Interhemispheric Connectivity and Compensation

Study Overview
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Brief Summary
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The goal of this study is to determine which parts of the brain make it possible for some people to move skillfully with their left non-dominant hand.

Detailed Description
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This is a one-visit study, in which right-handed participants (individuals with unilateral peripheral nerve injury to the right upper limb, and healthy controls) will complete surveys and perform movement tasks. Movement tasks will be performed inside and outside a magnetic resonance imaging (MRI) scanner. Some participants will also receive transcranial magnetic stimulation (TMS) to briefly interfere with these putative brain networks.

Official Title
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Interhemispheric Communication and Compensation in Peripheral Nerve Injury

Conditions
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Peripheral Nerve Injury Upper Limb, Healthy

Intervention / Treatment
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* Other: STEGA-MRI


Participation Criteria
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Eligibility Criteria
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This study contains two groups: typical controls and patients. Participants will be matched by age and sex between the two groups. No randomization will occur. A. Inclusion criteria (all participants): Age ≥ 18 English speaking and reading Able to fit in Prisma scanner bore (60 cm diameter) Right hand dominant (self report, and Edinburgh handedness ≥ +40) B. Inclusion criteria (patients only): Chronic unilateral upper extremity peripheral nerve injury to the right side Chronic defined as ≥ 6 months since injury Upper extremity defined as hand, arm, or shoulder (including e.g. brachial plexus) Injury defined as localized cause (e.g. mechanical/tumor, not distributed pathology), including compression Some impairment to writing, requiring both of: Difficulty writing, as determined by score 2+ (Mild+) on How much difficulty have you had in the last week with writing? (From Disabilities of the Arm, Shoulder, and Hand survey question #2) Box and Blocks motor performance ≥1 standard deviation below the mean of age-matched healthy adults (Mathiowetz et al. 1985, AJOT). C. Exclusion criteria (all participants) Currently intoxicated or otherwise non-compliant Chronic pain diagnosis unrelated to the nerve injury Uncorrected visual impairment that interferes with ability to see drawings in MRI Motor function diagnoses that affect function of the left hand, now or in past 2 years Motor function diagnoses currently affecting the right hand, unrelated to the nerve injury This is not meant to exclude a single event with complex consequences (e.g. nerve and tendon) This is not meant to exclude multiple nerve injuries in the same arm, if each one is eligible (II.B.1) This is meant to exclude e.g. injury and unrelated musculoskeletal disorder in same arm Upper extremity surgery, including peripheral nerve surgery, within last 2 months Contraindication for MRI Contraindication for transcranial magnetic stimulation (TMS) May exclude from TMS only (since not all participants undergo TMS), or exclude from full study Amputation affecting any part of thumb, index, or middle fingers (including higher level, e.g. whole hand) History of chronic cocaine use (based on medical record or volunteered; will not actively inquire) Diagnosis of schizophrenia or other rare psychiatric disorder This is not meant to exclude depression or anxiety History of major neurological diagnosis, e.g. stroke, traumatic brain injury, Alzheimer's, Parkinson's This is not meant to exclude concussion UNLESS < 6 months ago, or post-concussion syndrome (diagnosed or self-report) D. Exclusion criteria (controls only) 1. Motor function diagnoses that affect function of either hand, now or in past 2 years

Ages Eligible for Study
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Minimum Age: 18 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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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Interventional Model Description: The only intervention is the movement task. All participants receive the same task.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Movement task<br>All participants perform the STEGA-MRI (standardized tracing evaluation & grapheme assessment - MRI) precision drawing task during fMRI scanning. Motor assessments outside the MRI do not qualify as interventions. | Other: STEGA-MRI<br>* Precision drawing task (movement assessment)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| BOLD (blood oxygen level dependent) signal in ROIs (regions of interest) | BOLD signal in key ROIs (primary motor and posterior parietal cortex). ROI selection may be revisited after preliminary data review (35 participants) | Day 1 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Drawing smoothness | Velocity smoothness in STEGA-MRI (Standardized Tracing Evaluation and Grapheme Assessment - MRI version) task | Day 1 | 
| Hand choice | Percentage of grasps made with right hand | Day 1 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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laterality of motor control, movement, functional magnetic resonance imaging, functional laterality