Sensorimotor Cortex Excitability in Shoulder Impingement Syndrome

Study Overview
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Brief Summary
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Shoulder pain is a common musculoskeletal system complaint, accounting for 7-34% of patients in the clinic. The most common shoulder problem is subacromial impingement syndrome (SIS). Up to 45% of individuals with SIS may have unsuccessful treatment and still complain of symptoms after 2 years. This chronicity of pain may not be fully explained by structural injuries or damage, but may be related to sensorimotor changes. Decreased corticospinal excitability and increase inhibition have been found in individuals with SIS. These central motor changes may link to alteration in pain and nociception processing and the somatosensory system, which has been found in individuals with low back pain. Hyperalgesia has been found over both affected and unaffected shoulders in patients with SIS, indicating central and peripheral sensitization. However, no study has investigated whether there are changes in the central somatosensory system. Therefore, the objectives of this proposal are (1) to investigate the corticomotor and somatosensory system in patients with SIS (2) to investigate the relationship between the corticomotor and somatosensory alterations in patients with SIS. Subjects with chronic SIS and healthy subjects were recruited, with 32 people in each group. Electroencephalography (EEG) will be used to collect somatosensory activity, including somatosensory evoked potentials, spectral analysis of EEG oscillations and event-related spectral perturbation (ERSP) of the shoulder movement. Electromyography will be used to record muscle activity. Transcranial magnetic stimulation will be used to test corticomotor excitability, including active motor threshold, motor evoked potentials, cortical silent period, and intracortical inhibition and facilitation. The pressure pain threshold will be collected by a pressure algometer on the muscles of bilateral arms and legs. Pain intensity will be assessed with the Numeric Rating Scale. Shoulder function will be evaluated with the Disability of Arm, Shoulder and Hand questionnaire. Depression will be evaluated with Center for Epidemiologic Studies Depression Scale (CES-D).

Official Title
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Sensorimotor Cortex Excitability in Shoulder Impingement Syndrome and the Sensorimotor Excitability and Control in Acute/Subacute Stage Related to Development of Chronicity

Conditions
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Shoulder Impingement Syndrome, Chronic Pain, Transcranial Magnetic Stimulation, Electroencephalography, Central Nervous System

Intervention / Treatment
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* Other: No intervention


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria (chronic impingement syndrome group): individuals have shoulder pain localized at the anterior or lateral aspect of shoulder more than six months are aged 20 to 65 years old shoulder impingement syndrome, which is confirmed by having at least three of the following: (a) positive Neer's test, (b) positive Hawkins-Kennedy test, (c) positive empty can test, (d) positive resisted external rotation test, and (e) presenting painful arc during arm elevation Inclusion Criteria (acute/subacute impingement syndrome group): individuals have shoulder pain localized at the anterior or lateral aspect of shoulder less than six months are aged 20 to 65 years old shoulder impingement syndrome, which is confirmed by having at least three of the following: (a) positive Neer's test, (b) positive Hawkins-Kennedy test, (c) positive empty can test, (d) positive resisted external rotation test, and (e) presenting painful arc during arm elevation Inclusion Criteria (health control group) individuals without any shoulder and neck problems sex, age, and hand dominance match to impingement group Exclusion Criteria: have a history of dislocation, fracture, adhesive capsulities, or surgery of upper extremity arm elevation angle less than 150 degrees a history of direct contact injury to the neck or upper extremities within the past 12 months brain injury and neurological impairment inflammatory cause of the pain (e.g., rheumatoid arthritis) neck pain psychosis and symptom of headache or dizziness allergy to plaster contraindications to the use of TMS, assessed with a safety screening questionnaire

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 65 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| chronic shoulder impingement syndrome<br>Subjects with shoulder impingement more than 6 months will be included to assess pain threshold, neurophysiological measurements of scapular muscles. | Other: No intervention<br>* No intervention<br>|
| control group<br>Healthy controls without any shoulder and neck problems will be included to compare the differences in pain threshold, neurophysiological measurements of scapular muscles, scapular kinematics and muscle activation between healthy subjects and subjects with chronic or acute shoulder impingement syndrome. | Other: No intervention<br>* No intervention<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Corticomotor excitability measures - Active motor threshold | Active motor threshold (AMT) will be described with the percentage (%) of maximum stimulator output (MSO). | Immediately during the experiment | 
| Corticomotor excitability measures - Motor evoked potential | Motor evoked potential (MEP) will be described with millivolt (mV). | Immediately during the experiment | 
| Corticomotor excitability measures - Cortical silent period | Cortical silent period (CSP) will be measured with millisecond (ms) | Immediately during the experiment | 
| Corticomotor excitability 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 | Immediately during the experiment | 
| Corticomotor excitability 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 | Immediately during the experiment | 
| Corticomotor excitability measures - Long-interval intracortical inhibition | Long-interval intracortical inhibition (LICI) will be defined as percentage (%) of conditioning responses vs testing responses while the inter-stimulus interval is below 5 ms | Immediately during the experiment | 
| Corticomotor excitability - Area of cortical mapping | Area of cortical mapping will be described with square millimeter (mm2) | Immediately during the experiment | 
| Corticomotor excitability - 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 | Immediately during the experiment | 
| Corticomotor excitability - Center of gravity of cortical mapping | Center of gravity of cortical mapping will be described in a x-y coordinate system (mm). | Immediately during the experiment | 
| Resting brain activity - resting EEG with eye open/closed | EEG signals will be processed with power spectrum density analysis to calculate frequency power at Theta (3-8 Hz), alpha (8-13 Hz), beta (13-30 Hz) bands, and Gamma (30 Hz above). | Immediately during the experiment | 
| Somatosensory cortical activity - Somatosensory evoked potentials | Somatosensory evoked potentials (SEP) will be described with microvolt (µV) and millisecond (ms). | Immediately during the experiment | 
| Event-related synchronization or desynchronization - Movement evoked pain potentials | Movement evoked pain potentials will be processed with power spectrum density analysis to calculate frequency power at Theta (3-8 Hz), alpha (8-13 Hz), beta (13-30 Hz) bands, and Gamma (30 Hz above) while raising hand. | Immediately during the experiment | 
| Muscle activation during arm elevation | The root mean square of electromyography (EMG) data of the anterior deltoid and infraspinatus will be normalized by the maximum voluntary contraction amplitude (percentage of maximal voluntary contraction, %) and calculated in two segments, including arm elevating and arm lowering. | Immediately during the experiment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Shoulder pain and function-Taiwan version of the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire | Subjects will be asked 30 items related to shoulder functional movement. The overall score ranges from 0 (no disability) to 100 (most severe disability). | Immediately during the experiment | 
| Depression- Taiwan version of the Center for Epidemiologic Studies Depression Scale (CES-D) | Subjects will be asked 20 items to rate how often over the past week they experienced symptoms associated with depression. Response options range from 0 to 3 for each item. Scores range from 0 to 60, with high scores indicating greater depressive symptoms. | Immediately during the experiment | 
| Pressure pain thresholds | Pressure pain threshold of bilateral upper trapezius, levator scapulae, infraspinatus, pectoralis major, biceps brachii, middle deltoid and tibialis anterior will each be averaged and will be described with kg/cm2. | Immediately during the experiment | 
| Electrical sensory threshold | Electrical sensory threshold is the minimal intensity of stimulation required to produce the first perception of sensory and will be described with millivolts (mV). | Immediately during the experiment | 
| Electrical pain threshold | Electrical pain threshold is the minimal intensity of stimulation required to produce the first perception of pain and will be described with millivolts (mV). | Immediately during the experiment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Shoulder Impingement Syndrome, Corticospinal system, somatosensory system