Deliberately Light Interpersonal Contact Affects the Control of Head Stability During Walking in Children and Adolescents With Cerebral Palsy.

OBJECTIVE: To evaluate the potential of deliberately light interpersonal touch (IPT) for reducing excessive head and trunk sway during self-paced walking in children and adolescents with cerebral palsy (CP). DESIGN: Quasi-experimental, proof-of-concept study with between-groups comparison. SETTING: Ambulant care facility, community center. PARTICIPANTS: Children and adolescents (N=65), consisting of those with CP (spastic and ataxic, n=26; Gross Motor Function Classification System I-III; mean age, 9.8y; 11 girls, 15 boys) and those who were typically developed (TD, n=39; mean age, 10.0y; 23 girls, 16 boys). INTERVENTIONS: IPT applied by a therapist to locations at the back and the head. MAIN OUTCOME MEASURES: As primary outcomes, head and trunk sway during self-paced walking were assessed by inertial measurement units. Secondary outcomes were average step length and gait speed. RESULTS: CP group: apex and occiput IPT reduced head velocity sway compared with thoracic IPT (both P=.04) irrespective of individuals' specific clinical symptoms. TD group: all testing conditions reduced head velocity sway compared with walking alone (all P≤.03), as well as in apex and occiput IPT compared with paired walking (both P≤.02). CONCLUSIONS: Deliberately light IPT at the apex of the head alters control of head sway in children and adolescents with CP. The effect of IPT varies as a function of contact location and acts differently in TD individuals.

Relationship between the quality of children's handwriting and the Beery Buktenica developmental test of visuomotor integration after one year of writing tuition.

OBJECTIVE: We examined whether the three subtests of the Beery Buktenica developmental test of visuomotor integration predicted quality of handwriting across and within groups of boys and girls classified as proficient, at risk or non-proficient writers according to the Concise Assessment Scale for Children's Handwriting. METHOD: The Beery Buktenica developmental test of visuomotor integration and the Concise Assessment Scale for Children's Handwriting tests were administered to 240 grade 2 children. RESULTS: Proficient writers scored better on the visuomotor integration subtest than non-proficient writers, while proficient and at risk writers scored better than non-proficient writers on the motor coordination subtest. No differences were found on the visual perception subtest. Girls were more often classified as proficient writers than boys, and they scored better on the motor coordination subtest. Across groups, regression indicated that gender and both the visuomotor integration subtest and the motor coordination subtest were significant predictors for the quality of handwriting (i.e., accounted for 17% of the variance). CONCLUSIONS: After one year of writing tuition, the visuomotor integration subtest (and to a lesser extent the motor coordination subtest) but not the visual perception subtest significant relates to quality of children's handwriting as measured with the Concise Assessment Scale for Children's Handwriting. However, the relatively little variance explained also points to other abilities and/or task constraints that underlie quality of handwriting.

Upper limb activity in children with unilateral spastic cerebral palsy: the role of vision in movement strategies.

This article reviews the capacity of children with unilateral spastic cerebral palsy (USCP) to (re)organize the available degrees of freedom and to use visual information in interceptive actions during motion with either the impaired or the less-impaired hand. Atypical reaching movements, such as increased trunk movement or slower wrist velocity, are considered adaptive coordination patterns that are the result of a change in the constraints. It is argued that manipulation of the task context facilitates children with USCP to enhance performance. For example, when reducing the time available to intercept a ball, the children are found to exceed their usual maximum walking speed and to increase range of motion of the elbow. In addition, the children appear to rely on a visual information strategy similar to typically developing children ('bearing angle'), although more variability is observed when using the impaired arm. The implications for interventions are, it should be recognized, that these children adapt to the impairment by reorganizing the movement system and that this process can be influenced by changing the task context. Attention should be paid to the importance of using correct visual cues for initiation and guidance of interceptive actions, which may be provoked by using external visual triggers.

The Effects of Number and Separation of Support Lines on the Size, Velocity, and Smoothness of Handwriting.

We examined the effects of number of and separation between support lines on handwriting characteristics of primary school students with satisfactory and unsatisfactory handwriting. Students (mean age 7.9 years) copied a text on paper with a baseline and with two or four support lines with a separation of 3 or 4 mm between the central lines. Handwriting size, velocity, and smoothness were determined for the four conditions relative to baseline. Children with unsatisfactory handwriting wrote larger and had more lifts during baseline condition. Writing between support lines, especially with small separation, immediately reduced the size of handwriting, but also adversely affected velocity and smoothness. Future research is needed to assess long-term effects.

The positive effect of mirror visual feedback on arm control in children with spastic hemiparetic cerebral palsy is dependent on which arm is viewed.

Mirror visual feedback has previously been found to reduce disproportionate interlimb variability and neuromuscular activity in the arm muscles in children with Spastic Hemiparetic Cerebral Palsy (SHCP). The aim of the current study was to determine whether these positive effects are generated by the mirror per se (i.e. the illusory perception of two symmetrically moving limbs, irrespective of which arm generates the mirror visual feedback) or by the visual illusion that the impaired arm has been substituted and appears to move with less jerk and in synchrony with the less-impaired arm (i.e. by mirror visual feedback of the less-impaired arm only). Therefore, we compared the effect of mirror visual feedback from the impaired and the less-impaired upper limb on the bimanual coupling and neuromuscular activity during a bimanual coordination task. Children with SHCP were asked to perform a bimanual symmetrical circular movement in three different visual feedback conditions (i.e. viewing the two arms, viewing only one arm, and viewing one arm and its mirror image), combined with two head orientation conditions (i.e. looking from the impaired and looking from the less-impaired body side). It was found that mirror visual feedback resulted in a reduction in the eccentric activity of the Biceps Brachii Brevis in the impaired limb compared to the condition with actual visual feedback from the two arms. More specifically, this effect was exclusive to mirror visual feedback from the less-impaired arm and absent when mirror visual feedback from the impaired arm was provided. Across conditions, the less-impaired arm was the leading limb, and the nature of this coupling was independent from visual condition or head orientation. Also, mirror visual feedback did not affect the intensity of the mean neuromuscular activity or the muscle activity of the Triceps Brachii Longus. It was concluded that the positive effects of mirror visual feedback in children with SHCP are not just the result of the perception of two symmetrically moving limbs. Instead, in order to induce a decrease in eccentric neuromuscular activity in the impaired limb, mirror visual feedback from the 'unaffected' less-impaired limb is required.

Persistent handwriting problems are hard to predict: A longitudinal study of the development of handwriting in primary school.

BACKGROUND: After one year of tuition, up to a third of primary school children show insufficient handwriting. It is unclear whether this early insufficient handwriting predicts persistent handwriting problems, because there is a dearth of studies that followed developmental trajectories longitudinally. AIMS: To describe handwriting development in primary school children longitudinally and to determine predictive positive value and sensitivity of early handwriting assessment. To analyse whether underlying abilities helps early identification of persistent handwriting problems. METHODS: 173 primary school children were yearly assessed for four years using the Concise Assessment Scale for Children's Handwriting and the Beery Buktenica developmental test of visual-motor integration. RESULTS: Both quality and speed of handwriting increased with years of tuition, with a pronounced increase in quality between two and three years of writing tuition. Sensitivity and positive predictive value were low. The only significant predictor of handwriting quality was handwriting quality in the previous year. For handwriting speed, no significant developmental model was revealed. CONCLUSIONS: Quality and speed of handwriting after one year of tuition is not sufficiently predictive for distinguishing between transient insufficient handwriting and persistent handwriting problems three years later. Practitioners should hold back when referring children for remedial teaching.

Patterns of postural sway in high anxious children.

BACKGROUND: Current research suggests that elevated levels of anxiety have a negative impact on the regulation of balance. However, most studies to date examined only global balance performance, with little attention to the way body posture is organized in space and time. The aim of this study is to examine whether posturographic measures can reveal (sub)clinical balance deficits in children with high levels of anxiety. METHODS: We examined the spatio-temporal structure of the centre-of-pressure (COP) fluctuations in children with elevated levels of anxiety and a group of typically developing children while maintaining quiet stance on a force plate in various balance challenging conditions. Balance was challenged by adopting sensory manipulations (standing with eyes closed and/or standing on a foam surface) and using a cognitive manipulation (dual-tasking). RESULTS: Across groups, postural performance was strongly influenced by the sensory manipulations, and hardly by the cognitive manipulation. We also found that children with anxiety had overall more postural sway, and that their postural sway was overall less complex than sway of typically developing children. The postural differences between groups were present even in the simple baseline condition, and the group differences became larger with increasing task difficulty. CONCLUSION: The pattern of postural sway suggests that balance is overall less stable and more attention demanding in children with anxiety than typically developing children. The findings provide further evidence for a neuro-behavioral link between psychopathology and the effectiveness of postural control.

Children with cerebral palsy exhibit greater and more regular postural sway than typically developing children.

Following recent advances in the analysis of centre-of-pressure (COP) recordings, we examined the structure of COP trajectories in ten children (nine in the analyses) with cerebral palsy (CP) and nine typically developing (TD) children while standing quietly with eyes open (EO) and eyes closed (EC) and with concurrent visual COP feedback (FB). In particular, we quantified COP trajectories in terms of both the amount and regularity of sway. We hypothesised that: (1) compared to TD children, CP children exhibit a greater amount of sway and more regular sway and (2) concurrent visual feedback (creating an external functional context for postural control, inducing a more external focus of attention) decreases both the amount of sway and sway regularity in TD and CP children alike, while closing the eyes has opposite effects. The data were largely in agreement with both hypotheses. Compared to TD children, the amount of sway tended to be larger in CP children, while sway was more regular. Furthermore, the presence of concurrent visual feedback resulted in less regular sway compared to the EO and EC conditions. This effect was less pronounced in the CP group where posturograms were most regular in the EO condition rather than in the EC condition, as in the control group. Nonetheless, we concluded that CP children might benefit from therapies involving postural tasks with an external functional context for postural control.

Is there an effect of prenatal breech position on locomotion at 2.5 years?

The long-term effects of intra-uterine breech position on postnatal development of motor functions have not been systematically investigated. The aim of the present study was to investigate the possible effect of prenatal breech position on locomotion. Two complementary studies were conducted. Firstly, a gait analysis was carried out. Secondly, in a functional task the children were challenged to cross a gap until their maximum attainable crossing distance was reached. The mean age of the twenty-one children who participated in this study was 32.1 months (SD=4). Children who had lain in prenatal breech position (n=10) had a walking pattern comparable to the control group (n=11). There were no differences in step length, step width, foot rotation, foot rotation asymmetry, hip flexion, hip extension and range of motion of the hip. Thus, prenatal breech position, although a long-term effect was found, does not seem to have functional consequences on locomotion. However, the total amount of extra hip motion during the gap crossing was significantly smaller in children who had lain in breech position compared to the control group. This was due to significant less extra hip flexion at the side of the leading leg. Nevertheless, comparable maximum gaps were crossed in both groups. Apparently, these children had a different solution of the challenging task of gap crossing. They compensated the lack of extra hip flexion by applying more extra hip extension.

Dynamical structure of center-of-pressure trajectories with and without functional taping in children with cerebral palsy level I and II of GMFCS.

Postural control during quiet standing was examined in typical children (TD) and children with cerebral palsy (CP) level I and II of GMFCS. The immediate effect on postural control of functional taping on the thighs was analyzed. We evaluated 43 TD, 17 CP children level I, and 10 CP children level II. Participants were evaluated in two conditions (with and without taping). The trajectories of the center of pressure (COP) were analyzed by means of conventional posturography (sway amplitude, sway-path-length) and dynamic posturography (degree of twisting-and-turning, sway regularity). Both CP groups showed larger sway amplitude than the TD while only the CP level II showed more regular COP trajectories with less twisting-and-turning. Functional taping didn't affect sway amplitude or sway-path-length. TD children exhibited more twisting-and-turning with functional taping, whereas no effects on postural sway dynamics were observed in CP children. Functional taping doesn't result in immediate changes in quiet stance in CP children, whereas in TD it resulted in faster sway corrections. Children level II invest more attention in postural control than level I, and TD. While quiet standing was more automatized in children level I than in level II, both CP groups showed a less stable balance than TD.

No single factor has priority in action development a tribute to Esther Thelen's legacy.

Among Esther Thelen's most important contributions to developmental theory is that there is no single factor that has priority in driving development. In this paper, we discuss how this notion influenced our research on perceptual-motor development. We show that multiple factors constrain perceptual-motor development, but that a relatively minor change in one of them may lead to significant changes in the observed perceptual-motor behavior.

Health-Related Fitness, Motor Coordination, and Physical and Sedentary Activities of Urban and Rural Children in Suriname.

BACKGROUND: Health-related fitness (HRF) and motor coordination (MC) can be influenced by children's environment and lifestyle behavior. This study evaluates the association between living environment and HRF, MC, and physical and sedentary activities of children in Suriname. METHODS: Tests were performed for HRF (morphological, muscular, and cardiorespiratory component), gross MC (Körperkoordinations Test für Kinder), fine MC (Movement Assessment Battery for Children), and self-reported activities in 79 urban and 77 rural 7-year-old Maroon children. Urban-rural differences were calculated by an independent sample t test (Mann-Whitney U test if not normally distributed) and χ2 test. RESULTS: No difference was found in body mass index, muscle strength, and the overall score of gross and fine MC. However, urban children scored lower in HRF on the cardiorespiratory component (P ≤ .001), in gross MC on walking backward (P = .014), and jumping sideways (P = 0.011). They scored higher in the gross MC component moving sideways (P ≤ .001) and lower in fine MC on the trail test (P = .036) and reported significantly more sedentary and fewer physical activities than rural children. CONCLUSIONS: Living environment was associated with certain components of HRF, MC, and physical and sedentary activities of 7-year-old children in Suriname. Further research is needed to evaluate the development of urban children to provide information for possible intervention and prevention strategies.

Reflections on mirror therapy: a systematic review of the effect of mirror visual feedback on the brain.

BACKGROUND: Mirror visual feedback (MVF), a phenomenon where movement of one limb is perceived as movement of the other limb, has the capacity to alleviate phantom limb pain or promote motor recovery of the upper limbs after stroke. The tool has received great interest from health professionals; however, a clear understanding of the mechanisms underlying the neural recovery owing to MVF is lacking. OBJECTIVE: We performed a systematic review to assess the effect of MVF on brain activation during a motor task. METHODS: We searched PubMed, CINAHL, and EMBASE databases for neuroimaging studies investigating the effect of MVF on the brain. Key details for each study regarding participants, imaging methods, and results were extracted. RESULTS: The database search yielded 347 article, of which we identified 33 suitable for inclusion. Compared with a control condition, MVF increases neural activity in areas involved with allocation of attention and cognitive control (dorsolateral prefrontal cortex, posterior cingulate cortex, S1 and S2, precuneus). Apart from activation in the superior temporal gyrus and premotor cortex, there is little evidence that MVF activates the mirror neuron system. MVF increases the excitability of the ipsilateral primary motor cortex (M1) that projects to the "untrained" hand/arm. There is also evidence for ipsilateral projections from the contralateral M1 to the untrained/affected hand as a consequence of training with MVF. CONCLUSION: MVF can exert a strong influence on the motor network, mainly through increased cognitive penetration in action control, though the variance in methodology and the lack of studies that shed light on the functional connectivity between areas still limit insight into the actual underlying mechanisms.

Postural adaptation during arm raising in children with and without unilateral cerebral palsy.

Postural sway during arm movements were related to the size of the base of support (BOS) and the limits of stability (LOS) of children with unilateral cerebral palsy (USCP) and typically developing (TD) children. For half of the trials the mechanical disturbance due to the rapid arm movement was increased by attaching small weights at the wrists. The participants stood with both feet on a large force plate, which recorded the displacements of the center of pressure (CoP). The results showed that in the children with USCP the LOS forward and toward the non-dominant (more-affected) side were smaller than in the TD children whereas the LOS backward and toward the dominant (less-affected) side did not differ between the two groups. When rapidly moving the arms the children with USCP swayed over a larger portion of their base of support in the forward direction and toward their more-affected side. In addition, the maximal sway toward the more-affected side during arm movement exceeded the LOS while balance was maintained. These effects increased when the movements were performed with the weights at the wrists. These results show that an area of permissible sway, which was not spontaneously explored during the leaning task, was required to maintain balance during the supra-postural task. Training to enlarge the LOS that includes weight shifts toward the more-affected side might reduce the area of the BOS that is self-perceived as less secure.

Practicing a matching movement with a mirror in individuals with spastic hemiplegia.

This experimental study aimed to determine the effect of practicing a position matching task with (mirror) visual feedback of the less-impaired arm on the matching accuracy of the impaired arm in children and adolescents with spastic hemiparetic cerebral palsy. Practice consisted of 40 trials of bimanual target matching, where one group received regular visual feedback and a second group received mirror visual feedback of the less-impaired arm. On three occasions (pre, post, and after a 1-week-retention) position sense (matching accuracy measured as the endpoint error in cm) of the impaired arm was tested with a unimanual and bimanual matching task, performed without any visual information of either hand. Matching accuracy of the impaired arm was better in the post-test than in the pre-test, but this improvement was similar for both practice groups. In the retention-test, accuracy had returned to pre-test-level, which might be ascribed to the short duration of the practice period. These outcomes suggest that practicing a matching task with visual feedback of the less-impaired arm might help to improve the matching accuracy of the impaired arm in individuals with spastic hemiparetic cerebral palsy.

Matching accuracy in hemiparetic cerebral palsy during unimanual and bimanual movements with (mirror) visual feedback.

In the present study participants with Spastic Hemiparetic Cerebral Palsy (SHCP) were asked to match the position of a target either with the impaired arm only (unimanual condition) or with both arms at the same time (bimanual condition). The target was placed at 4 different locations scaled to the individual maximum reaching distance. To test the effect of mirror visual feedback of the less-impaired arm on the matching accuracy, an opaque screen or a mirror was placed in between the arms which masked vision of the impaired arm. Absolute endpoint error was smaller in the bimanual condition compared to the unimanual condition, but there was no effect of mirror visual feedback. Inspection of the individual data, however, showed that 13 out of 23 participants did experience a positive effect of mirror visual feedback. A positive correlation between the baseline error (screen) and the improvement in accuracy with mirror visual feedback seems to suggest that individuals with lower proprioceptive accuracy in the baseline condition may benefit more from mirror visual feedback. Together these findings indicate that bimanual therapy and therapy with mirror visual feedback might be valuable approaches for rehabilitation for a subset of the individuals with SHCP.

Deficits in upper limb position sense of children with Spastic Hemiparetic Cerebral Palsy are distance-dependent.

This study examined the arm position sense in children with Spastic Hemiparetic Cerebral Palsy (SHCP) and typically developing children (TD) by means of a contralateral matching task. This task required participants to match the position of one arm with the position of the other arm for different target distances and from different starting positions. Results showed that children with SHCP exhibited with both arms larger matching errors than the TD group, but only when the distance between the arms at the start of the movement was large. In addition, the difference in errors between the less-impaired and the impaired limb changed as a function of the distance in the SHCP group whereas no interlimb differences were found in the TD group. Finally, spasticity and restricted range of motion in children with SHCP were not related to the proportion of undershoot and size of absolute error. This suggests that SHCP could be associated with sensory problems in conjunction with their motor problems. In conclusion, the current study showed that accurate matching of the arms is greatly impaired in SHCP when compared to TD children, irrespective of which arm is used. Moreover, this deficit is particularly present for large movement amplitudes.

Visual feedback of the non-moving limb improves active joint-position sense of the impaired limb in Spastic Hemiparetic Cerebral Palsy.

This study examined the active joint-position sense in children with Spastic Hemiparetic Cerebral Palsy (SHCP) and the effect of static visual feedback and static mirror visual feedback, of the non-moving limb, on the joint-position sense. Participants were asked to match the position of one upper limb with that of the contralateral limb. The task was performed in three visual conditions: without visual feedback (no vision); with visual feedback of the non-moving limb (screen); and with visual feedback of the non-moving limb and its mirror reflection (mirror). In addition to the proprioceptive measure, a functional test [Quality of Upper Extremity Skills Test (QUEST)] was performed and the amount of spasticity was determined in order to examine their relation with proprioceptive ability. The accuracy of matching was significantly influenced by the distance that had to be covered by the matching limb; a larger distance resulted in a lower matching accuracy. Moreover it was demonstrated that static (mirror) visual feedback improved the matching accuracy. A clear relation between functionality, as measured by the QUEST, and active joint-position sense was not found. This might be explained by the availability of visual information during the performance of the QUEST. It is concluded that static visual feedback improves matching accuracy in children with SHCP and that the initial distance between the limbs is an influential factor which has to be taken into account when measuring joint-position sense.

Planning of an interceptive movement in children.

In the present study, we examined the spatio-temporal organization of the walking and reaching behaviour during an interception task in younger (6-9 years old) and older (10-13 years old) children. To this end, eighteen children had to walk towards an interception point to grasp a moving ball under three visual manipulation conditions. Walking and reaching behaviour were analysed during a condition allowing full vision of the ball trajectory and during two conditions in which vision towards the ball was partly occluded (enhanced planning requirement). The velocity of the ball was adapted to 50 or 70% of the maximum walking velocity of the participant. Results revealed that both younger and older children show a less accurate performance when the ball trajectory was occluded, while the walking profile and timing of the reach was not influenced by the occlusion manipulations. The findings seem to suggest that both groups were less accurate when the necessity of planning was enhanced.

Mirror visual feedback induces lower neuromuscular activity in children with spastic hemiparetic cerebral palsy.

The study examined the effects of mirror feedback information on neuromuscular activation during bimanual coordination in eight children with spastic hemiparetic cerebral palsy (SHCP) and a matched control group. The 'mirror box' creates a visual illusion, which gives rise to a visual perception of a zero lag, symmetric movement between the two arms. The study incorporated two additional visual feedback conditions by placing a glass or opaque screen between the arms. During bilateral symmetric circular arm movements mirror visual feedback induced lower neuromuscular intensities in the shoulder muscles of the less impaired arm of children with SHCP compared to the other visual conditions. In addition, the mirror lead to shorter relative durations of eccentric and concentric activity in the elbow muscles of the more impaired arm, whereas no effects of visual feedback were found in a matched control group. These results suggest that replacing veridical visual information of the more impaired arm with a mirror reflection of the less impaired arm improves the motor control of children with SHCP during interlimb coupling. The effects of the availability of visual feedback in individuals with hemiparesis are discussed with reference to: (1) increase ipsilateral motor cortex excitability and (2) congruence between afferent (visual) feedback and the internal copy of the motor commands.