Alterations in Central Control of Shoulder Muscles in Office Workers With Non-specific Chronic Neck Pain

Study Overview
=================
Brief Summary
-----------------
Non-specific chronic neck pain (NCNP) is commonly seen in office workers. Individuals with NCNP not only demonstrate impaired neck movement control and muscle activation, but also show abnormal scapular kinematics and muscle activation timing. Office workers with NCNP also show higher activity of upper trapezius during computer typing and have difficulty relaxing upper trapezius after typing. These changes related to scapula may increase strain over neck. In addition to the altered neuromuscular control, recent studies found neuroplasticity changes in the central nervous system on patients of chronic musculoskeletal disorders. Therefore, few studies found shifts and alterations of motor cortex representation of neck muscles in individuals with NCNP, which was correlated with delayed muscle activation of deep neck flexors muscle in functional activities. However, no studies have explored that whether this corticospinal adaptation also happens over scapular muscles, especially after a computer typing task. The objectives of this proposal are to investigate the differences in corticospinal and neuromuscular control of shoulder complex between office workers with and without NCNP. Thirty-five individuals with NCNP and 35 healthy controls will be recruited. Twenty young healthy subjects will be also recruited for a pilot study to test the reliability of all the measures. Scapular kinematics and muscle activation will be tested during arm elevation. Corticospinal parameters of trapezius and serratus anterior will be tested with transcranial magnetic stimulation (TMS), including active motor threshold, motor evoked potential, cortical silent period, short interval intracortical facilitation, short interval intracortical inhibition and cortical mapping. Corticospinal parameters, except cortical mapping, will be measured again after a 30-minute computer typing task. Scapular muscle activation will be also recorded during the typing task.

Official Title
-----------------
Alterations in Corticospinal and Neuromuscular Control of Shoulder Complex in Office Workers With Non-specific Chronic Neck Pain

Conditions
-----------------
Non-specific Chronic Neck Pain, Office Workers, Transcranial Magnetic Stimulation, Neuromuscular Control

Intervention / Treatment
-----------------
* Other: 30-minute computer typing task
* Other: 30-minute rest


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria of Patients with Non-specific Chronic Neck Pain Ages ranges from 20-40 years old Work with the computer at least 25 hours per week Neck pain of idiopathic origin ≥ 6 months during the past year Minimum of 3/10 on the numerical rating scale (NRS) in past 7 days No structural abnormalities which are confirmed by neck X-ray or negative results of all the following special tests Exclude nerve root compression: Cervical distraction test and Spurling's test Exclude cervical radiculopathy: Valsalva test Exclude cervical instability: Alar ligament test and Sharp-Purser test Specific head movements or maintaining the fixed posture for a long time reproduced neck pain Inclusion Criteria of Healthy Subjects in the control group Ages ranges from 20-40 years old Work with the computer at least 25 hours per week No history of neck and/or shoulder pain sustained over one week in the past one year Inclusion Criteria of Healthy subjects in the Pilot Study Ages ranges from 20-40 years old No history of neck and/or shoulder pain sustained over one week in the past one year Exclusion Criteria of Patients with Non-specific Chronic Neck Pain and All Healthy Subjects) Any known pathology or impairment in the shoulder joint, which is the origin of neck pain Current episode of neck pain related to a traumatic event (e.g., whiplash injury) Have a history of cervical and/or shoulder pathology (e.g., fracture, dislocation, trauma, surgery of spinal or shoulder joint, inflammatory disease, frequent headache or dizziness) Brain injury and neurological impairment (e.g., radiculopathy, myelopathy or stroke) Systematic diseases (e.g., rheumatoid arthritis, ankylosing spondylitis), fibromyalgia, tumor Contraindications to the use of transcranial magnetic stimulation (TMS), assessed with a safety screening questionnaire, including pregnancy, history of seizure, epilepsy and syncope, having cochlear implant, having medal implant and taking anti-depressant medication Any kind of previous manual and/or movement therapy on upper extremity and neck during in recent 3 months

Ages Eligible for Study
-----------------
Minimum Age: 20 Years
Maximum Age: 40 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Other
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Experimental group: Non-specific chronic neck pain group<br>Subjects with non-specific chronic neck pain will be included to perform 30-minute computer typing task and assess neurophysiological measurements of scapular muscles, scapular kinematics and muscle activation. | Other: 30-minute computer typing task<br>* The subject sits in front of a computer screen and perform computer typing tasks for 30 minutes. The same computer table and chair were used for all subjects. The height of the table and screen, and the distance of the keyboard from the subject were adjusted according to their familiar and comfortable position.<br>|
| Other: Control group: Healthy subjects group<br>Healthy subjects will be included to compare the differences in neurophysiological measurements of scapular muscles, scapular kinematics and muscle activation between healthy subjects and subjects with non-specific chronic neck pain. Subjects in this group will received the same assessment as the NCNP group. | Other: 30-minute computer typing task<br>* The subject sits in front of a computer screen and perform computer typing tasks for 30 minutes. The same computer table and chair were used for all subjects. The height of the table and screen, and the distance of the keyboard from the subject were adjusted according to their familiar and comfortable position.<br>|
| Other: Pilot study: Healthy subjects group<br>Healthy subjects will be included to test reliability of single-pulse and paired-pulse TMS, including its associated neurophysiological measurements, and also to test reliability of Liberty electromagnetic tracing system and surface electromyography. Subjects in this group will received the same assessment as the NCNP group. | Other: 30-minute rest<br>* Rest for 30 minutes<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neurophysiological measures - Active motor threshold | Active motor threshold (AMT) will be described with the percentage (%) of maximum stimulator output (MSO). | Change from baseline AMT after 30-minute computer typing task or 30-minute rest | 
| Neurophysiological measures - Motor evoked potential | Motor evoked potential (MEP) will be described with millivolt (mV). | Change from baseline MEP after 30-minute computer typing task or 30-minute rest | 
| Neurophysiological measures - Cortical silent period | Cortical silent period (CSP) will be measured with millisecond (ms) | Change from baseline CSP after 30-minute computer typing task or 30-minute rest | 
| Neurophysiological measures - Short interval cortical inhibition | Short interval cortical inhibition (SICI) will be defined as percentage (%) of conditioning responses vs testing responses while the inter-stimulus interval is below 5 ms | Change from baseline SICI after 30-minute computer typing task or 30-minute rest | 
| Neurophysiological measures - Short interval cortical facilitation | Short interval cortical facilitation (SICF) will be defined as percentage (%) of conditioning responses vs testing responses while the inter-stimulus interval is above 5 ms | Change from baseline SICF after 30-minute computer typing task or 30-minute rest | 
| Neurophysiological measures - Area of cortical mapping | Area of cortical mapping will be described with square millimeter (mm2) | Before 30-minute computer typing task | 
| Neurophysiological measures - Volume of cortical mapping | Volume of cortical mapping will be calculated with multiplying summation of motor evoke potentials on the map (mV) by the area of the map (mm2) with the unit of mV*mm2 | Before 30-minute computer typing task | 
| Neurophysiological measures - Center of gravity of cortical mapping | Center of gravity of cortical mapping will be described in a x-y coordinate system (mm). | Before 30-minute computer typing task | 
| Neurophysiological measures - Area of cortical mapping | Area of cortical mapping will be described with square millimeter (mm2) | Change from baseline area of cortical mapping after 30-minute rest (pilot subjects) | 
| Neurophysiological measures - Volume of cortical mapping | Volume of cortical mapping will be calculated with multiplying summation of motor evoke potentials on the map (mV) by the area of the map (mm2) with the unit of mV*mm2 | Change from baseline volume of cortical mapping after 30-minute rest (pilot subjects) | 
| Neurophysiological measures - Center of gravity of cortical mapping | Center of gravity of cortical mapping will be described in a x-y coordinate system (mm). | Change from baseline center of gravity of cortical mapping of cortical mapping after 30-minute rest (pilot subjects) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Scapular kinematics during arm elevation | Scapular kinematics, including anterior/posterior tilt, upward/downward rotation, and internal/external rotation in scapula plane elevation at 30°, 60°, 90°, and 120°, and will be described with degree (°). | Before 30-minute computer typing task | 
| Scapular kinematics during performing the computer task | The average of scapular kinematics, including anterior/posterior tilt, upward/downward rotation, and internal/external rotation will be calculated with a window of 10 seconds and will be described with degree (°). | Change from baseline during the 30-minute computer typing task at 5, 10, 15, 20, 25, 30 minutes of the task | 
| Scapular muscles activation during arm elevation | The root mean square of electromyography (EMG) data of the upper trapezius, lower trapezius, and serratus anterior will be normalized by the maximum voluntary contraction amplitude (percentage of maximal voluntary contraction, %) and calculated over three 30° increments of motion during arm elevation from 30° to 120°, including 30° - 60°, 60° - 90°, and 90° - 120°. | Before 30-minute computer typing task | 
| Scapular muscles activation during performing the computer task | The root mean square of electromyography (EMG) data of the upper trapezius, lower trapezius, and serratus anterior will be calculated with a window of 10 seconds and will be normalized by the maximum voluntary contraction amplitude (percentage of maximal voluntary contraction, %). | Change from baseline during the 30-minute computer typing task at 5, 10, 15, 20, 25, 30 minutes of the task | 
| Craniovertebral angle | Craniovertebral angle will be measured as the included angle between the tragus, C7 spinous process and the horizontal line and will be described with degree (°) | Before 30-minute computer typing task | 
| Craniovertebral angle | Craniovertebral angle will be measured as the included angle between the tragus, C7 spinous process and the horizontal line and will be described with degree (°) | Change from baseline during the 30-minute computer typing task at 5, 10, 15, 20, 25, 30 minutes of the task | 
| Scapular kinematics during arm elevation | Scapular kinematics, including anterior/posterior tilt, upward/downward rotation, and internal/external rotation in scapula plane elevation at 30°, 60°, 90°, and 120°, and will be described with degree (°). | Change from baseline scapular kinematics after 30-minute rest (pilot subjects) | 
| Scapular muscles activation during arm elevation | The root mean square of electromyography (EMG) data of the upper trapezius, lower trapezius, and serratus anterior will be normalized by the maximum voluntary contraction amplitude (percentage of maximal voluntary contraction, %) and calculated over three 30° increments of motion during arm elevation from 30° to 120°, including 30° - 60°, 60° - 90°, and 90° - 120°. | Change from baseline scapular muscles activation after 30-minute rest (pilot subjects) | 
| Craniovertebral angle | Craniovertebral angle will be measured as the included angle between the tragus, C7 spinous process and the horizontal line and will be described with degree (°) | Change from baseline craniovertebral angle after 30-minute rest (pilot subjects) | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Non-specific chronic neck pain, Transcranial magnetic Stimulation, Corticospinal system, Scapular kinematics, Scapular muscles activation