A.C.H. Geurts

Definition dependent properties of the cortical silent period in upper-extremity muscles, a methodological study

BackgroundTo explore if stimulus–response (S-R) characteristics of the silent period (SP) after transcranial magnetic stimulation (TMS) are affected by changing the SP definition and by changing data presentation in healthy individuals. This information would be clinically relevant to predict motor recovery in patients with stroke using stimulus–response curves.MethodsDifferent landmarks to define the SP onset and offset were used to construct S-R curves from the biceps brachii (BB) and abductor digiti minimi (ADM) muscles in 15 healthy participants using rectified versus non-rectified surface electromyography (EMG). A non-linear mixed model fit to a sigmoid Boltzmann function described the S-R characteristics. Differences between S-R characteristics were compared using paired sample t-tests. The Bonferroni correction was used to adjust for multiple testing.ResultsFor the BB, no differences in S-R characteristics were observed between different SP onset and offset markers, while there was no influence of data presentation either. For the ADM, no differences were observed between different SP onset markers, whereas both the SP offset marker “the first return of any EMG-activity” and presenting non-rectified data showed lower active motor thresholds and less steep slopes.ConclusionsThe use of different landmarks to define the SP offset as well as data presentation affect SP S-R characteristics of the ADM in healthy individuals.

EUROPEAN CONSENSUS TABLE ON THE USE OF BOTULINUM TOXIN TYPE A IN ADULT SPASTICITY

A group of clinicians from across Europe experienced in the use of botulinum toxin type A for the treatment of spasticity following acquired brain injury gathered to develop a consensus statement on best practice in managing adults with spasticity. This consensus table summarizes the current published data, which was collated following extensive literature searches, their assessment for level of evidence and discussion among the whole group. Published information is supplemented by expert opinion based on clinical experience from 16 European countries, involving 28 clinicians, who treat an average of approximately 200 patients annually, representing many thousand spasticity treatments with botulinum toxin per year.

The Effectiveness of the Bobath Concept in Stroke Rehabilitation: What is the Evidence?

Background and Purpose— In the Western world, the Bobath Concept or neurodevelopmental treatment is the most popular treatment approach used in stroke rehabilitation, yet the superiority of the Bobath Concept as the optimal type of treatment has not been established. This systematic review of randomized, controlled trials aimed to evaluate the available evidence for the effectiveness of the Bobath Concept in stroke rehabilitation. Method— A systematic literature search was conducted in the bibliographic databases MEDLINE and CENTRAL (March 2008) and by screening the references of selected publications (including reviews). Studies in which the effects of the Bobath Concept were investigated were classified into the following domains: sensorimotor control of upper and lower limb; sitting and standing, balance control, and dexterity; mobility; activities of daily living; health-related quality of life; and cost-effectiveness. Due to methodological heterogeneity within the selected studies, statistical pooling was not considered. Two independent researchers rated all retrieved literature according to the Physiotherapy Evidence Database (PEDro) scale from which a best evidence synthesis was derived to determine the strength of the evidence for both effectiveness of the Bobath Concept and for its superiority over other approaches. Results— The search strategy initially identified 2263 studies. After selection based on predetermined criteria, finally, 16 studies involving 813 patients with stroke were included for further analysis. There was no evidence of superiority of Bobath on sensorimotor control of upper and lower limb, dexterity, mobility, activities of daily living, health-related quality of life, and cost-effectiveness. Only limited evidence was found for balance control in favor of Bobath. Because of the limited evidence available, no best evidence synthesis was applied for the health-related quality-of-life domain and cost-effectiveness. Conclusions— This systematic review confirms that overall the Bobath Concept is not superior to other approaches. Based on best evidence synthesis, no evidence is available for the superiority of any approach. This review has highlighted many methodological shortcomings in the studies reviewed; further high-quality trials need to be published. Evidence-based guidelines rather than therapist preference should serve as a framework from which therapists should derive the most effective treatment.

Identification of static and dynamic postural instability following traumatic brain injury

OBJECTIVE Quantitative evaluation of static and dynamic aspects of postural instability as a long-term consequence of traumatic brain injury (TBI). DESIGN Experimental two-group design. SETTING Outpatient rehabilitation department. PATIENTS AND OTHER PARTICIPANTS From a consecutive sample of TBI patients at least 6 months after trauma, 20 subjects were selected who complained of reduced gross motor skills but showed no sensorimotor impairments in a standard neurological examination (11 men, 9 women; mean age 36.2 +/- 10.7 years). Thirteen patients had sustained mild, 2 moderate, and 5 severe TBI. Twenty healthy controls were matched for age and gender. INTERVENTION None. MAIN OUTCOME MEASURES A dual-plate force platform recorded the amplitude and velocity of the center-of-pressure fluctuations in the anteroposterior (AP) and lateral (LAT) sway directions during quiet standing. Also, the speed and fluency of weight shifting using visual feedback was registered. Both balance tasks were combined with an arithmetic task, whereas quiet standing was also tested with visual deprivation. RESULTS Compared to controls, TBI patients showed an increase of over 50% in AP and LAT sway, and a weight-shifting speed 20% lower. Dual-task interference was never significant. Visual deprivation was most detrimental for the TBI patients, particularly for LAT sway control. CONCLUSION A long-term overall reduction in both static and dynamic control of posture can be present after TBI, even in patients without clear neurological deficits. Force-plate recordings can identify such (latent) balance problems. Visual deprivation during quiet standing appears a simple, sensitive test for postural instability related to sensory integration deficits.

A Five-Week Exercise Program Can Reduce Falls and Improve Obstacle Avoidance in the Elderly

Background: Falls in the elderly are a major health problem. Although exercise programs have been shown to reduce the risk of falls, the optimal exercise components, as well as the working mechanisms that underlie the effectiveness of these programs, have not yet been established. Objective: To test whether the Nijmegen Falls Prevention Program was effective in reducing falls and improving standing balance, balance confidence, and obstacle avoidance performance in community-dwelling elderly people. Methods: A total of 113 elderly with a history of falls participated in this study (exercise group, n = 79; control group, n = 28; dropouts before randomization, n = 6). Exercise sessions were held twice weekly for 5 weeks. Pre- and post-intervention fall monitoring and quantitative motor control assessments were performed. The outcome measures were the number of falls, standing balance and obstacle avoidance performance, and balance confidence scores. Results: The number of falls in the exercise group decreased by 46% (incidence rate ratio (IRR) 0.54, 95% confidence interval (CI) 0.36–0.79) compared to the number of falls during the baseline period and by 46% (IRR 0.54, 95% CI 0.34–0.86) compared to the control group. Obstacle avoidance success rates improved significantly more in the exercise group (on average 12%) compared to the control group (on average 6%). Quiet stance and weight-shifting measures did not show significant effects of exercise. The exercise group also had a 6% increase of balance confidence scores. Conclusion: The Nijmegen Falls Prevention Program was effective in reducing the incidence of falls in otherwise healthy elderly. There was no evidence of improved control of posture as a mechanism underlying this result. In contrast, an obstacle avoidance task indicated that subjects improved their performance. Laboratory obstacle avoidance tests may therefore be better instruments to evaluate future fall prevention studies than posturographic balance assessments.

Postural control and cognitive task performance in healthy participants while balancing on different support-surface configurations

Postural control during normal upright stance in humans is a well-learned task. Hence, it has often been argued that it requires very little attention. However, many studies have recently shown that postural control is modified when a cognitive task is executed simultaneously especially in the elderly and in the presence of pathology. This study examined postural control modifications when a cognitive task of varying difficulty levels is added. Postural stance difficulty was also varied. Results from this study suggest that a generalized capacity interference may occur due to the larger interference found with the addition of a cognitive task in the more novel and difficult postural task. Because the performance of the cognitive task was tapered by a speed-difficulty trade-off, it was not possible to determine whether a change in the level of difficulty of the cognitive task occurred and if it would produce larger dual-task interference.

Effectiveness of modified constraint-induced movement therapy in children with unilateral spastic cerebral palsy: a randomized controlled trial.

Background. In children with unilateral spastic cerebral palsy (CP), there is only limited evidence for the effectiveness of modified constraint-induced movement therapy (mCIMT). Objective. To investigate whether 6 weeks of mCIMT followed by 2 weeks of bimanual task-specific training (mCIMT-BiT) in children with unilateral spastic CP improves the spontaneous use of the affected limb in both qualitative and quantitative terms more than usual care (UC) of the same duration. Methods. Children with unilateral spastic CP with Manual Ability Classification System (MACS) scores I, II, or III and aged 2.5 to 8 years were recruited and randomly allocated to either the mCIMT-BiT group (three 3-hour sessions per week: 6 weeks of mCIMT, followed by 2 weeks of task-specific training in goal-directed bimanual play and self-care activities) or to 1.5 hours of more general physical or occupational weekly plus encouragement to use the affected hand for the UC group. Primary outcome measures were the Assisting Hand Assessment and the ABILHAND-Kids. Secondary outcomes were the Melbourne Assessment of Unilateral Upper Limb Function, the Canadian Occupational Performance Measure, and the Goal Attainment Scale. Results. Twenty-eight children were allocated to mCIMT-BiT and 24 to UC. Except for the Melbourne, all primary and secondary outcome measures demonstrated significant improvements in the mCIMT-BiT group. Conclusion. mCIMT followed by task-specific training of goal-directed bimanual play and self-care activities is an effective intervention to improve the spontaneous use of the more affected upper limb in children with relatively good baseline upper extremity function.

Short-term Effects of Whole-body Vibration on Postural Control in Unilateral Chronic Stroke Patients: Preliminary Evidence

van Nes IJW, Geurts ACH, Hendricks HT, Duysens J: Short-term effects of whole-body vibration on postural control in unilateral chronic stroke patients: Preliminary evidence. Am J Phys Med Rehabil 2004;83:867–873. The short-term effects of whole-body vibration as a novel method of somatosensory stimulation on postural control were investigated in 23 chronic stroke patients. While standing on a commercial platform, patients received 30-Hz oscillations at 3 mm of amplitude in the frontal plane. Balance was assessed four times at 45-min intervals with a dual-plate force platform, while quietly standing with the eyes opened and closed and while performing a voluntary weight-shifting task with visual feedback of center-of-pressure movements. Between the second and third assessments, four repetitions of 45-sec whole-body vibrations were given. The results indicated a stable baseline performance from the first to the second assessment for all tasks. After the whole-body vibration, the third assessment demonstrated a reduction in the root mean square (RMS) center-of-pressure velocity in the anteroposterior direction when standing with the eyes closed (P < 0.01), which persisted during the fourth assessment. Furthermore, patients showed an increase in their weight-shifting speed at the third balance assessment (P < 0.05) while their precision remained constant. No adverse effects of whole-body vibration were observed. It is concluded that whole-body vibration may be a promising candidate to improve proprioceptive control of posture in stroke patients.

A clinical prediction rule for ambulation outcomes after traumatic spinal cord injury: a longitudinal cohort study

BACKGROUND Traumatic spinal cord injury is a serious disorder in which early prediction of ambulation is important to counsel patients and to plan rehabilitation. We developed a reliable, validated prediction rule to assess a patients chances of walking independently after such injury. METHODS We undertook a longitudinal cohort study of adult patients with traumatic spinal cord injury, with early (within the first 15 days after injury) and late (1-year follow-up) clinical examinations, who were admitted to one of 19 European centres between July, 2001, and June, 2008. A clinical prediction rule based on age and neurological variables was derived from the international standards for neurological classification of spinal cord injury with a multivariate logistic regression model. Primary outcome measure 1 year after injury was independent indoor walking based on the Spinal Cord Independence Measure. Model performances were quantified with respect to discrimination (area under receiver-operating-characteristics curve [AUC]). Temporal validation was done in a second group of patients from July, 2008, to December, 2009. FINDINGS Of 1442 patients with spinal cord injury, 492 had available outcome measures. A combination of age (<65 vs ≥65 years), motor scores of the quadriceps femoris (L3), gastrocsoleus (S1) muscles, and light touch sensation of dermatomes L3 and S1 showed excellent discrimination in distinguishing independent walkers from dependent walkers and non-walkers (AUC 0·956, 95% CI 0·936-0·976, p<0·0001). Temporal validation in 99 patients confirmed excellent discriminating ability of the prediction rule (AUC 0·967, 0·939-0·995, p<0·0001). INTERPRETATION Our prediction rule, including age and four neurological tests, can give an early prognosis of an individuals ability to walk after traumatic spinal cord injury, which can be used to set rehabilitation goals and might improve the ability to stratify patients in interventional trials. FUNDING Internationale Stiftung für Forschung in Paraplegie.

Assessment of motor recovery and decline

Assessment of motor disorders forms an important ingredient of neurology, rehabilitation medicine and orthopaedics. Until now, however, many of the employed assessment tools are derived from empirical knowledge. Almost no relation exists with modern theoretical notions about motor control. In the present article, motor control theory is reviewed in the light of its potential contribution to understanding motor recovery. An attempt is made to present a theoretical framework for the assessment of motor disorders related to recent insights in motor control. The framework emphasizes the dynamical character of recovery. The principle of output optimization is discussed and it is stressed that compensation plays a permanent role in adapting to damage of the body or to changes in the environment. An assessment procedure is introduced to measure the (mental) costs of this compensation. It is argued that changes in the costs of compensation across time reflect recovery.