Horst Hummelsheim

Evidence-based physiotherapeutic concepts for improving arm and hand function in stroke patients: a review.

In recent years, our understanding of motor learning, neuroplasticity and functional recovery after the occurrence of brain lesion has grown significantly. New findings in basic neuroscience provided stimuli for research in motor rehabilitation. Repeated motor practice and motor activity in a real world environment have been identified in several prospective studies as favorable for motor recovery in stroke patients. EMG initiated electrical muscle stimulation – but not electrical muscle stimulation alone – improves motor function of the centrally paretic arm and hand. Although a considerable number of physiotherapeutic “schools” has been established, a conclusive proof of their benefit and a physiological model of their effect on neuronal structures and processes are still missing. Nevertheless, evidence-based strategies for motor rehabilitation are more and more available, particularly for patients suffering from central paresis.

Change of facilitation during voluntary bilateral hand activation after stroke

BACKGROUND AND PURPOSE The relearning of daily activities after stroke also involves performance of bimanual tasks. This raises the possibility that concurrent activation of the healthy hemisphere interferes with reorganization processes in the affected hemisphere due to inhibitory pathways between homologous motor cortex representations. This study investigated the effect of voluntary, simultaneous activation of both hands upon the non-dominant (healthy subjects) or affected (stroke patients) hemisphere. METHODS Eleven healthy subjects and 16 stroke patients were investigated using transcranial stimulation (TMS). TMS was applied over the non-dominant/affected hemisphere during performance of an isometric pinch grip at different force levels (10% or 50% of maximal voluntary contraction) with the contralateral hand. The ipsilateral hand had to perform the pinch grip at various force levels (10%, 50%, or 100% of maximal voluntary contraction) simultaneously. Peak-to-peak amplitudes of motor evoked potentials (MEPs) were compared to assess differences in motor cortex excitability. RESULTS Unilateral activity of either hand alone exerted a facilitatory effect upon the non-dominant or affected hemisphere. In healthy subjects, the activation of the ipsilateral hand simultaneously with the contralateral hand did not produce any significant change of the MEP amplitudes compared to unilateral activation of the contralateral hand. In patients, however, the additional activation of the ipsilateral hand caused an additional increase of the peak-to-peak amplitudes. CONCLUSION In healthy subjects voluntary activation of the ipsilateral hand does not change the excitability of the motor cortex of the non-dominant hemisphere, when the contralateral hand is simultaneously activated. The facilitation of the contralateral hand seems to gate further facilitation by the ipsilateral hand. However, in stroke patients simultaneous activation of both hands causes an additional facilitation compared to activation of the affected hand alone.

Is the repetitive training of complex hand and arm movements benefi cial for motor recovery in stroke patients

Objective: To determine whether a repetitive training of complex movements of arm and hand contributes to functional recovery in stroke patients. Design: Prospective, longitudinal, multiple baseline design across individuals. Setting: Neurological rehabilitation centre. Subjects: Twenty-one patients with stroke in the middle cerebral artery territory. Interventions: Baseline phase: ‘house-typical’ occupational and physiotherapy; training phase: ‘house-typical’ therapy supplemented by repetitive training of (1) grasping and transport movements and (2) sawing movements of the affected arm over 10 minutes each, twice daily, five days per week. Main outcome measures: Rivermead Motor Assessment (RMA, arm section), grip strength, rapid isotonic hand extension, three-dimensional motion analysis. Results: Patients experienced a continuous functional improvement of the affected arm (RMA score from initial 4.9 ± 2.1 to 8.0 ± 4.6, p < 0.001) and an increase of grip strength during the baseline and the training phase (from initial 102.4 ± 43.3 N to 150.6 ± 118.9 N, p < 0.05). Movement analysis revealed a trend to a more precise movement execution. The repetitive training of complex movements did not result in an additional benefit. Conclusion: The repetitive training of complex movements does not further enhance the functional recovery of the affected arm and hand in stroke patients compared with functionally based occupational and physiotherapy.

Is the reduction of spasticity by botulinum toxin a beneficial for the recovery of motor function of arm and hand in stroke patients

To determine the functional benefit of botulinum toxin A (BtxA) in spasticity of arm flexors, we conducted an open-label study with 10 stroke patients. 480 mouse units BtxA (Dysport®) were injected into flexor muscles. Outcome measures were done by the Modified Ashworth Scale, Rivermead Motor Assessment (arm section), active and passive ranges of motion (ROM), grip strength and a 3-dimensional motion analysis. The functional capacity of the entire arm, even of the shoulder, and the ROM of fingers and wrist increased. Despite a diminution of muscle tone, grip strength remained unchanged or increased. An improvement of forearm extension was only observed in cases of preserved voluntary extensor motricity. Injection of BtxA into spastic distal flexor muscles may lead to a functional improvement of the entire arm. Grip strength is not necessarily reduced.

Enhanced Motor Cortex Excitability During Ipsilateral Voluntary Hand Activation in Healthy Subjects and Stroke Patients

Background and Purpose— It is still a matter of debate whether the ipsilateral voluntary hand activation has a facilitatory or inhibitory effect on the nondominant or affected hemisphere. To give an answer to this question is of great importance for the rehabilitation of stroke patients, because they often use the unaffected hand for compensation. Methods— Ten healthy volunteers and 11 stroke patients were investigated using transcranial magnetic stimulation (TMS). TMS was applied to the dominant/unaffected hemisphere during performance of different tasks (simple index finger abduction, pinch grip, and power grip) at various force levels (5%, 10%, 50%, and 100% maximal voluntary contraction) with the ipsilateral hand. Peak-to-peak amplitudes of motor-evoked potentials were used as measure for motor cortex excitability. Results— Both simple and complex tasks led to a facilitation of the contralateral corticospinal system at all levels of applied force. Not only the facilitatory effect in general but also the slope of the relationship between force level and MEP amplitude were significantly lower in stroke patients indicating that both the general activation level of the impaired motor system and the bandwidth of possible activation levels are diminished. Conclusion— Voluntary activation of the hand does not exert an inhibitory effect on the excitability of the ipsilateral hemisphere in healthy volunteers or in stroke patients.

The influence of gender on the injury severity, course and outcome of traumatic brain injury

Objective: To examine the independent association of gender with injury severity, clinical course, pituitary dysfunction and outcome after traumatic brain injury (TBI). Design: Prospective cohort, analysis of a data sub-set collected as part of the nation-wide database ‘The Structured Data Assessment of Hypopituitarism after TBI and SAH’. Methods and procedures: Four hundred and twenty-seven patients following TBI were observed from acute care through neurological rehabilitation. Outcome was measured by Glasgow Outcome Scale (GOS), employment status and living situation post-injury. As a secondary outcome measure anterior pituitary function was assessed. Results: There were no differences in injury severity between men and women. Age had a significant effect on the GCS score (p = 0.0295), but gender did not (p = 0.4105). The outcome was equivalent between men and women once corrected for age. Logistic regression revealed that gender had no effect (p = 0.8008), but age (p = 0.0021) and initial injury severity (p = 0.0010) had an effect on the GOS. After correcting for pre-injury living situation and employment only initial injury severity (p = 0.0005) influenced GOS. Pituitary insufficiency was not affected by sex or age. Conclusion: Gender does not seem to influence the course and outcome of TBI. Outcome parameters were affected foremost by initial injury severity and by age, but not by sex.

Cortical neuromagnetic fields evoked by voluntary and passive hand movements in healthy adults

Summary Neuromagnetic fields were recorded from the left cerebral hemisphere of six healthy right-handed subjects under three different conditions: (1) externally triggered rapid voluntary extension and flexion of the right hand, (2) passive extension and flexion of the right hand, and (3) stimulation of the skin of the right index finger by means of air pressure. Location analysis using the current density analysis did not reveal any differences between motor evoked field I (MEF I) in active and passive movements, and met the maximum of cerebral activation in the contralateral precentral region. In contrast, the sensory evoked field was located clearly in the contralateral postcentral region. Additionally, a significantly shorter latency of MEF I (with respect to movement onset) was observed in flexion compared with extension in both passive and active movements. These results support the assumption that MEF I is generated by cortical activation resulting from proprioceptive, probably muscle spindle, input. The current density analysis has proved to be an appropriate method for investigating movement-related fields. Furthermore, the described method seems to be appropriate for evaluating the processes of cortical reorganization and the influence of neurorehabilitation within longitudinal studies in patients with lesions in motor centers of the brain.

Early prediction of functional outcome after stroke

Objectives: (I) To obtain biomechanical parameters and assessment scores applied at a very early stage after stroke that predict best the functional outcome after rehabilitation. (II) To evaluate the predictive value of changes (i.e. increase or decrease) of these parameters during the first week in relation to the predictive value of their absolute scores. Design: Prospective outcome study. Subjects: Forty-one stroke patients, admitted to the stroke unit within 24 hours. Main outcome measures: Barthel Index, Rivermead Motor Assessment, Motor Club Assessment and Functional movement activities, NIH-Stroke scale (NIH-SS), Grip strength. Results: Parameters assessed within the first hours after stroke correlated only weakly with the outcome. The best model predicting functional outcome and independence in activities of daily living of stroke patients after 6 months was that including NIH-SS, grip strength, age and previous stroke explaining 79% of the variance. These parameters assessed on day 7 post-stroke are more predictive than the difference between stroke onset and day 7 post-stroke. Conclusion: Parameters for predicting outcome should not be assessed before day 7 post-stroke.

Change of Strength and Rate of Rise of Tension Relate to Functional Arm Recovery After Stroke

OBJECTIVE To examine the relationship between individual strength parameters and functional motor ability over time during rehabilitation in stroke patients. DESIGN A multiple-baseline experiment with assessment at inclusion and after 3 and 6 weeks. SETTING Secondary-care rehabilitation center. PARTICIPANTS A convenience sample of 16 subacute stroke patients. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Maximal voluntary force and rate of rise of tension of hand grip, wrist extension, and elbow flexion and extension were recorded at all 3 times. At the same time, functional motor assessments were evaluated by the Action Research Arm Test (ARAT), Box and Block test, and Rivermead Test. RESULTS We found no correlation between maximal voluntary force increases of various muscle contractions measurements. Neither the increase of grip strength nor that of wrist extension force correlated with improvement in ARAT score. Yet the improvement in the rate of rise of tension of hand grip (Spearman rho=.91) and of wrist extension (Spearman rho=.73) correlated with the improvement of the ARAT score and explained 77% of the variance of the ARAT. CONCLUSIONS The change in the rate of rise of tension of the hand grip has a better predictive value for the functional recovery compared to the change in maximal voluntary force in patients with moderate arm and hand weakness after stroke. The rate of rise of tension of hand grip seems an adequate quantifiable parameter to detect small improvements during functional recovery.

Motor-evoked potentials are facilitated during perceptual identification of hand position in healthy subjects and stroke patients

Objective: To delineate the facilitatory and/or inhibitory influence of relevant and irrelevant sensory afferent information to the motor cortex. The study is based on the assumption that sensorimotor coupling is crucial for motor learning and recovery. Design: The interaction of a standard transcranial magnetic stimulus (TMS) with the facilitatory and/or inhibitory influence that proprioceptive afferent information exerts on the motor cortex was investigated. Setting: A neurological rehabilitation hospital. Subjects: Sixteen healthy subjects and 14 stroke patients. Main outcome measures: Amplitudes and latencies of motor-evoked potentials (MEPs) recorded from the extensor carpi radialis muscle. The influence of a sensory discrimination task was compared with the influence of a sensory input irrelevant for the task and to a verbal memory task. Recordings were taken after the hand had been moved passively in one of four different positions. Results: In the first trial, TMS was applied without any demand on the subjects. In the second trial, subjects were asked to identify the respective hand position and in the third trial a noun presented at a respective hand position had to be memorized and reproduced after TMS. The sensory discrimination task exerted by far the most prominent facilitatory effect on MEP amplitudes and latencies. An unspecific, albeit reproducible influence on MEP amplitudes was observed when a noun presented at a respective hand position had to be remembered. Conclusions: Using a neurophysiological approach the study demonstrates that a sensory discrimination task based on relevant afferent information to motor centres of the brain forms a prominent facilitatory intervention for those muscle groups that are involved in the task. This holds true for healthy subjects and for hemiparetic stroke patients.