Sensorimotor impairments following stroke can lead to substantial disability involving the upper extremity. These impairments often involve complex pathological changes across multiple joints and multiple degrees-of-freedom (MJMD) of the arm and hand, thereby rendering them difficult to diagnose and to treat. Many potential mechanisms, such as weakness, motoneuronal hyperexcitability, and elevated passive impedance, can contribute to the impairment, thereby making it difficult to discern where best to focus treatment. The objectives of this study are to quantify the progression of neuromechanical properties throughout the upper extremity during recovery from stroke.
The aim of this study is to examine neuromechanical properties throughout the entire upper extremity in stroke survivors over a period of 6 months and throughout the progression from the acute to the subacute to the chronic phases of recovery. The researchers hypothesize that excessive local and cross-coupled stiffness, heteronymous reflexes, and diminished individuation and proprioceptive acuity will be present among multiple DOFs in the upper limb. The stiffness and spasticity will increase with time post-stroke.
BACKGROUND AND SIGNIFICANCE Stoke is the leading cause of adult disability and the third leading cause of death (killing 160,000 Americans/year) in the United States; about 750,000 first ever and recurrent strokes occur in the United States each year. The economic burden is huge, and stroke is estimated to cost the United Stated $62.7 billion in medical expenses and lost wages. Stroke is commonly associated with motor-related disabilities. Motor impairments in stroke survivors typically affect the shoulder, elbow, wrist, and fingers of the arm simultaneously. Patients may develop spastic hypertonia and reduced range of motion (ROM) at multiple joints. Several stereotypical patterns of arm impairments with multiple joints involved are commonly seen in patients with neurological impairments, including adducted/internally rotated shoulder, flexed elbow, pronated forearm, flexed wrist, and clenched fist. Furthermore, the impaired arm of a stroke survivor commonly develops abnormal coupling among multiple joints and among multiple DOFs (e.g. shoulder abduction, flexion, and rotation) at a given joint. Stroke survivors may lose independent movement of individual joints and appropriate coordination among joints. There is a strong need to treat stereotypical deformity, impairment of hypertonic arms and multiple involved joints simultaneously on a frequent basis to reduce spasticity/contracture and increase mobility in those who have had a stroke, which will be address in the proposed study.
METHODS The aim of this study will be addressed through a longitudinal evaluation of stroke survivors over the first 6 months following their stroke. Specifically, upper extremity control and neuromechanical properties will be measured at up to 7 different time points over 6 months.
Selection of Subjects Twenty-four stroke survivors will be recruited over the 5 years of the study. All participants will be in the acute phase of recovery at time of enrollment from a first-ever focal unilateral lesion (ischemic or hemorrhagic) as diagnosed by MRI or CT. Participants will be recruited from the inpatient population at RIC and Northwestern Memorial Hospital.
Subjects will be asked to come to our labs at the Rehabilitation Institute of Chicago to be consented and participate in an initial screening. Designated study personnel will obtain consent and complete the screening visit. If qualified and enrolled, the subject will be asked to complete 7 evaluations at times indicated in Outcome Measures Section.
Subject participation will last for 6 months total. If the subject has persistent or severe pain, he/she will not continue until he/she feels sufficiently recovered enough and continued participation is deemed appropriate by a clinician.
Evaluation and Measurement In an initial screening session, after the subject has been consented, a clinician will check the subject's health status and conduct several clinical assessments to determine if the subject meets the inclusion and exclusion criteria. The screening evaluations will take about one half hour.
If the subject qualifies for the study, they will participate in evaluation sessions at 7 time points spaced throughout the study. For each evaluation session he/she will be asked to come to our laboratories on the 13th floor of the Rehabilitation Institute of Chicago. Evaluation of subjects will have neuromechanical and clinical components; the neuromechanical components of the evaluation will take approximately two hours and the clinical components will also take approximately two hours. Clinical and neuromechanical evaluations may be spilt into two separate visits.
Neuromechanical evaluations The neuromechanical portion of the evaluation the subject will sit upright comfortably on a sturdy barber's chair, with the trunk trapped to the backrest. The arm, forearm and hand will be strapped to their corresponding braces with the relevant axes of the IntelliArm aligned with the arm at the shoulder, elbow, wrist, and fingers. The position of the elbow, wrist, and finger servomotors can be adjusted for different arm, forearm and hand lengths. The subject's arm will be moved at different speeds including one joint at a time and multiple joints simultaneously. Similarly, the subject will be asked to move his/her arm one joint at a time and multiple joints simultaneously. During the evaluation sessions, signal from the subject's muscles called electromyography (EMG) may be recorded to monitor activities of the subject's upper limb muscles. The skin over the muscle belly will be cleaned with an alcohol pad and may be shaved by disposable razors. Self-adhesive electrodes will be placed on the cleaned sites and connected to the instrument and computer. The electrodes are just used for recording the signal generated by the muscles and the subject will not feel any shocks during the evaluations. Non-invasive electroencephalography (EEG) electrodes may be attached on the scalp to record brain activity signals. A video or some photos may be taken as an option to evaluate the movement patterns during the evaluations.
In diagnosing the multi-joint and multi-DOF biomechanics changes, the IntelliArm will operate both passive and active modes. In the passive mode, the multi-joint arm robot will move the shoulder, elbow, and wrist of the impaired arm of stroke survivors throughout the ROMs both simultaneously and individually in well-controlled patterns with multi-axis torques and positions measured at the should, elbow and wrist simultaneously. In the active mode, the patient will move the impaired arm voluntarily and the multi-joint and multi-DOF dynamic properties will be measured at the shoulder, elbow and wrist simultaneously.
Measures of stiffness and of hyperexcitability of the long finger flexor muscles, namely spasticity and relaxation time, will be made using techniques we have implemented successfully in the past. Spasticity of finger muscles will be measured as the reflex response to imposed rotation of the metacarpophalangeal (MCP) joints of the four fingers. A servomotor will create either fast MCP rotation (300°/s) to invoke a stretch reflex or slow constant-velocity rotation (10°/s) to measure nominally passive stiffness. Wrist orientation will be fixed with a fiberglass cast which is subsequently clamped to a table to prevent arm translation. MCP angle, angular velocity, and torque are recorded for analysis of spasticity. EMG recordings will be obtained with surface electrodes (Bagnoli, Delsys, Inc., Boston, MA) from selected superficial muscles such as extensor digitorum communis (EDC) and flexor digitorum superficialis (FDS). Relaxation time will be quantified by examining FDS activity. The subject will be instructed to maximally grip a dynamometer upon hearing an audible tone. The subject should then relax his grip as quickly as possible after hearing a second tone. The relaxation time is defined as elapsed time from the second tone to the point at which the FDS magnitude returns to the baseline level + three standard deviations.
Clinical evaluations During clinical evaluations subjects will undergo a battery of standardized clinical assessments. These assessments require subjects to complete functional movements and tasks using their arms and hands.
Potential additional evaluations Additionally, subjects may be asked to wear a small motion tracker (datalogger) for up to 6 hours. This will record the subject's arm movements in his/her own living environment, thereby providing a measure of real-world activity, taking personal and environmental factors into consideration. The datalogger consists of motion sensors, that attach to the subject's arm via straps, and a small recorder that can clip on to the belt. The subject will take the datalogger home. After wearing it for the time described above, the subject will take the datalogger off (as instructed during the evaluation session in our lab) and return it at the next training session.
As an option, changes in corticospinal activation may be evaluated using transcranial magnetic stimulation (TMS) in some subjects, provided the subjects meets inclusionary/exclusionary criteria, such as no implanted cardiac pacemaker or metal implants in the head/face. TMS is used to evaluate corticomotor excitability. It is delivered via Magstim BiStim stimulator (Magstim Co, Dyfed, UK) that will be used to deliver stimuli via a figure-of-eight coil (70mm windings). Responses will be examined in bilateral muscles using surface electrodes. While stimulating over the affected (or unaffected) hemisphere, motor evoked potentials (MEPs) are recorded over the muscles contralateral to the affected (or unaffected) hemisphere. The participants are seated comfortably during the evaluation. Foam earplugs are inserted into the patient's external ear canals to attenuate the stimulator discharge sound. Surface electromyography electrodes are placed over the muscles bilaterally for recording TMS MEP responses.
Protection Against Risk:
A number of safeguards have been implemented. Mechanical/electrical stops will be used to restrict the motion of the robots to safe ranges. Velocity limits will also be set to restrict the speed of the movement. Joint angle, velocity, and force will be monitored continuously to ensure they fall within the appropriate range. Exceeding the thresholds will result in motor shut-down. Additionally, the motors can be turned off at any time using an accessible on/off switch to protect from discomfort or potential injuries. The IntelliArm and the hand jig have previously been used safely with a number of stroke survivors. Rest breaks will be provided as needed during therapy to prevent excessive muscle soreness and fatigue.
A cast saw will be used to remove the fiberglass cast used in evaluations. Improper use of the saw could produce a burn. Project staff has been trained in the operation of the saw and proper procedures to follow. Adhesive used to secure the surface electrode could irritate the skin. The skin will be carefully prepared before applying the electrode and then cleaned when the electrode is removed.
Specific to TMS, although rare instances of seizure have been reported when long trains of high frequency excitatory TMS were applied, these events have not been reported when recommended guidelines have been followed. The parameters proposed in this study are well within these published safety guidelines, and individuals who've suffered stroke are one of the most commonly requited populations for TMS studies. Providing they have never had a seizure and do not meet any of the other exclusion criteria listed above, they are a clinical population to which TMS can be safely applied.
To relate and find the relationship between physiological data and functional performance, the data will be evaluated using a) biomechanics data analysis, b) correlation and principle component analysis, c) regression, d) Rasch analysis, and e) structural equation modeling. Physiological data obtained from the IntelliArm (e.g. abnormal coupling between the joints/DOFs, passive workspace and active workspace, multiple joint DOF/stiffness) will be analyzed to describe and characterize the arm impairment. Similar measures will be obtained for the fingers to characterize hand impairment. We will especially examine how these measures change over time. Curves will be fit to the data to approximate functions describing the changes in neuromechanical measurements over time. Similarly, the scores from the clinical evaluations (GWMFT, ARAT, FMUE, MAS) will be assessed over the time course of the recovery period.
The potential relationships among the physiological data and the clinical data are of special interest. To determine the proper physiological measurements in stroke progression and to relate them to functional performances, correlation analysis and principal component analysis will be conducted as initial steps to find which physiological variables have high correlations with functional measures and cluster together as similar indicators. Those potential indicators will be filtered through data reduction procedures and then used in a multiple regression analysis to predict functional outcomes at the activity level (assessed by GWMFT, ARAT) and participation level (assessed by the datalogger) with adjusted person information and environmental factors serving as categorical variables. Rasch analysis will be used to evaluation the item difficulty hierarchy and item fit to link the subject's functional ability level with specific functional tasks. This will help to find the clinical potential thresholds/cut-off points if there is a consistent pattern between the physiological data and functional measures. Furthermore, an ICF model will be evaluated using structural equation modeling, which can test a set of regression equations simultaneously and exam the relationship among the impairment ability, participation variables with the personal and environmental factors taken into consideration.
Data Collection and Record Keeping:
Designated study personnel will enter de-identified data into a password protected computer. Paper records of any kind collected during evaluation and treatment sessions will be stored in a locked cabinet. Data will be kept for 3 years after the end of the study and then destroyed by a secure document destruction service.
- Observation: Cohort
- Perspective: Prospective
- Sampling: Non-Probability Sample
patients at a rehabilitation hospital, patients at an acute care hospital, patients from outpatient clinics, patients from day rehabilitation programs.
|Type||Measure||Time Frame||Safety Issue|
|Primary||Fugl-Meyer Upper Extremity (FMUE) - 2 weeks Post||2 weeks Post Stroke||No|
|Primary||Fugl-Meyer Upper Extremity (FMUE) - 1 month Post||1 month Post Stroke||No|
|Primary||Fugl-Meyer Upper Extremity (FMUE) - 2 months Post||2 months Post Stroke||No|
|Primary||Fugl-Meyer Upper Extremity (FMUE) - 3 months Post||3 months Post Stroke||No|
|Primary||Fugl-Meyer Upper Extremity (FMUE) - 4 months Post||4 months Post Stroke||No|
|Primary||Fugl-Meyer Upper Extremity (FMUE) - 5 months Post||5 months Post Stroke||No|
|Primary||Fugl-Meyer Upper Extremity (FMUE) - 6 months Post||6 months Post Stroke||No|
|Secondary||Graded Wolf Motor Function Test (GWMFT) - 2 weeks Post||2 weeks Post Stroke||No|
|Secondary||Graded Wolf Motor Function Test (GWMFT) -1 month Post||1 month Post Stroke||No|
|Secondary||Graded Wolf Motor Function Test (GWMFT) - 2 months Post||2 months Post Stroke||No|
|Secondary||Graded Wolf Motor Function Test (GWMFT) - 3 months Post||3 months Post Stroke||No|
|Secondary||Graded Wolf Motor Function Test (GWMFT) - 4 months Post||4 months Post Stroke||No|
|Secondary||Graded Wolf Motor Function Test (GWMFT) - 5 months Post||5 months Post Stroke||No|
|Secondary||Graded Wolf Motor Function Test (GWMFT) - 6 months Post||6 months Post Stroke||No|
|Secondary||Arm Stiffness - 2 weeks Pos Stroke||2 weeks Post Stroke||No|
|Secondary||Arm Stiffness - 1 month Post||1 month Post Stroke||No|
|Secondary||Arm Stiffness - 2 months Post||2 months Post Stroke||No|
|Secondary||Arm Stiffness - 3 months Post||3 months Post Stroke||No|
|Secondary||Arm Stiffness - 4 months Post||4 months Post Stroke||No|
|Secondary||Arm Stiffness - 5 months Post||5 months Post Stroke||No|
|Secondary||Arm Stiffness - 6 months Post||6 months Post Stroke||No|
|Secondary||Spasticity of Finger Flexors - 2 weeks Post||2 weeks Post Stroke||No|
|Secondary||Spasticity of Finger Flexors - 1 month Post||1 month Post Stroke||No|
|Secondary||Spasticity of Finger Flexors - 2 months Post Stroke||2 months Post Stroke||No|
|Secondary||Spasticity of Finger Flexors - 3 months Post Stroke||3 months Post Stroke||No|
|Secondary||Spasticity of Finger Flexors - 4 months Post Stroke||4 months Post Stroke||No|
|Secondary||Spasticity of Finger Flexors - 5 months Post Stroke||5 months Post Stroke||No|
|Secondary||Spasticity of Finger Flexors - 6 months Post Stroke||6 months Post Stroke||No|