Simona Bar-Haim

Comparison of efficacy of Adeli suit and neurodevelopmental treatments in children with cerebral palsy

This study compared the efficacy of Adeli suit treatment (AST) with neurodevelopmental treatment (NDT) in children with cerebral palsy (CP). Twenty‐four children with CP, Levels II to IV according to the Gross Motor Function Classification System (GMFCS), were matched by age and functional status and randomly assigned to the AST or NDT treatment groups. In the AST group (n=12; eight males, four females; mean age 8.3y [SD 2.0]), six children had spastic/ataxic diplegia, one triplegia and five spastic/mixed quadriplegia. In the NDT group (n=12; nine males, three females; mean age 8.1y [SD 2.2]), five children had spastic diplegia and seven had spastic/mixed quadriplegia. Both groups were treated for 4 weeks (2 hours daily, 5 days per week, 20 sessions). To compare treatments, the Gross Motor Function Measure (GMFM‐66) and the mechanical efficiency index (EIHB) during stair‐climbing were measured at baseline, immediately after 1 month of treatment, and 10 months after baseline. The small but significant time effects for GMFM‐66 and EIHB that were noted after 1 month of both intensive physiotherapy courses were greater than expected from natural maturation of children with CP at this age. Improvements in motor skills and their retention 9 months after treatment were not significantly different between the two treatment modes. Post hoc analysis indicated a greater increase in EIHB after 1 month (p=0.16) and 10 months (p=0.004) in AST than that in NDT, predominantly in the children with higher motor function (GMFCS Levels II and III). The results suggest that AST might improve mechanical efficiency without a corresponding gain in gross motor skills, especially in children with higher levels of motor function.

Effectiveness of motor learning coaching in children with cerebral palsy: a randomized controlled trial

Objective: To evaluate effectiveness of motor learning coaching on retention and transfer of gross motor function in children with cerebral palsy. Design: Block randomized trial, matched for age and gross motor function. Setting: Coordinated, multinational study (Israel, Jordan and Palestinian Authority) in schools and rehabilitation centers. Subjects: 78 children with spastic cerebral palsy, gross motor functional levels II and III, aged 66 to 146 months. Interventions: 1 hr/day, 3 days/week for 3 months treatment with motor learning coaching or neurodevelopmental treatment: two groups. Main measures: Gross motor function Measure (GMFM-66), stair-climbing mechanical efficiency (ME) and parent questionnaire rating their child’s mobility. Immediate treatment effects were assessed after 3 months and retention determined from follow-up measurements 6 months after treatment. Results: GMFM-66, ME and parent questionnaires were obtained from 65, 31 and 64 subjects, respectively. Although both groups increased GMFM-66 score over 3 months, measurements 6 months later indicated retention was significantly superior by 2.7 in the motor learning coaching children of level-II. Similar retention trend was evident for ME, increasing 6 months after motor learning coaching by 1.1% and declining 0.3% after neurodevelopmental treatment. Mobility performance in the outdoors and community environment increased 13% from 3 to 9 months after motor learning coaching and decreased 12% after neurodevelopmental treatment. Minor group differences occurred in children of level-III. Conclusions: In higher functioning children with cerebral palsy, the motor learning coaching treatment resulted in significantly greater retention of gross motor function and transfer of mobility performance to unstructured environments than neurodevelopmental treatment.

Kinetic adaptation during locomotion on a split-belt treadmill

It has been suggested that a feedforward control mechanism drives the adaptation of the spatial and temporal interlimb locomotion variables. However, the internal representation of limb kinetics during split-belt locomotion has not yet been studied. In hand movements, it has been suggested that kinetic and kinematic parameters are controlled by separate neural processes; therefore, it is possible that separate neural processes are responsible for kinetic and kinematic locomotion parameters. In the present study, we assessed the adaptation of the limb kinetics by analyzing the ground reaction forces (GRFs) as well as the center of pressure (COP) during adaptation to speed perturbation, using a split-belt treadmill with an integrated force plate. We found that both the GRF of each leg at initial contact and the COP changed gradually and showed motor aftereffects during early postadaptation, suggesting the use of a feedforward predictive mechanism. However, the GRF of each leg in the single-support period used a feedback control mechanism. It changed rapidly during the adaptation phase and showed no motor aftereffect when the speed perturbation was removed. Finally, we found that the motor adaptation of the GRF and the COP are mediated by a dual-rate process. Our results suggest two important contributions to neural control of locomotion. First, different control mechanisms are responsible for forces at single- and double-support periods, as previously reported for kinematic variables. Second, our results suggest that motor adaptation during split-belt locomotion is mediated by fast and slow adaptation processes.

Savings in locomotor adaptation explained by changes in learning parameters following initial adaptation

Faster relearning of an external perturbation, savings, offers a behavioral linkage between motor learning and memory. To explain savings effects in reaching adaptation experiments, recent models suggested the existence of multiple learning components, each shows different learning and forgetting properties that may change following initial learning. Nevertheless, the existence of these components in rhythmic movements with other effectors, such as during locomotor adaptation, has not yet been studied. Here, we study savings in locomotor adaptation in two experiments; in the first, subjects adapted to speed perturbations during walking on a split-belt treadmill, briefly adapted to a counter-perturbation and then readapted. In a second experiment, subjects readapted after a prolonged period of washout of initial adaptation. In both experiments we find clear evidence for increased learning rates (savings) during readaptation. We show that the basic error-based multiple timescales linear state space model is not sufficient to explain savings during locomotor adaptation. Instead, we show that locomotor adaptation leads to changes in learning parameters, so that learning rates are faster during readaptation. Interestingly, we find an intersubject correlation between the slow learning component in initial adaptation and the fast learning component in the readaptation phase, suggesting an underlying mechanism for savings. Together, these findings suggest that savings in locomotion and in reaching may share common computational and neuronal mechanisms; both are driven by the slow learning component and are likely to depend on cortical plasticity.

Duration and patterns of habitual physical activity in adolescents and young adults with cerebral palsy

Adolescents and young adults with cerebral palsy (CP) show reduced motor function and gait efficiency, and lower levels of habitual physical activity (HPA), than adolescents with typical development and children with CP. This study examined activity duration and patterns in this population in the Middle East through long‐term monitoring of a large sample using accelerometers.

Random perturbation: A potential aid in treatment of children with cerebral palsy

Background and purpose. The motor behaviour of children with cerebral palsy (CP) can be viewed in terms of a stable mode with very little flexibility that prevents adaptation to tasks. We hypothesized that the use of random perturbations (RP) would weaken excessive stability, introduce flexibility and enhance the effects of physical treatment. The objective was to evaluate the contribution of RP to gross motor function and mechanical efficiency (MEg) during intensive physiotherapy in children with CP. Methods. A convenience sample of 20 children with CP (mean age 8.2, range: 5.9 – 12.9 yrs) were matched by age and GMFCS level, and randomly assigned to structured intensive treatment (SIT) or to SIT + RP groups. Groups received one month of daily treatment. RP was applied by engine-induced random passive cycling for upper and lower limbs for up to 10 min in a 90-min treatment session. Gross Motor Function Measure (GMFM)-66 and gross mechanical efficiency (MEg) during stair climbing (MEg) were measured before and after treatment. Results. GMFM-66 scores increased by about 1.0 in both groups. However, external work and MEg increased significantly more in SIT + RP than SIT. The increase in MEg in SIT + RP was independent of the level of motor function at baseline. Conclusion. The addition of RP in treatment of children with CP may have weakened previously established stereotypical motor patterns and introduced flexibility, thereby improving mechanical efficiency of a complex motor task. RP may enhance the effects of intensive treatment.

Lack of Predictive Control in Lifting Series of Virtual Objects by Individuals With Diplegic Cerebral Palsy

To date, research on the motor control of hand function in cerebral palsy has focused on children with hemiplegia, although many persons with diplegic cerebral palsy (dCP) have asymmetrically decreased hand function. We explored the predictive capabilities of the motor system in a simple motor task of lifting a series of virtual objects for five persons with spastic dCP and five age-matched controls. When a person lifts an object, s/he uses an expectation of the weight of the object to generate a motor command. We asked the study subjects to lift a series of increasing weights and determined whether they extrapolated from past experience to predict the next weight in the series, even though that weight had never been experienced. Planning of precision grasp was assessed by measurement of the grip force at the beginning of the lifting task and by estimating the motor command. Execution of precision grasp was assessed by measurement of the time interval between the onset of grip and the onset of movement. We found that persons with dCP demonstrated a lack of predictive feed-forward control in their lifting movements: they exhibited a significantly longer time between onset of grip and onset of movement than the control subjects and they did not predict the weight of the next object in the lifting task. In addition, for subjects with dCP, the time between the onset of grip and the onset of movement of the dominant hand correlated strongly with the outcome of a hand function test. We postulate that a higher-order motor planning deficit in addition to execution deficit are evident in the subjects with spastic diplegic.

Increased Adaptation Rates and Reduction in Trial-by-Trial Variability in Subjects with Cerebral Palsy Following a Multi-session Locomotor Adaptation Training

Cerebral Palsy (CP) results from an insult to the developing brain and is associated with deficits in locomotor and manual skills and in sensorimotor adaptation. We hypothesized that the poor sensorimotor adaptation in persons with CP is related to their high execution variability and does not reflect a general impairment in adaptation learning. We studied the interaction between performance variability and adaptation deficits using a multi-session locomotor adaptation design in persons with CP. Six adolescents with diplegic CP were exposed, during a period of 15 weeks, to a repeated split-belt treadmill perturbation spread over 30 sessions and were tested again 6 months after the end of training. Compared to age-matched healthy controls, subjects with CP showed poor adaptation and high execution variability in the first exposure to the perturbation. Following training they showed marked reduction in execution variability and an increase in learning rates. The reduction in variability and the improvement in adaptation were highly correlated in the CP group and were retained 6 months after training. Interestingly, despite reducing their variability in the washout phase, subjects with CP did not improve learning rates during washout phases that were introduced only four times during the experiment. Our results suggest that locomotor adaptation in subjects with CP is related to their execution variability. Nevertheless, while variability reduction is generalized to other locomotor contexts, the development of savings requires both reduction in execution variability and multiple exposures to the perturbation.

Mechanical efficiency and balance in adolescents and young adults with cerebral palsy.

Mechanical efficiency (ME) during stair-climbing measures ambulation ability. This study investigated the relationship between ME and age, anthropometric, functional walking, and balance parameters in 52 adolescents with cerebral palsy (CP), age 13.5-23.3 yrs, who participated in an intervention study to improve walking. Measurements included ME, 6-min and 10-m walk tests and the Berg balance scale (BBS). Walk test measures correlated significantly with ME, as expected, as did BBS (r=0.68) and age (r=0.51). The multiple correlation coefficient with both age and BBS increased to 0.80. The measurements were divided into two groups of low (<40, n=19) and high (>40, n=33) BBS scores. Repeating regression analyses, demonstrated that in the low BBS group ME was significantly related to BBS, but not age, in contrast to opposite results in the high BBS group. Regressions were calculated for each of the 14 items of the BBS with ME. For the whole group, 12 items correlated significantly, but only three in the high BBS group (one leg standing, reach while standing and tandem standing). In the low BBS group 10 of the items correlated significantly, with the former three ranking near the top. Balance is an important component of ambulation in children with CP. Mobility in those scoring>40 is related to age, but in those more deficient in balance (<40) mobility is more closely associated with balance than age. Effective therapy to improve walking in younger children might incorporate more balance-focused exercises, similar to those related to BBS items strongly associated with ME.

A stair-climbing test for measuring mechanical efficiency of ambulation in adults with chronic stroke.

Abstract Purpose: Mechanical efficiency can assess motor performance in individuals with physical disabilities. The purpose was to determine the utility of predicting it from heart rate (HR) during a self-paced stair-climbing test in adults with chronic hemiparesis after stroke and to determine the minimal detectable change of net mechanical efficiency (MEnet) measured by this exercise. Methods: First, 15 subjects with chronic hemiparesis participated in a validation study (A) and then 28 took part in a repeatability study (B). In study A the MEnet was calculated from external work and oxygen uptake above rest (dVO2), as directly measured and as predicted from body weight and increase in heart rate (dHR). In study B, predicted dVO2 was used to obtain MEnet for duplicate stair-climbing tests (T1, T2) with >30 min rest between. Results: Measured MEnet was closely related to predicted MEnet (r = 0.97, p < 0.001). In study B predicted MEnet for T2 and T1 were closely related (r = 0.91, ICC = 0.90). Conclusion: With a minimal detectable change of 0.6% (0.053 of average MEnet score of 10.4%), MEnet values from the stair-climbing test seem sufficiently meaningful to estimate ambulatory ability and its changes with interventions or walking aids in adults with hemiparesis. Implications for Rehabilitation Ambulatory ability can be estimated from mechanical efficiency, obtained from a 5-min stair-climbing test utilizing a 4-step stair, to measure external work, and the change in heart rate above rest to estimate the metabolic cost of the task. A change of > 0.6% in mechanical efficiency by this stair-climbing test indicates a significant change in ambulatory ability of persons with hemiparesis.