The challenge point framework to improve stepping reaction and balance in children with hemiplegic cerebral palsy: A case series study

PURPOSE

This study investigated the effects of the challenge point framework (CPF) to improve stepping reactions and enhance balance in children with hemiplegic cerebral palsy (HCP). The CPF relates practice variables to the skill level of the individual and task difficulty.

METHODS

Nine children with HCP (age: 7.7±2.4 years) completed six weeks (12 sessions) of a CPF intervention which consisted of progressively fewer sets and repetitions of a stepping reaction task wherein participants sought to improve both step length and reaction rate. Stepping reaction (step length and reaction rate) to a balance perturbation in the anterior, posterior, and lateral directions and static and dynamic balance (via the Pediatric Balance Scale) were measured at baseline, a second baseline 3 weeks later, and post-intervention. Repeated measures ANOVAs determined within-group changes. Cohen's d effect sizes were calculated.

RESULTS

Participants improved balance (d = 0.948, p = 0.010), step length (forward d = 0.938, p = 0.002; backward d = 0.839, p = 0.001; and lateral d = 0.876, p = 0.002), and reaction rate (forward d = 0.249, p = 0.042; backward d = 0.21, p = 0.047; and lateral d = 0.198, p = 0.049).

CONCLUSION

These findings indicate that children with HCP may benefit from completing a CPF program with a motor learning approach. This approach of retraining stepping reactions helped to improve static and dynamic balance. The CPF may aid progression of functional task training in children with HCP aged 4-12, though more studies with a long-term follow-up analysis are needed to confirm this result.

An Examination of the Contextual Interference Effect and the Errorless Learning Model during Motor Learning

The purpose of this study was to investigate the combined effects of random and block practice, with errorless and errorful conditions, on motor learning. One hundred-twenty participants (all male, Mage = 21.19 ± 1.4 years) were randomly assigned to one of eight groups. Participants completed a dart throwing task across the experimental phases. In the retention test, evidence supporting the CI effect was found in the 'errorless' conditions, but not in the 'errorful' conditions. In the transfer tests, the findings indicated that the impact of errorless and errorful conditions on participants' automation levels depends on the structure of practice. Participants in the Random-Errorless group performed better in the transfer tests than those in the Random group and the Random-Errorful group, suggesting greater automation levels following errorless practice.

Mental Fatigue Reduces the Benefits of Self-Controlled Feedback on Learning a Force Production Task

This study investigated the impact of mental fatigue and self-controlled versus yoked feedback on learning a force production task. We randomly assigned 44 non-athlete male students (Mage = 21.4, SD = 1.4 years) to four groups; (a) MF&SCF = mental fatigue & self-controlled feedback, (b) MF&Y = mental fatigue & yoked, (c) NMF&SCF = no mental fatigue & self-controlled feedback, and (d) NMF&Y = no mental fatigue & yoked). SCF group participants were provided feedback whenever they requested it, while YK group participants received feedback according to a schedule created by their SCF counterparts. To induce mental fatigue, participants performed a Stroop color-word task for one hour. During the acquisition (practice) phase, participants were asked to produce a given percentage of their maximum force (20%) in 12 blocks of six trials. We recorded the participants' absolute error at the end of the acquisition phase, the immediate retention test, the first transfer test, and the second transfer test (after 24 hours and without any further mental fatigue). The acquisition phase data were analyzed in a 2 (feedback) × 2 (mental fatigue) × 12 (block) ANOVA with repeated measures on the last factor, while the retention and transfer data were analyzed in 2 (feedback) × 2 (mental fatigue) ANOVAs. We found that all four groups made significant progress during practice (p < .001), but there were no significant group differences during this phase (p>.05). There was a significant interaction effect of self-controlled feedback and mental fatigue at retention (p = .018) and transfer testing (p < .001). In the mental fatigue condition, participants in the self-controlled group had poorer learning compared to participants in the yoked group; but when not mentally fatigued, participants in the self-controlled group had better learning than those in the yoked group. These findings suggest that mental fatigue reduces typical advantages of self-controlled feedback in motor learning.

Effect of Physical Guidance on Learning a Tracking Task in Children with Cerebral Palsy

The purpose of this study was to investigate the effect of physical guidance (PG) frequency on learning a tracking task in children with hemiplegic spastic cerebral palsy (CP). For this purpose, 25 children, aged 7–15 years with CP affecting the left side of the body, who were classified in levels II–III of Manual Abilities Classification System (MACS) and levels III–IV of Gross Motor Function Classification System (GMFCS), were recruited from 10 clinical centers. A pre-test including two blocks of 12 trials of the tracking task without any PG was performed by all participants, after that they were assigned into five homogenous groups (with 100%, 75%, 50%, 25%, and 0% of PG) through blocked randomization according to their age. All participants involved in an intervention consisted of eight sessions (four blocks of 12 trials in each session) practicing a tracking task. The 0% PG group received no PG, the 25% PG group received PG for three trials, the 50% PG group received PG for six trials, the 75% PG group received PG for nine trials, and the 100% PG group received PG for all twelve trials. PG consisted of placing the experimenter’s hand around the child’s less-involved hand guiding to stay on the track and complete the task. Learning was inferred by acquisition and delayed retention tests. The results showed that the higher frequency of PG led to more accurate performance during practice phase. However, the group that received 75% PG had significantly better performance compared to the other groups in the retention phase. It is concluded that optimum level of PG, about 75% of trials, can be helpful for learning a tracking task in children with spastic hemiplegic CP, supporting the challenge point framework.

Motor Behavior Concepts in the Study of Balance: A Scoping Review

Previous research suggests that using Fitts' law; attentional focus or challenge point framework (CPF) is beneficial in balance control studies. A scoping review was conducted to examine studies that utilized these motor behavior concepts during balance control tasks. An extensive literature search was performed up to January 2018. Two independent reviewers conducted a study selection process followed by data extraction of the search results. Forty-six studies were identified, with 2 studies related to CPF, 12 studies related to Fitts' law and 32 studies related to focus of attention. The CPF appears to be a useful method for designing a progressive therapeutic program. Fitts' law can be used as a tool for controlling the difficulty of motor tasks. Focus of attention studies indicate that adopting an external focus of attention improves task performance. Overall, studies included in this review report benefit when using the selected motor behavior concepts. However, the majority (>80%) of studies included in the review involved healthy populations, with only three clinical trials. In order to ascertain the benefits of the selected motor behavior concepts in clinical settings, future research should focus on using these concepts for clinical trials to examine balance control among people with balance impairments.