Effects of Different Lumbar Vibration Parameters on Somatosensory Cortical Responses in Office Workers With Chronic Nonspecific Low Back Pain: A Randomized Crossover Study
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 入组人数
- 36
- 试验地点
- 1
- 主要终点
- Change in oxygenated hemoglobin concentration in bilateral primary somatosensory cortex
研究概览
简要总结
This study aims to determine the optimal parameters of lumbar sensory stimulation in office workers with chronic nonspecific low back pain. Participants will attend two laboratory sessions. The first session will characterize baseline clinical and sensorimotor function using clinical assessments, transcranial magnetic stimulation, functional near-infrared spectroscopy during unstable sitting, inertial measurement units, decomposition electromyography, and rehabilitative ultrasound imaging. The second session will use a randomized within-participant crossover design in which participants receive eight combinations of lumbar vibration frequency, amplitude, and direction while bilateral primary somatosensory cortex hemodynamic responses are continuously measured using functional near-infrared spectroscopy. The primary objective is to identify vibration parameters that produce a favorable and consistent cortical response while meeting predefined comfort, safety, and technical criteria.
详细描述
Phase II is an experimental laboratory study designed to optimize the neurophysiological parameters of lumbar sensory stimulation in office workers with chronic nonspecific low back pain. The primary objective is to determine which combination of vibration frequency, amplitude, and direction produces the most favorable cortical response in the bilateral primary somatosensory cortex (S1), while meeting predefined safety, comfort, and technical criteria.
Participants will complete two laboratory visits separated by approximately 48-72 hours. The two visits have different purposes and are not intended to constitute a pre- and post-intervention comparison.
Visit 1: Baseline clinical and sensorimotor characterization During the first visit, participants will undergo clinical and neurophysiological assessments to characterize their baseline clinical and sensorimotor profiles. Clinical assessments will include pain intensity, low back pain-related disability, work-related musculoskeletal discomfort, movement-control testing, tactile acuity, and pressure pain threshold.
Corticospinal excitability will be assessed using single-pulse transcranial magnetic stimulation (TMS), with motor-evoked potentials recorded from the lumbar multifidus and erector spinae muscles. Somatosensory cortical and postural responses will be assessed during unstable sitting using functional near-infrared spectroscopy (fNIRS) over the bilateral S1 together with inertial measurement units (IMUs). Participants will also perform a repeated loaded forward-bending task while lumbar multifidus motor-unit behavior is recorded using decomposition electromyography (dEMG) and trunk movement is recorded using IMUs. Finally, lumbar multifidus morphology and contractile response will be assessed using rehabilitative ultrasound imaging (RUSI) at rest and during contralateral arm lifting.
The measurements obtained during Visit 1 are intended to characterize individual baseline sensorimotor function and to permit exploratory analyses of associations between clinical characteristics, corticospinal excitability, cortical responses, postural control, motor-unit behavior, lumbar multifidus contractile response, and responses to lumbar sensory stimulation. These measurements are not intended to serve as pre-intervention values for an acute pre-post comparison with Visit 2.
研究设计
- 研究类型
- Interventional
- 分配方式
- Na
- 干预模型
- Single Group
- 主要目的
- Other
- 盲法
- None
入排标准
- 年龄范围
- 20 Years 至 60 Years（Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Office workers who currently sit for at least 6 hours per workday.
- •Age 20-60 years.
- •Chronic nonspecific low back pain for at least 3 months.
- •Current pain intensity of at least 2/10 on the Numeric Pain Rating Scale.
排除标准
- •History of seizure for either the subject or any family member
- •Implanted pacemaker
- •Contraindications for TMS and fNIRS, including open wound, infection, lesions, arteriosclerosis, history of hemophilia, or demand-type pacemaker
- •Acute cerebral hemorrhage
- •History of major spinal surgery, fracture, or traumatic injury to the lumbar spine.
- •Evidence of neurological deficits (e.g., radiculopathy, loss of sensation, or motor weakness in lower limbs).
- •Diagnosis of systemic inflammatory conditions (e.g., Ankylosing Spondylitis, Rheumatoid Arthritis).
- •Allergy to adhesives or history of severe skin sensitivity to vibration/mechanical pressure.
- •Body Mass Index (BMI) > 30 kg/m2 (to ensure clarity of RUSI, dEMG, and fNIRs signal quality).
- •Pregnancy (due to changes in spinal biomechanics and hormones)
研究组 & 干预措施
Vibration parameter
A customized vibration apparatus will deliver controlled mechanical stimulation over the bilateral lumbar multifidus region. Participants will receive eight randomized combinations of vibration frequency, amplitude, and direction. Each condition will be delivered for 1 minute, followed by a 5-minute passive rest period.
干预措施: Lumbar sensory stimulation (Device)
结局指标
主要结局
Change in oxygenated hemoglobin concentration in bilateral primary somatosensory cortex
时间窗: During each 1-minute vibration condition relative to its corresponding pre-stimulation baseline during the single Phase II parameter-optimization session.
Baseline-corrected change in oxygenated hemoglobin concentration (ΔHbO) recorded from the bilateral primary somatosensory cortex using an eight-channel functional near-infrared spectroscopy system during lumbar vibration.
次要结局
- Change in deoxygenated hemoglobin concentration in the bilateral primary somatosensory cortex(During each vibration condition relative to the immediately preceding resting baseline during the Phase II parameter-optimization session)
- Change in total hemoglobin concentration in the bilateral primary somatosensory cortex(During each vibration condition relative to the immediately preceding resting baseline during the Phase II parameter-optimization session)
- Peak oxygenated hemoglobin response in the bilateral primary somatosensory cortex(During each vibration condition relative to the immediately preceding resting baseline during the Phase II parameter-optimization session)
- Area under the oxygenated hemoglobin response curve in the bilateral primary somatosensory cortex(During each vibration condition relative to the immediately preceding resting baseline during the Phase II parameter-optimization session)
- Corticospinal excitability of the lumbar multifidus measured by transcranial magnetic stimulation(During Visit 1 of Phase II, prior to the vibration-parameter optimization session)
- Corticospinal excitability of the lumbar erector spinae measured by transcranial magnetic stimulation(During Visit 1 of Phase II, prior to the vibration-parameter optimization session)
- Change in oxygenated hemoglobin concentration during unstable sitting(During each sitting condition relative to the immediately preceding resting baseline in visit 1.)
- Postural-control response during unstable sitting(During each vibration condition relative to the immediately preceding resting baseline in visit 1)
- Lumbar multifidus motor-unit behavior during loaded forward bending(During the loaded forward-bending assessment at baseline in Visit 1.)
- Lumbar multifidus contractile response measured by rehabilitative ultrasound imaging(During the baseline assessment in Visit 1)
研究者
Peemongkon Wattananon
Associate Professor
Mahidol University