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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. LAS, ES and combined LAS/ES were applied to healthy subjects during visually guided bilateral hand flexion-extension movements. Muscle responses to the different stimuli were evaluated by electrophysiological recordings. Unilateral electrical ulnar nerve stimulation resulted in neural coupling responses in the forearm extensors (FE) of both sides. Interestingly, LAS evoked bilateral EMG responses that were similar in their configuration to those induced by ES. The presence of startles was associated with a shift of the onset and enhanced amplitude of LAS-induced coupling-like responses. Upon combined LAS/ES application, ES facilitated ipsilateral startles and coupling-like responses. Modulation of coupling-like responses by startles, the similarity of the responses to ES and LAS, and their interaction following combined stimulation suggests that both responses are mediated by the reticulospinal system. Our findings provide novel indirect evidence that the reticulospinal system is involved in the neural coupling of hand movements. This becomes clinically relevant in subjects with a damaged corticospinal system where a dominant reticulospinal system leads to involuntary limb coupling, referred to as associated movements. KEY POINTS: Automatic coordination of hand movements is assumed to be mediated by a neural coupling mechanism reflected by bilateral reflex responses in forearm muscles to unilateral electrical arm nerve stimulation (ES). Loud acoustic stimuli (LAS) were applied to assess a potential involveme

Background: The description of the natural course of recovery from a spinal cord injury (SCI) with spontaneous improvement of neurological, neurophysiological, and functional measures is an important prerequisite in appraising effects of upcoming interventional therapies. Objective: To describe the spontaneous evolution of motor-evoked potentials of the anterior tibial muscle (TA-MEP) and their relation to outcomes of lower extremity motor scores (LEMS) and walking function in patients recovering from an acute SCI. Methods: TA-MEPs were assessed in 255 SCI subjects within 5 time intervals throughout the first year after SCI with combined neurological and functional measures. Tibial nerve conduction studies were performed to screen for peripheral nerve damage. Results: TA-MEP allowed stratification of SCI according to lesion severity and outcome. As MEP amplitudes increased over 12 months after SCI, this was paralleled by a significant improvement of LEMS and walking function. TA-MEP latencies remained usually stable. Conclusion: Clinical outcome and walking function after SCI can be predicted independent of clinical measures by assessment of TA-MEP reflecting corticospinal tract integrity.

The application of rehabilitation therapy technologies in children with neurological impairments appears promising. Characteristics of these robotic-supported and computer-assisted therapies are in line with principles of motor learning. They include high numbers of repetitions, prolonged training durations, and online feedback about the patient’s active participation. When applied by experienced therapists, the technologies provide a safe and simultaneously fun and motivating therapy to young patients. Furthermore, the evidence of the effectiveness for lower and upper limb applications is rising. We wrote this chapter to account for the lack of knowledge concerning the implementation and evidence-based application of such technologies. We discuss in this chapter the complementary role of rehabilitation therapy technologies and present general considerations for their implementation and application. Furthermore, we propose a conceptual ordering of categories of lower and upper limb rehabilitation therapy technologies, based on whether the systems provide weight support, physical assistance, or ‘only’ augmented feedback. Finally, we present some of these technologies representing the categories in more detail and summarize the research and evidence of these technologies.

This chapter focuses on robotic gait training. As a basis, it summarizes the neurophysio-logical rationale for such training. These neurophysiological findings are mostly based on animal studies. The observations from these studies led to the development of theories such as the spinal central pattern generator (CPG). In a deductive manner, studies have then also been performed on human participants showing similar phenomena. Based on the neurophysiological mechanisms, robot-assisted locomotor training is justified even in patients with severe functional limitations.Those patients would not be able to maintain an upright posture while performing stepping movements in a conventional training condition.The clinical application of robotic gait training is, therefore, another focus of this chapter. Different robotic devices and their relevant characteristics are introduced. Not all devices are designed to purely assist locomotor training by maximally exploiting the neuroplastic potential of the central nervous system. Some devices can also be considered assistive technologies which support patients in their daily life mobility. General aspects which are relevant for robotic gait training during rehabilitation are summarized. Then the chapter takes the translation of the fundamental principles one step further and addresses the application of robotic gait training in specific neurological conditions, that is, in stroke, traumatic brain injury (TBI), spinal cord injury (SCI), multiple sclerosis (MS), and Parkinson’s disease. These parts are written by experts in their respective fields. Every section follows the same structure and informs the reader about the condition in general, specific gait limitations, and the rehabilitation thereof. If available, the latter is supported by recent high-level evidence. In the other cases, relevant primary studies are summarized. Because specific clinical guidelines for the application of robotic gait training are largely missing, the e

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. This capacity can be exploited by a repetitive execution of functional movements (supported as far as required), irrespective of the intensity and technology applied. Elderly subjects have difficulties to translate the recovery of motor deficit into function. Alternative, non-training approaches to restore motor function, such as epidural or deep brain stimulation as well as CNS repair are still in an early clinical or in a translational stage.