Investigaciones fisiológicas de los trastornos del movimiento

Healthy Volunteers

Transcranial direct current stimulation involves the application of weak direct currents, delivered between two surface electrodes, placed over the scalp.

The purpose of this device is to assess eye movement. Participants may sit down in front of a computer screen or a real-world environment, stand on a treadmill, or lie down in an MRI scanner. Small infrared cameras attached to the cap or glasses will be positioned in front of their eyes. Eye tracking might be performed alone, or in conjunction with EEG, EMG, fMRI or treadmill. The eye- tracking device is FDA approved and commercially available.

This device would be used in experiments to see if gait can be improved and, if so, what parameters of stimulation are optimal.

The Gait Trainer is a specialized rehabilitation treadmill, which operates in both the forward and backwards mode allowing subjects to both train and undergo performance tasks in a relatively safe and expedient manner. The GTT is equipped with a mounted deck with built in sensors which monitors and records subjects gait speed, step length, right to left time distribution, and symmetry in real time in both forward and reverse modes.

Scales of motor function, cognitive function and psychiatric function are valuable supplements to clinical assessments of patients, giving quantitative information concerning these different aspects of brain function. Selected scales would be used only when potentially useful in a sub-study where such quantitative information would be correlated with a physiological or imaging result.

This test uses the iMobility system. iMobility Device is a small device designed to measure movement through sensors (test monitors) worn by a patient via Velcro straps around an ankle or wrist or worn as a pendant around the neck to lie over the sternum. The device is a nonsignificant risk device.The iMobility Device has been used before, in the same format with a similar paradigm, in previous NIH studies.

The purpose of this study is to assess the ability of the QMAT (quantitative motor assessment tool) to assess slowness of movement associated with Parkinson Disease. The QMAT device is FDA approved and has been used before, in the same format with a similar paradigm, in previous NIH studies.

Subjects will be fitted in a weight support harness for safety. Sensors will be placed on the subject s shoes and harness. The sensors (VICON system) will be used to record their stride length, position and velocity as they walk on a treadmill. This system is a motion-tracking system that is designed to measure various aspects of a person s gait.

The purpose of the Arm Intellistretch device is to objectively quantify wrist tone. It is used for rehabilitation applications in hospitals and office settings. Currently, rigidity is evaluated clinically using a subjective scale, zero to four and is part of the UPDRS. The Arm Intellistretch device is manufactured by Rehabtek, Inc., is FDA approved, and has been determined to be a non-significant risk device by the CNS IRB.

Transcranial sonography will be conducted by a physician in the Clinical Center using the Acuson Antares ultrasound machine. This techniques uses ultrasound signals to image the brain. It entails having the subject sit in a chair or lay in a bed while the sonographer places a lubricated 2-inch ultrasound probe over the skin of the temporal area just above the patient s ear. Ultrasound images are then recorded. The procedure is not invasive and will last about 45 minutes.

To assess the changes in cerebral physiology in the brain, subjects will be presented sensory stimuli (e.g., primary visual stimulation with flashing lights or checkerboard, auditory with tone or speech, or olfactory stimuli), or will be asked to perform non-exercise motor tasks (e.g., tapping of fingers, squeezing ball, moving joystick), to perform cognitive tasks such as a working memory task (e.g., n-back with or without catch rules, word finding), or to just rest or sleep.

For MEP acquisition during TMS, electrodes will be placed over the belly and the tendon of the distal muscles of the hand or foot and/or proximal muscles (see sub-section EMG 7.1.3.1 for the details of the procedure).

MEG recordings will be performed together with experienced personnel in the NIMH MEG lab in the NMR center in Building 10. For these recording sessions, subjects will sit in a chair or lay down with a helmet placed over the head. The helmet used for MEG does not require the application of conductive gel. Scan times vary from 20 minutes to 2 hours.

EEGs will be recorded by, or together with, experienced personnel in the HMCS EEG lab in Building 10, or in the NMR center.

MRI sub-studies will be conducted on 3.0 T or 7T units in the NMR Research Center. All volunteers will comply with the yearly requirement of a standard clinical diagnostic MRI scan of the head performed at 3.0T, to be submitted to the Diagnostic Radiology Department of the Clinical Center for interpretation. If the subject does not have a clinical scan performed within 12 month of the exam, a standard clinical MRI will be performed and reviewed before the research MR. The standard examination takes approximately 15 minutes to complete; after that, the research MR scans will be performed. Standard clinical MRI of the head will be repeated on an annual basis and read by the Diagnostic Radiology Department of the Clinical Center.

Constant-current, 0.1 to 0.5 ms square-wave single pulses of electrical stimulation will be delivered through standard bar electrodes to nerves of the upper limb or of the lower limb. To study somatosensory evoked potentials, for example, the stimulus intensity will be set at just above the motor threshold for evoking a slight limb movement. Location of the electrical stimulation will depend on the specific objective of the sub-study. Peripheral nerve stimulation might be delivered during other types of experiments as well.

EMG measures the electrical activity of muscles. For our research purposes, only surface EMG will be used to measure the effects of central and peripheral nervous system stimulation. For surface EMG, electrodes will be coated with a conductive gel and taped to the skin. For motor evoked potential (MEP) acquisition during TMS, electrodes will be placed over the belly and the tendon of the distal muscles of the hand or foot and/or proximal muscles.

Direct current (DC) stimulation is a non invasive tool used to promote plasticity of the central nervous system. Recently, DC stimulation has been applied to the human spinal cord, and known as transcutaneous spinal direct current stimulation (tsDCS).

Subjects diagnosed with movement disorder

Transcranial direct current stimulation involves the application of weak direct currents, delivered between two surface electrodes, placed over the scalp.

The purpose of this device is to assess eye movement. Participants may sit down in front of a computer screen or a real-world environment, stand on a treadmill, or lie down in an MRI scanner. Small infrared cameras attached to the cap or glasses will be positioned in front of their eyes. Eye tracking might be performed alone, or in conjunction with EEG, EMG, fMRI or treadmill. The eye- tracking device is FDA approved and commercially available.

This device would be used in experiments to see if gait can be improved and, if so, what parameters of stimulation are optimal.

The Gait Trainer is a specialized rehabilitation treadmill, which operates in both the forward and backwards mode allowing subjects to both train and undergo performance tasks in a relatively safe and expedient manner. The GTT is equipped with a mounted deck with built in sensors which monitors and records subjects gait speed, step length, right to left time distribution, and symmetry in real time in both forward and reverse modes.

Scales of motor function, cognitive function and psychiatric function are valuable supplements to clinical assessments of patients, giving quantitative information concerning these different aspects of brain function. Selected scales would be used only when potentially useful in a sub-study where such quantitative information would be correlated with a physiological or imaging result.

This test uses the iMobility system. iMobility Device is a small device designed to measure movement through sensors (test monitors) worn by a patient via Velcro straps around an ankle or wrist or worn as a pendant around the neck to lie over the sternum. The device is a nonsignificant risk device.The iMobility Device has been used before, in the same format with a similar paradigm, in previous NIH studies.

The purpose of this study is to assess the ability of the QMAT (quantitative motor assessment tool) to assess slowness of movement associated with Parkinson Disease. The QMAT device is FDA approved and has been used before, in the same format with a similar paradigm, in previous NIH studies.

Subjects will be fitted in a weight support harness for safety. Sensors will be placed on the subject s shoes and harness. The sensors (VICON system) will be used to record their stride length, position and velocity as they walk on a treadmill. This system is a motion-tracking system that is designed to measure various aspects of a person s gait.

The purpose of the Arm Intellistretch device is to objectively quantify wrist tone. It is used for rehabilitation applications in hospitals and office settings. Currently, rigidity is evaluated clinically using a subjective scale, zero to four and is part of the UPDRS. The Arm Intellistretch device is manufactured by Rehabtek, Inc., is FDA approved, and has been determined to be a non-significant risk device by the CNS IRB.

Transcranial sonography will be conducted by a physician in the Clinical Center using the Acuson Antares ultrasound machine. This techniques uses ultrasound signals to image the brain. It entails having the subject sit in a chair or lay in a bed while the sonographer places a lubricated 2-inch ultrasound probe over the skin of the temporal area just above the patient s ear. Ultrasound images are then recorded. The procedure is not invasive and will last about 45 minutes.

To assess the changes in cerebral physiology in the brain, subjects will be presented sensory stimuli (e.g., primary visual stimulation with flashing lights or checkerboard, auditory with tone or speech, or olfactory stimuli), or will be asked to perform non-exercise motor tasks (e.g., tapping of fingers, squeezing ball, moving joystick), to perform cognitive tasks such as a working memory task (e.g., n-back with or without catch rules, word finding), or to just rest or sleep.

For MEP acquisition during TMS, electrodes will be placed over the belly and the tendon of the distal muscles of the hand or foot and/or proximal muscles (see sub-section EMG 7.1.3.1 for the details of the procedure).

MEG recordings will be performed together with experienced personnel in the NIMH MEG lab in the NMR center in Building 10. For these recording sessions, subjects will sit in a chair or lay down with a helmet placed over the head. The helmet used for MEG does not require the application of conductive gel. Scan times vary from 20 minutes to 2 hours.

EEGs will be recorded by, or together with, experienced personnel in the HMCS EEG lab in Building 10, or in the NMR center.

MRI sub-studies will be conducted on 3.0 T or 7T units in the NMR Research Center. All volunteers will comply with the yearly requirement of a standard clinical diagnostic MRI scan of the head performed at 3.0T, to be submitted to the Diagnostic Radiology Department of the Clinical Center for interpretation. If the subject does not have a clinical scan performed within 12 month of the exam, a standard clinical MRI will be performed and reviewed before the research MR. The standard examination takes approximately 15 minutes to complete; after that, the research MR scans will be performed. Standard clinical MRI of the head will be repeated on an annual basis and read by the Diagnostic Radiology Department of the Clinical Center.

Constant-current, 0.1 to 0.5 ms square-wave single pulses of electrical stimulation will be delivered through standard bar electrodes to nerves of the upper limb or of the lower limb. To study somatosensory evoked potentials, for example, the stimulus intensity will be set at just above the motor threshold for evoking a slight limb movement. Location of the electrical stimulation will depend on the specific objective of the sub-study. Peripheral nerve stimulation might be delivered during other types of experiments as well.

EMG measures the electrical activity of muscles. For our research purposes, only surface EMG will be used to measure the effects of central and peripheral nervous system stimulation. For surface EMG, electrodes will be coated with a conductive gel and taped to the skin. For motor evoked potential (MEP) acquisition during TMS, electrodes will be placed over the belly and the tendon of the distal muscles of the hand or foot and/or proximal muscles.

Direct current (DC) stimulation is a non invasive tool used to promote plasticity of the central nervous system. Recently, DC stimulation has been applied to the human spinal cord, and known as transcutaneous spinal direct current stimulation (tsDCS).

analyze measures such as the amplitude of the BOLD signal (fMRI); tractography between seed and target regions of interest (using DTI); morphometry of brain regions (using VBM); and different neurotransmitter levels in brain regions of interest (using MRS).

quantify measures such as event- or task-related potentials, synchronization/desynchronization, and coherence between sensors or sources located close to the brain areas of interest.

analyze measures such as MEP amplitude and central conduction time.

quantify measures such as reaction times to initiate movements, EMG patterns, movement kinematics (position, velocity, acceleration, curvature), eye movement.