Neural coordination of bilateral hand movements: evidence for an involvement of brainstem motor centres.

Bilateral hand movements are assumed to be coordinated by a neural coupling mechanism. Neural coupling is experimentally reflected in complex electromyographic (EMG) responses in the forearm muscles of both sides to unilateral electrical arm nerve stimulation (ES). The aim of this study was to examine a potential involvement of the reticulospinal system in neural coupling by the application of loud acoustic stimuli (LAS) known to activate neurons of this system.

Restoration of motor function after CNS damage: is there a potential beyond spontaneous recovery?

What determines the effectiveness of neurorehabilitation approaches on the outcome of function in stroke or spinal cord injured subjects? Many studies claim that an improvement of function is based on the intensity of training, while some actual studies indicate no additional gain in function by a more intensive training after a stroke. Inherent factors seem to determine outcome, such as damage of specific tracts in stroke and level of lesion in spinal cord injured subjects, while the improvement of function achieved by an intensive training is small in relation to the spontaneous recovery. It is argued that an individual capacity of recovery exists depending on such factors.

Neural coordination of bilateral power and precision finger movements.

The dexterity of hands and fingers is related to the strength of control by cortico-motoneuronal connections which exclusively exist in primates. The cortical command is associated with a task-specific, rapid proprioceptive adaptation of forces applied by hands and fingers to an object. This neural control differs between "power grip" movements (e.

Differential neural coordination of bilateral hand and finger movements.

Cooperative hand movements (e.g., opening a bottle) require a close coordination of the hands.

Management of pain in individuals with spinal cord injury: Guideline of the German-Speaking Medical Society for Spinal Cord Injury.

Pain is a prominent complication in spinal cord injury (SCI). It can either occur as a direct or as an indirect consequence of SCI and it often heavily influences the quality of life of affected individuals. In SCI, nociceptive and neuropathic pain can equally emerge at the same time above or below the level of injury.

In vivo evidence of remote neural degeneration in the lumbar enlargement after cervical injury.

Objective: To characterize remote secondary neurodegeneration of spinal tracts and neurons below a cervical spinal cord injury (SCI) and its relation to the severity of injury, the integrity of efferent and afferent pathways, and clinical impairment.

Methods: A comprehensive high-resolution MRI protocol was acquired in 17 traumatic cervical SCI patients and 14 controls at 3T. At the cervical lesion, a sagittal T2-weighted scan provided information on the width of preserved midsagittal tissue bridges.

Neuroplastic Changes in Older Adults Performing Cooperative Hand Movements.

The aim of this study was to examine whether older adults use the same task-specific brain activation patterns during two different bimanual hand movement tasks as younger adults. Functional magnetic resonance brain imaging was performed in 18 younger (mean age: 30.3 ± 3.

Rehabilitation robots for the treatment of sensorimotor deficits: a neurophysiological perspective.

The past decades have seen rapid and vast developments of robots for the rehabilitation of sensorimotor deficits after damage to the central nervous system (CNS). Many of these innovations were technology-driven, limiting their clinical application and impact. Yet, rehabilitation robots should be designed on the basis of neurophysiological insights underlying normal and impaired sensorimotor functions, which requires interdisciplinary collaboration and background knowledge.

Cooperative hand movements: effect of a reduced afference on the neural coupling mechanism.

The aim of this study was to evaluate the influence of unilateral reduction of afferent input on the 'neural coupling' mechanism during cooperative hand movements. This 'neural coupling' is reflected in the task-specific appearance of contralateral reflex responses in forearm muscles to unilateral arm nerve stimulation. Sensory input from the right hand was reduced by ischemic nerve block at the right wrist.

Neural coupling of cooperative hand movements after stroke: role of ipsilateral afference.

We investigated the role of ipsilateral ascending pathways in the neural coupling underlying cooperative hand movements of stroke subjects. Ipsi- and contralateral somatosensory evoked potentials (SSEP) were recorded following ulnar nerve stimulation during cooperative and non-cooperative hand movements. The amplitude ratio, that is, ipsilateral divided by contralateral amplitude, was highest during the cooperative task when the affected arm was stimulated, reflecting an enhanced afferent volley to the unaffected hemisphere.

Effectiveness of Automated Locomotor Training in Patients with Acute Incomplete Spinal Cord Injury: A Randomized, Controlled, Multicenter Trial.

The aim of this study was to evaluate whether the effect of longer training times (50 instead of 25 min per day) using a robotic device results in a better outcome of walking ability of subjects with a subacute motor complete (American Spinal Injury Association Impairment Scale [AIS]-B) and incomplete (AIS-C) spinal cord injury. Twenty-one patients were enrolled in the study, whereof 18 completed, on average, 34 trainings in 8 weeks. Longer training times resulted in better locomotor function.

Effect of Locomotor Training on Exhaustion of Leg Muscle Activity in Chronic Complete Spinal Cord Injury.

The aim of this study was to evaluate the effect of a continuous locomotor training on leg muscle electromyographic (EMG) exhaustion during assisted stepping movements in a patient with motor complete spinal cord injury (SCI). EMG exhaustion and loss of potentials starts to develop in untrained patients at ∼6 months after injury. In the trained patient examined in this study, exhaustion was also observed but occurred with a delay of several months.

Improving outcome of sensorimotor functions after traumatic spinal cord injury.

In the rehabilitation of a patient suffering a spinal cord injury (SCI), the exploitation of neuroplasticity is well established. It can be facilitated through the training of functional movements with technical assistance as needed and can improve outcome after an SCI. The success of such training in individuals with incomplete SCI critically depends on the presence of physiological proprioceptive input to the spinal cord leading to meaningful muscle activations during movement performances.

From the Rodent Spinal Cord Injury Model to Human Application: Promises and Challenges.

Repair of the spinal cord and improvement of mobility after injury has been a matter of basic and clinical research for several decades. A number of repair approaches were performed in animals, mainly rodent models of spinal cord injury (SCI). Some of these experimental therapies resulted in significant regeneration of tract fibers, formation of new connections and circuits, and associated improvement of mobility.

Control of functional movements in healthy and post-stroke subjects: Role of neural interlimb coupling.

In recent years it has become evident that, in a number of functional movements, synergistically acting limbs become task-specifically linked by a soft-wired 'neural coupling' mechanism (e.g. the legs during balancing, the arms and legs during gait and both arms during cooperative hand movements).

Cooperative hand movements in post-stroke subjects: Neural reorganization.

Objective: Recent research indicates a task-specific neural coupling controlling cooperative hand movements reflected in bilateral electromyographic reflex responses in arm muscles following unilateral nerve stimulation. Reorganization of this mechanism was explored in post-stroke patients in this study.

Methods: Electromyographic reflex responses in forearm muscles to unilateral electrical ulnar nerve stimulation were examined during cooperative and non-cooperative hand movements.

Task-specific role of ipsilateral pathways: somatosensory evoked potentials during cooperative hand movements.

Task-specific neural coupling during cooperative hand movements has been described in healthy volunteers, manifested by bilateral reflex electromyographic responses in forearm muscles following unilateral ulnar nerve stimulation and by task-specific activation of secondary somatosensory cortical areas (S2) in functional MRI. The aim of this study was to investigate the role of sensory input to the ipsilateral and contralateral cortex during a cooperative task. Somatosensory evoked potentials from the ulnar nerve were recorded over the ipsilateral and contralateral cortex during resting and during cooperative and noncooperative hand movements.

Recovery of sensorimotor function and activities of daily living after cervical spinal cord injury: the influence of age.

This retrospective study was designed to examine the influence of age on the outcome of motor function and activities of daily living (ADLs) in patients with a cervical spinal cord injury (SCI). The study is based on the data registry of the European Multicenter Study of Spinal Cord Injury (EMSCI) study group. Initial upper-extremity motor score (UEMS) and its change over 5 months, as well as the initial Spinal Cord Independence Measure (SCIM) score, did not differ between younger adults (20-39 years) and elderly (60-79 years) patients.

Three-dimensional, task-specific robot therapy of the arm after stroke: a multicentre, parallel-group randomised trial.

Background: Arm hemiparesis secondary to stroke is common and disabling. We aimed to assess whether robotic training of an affected arm with ARMin--an exoskeleton robot that allows task-specific training in three dimensions-reduces motor impairment more effectively than does conventional therapy.

Methods: In a prospective, multicentre, parallel-group randomised trial, we enrolled patients who had had motor impairment for more than 6 months and moderate-to-severe arm paresis after a cerebrovascular accident who met our eligibility criteria from four centres in Switzerland.

Neural coupling of cooperative hand movements: a reflex and fMRI study.

The neural control of "cooperative" hand movements reflecting "opening a bottle" was explored in human subjects by electromyographic (EMG) and functional magnetic resonance imaging (fMRI) recordings. EMG responses to unilateral nonnoxious ulnar nerve stimulation were analyzed in the forearm muscles of both sides during dynamic movements against a torque applied by the right hand to a device which was compensated for by the left hand. For control, stimuli were applied while task was performed in a static/isometric mode and during bilateral synchronous pro-/supination movements.

Restoration of sensorimotor functions after spinal cord injury.

The purpose of this review is to discuss the achievements and perspectives regarding rehabilitation of sensorimotor functions after spinal cord injury. In the first part we discuss clinical approaches based on neuroplasticity, a term referring to all adaptive and maladaptive changes within the sensorimotor systems triggered by a spinal cord injury. Neuroplasticity can be facilitated through the training of movements with assistance as needed, and/or by electrical stimulation techniques.

Undirected compensatory plasticity contributes to neuronal dysfunction after severe spinal cord injury.

Severe spinal cord injury in humans leads to a progressive neuronal dysfunction in the chronic stage of the injury. This dysfunction is characterized by premature exhaustion of muscle activity during assisted locomotion, which is associated with the emergence of abnormal reflex responses. Here, we hypothesize that undirected compensatory plasticity within neural systems caudal to a severe spinal cord injury contributes to the development of neuronal dysfunction in the chronic stage of the injury.

Arm movements can increase leg muscle activity during submaximal recumbent stepping in neurologically intact individuals.

Facilitation of leg muscle activity by active arm movements during locomotor tasks could be beneficial during gait rehabilitation after spinal cord injury. The present study explored the effects of arm movements on leg muscle activity during submaximal recumbent stepping. Healthy subjects exercised on a recumbent stepping machine both with and without arm movements.