Brain Control of Movements in Cerebral Palsy
This study will examine how the brain controls movements in patients with certain types of cerebral palsy. In healthy people, one side of the body usually controls movements on the other side of the body. In patients with cerebral palsy, this pattern may be altered, and one side of the brain may control movements on the same side of the body. Information obtained from this study may lead to improved rehabilitation therapy strategies for patients with cerebral palsy.
Healthy volunteers and patients with cerebral palsy between 6 and 18 years of age may be eligible for this study. All candidates will be screened with a medical history, physical examination, and psychological testing. In addition, patients with cerebral palsy will have hearing and vision tests, a review of their medical records, and a magnetic resonance imaging (MRI) scan if one has not been done within the past year. For this test, the patient lies on a table that slides into a narrow metal cylinder with a strong magnetic field (the scanner). The scanning time usually lasts between 45 and 90 minutes.
Patients enrolled in the study also will be evaluated by a physiatrist and physical and occupational therapists. They will be examined for muscle stiffness and reflexes. Their gait and movements (e.g., how they pick up a glass of water) will be evaluated. They will be asked about their ability to perform activities around the house and at school and whether a wheelchair or walker is needed to get around. Patients may also be asked about how they are dealing with their movement problems and how it affects their caregivers.
All participants will undergo three tests, described below, to evaluate movement control. The first two tests use electrodes (small metal discs) taped to the skin over the muscles in both hands to measure muscle activity. A small disc placed on the fingers detects and measures the hand movements. The third test uses magnetic pulses that stimulate the brain to study how the brain controls movements.
- Quantitative test of fine motor function: For this test, the subject taps buttons at different speeds on a box attached to a computer. The test is similar to playing simple computer games.
- Long latency reflexes: For this test, the subject's hand is lightly strapped into a holder that holds the hand still while a motor moves the index finger with sudden small movements. These reflexes may also be tested using a gentle shock to the finger delivered through a ring electrode.
- Transcranial magnetic stimulation: For this test, the subject sits in a comfortable chair. An insulated coil is held on the scalp. A magnetic pulse from the coil stimulates the brain. The subject may hear a click and feel a snap or pulling sensation on the scalp under the coil. The stimulation may also cause twitching in the muscles of the arm or leg. During the stimulation, the subject may be asked to move certain muscles or perform other simple actions.
|Official Title:||Brain Reorganization in Cerebral Palsy|
|Study Start Date:||January 2004|
|Estimated Study Completion Date:||December 2007|
Although the capacity of the immature nervous system to recover after injury is superior to that of the adult brain, children with cerebral palsy carry a great burden of morbidity for their entire life. Functional outcome may be determined not only by characteristics of the lesion (size, location, and timing) but also by the response of the brain to the lesion (cortical re-organization). Little is known about how underlying limitations, such as inefficient cortical re-organization, affect functional outcome and response to therapy in children with cerebral palsy. Because of this, individual rehabilitation strategies are based solely on the level of functioning rather than on the underlying impairment. Research demonstrates that novel rehabilitation strategies can manipulate plasticity of the motor cortex and, in this way, improve functional outcome in adults who have suffered a stroke. There is preliminary evidence that these treatments may also benefit patients with cerebral palsy. However, cortical re-organization after an injury to the developing brain may not be similar to that which occurs after a stroke in the adult brain. It would be of benefit to have a greater understanding of the impairments that arise from inefficient cortical re-organization in children with cerebral palsy. It is also important to have the research methodology to assess the effect of these novel treatments in order to measure their true benefit.
Cortical re-organization can lead to enhanced participation of the unaffected hemisphere via anomalous ipsilateral corticofugal motor projections. Recent evidence suggests that this form of neural re-organization may not be efficient. Three different types of ipsilateral projections are thought to exist: 1) fast-conducting developmental ipsilateral projections that persist beyond the age at which they normally disappear; 2) slow-conducting ipsilateral tracts present in healthy subjects that become more accessible after injury; 3) fast-conducting projections that arise de novo from the ipsilateral primary motor cortex after injury to the developing brain. Each type has a distinct neurophysiologic profile that can be characterized using transcranial magnetic stimulation (TMS) and electromyography (EMG).
To date, the relationship between anomalous ipsilateral corticofugal motor projections and functional outcome has not been examined in detail. There is preliminary evidence that the presence of these anomalous ipsilateral projections is associated with poor outcome, suggesting that they represent an inefficient cortical re-organization process. In addition, the anomalous projections that arise de novo from the ipsilateral primary motor cortex appear to have the worst prognosis. The proposed research study will characterize anomalous ipsilateral corticofugal motor projections in a group of children with spastic hemiplegia and spastic diplegia subtypes of cerebral palsy using TMS and EMG. We will evaluate functional limitations of the hand in these children and will examine the relationship between each type of ipsilateral pathway and functional outcome. In this way, it will be possible to determine which anomalous ipsilateral projections are associated with poor function in patients with cerebral palsy.
This study will increase our understanding of the functional significance of these ipsilateral projections and will make it possible to identify these ipsilateral projections in individual children. The neurophysiologic techniques developed in this study will provide essential research methodology to assess brain re-organization before and after novel therapeutic approaches.
|United States, District of Columbia|
|Childrens National Medical Center|
|Washington, District of Columbia, United States|
|Georgetown University Medical Center|
|Washington, District of Columbia, United States|