Clinical Neuroplasticity Research

  

Mental Imagery to Reduce Motor Deficits in Stroke

Many stroke survivors have limitations in motor ability and compromised quality of life. Therapeutic interventions designed to enhance motor function and promote independent use of an impaired upper extremity following stroke are limited. There is a need to translate unique behavioral and cognitive techniques shown to have an impact on plasticity in the nervous system into practical, evidence-based, therapeutic interventions. One technique, constraint induced therapy (CIT), has produced results that can substantially reduce the incapacitating deficits of many patients with stroke and can increase their independence. Recent studies have shown that a complementary treatment, mental practice, can improve the performance of motor skills. Investigators have proposed the use of mental practice in physical rehabilitation as a cost-efficient means to promote motor recovery after damage to the central nervous system. The primary purpose of the proposed study is to collect data in an effort to estimate the clinical effectiveness of implementing one form of CIT, repetitive task practice (RTP) in conjunction with mental imagery training (MIT) to improve upper extremity motor function and quality of life of chronic stroke patients. Therefore, we hypothesize that mental imagery of a motor task combined with RTP may lead to decreased upper extremity (UE) impairment and improved UE functional outcome compared to RTP alone, and that common neural structures can be investigated using fMRI. Specific aims will seek to estimate: 1) the effectiveness of using RTP in conjunction with MIT on motor recovery of patients with stroke, 2) the effectiveness of using RTP in conjunction with MIT on health related quality of life of patients with stroke, and 3) the association between changes in the organization of cortical activation maps during the performance of a specific task (executed vs. imagined finger flexion-extension sequence) and improvement in clinical motor function of patients with stroke when receiving RTP + MIT compared to MIT alone. (PI: A. Butler, Sponsor, NIH 5R21AT002138-03)

     

Enhanced Motor Learning Using Brain Stimulation

The core goal of the work proposed is to test if repetitive transcranial magnetic simulation (rTMS) can improve motor recovery after stroke. Experiments will initially test whether short term high frequency rTMS alters the performance of healthy individuals in a speed-accuracy tracking task compared to treatment with a sham rTMS. Experiments will then test whether a shorter term high frequency rTMS alters the performance of patients with stroke in a speed-accuracy tracking task. Finally, testing will elucidate whether daily (5 day per week for 4 weeks) short term high frequency rTMS improves the performance outcome measure in patients with stroke and if this improvement is sustained. A secondary outcome variable will be disability score changes in the group treated daily for 4 weeks. This work is conducted at the Atlanta VA Medical Center, Rehabilitation Research and Development Center (RR&D) (PI: A. Butler, Sponsor: VA B3902)

Improving Upper Limb Function in Stroke Patients by Engaging in Synchronous Tongue Motion

Rehabilitative therapy for those with significant loss of voluntary wrist movement after stroke is limited. If impairment is severe enough, therapists may focus more on training compensatory functional movements without the use of the involved upper extremity so the patient can perform daily tasks and transition to the home. Therapists may also utilize passive treatment modalities, such as stretching and passive range of motion to limit loss of mobility, however these treatments do not engage the neural pathways necessary for neuro-remodeling and repair. To date, the best approach to regain upper extremity voluntary movement seems to be intensive physical therapy (i.e. CIT, robotic and bilateral training). However, the results are limited to those stroke survivors who exhibit a minimum of 10° extension of finger and wrist active range of motion (AROM). Functional gains are often minimal following therapy if patients do not demonstrate this degree of finger extension. Robot-assisted therapy (RT) shows great promise for improving voluntary wrist movement in patients following stroke and has gained increasing popularity in the past 15 years. RT incorporates key elements of motor learning into treatment, including highly intensive, task-specific, reproducible, and interactive practice. Cumulative research evidence and systematic reviews support the efficacy of upper limb RT for improving motor and functional outcomes in stroke patients.  RT has the ability to actively assist wrist and finger extension in stroke survivors who cannot actively perform the movement. Recent advances in therapeutic technology, including a robotic hand therapy device (Hand Mentor, or HM) and a robotic device driven by tongue movements (Tongue Drive System, or TDS), have the potential to broaden the possibilities for attaining meaningful improvements in range of motion and function in this patient population. Similar to that of the fingers and hand, the tongue’s motor cortex provides the tongue with sophisticated motor control with many degrees of freedom, evident in speech and ingestion.  Furthermore, the tongue can move rapidly and accurately in almost every direction within the oral space with the added benefit of fatigue-resistant muscle fibers for extended exercise periods. Although speech is often affected by stroke, patients generally maintain voluntary tongue control. Research has demonstrated that topographical alterations of the brain can shift the motor cortex of the tongue into the region of the hand. By using the TDS-HM, representations in the primary motor cortex will be reorganized to coordinate tongue and hand motion together, thereby establishing a new sensorimotor pathway for the paretic upper limb. If our hypothesis is correct, following a period of exercise, patients will be able to facilitate motor activities without the help of the TDS-HM by simply engaging their voluntary tongue motions in conjunction with desired upper limb movements. The primary purposes of this feasibility study are (1) to determine the effect of wearable tongue drive therapy paired with robotic hand mentor therapy (TDS-HM) on improving upper extremity motor recovery for stroke survivors with severe hemiparesis, and (2) to determine the effect of using TDS-HM therapy on health related quality of life (HRQOL).

Brain Connectivity Using NIRS Changes in Serial Optical Topography during Task Performance after Stroke

Stroke is one of the more common diseases that affect the human brain, and is the leading cause of acquired disability. Once affected, the recovery of neural tissue of human subjects is limited. Advances in rehabilitation medicine have been advocating the evidence of plastic changes of the human brain following treatment. Strategies of rehabilitative therapies to improve motor recovery have been suggested and developed based on research findings of neural plasticity. However, many of these findings were derived from only a few patients who achieved high functioning. It was suggested that there might be different mechanisms of recovery according to the severity of impairment. If the recovery mechanism of one group of patients is different from another, rehabilitation strategies based on one recovery mechanism may not be affective in both groups, and could potentially lead to maladaptive outcomes. Though recent technical advances, such as functional MRI and transcranial magnetic stimulation, make it possible to reveal underlying mechanisms of neural plasticity by human experimentation, each technology has its own merits and drawbacks. One limitation of these technologies is the inability to measure the course of recovery. In both instances, one may measure recovered function at selected time points, but not the recovery process itself. Optical topography is a promising tool that may allow rehabilitation scientists to explore brain recovery in real time during an intervention. The purpose of this proposal is to explore the mechanisms of recovery in terms of cortical reorganization according to severity of stroke, and to compare the plastic changes of the brain during different intensities of rehabilitation. To enhance the efficiency of research, this proposal is designed as a collaborative research initiative between a university in the U.S. and a foreign rehabilitation institute. The results of this research will provide more valid knowledge of cortical reorganization during the rehabilitation process after stroke in a wide range of patients, and in turn stimulate the development of relevant rehabilitation strategies in various patient profiles and various healthcare environments. This work is conducted at the Atlanta VA Medical Center, Rehabilitation Research and Development Center (RR&D) (PI: A. Butler, Sponsor: VA B3902)

Robotic Therapy

The following innovations were selected for funding from Industry Innovation Competitions. The overall purpose of this field test is to evaluate the feasibility of increasing access to stroke therapy results from an existing commercial home-based robotic stroke therapy program. The purpose of this open trial is to evaluate the potential of this system to reduce backlogs and deliver rehabilitation benefits sooner for veterans. Twenty patients (8 in the first year and 12 in the second year) will be recruited over two years. The subjects will have experienced a stroke within the past 24 months and are either waiting for therapy or having difficulty in accessing a therapy program. For selected subjects, the referring physician has determined that either hand function or foot function is a major deterrent for the patient participating in activities of daily living. Patients that conform to the Inclusion and Exclusion Criteria will be given either a Hand Mentor or a Foot Mentor therapy device for use at home for a maximum of 3 months or until they have access to a clinic-based therapy program. The performance of the patient and compliance with treatment are automatically sent to a secure server where they will be monitored remotely by a therapist at least once a week. The therapist will provide feedback on the therapy to each subject through telephone calls as needed. Enrolled subjects will use either a HM or FM in their home until either they are able to participate in a clinic-based stroke rehabilitation program of they have used the robotic stroke therapy device at home for three months. This work is conducted at the Atlanta VA Medical Center, Rehabilitation Research and Development Center (RR&D). Currently this work has been expanded with a partnership with the Office of Rural Health to place therapy devices in the homes of veterans who have experienced a stroke living in highly rural areas in northern Georgia. These participants have great difficulty attending formal therapy sessions in a clinic due to access and location. (PI: A. Butler, Sponsor: U.S. Veterans Administration)

SVIPT: Sequential Visual Isometric Pinch Task

Accurate motor performance is important to almost everything we do, from typing, to driving, to playing sports. Having a motor skill implies a level of performance in a given task that is only achievable through practice. Evidence indicates that motor skill learning can continue over a prolonged time period from days to weeks. The purpose of this study is to examine upper limb motor skill learning over the course of one month in able-bodied individuals.

Participants in this study will perform a Sequential Visual Isometric Pinch Task (SVIPT) first described by Reiss et al. 2009. Volunteers are seated in an arm chair approximately 60 cm in front of a 20 inch monitor and hold a force transducer between the thumb and index finger of the dominant hand. Squeezing the force transducer will move a screen cursor horizontally to the right while relaxing will cause the cursor to move to the left. Upon presentation of a "GO" signal, the goal is to move the cursor quickly and accurately between the start position (home) and a numbered order of gates (Home-1, Home-2, Home-3, Home-4, Home-5). A "STOP" signal appears when stopping at gate 5. Volunteers are asked to complete 200 of these trials per day in 6 blocks during the training and follow up sessions.