation during MVIC and record back extension force from hand-held dynamometer
      attached to the thorax. The investigator will decrease NMES intensity to zero. Subject will
      rest for 10 minutes. After that, the subject will be asked to perform another MVIC of lumbar
      multifidus muscle without NMES. Rater-A will measure lumbar multifidus muscle activation and
      record back extension force. The NMES electrodes will be removed and subject's skin will be
      cleaned. Pre- and post-intervention data will be used to determine the feasibility of the
      proposed intervention.

      Phase II: Randomized controlled trial study Phase II study will use a sample of convenience
      between the ages of 20 and 40. Subjects with and without history of low back pain will be
      recruited by flyers posted in 2 university physical therapy clinics, as well as word of mouth
      from subjects and friends. Subjects who are interested in participation will undergo a
      screening process using inclusion-exclusion criteria checklist and receive brief information
      regarding the study. If they meet all inclusion criteria, the consent process will be
      performed.

      After obtaining the written informed consent, all subjects will fill out the information
      sheet for demographic data. Then, subjects will be asked to change their cloth to lab tank
      top to expose their lower back area. The same body landmarks as preliminary study will be
      identified. The subjects will be in prone position on treatment table with thorax (T3 level)
      and pelvis (S2 level) securely fastened to the bed. Hand-held dynamometer will be placed at
      the thorax to measure back extension force. The NMES electrodes will be placed to bilateral
      lumbar multifidus muscles, and the system will be set at interferential mode. Then,
      ultrasound transducer will be placed at right L4-5 facet joint by rater-A.

      Subject will be asked to perform 2 repetitions of MVIC of back extensor muscle with 1 minute
      rest between repetitions. Rater-A will measure right and left lumbar multifidus muscle
      activation at rest and during MVIC, as well as record back extension force from hand-held
      dynamometer for both repetitions. The investigator will increase NMES intensity until lumbar
      multifidus muscle 10% increase in thickness. Then, subject will be asked to perform MVIC of
      back extensor muscle. Rater-A will measure right and left lumbar multifidus muscle activation
      during MVIC and record back extension force from hand-held dynamometer attached to the
      thorax. The NMES electrodes will be removed and subject's skin will be cleaned. The data
      (MVIC and MVIC+NMES) will be used to determine the existence of arthrogenic muscle inhibition
      of lumbar multifidus muscle. After pre-intervention data collection, subjects with impaired
      LPC will be randomly assigned to either combined NMES with motor control training group
      (COMB), or motor control training alone group (MCT) using randomly generated number in
      concealed envelopes.

      The COMB group will receive the NMES using interferential mode on bilateral lumbar multifidus
      muscles. The intensity will be set at the subject's maximum tolerance. Stimulation will be
      set at 10 seconds on and 60 seconds off to minimize muscle fatigue. The total NMES time is 15
      minutes. After the NMES, the COMB group will receive 30 minutes motor control training based
      on movement system impairment concept. This motor control training will focus on the control
      of the lumbar multifidus muscle in various functional tasks. It is believed to restore the
      motor units in individuals with arthrogenic muscle inhibition. This motor control training
      with take approximately 30 minutes. The COMB group will receive intervention twice a week for
      8 weeks. We use the 8-week motor training program because several studies have showed
      significant improvement after 8-week exercise program.1,8 For subjects in MCT group, they
      will receive placebo NMES (no electrical current) and the same motor control training program
      as the COMB group. Therapist who provides motor control training will be blinded to the group
      assignment. After completion of the intervention program, each subject will undergo
      post-intervention data collection immediately after the first session (Post-1) and after
      8-week (Post-2) of intervention to determine the effect of combined neuromuscular electrical
      stimulation and motor control training in individual with impaired lumbopelvic control.
    

Intervention name(s): Combined NMES and motor control; Motor control and placebo NMES
Intervention type(s): Other; Other
Intervention description(s): This group will receive the neuromuscular electrical stimulation using interferential mode (6000 Hz, beat frequency 20-50 Hz, scanning effect) on bilateral lumbar multifidus muscles. The intensity will be set at the subject's maximum tolerance. Stimulation will be set at 10 seconds on and 60 seconds off to minimize muscle fatigue. The total stimulation time is 15 minutes. After that, this group will receive 30 minutes motor control training. This motor control training will focus on the control of the lumbar multifidus muscle in various functional tasks. It is believed to restore the motor units in individuals with arthrogenic muscle inhibition. This motor control training will take approximately 30 minutes. This group will receive intervention twice a week for 8 weeks.; This group will the neuromuscular electrical stimulation without turning the electrical current for 15 minutes. After that, this group will receive 30 minutes motor control training. This motor control training will focus on the control of the lumbar multifidus muscle in various functional tasks. This motor control training will take approximately 30 minutes. This group will receive intervention twice a week for 8 weeks.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Subjects with impaired lumbopelvic control will be randomly assigned to either combined NMES with motor control training group, or motor control training alone group using randomly generated number in concealed envelopes.
Masking: Triple (Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Clinical lumbar instability; History of low back pain; Arthrogenic muscle inhibition; Neuromuscular electrical stimulation; Motor control training