Stroke
Conditions
Keywords
operant conditioning, motor evoked potential, transcranial magnetic stimulation, muscle synergy, motor control, motor coordination
Brief summary
The purposes of this study include: 1. To test if multiple upper extremity muscles represented within a discrete primary motor cortex site reflect existing muscle synergies after stroke. 2. To test if altered muscle synergies and intermuscular coordination are malleable to motor evoked potential conditioning that induces corticospinal plasticity for the targeted muscle, wrist extensor carpi radialis
Detailed description
Stroke is a leading cause of long-term disabilities in the U.S., which can markedly impact the function of the upper extremity (UE). One of the major UE motor impairments is abnormal intermuscular coordination, which leads to impaired post-stroke function and life participation. Also, relatively little is understood about how stroke affects the corticospinal innervation of multiple UE muscles, visualized as multi-muscle motor evoked potentials (MEPs) to transcranial magnetic stimulation (TMS) of the primary motor cortex (M1), and its association with intermuscular coordination and impaired UE motor function in stroke. Some studies have shown that improvement in corticospinal excitability for the affected limb may be able to improve intermuscular coordination and enhance motor function recovery after stroke. Operant conditioning is a method that can be used to produce not only targeted plasticity but also wider beneficial plasticity in multiple spinal/supraspinal pathways. Recent studies have shown that MEP operant up-conditioning can increase the corticospinal excitability for the targeted muscle in people with SCI in the UE and lower extremity (LE) and in the LE of multiple sclerosis. For the aim 1 of the project, MEPs elicited by TMS will be applied at the hot spot for the wrist ECR. EMG signal from 15 UE muscle will be collected simultaneously during isometric force generation tasks. This aim will enroll 10 age-matched (age of 40-75 yo) healthy adult and 10 adult (age of 40-75 yo) stroke survivors. Each participant will have a single measurement session. For the aim 2 of the project, 4 randomized out of 10 stroke survivors will perform operant conditioning method of the wrist ECR; also, assessment of the intermuscular coordination, UE Fugl-Meyer (FM), and Action Research Arm Test (ARAT) will be performed. Participants will have three visits per week for 10 weeks for training session. Finally, to test retention of the intervention effect, they will perform two assessment sessions one and three months after finishing the training.
Interventions
MEPs elicited by TMS will be applied at the hot spot for the wrist extensor carpi radialis. During training trials, participants will be asked to increase the size of their MEP response. During assessment trials, a physical therapist or occupational therapist will rate the functional level of arm impairment using FMA and ARAT.
Sponsors
National Center of Neuromodulation for Rehabilitation
University of Houston
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
40 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
for aged matched healthy group * Male or female whose age range between 40 and 75 * no known neurological injuries
Exclusion criteria
for aged matched healthy group * have an orthopedic disorder involving upper limbs; * have a history of any neurologic disease; * have any history of epilepsy of the potential participants and/or their family members; * had an adverse reaction to TMS; * are unable to consent; * are pregnant. Inclusion criteria for stroke group * male or female hemiparetic chronic stroke survivors; * age ranging between 40-75 year; * with single unilateral ischemic or hemorrhagic middle cerebral artery stroke; * neurologically stable for \>6 months; * have an expectation that current medication will be maintained without changes for at least 3 months. Stable use of anti-spasticity medication (e.g., baclofen, diazepam, tizanidine) is accepted; * with moderate-to-severe impairments (FMA\<45/66); * with weak wrist extension (i.e., \<4 by manual muscle strength test); * eligible to receive transcranial magnetic stimulation (TMS), and extensor carpi radialis (ECR) motor evoked potential (MEP) must be present in the more affected arm; * without severe spasticity (Modified Ashworth (MA) \<4); * have not received botulinum toxin on the impaired arm within 3 months.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in intermuscular coordination patterns (ICoPs) | before any training, after the 12th and 24th conditioning sessions, respectively, and 1 and 3 months after the 24th conditioning, respectively | EMGs will be recorded from 15 muscles. To assess whether wrist extensor MEP OC induces changes in the composition of intermuscular coordination patterns, non-negative matrix factorization will be applied to EMGs to identify and compare ICoPs. |
| Change in motor evoked potential (MEP) | before any training, after the 12th and 24th conditioning sessions, respectively, and 1 and 3 months after the 24th conditioning, respectively | To measure the amount of the corticospinal excitability of the target muscle (extensor carpi radialis) and its antagonist (flexor carpi radialis), MEPs will be elicited while the participant provides \ 30% maximum voluntary contraction level of each muscle background electromyographic (EMG) signals. For all trials, transcranial magnetic stimulation at \ 10% above active motor threshold at the optimum location of the cortex will be used to elicit the MEP. |
| Change in Fugl-Meyer Assessment (FMA) score | Time Frame: before any training, after the 12th and 24th conditioning sessions, respectively, and 1 and 3 months after the 24th conditioning, respectively | To measure severity of motor impairment after stroke, FMA will be performed in the human upper extremity. FMA is commonly used to assess severity of motor impairment and motor recovery. The maximum FMA upper extremity motor score is 66 (i.e., 0: complete motor impairment; 66: normal motor performance). Each item is scored on a 3-point scale (0 = cannot perform, 1 = performs partially, 2 = performs fully). |
| Change in Action Research Arm Test (ARAT) score | before any training, after the 12th and 24th conditioning sessions, respectively, and 1 and 3 months after the 24th conditioning, respectively | To measure motor function after stroke, ARAT will be performed in the human upper extremity. 19 Items comprising the ARAT are categorized into four subscales (grasp, grip, pinch, and gross movement) and arranged in order of decreasing difficulty, with the most difficult task examined first, followed by the least difficult task. Task performance is rated on a 4-point scale, ranging from 0 (no movement) to 3 (movement performed normally). |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in force errors that occur during isometric wrist force tracking tasks | before any training, after the 12th and 24th conditioning sessions, respectively, and 1 and 3 months after the 24th conditioning, respectively | As a mechanistic outcome, force errors that occur during isometric wrist force tracking tasks (ramp up-hold-ramp down) will be recorded to assess wrist motor control function that can change as corticospinal excitability increases through MEP up-conditioning. |
Countries
United States
Contacts
Primary ContactJinsook Roh, PhD
Backup ContactManuel A Portilla-Jiménez, MS, BME
Outcome results
None listed