[Immediate effects of therapeutic interventions on the central motor system and their practical consequences]. / Unmittelbare Effekte therapeutischer Interventionen auf das zentrale motorische System und deren Konsequenzen für die Praxis.

Physiotherapy and occupational therapy have changed over recent years influenced by our growing neurophysiological knowledge especially about motor learning. Understanding the direct effects of therapeutic interventions on the central motor system is crucial for further development of therapeutic approaches. Recent studies are discussed dealing with the facilitatory effects of different therapeutic interventions and the question whether or not the activation of the healthy upper limb has a facilitatory or inhibitory net-effect on the damaged central motor system. In a controlled study using transcranial magnetic stimulation (TMS) we could show that motor system excitability is not influenced by the contraction type (isometric or isotonic), neither in healthy nor in stroke patients. Two TMS-studies could show that voluntary exercises of the non-affected hand alone or in bimanual tasks do not have an inhibitory effect on the damaged central motor system. However, the strongest facilitation of the damaged motor area could be achieved by voluntary activation of the affected extremity. The therapeutic approach in severely or completely paretic upper limbs should, hence, be focussed on functional compensation. As soon as voluntary activity is obtainable intensive voluntary exercises should however be preferred, with contraction type (isometric or isotonic) seeming not to be important.

[Patient-individual care pathways in phase D neurological rehabilitation]. / Patientenindividuelle Behandlungspfade in der neurologischen Rehabilitation der Phase D.

The "patient-individual neurological care pathways" are a concept for qualified decision-making about rational rehabilitative strategies in the treatment of neurological diseases. Such clinical pathways include available scientific evidence and treatment guidelines. In neurological rehabilitation all treatments have a decidedly interdisciplinary character. All members of the team need highly specialized knowledge, a high potential for teamwork, as well as efficient organisation of work time. Here, computer aided decision-making tools such as the "patient-individual neurological care pathways" facilitate rational decisions and reduce the need for reorganization of therapies. In rehabilitation of neurological patients a symptom-oriented and function-related perspective of the individual treatment goals is indispensable for optimal choice of therapy approaches. This function-oriented classification of patients and creation of individual treatment plans are realized within the Excel-based care pathways. This system has been proved on the one hand as an instrument for streamlining and optimisation and, on the other, as a useful tutoring tool in the medical rehabilitation process.

Rapidly induced changes in neuromagnetic fields following repetitive hand movements.

Sensory feedback plays a major role in movement execution and motor learning, particularly in motor rehabilitation. Whilst elaborating therapeutic strategies, it is of interest to visualize the effect of a therapeutic intervention at the moment of its application. We analyzed the effect of repeated execution of a simple extension and flexion movement of the wrist on the sensorimotor cortex of seven healthy subjects using magnetoencephalography. Spatial filtering based on current dipoles was used to quantify the strength of cortical activation. Our results showed an increase of cortical activation reflecting activity of efferent neurons, whereas the activity of proprioceptive afferent neurons was not affected. Since only efferent activity increased, it is suggested that this reflects phenomena of long-term potentiation.

[Functional outcome after decompressive craniectomy: a retrospective and prospective clinical study]. / Funktionelles Outcome nach dekompressiver Kraniektomie: eine retro- und prospektive klinische Studie.

Decompressive craniectomy has been revived as a radical surgical treatment in increased ICP. While the life saving effect is undisputable, reports about the functional outcome are controversial. Furthermore, there are no data comparing the outcome of craniectomised patients with different aetiologies. In a retrospective and prospective study we assessed the functional outcome of craniectomised patients (41 stroke and 24 traumatic brain injury (TBI) patients). The majority of patients considerably benefits from the rehabilitation process. Nevertheless, most of them remained dependent upon caregivers. In stroke patients there was a significant negative correlation between age and outcome. Even though TBI were younger than stroke patients there were no outcome differences between these groups. We found no correlation between the side of the hemisphere injured and outcome.

Repetitive training of compensatory steps: a therapeutic approach for postural instability in Parkinson's disease.

BACKGROUND: Postural instability (PI) is a common and serious problem in Parkinson's disease (PD). Dopaminergic medication is of negligible use and a positive effect of deep brain stimulation on this issue has not been reported. OBJECTIVE: To develop a method of repetitive training of compensatory steps to enhance protective postural responses by using training strategies based on recent neurophysiological research. METHODS: Fourteen patients with PD took part in a multiple baseline design study and were trained for 14 days in an ambulant setting consisting of two daily sessions. RESULTS: After training, the length of compensatory steps increased and the step initiation shortened. In a gait analysis, the cadence and the step length increased, gait velocity improved, and the period of double support shortened. The "mobility" subscore of a quality of life questionnaire (PDQ-39) also improved. All these changes were significant (p < 0.05). These effects were stable for two months without additional training. CONCLUSION: The repetitive training of compensatory steps is an effective approach in the treatment of PI and should be applied if PI is evident clinically or in a patient's history.

Neurological disease-associated autoantibodies against an unknown protein encoded by a RES4-22 homologous gene.

Screening a human small intestinal library with human serum yielded a clone which encoded a protein res4-22 the gene of which was highly homologous to a recently described gene located in the Huntington's disease locus. Autoantibodies against res4-22 (anti-res4-22), mainly of the immunoglobulin (Ig)A type, were detected in patients with neurological disorders at a higher frequency (18.4%) than in healthy blood donors (8.0%). In neurological patients with cerebral ischaemia anti-res4-22 was found significantly more often (47.4%) than in the total group of neurological patients. Anti-res4-22 positive sera showed significantly more frequently myelin staining in cerebellum and nerve sections than anti-res4-22 negative sera. Our findings demonstrate a new species of human autoantibodies against a newly described protein the function of which is still unknown.

Repetitive sensorimotor training for arm and hand in a patient with locked-in syndrome.

The locked-in syndrome is characterized by quadriplegia, preserved consciousness and inability to respond to the outside world. In recent years, the repetitive execution of identical movements has been demonstrated to be crucial for the recovery of arm and hand function in stroke patients. The present study aimed at investigating the efficiency of repetitive training in a patient suffering from locked-in syndrome due to an occlusion of the basilar artery. Seven months after the brainstem lesion and after a 15-week period of standard inpatient therapy, the repetitive training was applied to the (most affected) right upper extremity in addition to usual therapy. After 42 weeks of the repetitive training for the right arm, it was applied to the left arm. The ranges of active motion as well as functional motor capacity and muscle tone were regularly assessed. During those phases when the repetitive sensorimotor training was applied to the right or left arm, the ranges of active motion, muscle strength and functional motor capacity of the trained arm increased significantly accompanied by a continuous normalization of muscle tone in the flexor muscle groups. Since the prominent functional improvements of the right and left arms were observed during those phases when the repetitive training was applied, these effects were likely to be due to the training rather than to the standard rehabilitation program or extraneous influences. The repetitive sensorimotor training, therefore, appears to be appropriate to improve motor function of the arm and hand and to accelerate the time course of recovery even in patients with almost complete central paralysis of both arms.

Rationales for improving motor function.

New findings in basic neuroscience, and the growing knowledge regarding neuroplasticity and motor learning have exerted influence and have provided stimuli for motor rehabilitation research. Repeated motor practice has been identified as crucial for motor recovery. Further novel and scientifically based therapeutic approaches have been developed: constraint-induced movement therapy, electromyogram-initiated neuromuscular stimulation, motor imagery and music therapy are all discussed in the present review.

Facilitation of motor evoked potentials after repetitive voluntary hand movements depends on the type of motor activity.

Recent neurophysiological studies suggest that repetitive execution of identical movements is crucial for motor learning. During and after repetitive motor action, changes in motor cortical excitability have been demonstrated by means of transcranial magnetic stimulation. Nevertheless, the frequency and intensity of movement repetition that are necessary to achieve an optimal improvement in motor function are unknown. Fourteen healthy volunteers participated in the present study, which deals with the post-exercise facilitatory and/or inhibitory effects of 5 different motor conditions, including repetitive isotonic contractions at the wrist at two different velocities and two different forearm positions, a sustained isometric hand extension and repetitive hand extensions at the wrist induced by means of transcutaneous electrical muscle stimulation. The modification of muscular response potentials in the extensor carpi radialis muscle was measured following the various motor tasks and the electrical muscle stimulation. The only statistically significant facilitatory effect was observed following an extension-relaxation task at low frequency. Furthermore, the duration of transcranially induced silent periods showed a significant reduction after this motor task.

The functional value of electrical muscle stimulation for the rehabilitation of the hand in stroke patients.

The influence of suprathreshold electrical stimulation of the extensor and flexor carpi radialis muscles on biomechanical and functional movement parameters is compared with the effect of a standardized active repetitive training of hand and fingers. Twelve patients suffering from ischaemic lesions in the territory of the middle cerebral artery participated in the study, which was conducted using a multiple baseline design. Following a baseline phase that lasted between one and three weeks all patients received electrical muscle stimulation for 20 minutes twice daily. In a third phase the repetitive training of hand and fingers was conducted for 20 minutes twice daily. Both interventions were applied in addition to conventional occupational therapy and physiotherapy. With the exception of spasticity in hand and finger flexors, repetitive electrical muscle stimulation does not improve biomechanical or functional motor parameters of the centrally paretic hand and arm. The repetitive motor training, however, is appropriate to improve biomechanical and functional movement parameters significantly. Apart from a possible effect on the muscle cell itself, the electrical muscle stimulation is thought to represent a mainly sensory, i.e. proprioceptive, and cutaneous intervention, whereas the active motor training is characterized by a continuous sensorimotor coupling within motor centres of the brain. The underlying neurophysiological mechanisms as well as basic principles concerning the role of afferent input for motor learning and recovery are discussed.

Facilitation of motor evoked potentials in hand extensor muscles of stroke patients: correlation to the level of voluntary contraction.

The influence of ongoing voluntary isometric contractions (ranging from 2.5% to 100% of maximum force production) on motor evoked potentials in the extensor carpi radialis muscle was investigated in 20 healthy subjects and 25 hemiparetic stroke patients using transcranial magnetic stimulation at threshold and at 90% of maximum stimulus intensity. In healthy subjects and in stroke patients, an initial sharp decay in response latencies was observed at low contraction levels. In hemiparetic patients, however, no significant further reduction of response latencies with increasing contraction levels was observed irrespective of whether threshold or 90% stimulus intensities were applied. The continuous decrease in latency in the healthy subjects is supposed to result from an enhanced involvement of rapidly conducting corticospinal neurones that are preferentially damaged in the patient group. In healthy subjects and in hemiparetic patients, however, the increase in response amplitudes runs in parallel with increasing force production, at least with threshold stimulus intensity. Contrary to response latencies, amplitude facilitation appears to be less dependent on the involved corticospinal fibre spectrum but to be predominantly based on temporal and spatial summation effects. The relevance of the latency and amplitude data obtained in healthy subjects and in stroke patients for physiology and localization of facilitatory processes, i.e. whether cortical or spinal, is discussed. For the rehabilitation of stroke patients it is concluded that the effect of slight voluntary contractions is indeed superior to most other facilitatory approaches. The functional relevance is discussed.

The influence of EMG-initiated electrical muscle stimulation on motor recovery of the centrally paretic hand.

The present study compares the effect of EMG-initiated electrical stimulation of hand extensors and flexors with the influence of a standardized repetitive training of the hand that had been proven to ameliorate arm and hand function significantly. Twenty hemiparetic stroke patients participated in the study. Following a 2 week baseline phase in which conventional inpatient occupational and physiotherapy was applied, all patients received EMG-initiated electrical muscle stimulation twice daily during 20 min periods followed by a third phase with a standardized repetitive training of the hand. Both training procedures were conducted in addition to conventional occupational and physiotherapy. Grip strength, peak force of isometric hand extensions as well as peak acceleration of isotonic hand extensions were measured as indicators of motor performance. Spasticity of hand flexors was assessed by means of the modified Ashworth scale. Motor capacity of the affected arm was scored by means of the Rivermead motor assessment, arm section. Contrary to usual occupational and physiotherapy, both the EMG-initiated stimulation and the repetitive training are appropriate to improve all biomechanical and functional parameters significantly whereas no difference in the efficacy of both methods could be detected. The functional significance of frequent active repetition of identifcal movements and the role of time-locked afferent information about the unfolding movement for motor learning and recovery are discussed.

Repetitive training of isolated movements improves the outcome of motor rehabilitation of the centrally paretic hand.

The effect of a standardized training on movements of the affected hand has been studied in 27 hemiparetic patients using a multiple baseline approach across individuals. The training consisted of repetitive hand and finger flexions and extensions against various loads and was carried out twice daily during 15-min periods. Grip strength (p < 0.006), peak force of isometric hand extensions (p < 0.05), peak acceleration (p < 0.05) of isotonic hand extensions as well as contraction velocities as indicators of motor performance significantly improved during the training period. In contrast to the standardized training of hand and finger movements, therapeutic strategies following the Bobath concept aim at reducing enhanced muscle tone without reinforcing the activity in centrally paretic distal muscle groups directly. Patients undergoing this treatment approach alone did not experience a significant improvement in the motor capacity of the hand. Therefore, the results of the present study emphasize the importance of frequent movement repetition for the motor rehabilitation of the centrally paretic hand and challenge conventional physiotherapeutic strategies that focus on spasticity reduction instead of early initiation of active movements.

Influence of physiotherapeutic facilitation techniques on motor evoked potentials in centrally paretic hand extensor muscles.

In the rehabilitation of stroke patients, various facilitation techniques are applied to reduce weakness in centrally paretic muscles and to improve functional motor capacity. The present investigation compared the facilitatory effect of 5 different physiotherapeutic approaches onto the centrally paretic extensor carpi radialis muscle in 30 stroke patients classified into 3 groups according to the individual degree of paresis. In order to quantify the influence of the respective facilitation manoeuvre, single transcranial magnetic stimuli were applied before and during the application of cutaneous/proprioceptive stimuli, a weight bearing task, contraction of the affected and the non-affected extensor carpi radialis muscle and during proximal preinnervation on the affected side. All procedures, indeed, enhanced the frequency of occurrence of muscular response potentials and their amplitudes while diminishing their response latencies. The most prominent effects were observed when the muscle itself was voluntarily activated. A similarly strong facilitation was obtained in the most severely affected patients with cutaneous and proprioceptive stimuli, but such stimuli had inhibitory effects in the healthy control group. The present study illustrates the interaction of cortically evoked motor potentials with peripherally or centrally generated inputs, contributes to the understanding of the neurophysiological mechanisms underlying physiotherapeutic facilitation techniques and helps in providing rational criteria to decide about the most appropriate facilitation method.

Influence of sustained stretch on late muscular responses to magnetic brain stimulation in patients with upper motor neuron lesions.

Late muscular responses to transcranial magnetic stimulation occur in healthy subjects only in tonically active muscles with a proportional relationship between the amount of the EMG-response and the voluntary innervation strength. In hemiparetic stroke patients late potentials are elicited in chronically spastic hand flexors without voluntary background muscular activity probably reflecting enhanced excitability of spinal alpha-motoneurons in the spastic state. When spastic muscle hypertonus has been diminished by sustained muscle stretch late EMG-potentials are reduced or have disappeared completely. The relation between spastic muscle hypertonus and the late muscular response potentials as well as the possible mechanisms of sustained muscle stretch on the response characteristics to transcranial magnetic stimulation in spastic flexor muscles of the hand are discussed.

[The neurophysiological basis of exercise physical therapy in patients with central hemiparesis]. / Neurophysiologische Grundlagen krankengymnastischer Ubungsbehandlung bei Patienten mit zentralen Hemiparesen.

According to everyday experience in rehabilitation, stroke patients suffering from central hemiparesis physiotherapy is efficacious in reducing the degree of motor impairment. This paper describes the various therapeutic techniques used in the traditional physiotherapeutic concepts (Rood, Bobath, Brunnstrom, proprioceptive neuromuscular facilitation, Vojta) and their basic neurophysiological mechanisms, as far as they are known today. Furthermore, the significant role of treating impaired sensation and perception for movement execution is discussed and various therapeutic concepts (traditional sensibility training, methods according to Affolter and Perfetti, forced use) are described.

A premovement silent period does not occur prior to rapid changes of velocity during human limb movements.

Surface electromyographic activity (EMG) of the interosseous dorsalis I, the hand extensors and the biceps muscles was analysed in human young normal subjects for the occurrence of a precontraction (PCSP) or a premovement silent period (PMSP) before a sudden increase in tension or rapid change of position after a small isometric contraction or slow isotonic movement. Contrary to the results of Conrad et al. (Exp. Brain Res., 51 (1983) 310-313), in whose experiments the contraction condition changed from isometric to isotonic, a PCSP or PMSP could never be observed in our experiments, where contractions or movements first started at a low force level or with a low speed which had to be changed most rapidly after 2 s and where the recording condition remained strictly either isometric or isotonic. It is concluded that the central nervous system resets the motoneuronal pool activity when the central program is changed from the control of an isometric to the control of an isotonic contraction.

Sensory inputs to the agranular motor fields: a comparison between precentral, supplementary-motor and premotor areas in the monkey.

Kinesthetic responses of neurones in the motor cortex, including the primary motor (MI), the supplementary motor (SMA) and the postarcuate premotor (PMC) areas, were investigated in the awake, chronically prepared monkey. In all three subareas, neurones were recorded which responded to passive elbow flexions and extensions induced by a torque motor. In the SMA, such cells were restricted to its posterior portion where intracortical microstimulation produced limb and trunk movements. The majority of SMA cells responds to both displacement directions, a quarter to either flexion or extension. Although the total proportion of SMA neurones responding to arm displacements was low (15%), it was noted that in 'correct' somatotopic penetrations, the responsiveness could be prominent. The latency distribution of the kinesthetic responses was similar to that of MI neurones with slightly less response latencies shorter than 20 ms in the SMA. With manually applied stimuli, SMA neurones responded mostly to joint rotations, but not to light cutaneous stimuli. Only two SMA neurones with somatosensory responses were identified as descending projection neurones, and some neurones were found to be modulated also during active grasping. In the PMC, a higher proportion of neurones (27%) reacted to the standardized arm displacements, the majority again responding to both directions. The latency distribution of the kinesthetic responses was similar to that of SMA neurones. In contrast to SMA neurones, many PMC neurones responded to light cutaneous stimuli. It was found that some of the 'somatosensory' PMC neurones were sometimes driven also by moving visual and, rarely, by auditory stimuli. Although there are obvious differences in the nature and possibly also in the amount of sensory inputs to the three motor cortical areas, the present results indicate that all three subareas receive somatosensory feedback and that they might therefore all be implicated in the generation of sensory-driven motor output.

Transient responses to load perturbations of the forearm in a monkey with a chronic lesion in the internal capsule.

Small electrolytic lesions were produced in the internal capsule of a monkey. The changes in muscle tone were quantified by studying the EMG responses of elbow muscles and the mechanical responses of the forearm to pseudo-random torque perturbations applied to the elbow joint. Immediately following the lesion, the EMG responses of both biceps and triceps muscles were depressed. Subsequently, biceps responses recovered and became eventually greater than in the control. Triceps responses, instead, remained low throughout the follow-up period (3 months). The mechanical behavior of the forearm was characterized in terms of the dynamic relationship between the applied torque perturbations and the resulting changes in elbow angle. After the lesion, the damping of the elbow responses decreased relative to the control. Possible mechanisms for the observed changes in the EMG and mechanical behavior are discussed.