Checks and balances: a meta-analysis on the known-groups validity of functional postural control tests in children.

INTRODUCTION: Pediatric physical therapists commonly treat children with postural control deficits. Ideally, pediatric functional postural control tests should therefore be able to identify postural control deficits in children with various disorders. Despite a plethora of available tests, evidence for their validity - especially known-groups - remains scarce. This review aims to determine the known-group validity of available functional postural control tests to differentiate various pediatric pathological groups of different ages from their typically developing (TD) peers. EVIDENCE ACQUISITION: PubMed, Web of Science and Scopus were systematically searched (last update: February 2023; PROSPERO: CRD42023408982). Forty case-control studies with a pathological pediatric sample (N.=1331) and TD peers (N.=1889) were included and selected for data-extraction and -analysis. Risk of bias was assessed using the SIGN checklist and level of evidence was scored using GRADE. Random-effect meta-analyses were performed to estimate pooled standardized mean differences (SMD) for the various test types and subclassified based on pathology and/or age. EVIDENCE SYNTHESIS: When compared with TD peers, children with underlying pathologies performed significantly worse on pediatric functional postural control test batteries (SMD=-2.21), the Timed Up and Go Test and variants (SMD=2.30), the One Leg Stance test and variants (SMD=-2.14), while the Reach tests showed a smaller difference (SMD=-1.19). Subclassification within the meta-analyses showed that pathology was an influencing factor for the test batteries and the one leg stance test and variants. Age was an influencing factor for the reach tests. None of the included functional postural control tests exceeded a low level of evidence. CONCLUSIONS: Pediatric functional postural control tests that assess multiple aspects of postural control (such as test batteries) seem to offer higher known-groups validity than single-task tests (e.g. reach tests). The underlying pathology has a larger impact on the validity of these tests than age. There remains an overall low level of evidence for the known-groups validity of pediatric functional postural control tests indicating the need for research with more homogenous groups and norm reference data.

Does somatosensory discrimination therapy alter sensorimotor upper limb function differently compared to motor therapy in children and adolescents with unilateral cerebral palsy: study protocol for a randomized controlled trial.

BACKGROUND: Besides motor impairments, up to 90% of the children and adolescents with unilateral cerebral palsy (uCP) present with somatosensory impairments in the upper limb. As somatosensory information is of utmost importance for coordinated movements and motor learning, somatosensory impairments can further compromise the effective use of the impaired upper limb in daily life activities. Yet, intervention approaches specifically designated to target these somatosensory impairments are insufficiently investigated in children and adolescents with uCP. Therefore, the aim of this randomized controlled trial (RCT) is to compare the effectiveness of somatosensory discrimination therapy and dose-matched motor therapy to improve sensorimotor upper limb function in children and adolescents with uCP, who experience somatosensory impairments in the upper limb. We will further explore potential behavioral and neurological predictors of therapy response. METHODS: A parallel group, evaluator-blinded, phase-II, single-center RCT will be conducted for which 50 children and adolescents with uCP, aged 7 to 15 years, will be recruited. Participants will be randomized to receive 3 weekly sessions of 45 minutes of either somatosensory discrimination therapy or upper limb motor therapy for a period of 8 weeks. Stratification will be performed based on age, manual ability, and severity of tactile impairment at baseline. Sensorimotor upper limb function will be evaluated at baseline, immediately after the intervention and after 6 months follow-up. The primary outcome measure will be bimanual performance as measured with the Assisting Hand Assessment. Secondary outcomes include a comprehensive test battery to objectify somatosensory function and measures of bimanual coordination, unimanual motor function, and goal attainment. Brain imaging will be performed at baseline to investigate structural brain lesion characteristics and structural connectivity of the white matter tracts. DISCUSSION: This protocol describes the design of an RCT comparing the effectiveness of somatosensory discrimination therapy and dose-matched motor therapy to improve sensorimotor upper limb function in children and adolescents with uCP. The results of this study may aid in the selection of the most effective upper limb therapy, specifically for children and adolescents with tactile impairments. TRIAL REGISTRATION: ClinicalTrials.gov (NCT06006065). Registered on August 8, 2023.

How do paediatric physical therapists teach motor skills to children with Developmental Coordination Disorder? An interview study.

BACKGROUND: When teaching motor skills, paediatric physical therapists (PPTs) use various motor learning strategies (MLSs), adapting these to suit the individual child and the task being practised. Knowledge about the clinical decision-making process of PPTs in choosing and adapting MLSs when treating children with Developmental Coordination Disorder (DCD) is currently lacking. Therefore, this qualitative study aimed to explore PPTs' use of MLSs when teaching motor skills to children with DCD. METHODS: Semi-structured individual and group interviews were conducted with PPTs with a wide range of experience in treating children with DCD. A conventional content analysis approach was used where all transcripts were open-coded by two reviewers independently. Categories and themes were discussed within the research group. Data were collected until saturation was reached. RESULTS: Twenty-six PPTs (median age: 49 years; range: 26-66) participated in 12 individual interviews and two focus-group interviews. Six themes were identified: (1) PPTs treated children in a tailor-made way; (2) PPTs' teaching style was either more indirect or direct; (3) PPTs used various strategies to improve children's motivation; (4) PPTs had reached the optimal level of practice when children were challenged; (5) PPTs gave special attention to automatization and transfer during treatment; and (6) PPTs considered task complexity when choosing MLSs, which appeared determined by task constraints, environmental demands, child and therapist characteristics. CONCLUSION: PPTs' clinical decision-making processes in choosing MLSs appeared strongly influenced by therapist characteristics like knowledge and experience, resulting in large variation in the use of MLSs and teaching styles to enhance motivation, automatization, and transfer. This study indicates the importance of the level of education on using MLSs to teach children motor skills, and clinical decision-making. Future research should focus on implementing this knowledge into daily practice.

Effects of a highly intensive balance therapy camp in children with developmental coordination disorder - An intervention protocol.

BACKGROUND: Children with Developmental Coordination Disorder (DCD) often (<87 %) experience postural control problems, impacting all levels of the International Classification of Functioning, Disability and Health (ICF) including their daily participation, self-esteem and mental health. Due to the multisystemic nature of postural control, comprehensive therapy should target all systems which is currently not the case. Highly intensive therapy is effective and commonly used in pediatric populations, but has not been explored yet to train postural control in children with DCD. AIMS: To investigate the effects of a highly intensive functional balance therapy camp at all ICF levels in children with DCD. METHODS AND PROCEDURES: The effects on postural control, muscle activity, brain alterations, self-perceived competence, self-identified goals, gross motor activities and participation are evaluated. Participants are assessed pre- and post-intervention, including a 3 months follow-up. Forty-eight children with DCD, aged 6-12 years old, receive 40 h of comprehensive balance training. This intervention is fun, individually tailored, targets all postural control systems, implements different motor learning strategies and includes both individual and group activities. CONCLUSION: Novel insights into the effects of a highly intensive comprehensive balance therapy camp designed for children with DCD will be gained at all levels of the ICF.

Experts' perspectives on how to promote implicit and explicit motor learning in children: A mixed-methods study.

BACKGROUND: Little is known about how motor learning strategies (MLSs) can promote implicit and explicit motor learning processes. This study aimed to explore experts' perspectives on therapists' use of MLSs to promote specific learning processes in children with and without developmental coordination disorder (DCD). METHODS: In this mixed-methods study, two consecutive digital questionnaires were used to ascertain the opinions of international experts. Questionnaire 2 explored the findings of Questionnaire 1 in greater depth. In order to reach a certain level of agreement about the classification of MLSs as promoting either (more) implicit or (more) explicit motor learning, 5-point Likert scales were used in addition to open-ended questions. The open-ended questions were analysed with a conventional analysis approach. Open coding was performed by two reviewers independently. Categories and themes were discussed within the research team, taking both questionnaires as one dataset. RESULTS: Twenty-nine experts from nine different countries with different backgrounds in research, education and/or clinical care completed the questionnaires. The results of the Likert scales showed large variation. Two themes emerged from the qualitative analyses: (1) Experts found it difficult to classify MLSs as promoting either implicit or explicit motor learning, and (2) experts stressed the need for clinical decisionmaking when choosing MLSs. CONCLUSIONS: Insufficient insight was gained into how MLSs could promote (more) implicit or (more) explicit motor learning in children in general and in children with DCD specifically. But this study demonstrated the importance of clinical decisionmaking to model and adapt MLSs to child, task and environment, with therapists' knowledge of MLSs being an important prerequisite. Research is needed to better understand the various learning mechanisms of children and how MLSs can be used to manipulate these mechanisms.

Reference curves of motor function outcomes in young steroid-naïve males with Duchenne muscular dystrophy.

AIM: To investigate functional motor performance in a large cohort of young steroid-naïve males with Duchenne muscular dystrophy (DMD) and typically developing males, and to develop specific reference curves for both groups. Also, to describe associations between anthropometric values and functional motor outcomes. METHOD: Cross-sectional data of 196 steroid-naïve males with DMD aged 4 to 8 years and 497 typically developing males aged 2 years 6 months to 8 years were included. Both groups were evaluated with the time to rise from the floor test, 10-metre walk/run test, 6-minute walk test, and North Star Ambulatory Assessment. Reference curves with centiles 5%, 10%, 25%, 50%, 75%, 90%, and 95% were estimated using quantile regression. RESULTS: Males with DMD scored significantly worse on all functional motor outcomes than age-matched typically developing males (p < 0.001): 89% to 95% of the males with DMD scored below the 5th centile of the typically developing males. No or weak correlations exist between anthropometric values and functional motor outcomes. INTERPRETATION: The estimated reference curves can support consultation with families of young males with DMD and can support the evaluation of treatment for reaching motor skills and functional motor outcomes compared with typically developing males.

In-depth quantification of bimanual coordination using the Kinarm exoskeleton robot in children with unilateral cerebral palsy.

BACKGROUND: Robots have been proposed as tools to measure bimanual coordination in children with unilateral cerebral palsy (uCP). However, previous research only examined one task and clinical interpretation remains challenging due to the large amount of generated data. This cross-sectional study aims to examine bimanual coordination by using multiple bimanual robotics tasks in children with uCP, and their relation to task execution and unimanual performance. METHODS: The Kinarm exoskeleton robot was used in 50 children with uCP (mean age: 11 years 11 months ± 2 years 10 months, Manual Ability Classification system (MACS-levels: l = 27, ll = 16, lll = 7)) and 50 individually matched typically developing children (TDC). All participants performed three tasks: object-hit (hit falling balls), ball-on-bar (balance a ball on a bar while moving to a target) and circuit task (move a cursor along a circuit by making horizontal and vertical motions with their right and left hand, respectively). Bimanual parameters provided information about bimanual coupling and interlimb differences. Differences between groups and MACS-levels were investigated using ANCOVA with age as covariate (α < 0.05, [Formula: see text]). Correlation analysis (r) linked bimanual coordination to task execution and unimanual parameters. RESULTS: Children with uCP exhibited worse bimanual coordination compared to TDC in all tasks (p ≤ 0.05, [Formula: see text] = 0.05-0.34). The ball-on-bar task displayed high effect size differences between groups in both bimanual coupling and interlimb differences (p < 0.001, [Formula: see text] = 0.18-0.36), while the object-hit task exhibited variations in interlimb differences (p < 0.001, [Formula: see text] = 0.22-0.34) and the circuit task in bimanual coupling (p < 0.001, [Formula: see text] = 0.31). Mainly the performance of the ball-on-bar task (p < 0.05, [Formula: see text] = 0.18-0.51) was modulated by MACS-levels, showing that children with MACS-level lll had worse bimanual coordination compared to children with MACS-level l and/or II. Ball-on-bar outcomes were highly related to task execution (r = - 0.75-0.70), whereas more interlimb differences of the object-hit task were moderately associated with a worse performance of the non-dominant hand (r = - 0.69-(- 0.53)). CONCLUSION: This study gained first insight in important robotic tasks and outcome measures to quantify bimanual coordination deficits in children with uCP. The ball-on-bar task showed the most discriminative ability for both bimanual coupling and interlimb differences, while the object-hit and circuit tasks are unique to interlimb differences and bimanual coupling, respectively.

Effectiveness of the home-based training program Tele-UPCAT (Tele-monitored UPper Limb Children Action Observation Training) in unilateral cerebral palsy: a randomized controlled trial.

BACKGROUND: The effects of unilateral cerebral palsy (UCP) are largely observed in the upper limb (UL), which represents the main focus of rehabilitation for this disorder. Thanks to an increment in home training and progress in technology innovative systems have been created. The Tele-UPCAT (Tele-monitored UPper Limb Children Action Observation Training) platform is dedicated to the delivery at home of a program for UL rehabilitation, based on action observation therapy (AOT). AIM: This study aimed to investigate the immediate effectiveness of Tele-UPCAT for promoting UL skills in children with UCP and to determine if immediate effects were retained in the medium and long term. DESIGN: Tele-UPCAT was conducted on an intention-to-treat basis and was proposed as a randomized, allocation concealed (waitlist controlled) and evaluator-blinded clinical trial with two investigative arms: intensive in-home AOT program and standard care (SC). SETTING: This is a home-based AOT program delivered with a customized ICT platform. POPULATION: Thirty children (mean age 11.61±3.55 years) with confirmed diagnosis of spastic UCP with predominant UL involvement and cognitive level within or at normal limits were enrolled in this study. Orthopedic surgery or an intramuscular botulinum toxin A injection in the UL within 6 months prior to enrolment represented an exclusion criteria. METHODS: Participants were randomized using concealed random allocation. They were assessed according to the study design with the Assisting Hand Assessment (AHA), the Box and Block Test (BBT) and the Melbourne Assessment 2 (MA2). Linear mixed models were used for statistical analysis. RESULTS: A significant difference between the AOT and SC groups was identified immediately after the training on the AHA (6.406 [2.73] P=0.021) with an effect size (ES) of 1.99, and for the BBT of the less affected hand (9.826 [4.535] P=0.032) with an ES of 1.44. These effects were sustained at medium and long term. CONCLUSIONS: This study supports the effectiveness of AOT home training in promoting UL skills in children with UCP, with immediate effects lasting for 6 months. CLINICAL REHABILITATION IMPACT: This should encourage the use of technology for rehabilitative purposes and further applications of the AOT paradigm.

Insights on action observation and imitation abilities in children with Developmental Coordination Disorder and typically developing children.

BACKGROUND: Children with Developmental Coordination Disorder (DCD) face difficulties in motor learning. Action observation and imitation are strategies frequently used to teach motor skills. AIMS: (1) To study action observation and imitation abilities in children with DCD compared with typically developing peers with a new protocol. (2) To gain insights in the relation between action observation, imitation, motor performance and activities of daily living (ADL). METHOD: Twenty-one children with DCD (mean age 7 years 9 months, range 6-10 years) and 20 age-matched controls (mean age 7 years 8 months, range 6-10 years) were included. A newly developed protocol was used for testing action observation and imitation proficiency. Motor performance were evaluated with the Movement Assessment Battery for Children-2. ADL were investigated with DCD Questionnaire'07. RESULTS: Children with DCD presented significantly lower action observation (p = .037) and imitation abilities (p < .001) than peers. Worse action observation and imitation abilities were related to lower motor performance and ADL skills and a younger age. Non-meaningful gestures imitation proficiency had predictive value for global motor performance (p = .009), manual dexterity (p = .02) and ADL (p = .004). CONCLUSIONS: The new protocol for action observation and imitation abilities can be helpful for detecting motor learning difficulties and for delineating new opportunities for motor teaching approaches in children with DCD.

Therapists' Use of Instructions and Feedback in Motor Learning Interventions in Children with Developmental Coordination Disorder: A Video Observation Study.

AIM: This qualitative study explored therapists' use of instructions and feedback when teaching motor tasks to children with developmental coordination disorder (DCD) as a first step in developing practical recommendations. METHODS: A conventional content analysis approach was used to analyze videotaped treatment sessions of physical therapists using a newly developed analysis plan. Inductive coding was used to code purposively selected video segments. The codes were sorted into categories to identify key themes. Analyses were performed independently by two researchers until data saturation was reached. RESULTS: Ten video-taped sessions were analyzed and 61 segments were coded. Three key themes were identified: (1) therapists' intention with the instructions and feedback was to motivate or to provide information; (2) the preferred therapists' teaching style was either direct or indirect; and (3) parameters to shape specific instructions and feedback were the focus of attention, modality, information content, timing and frequency. CONCLUSION: Therapists used numerous instructions and feedback with different information content, often shaped by multiple focuses and/or modalities to motivate children or to provide specific information about task performance. Although therapists adapted instructions and feedback to child and task, future research should explore how characteristics of child and task can guide therapists' clinical decision-making.

Children With Cerebral Palsy Show Higher Static-But Not Higher Dynamic-Motor Fatigability in Grip and Pinch Tasks Than Children With Typical Development Do.

OBJECTIVE: The purpose of this study was to investigate differences in static and dynamic motor fatigability during grip and pinch tasks between children with unilateral spastic cerebral palsy (USCP) and children with typical development (TD) and between preferred and nonpreferred hands. METHODS: Fifty-three children with USCP and 53 age-matched children with TD (mean = 11 years 1 month; SD = 3 years 8 months) participated in 30-second maximum exertion sustained and repeated grip and pinch tasks. For sustained tasks, the Static Fatigue Index and the ratio of mean force between the first and last thirds of the curve were calculated. For repeated tasks, the ratio of mean force and the ratio of numbers of peaks between the first and last thirds of the curve were calculated. RESULTS: Higher Static Fatigue Index scores for grip and pinch were found with USCP in both hands and between hands in both groups. Dynamic motor fatigability showed inconsistent results, with higher levels of fatigability in children with TD than in children with USCP for grip in the ratio of mean force between the first and last thirds of the curve in nonpreferred hands and in the ratio of number of peaks between the first and last thirds of the curve in preferred hands. CONCLUSION: Higher motor fatigability in children with USCP than in children with TD was found for static but not dynamic grip and pinch. Underlying mechanisms may play different roles in static and dynamic motor fatigability. IMPACT: These results highlight that static motor fatigability in grip and pinch tasks should be part of a comprehensive upper limb assessment and that this could be the target of individualized interventions.

Exploring structural connectomes in children with unilateral cerebral palsy using graph theory.

We explored structural brain connectomes in children with spastic unilateral cerebral palsy (uCP) and its relation to sensory-motor function using graph theory. In 46 children with uCP (mean age = 10 years 7 months ± 2 years 9 months; Manual Ability Classification System I = 15, II = 16, III = 15) we assessed upper limb somatosensory and motor function. We collected multi-shell diffusion-weighted, T1-weighted and T2-FLAIR MRI and identified the corticospinal tract (CST) wiring pattern using transcranial magnetic stimulation. Structural connectomes were constructed using Virtual Brain Grafting-modified FreeSurfer parcellations and multi-shell multi-tissue constrained spherical deconvolution-based anatomically-constrained tractography. Graph metrics (characteristic path length, global/local efficiency and clustering coefficient) of the whole brain, the ipsilesional/contralesional hemisphere, and the full/ipsilesional/contralesional sensory-motor network were compared between lesion types (periventricular white matter (PWM) = 28, cortical and deep gray matter (CDGM) = 18) and CST-wiring patterns (ipsilateral = 14, bilateral = 14, contralateral = 12, unknown = 6) using ANCOVA with age as covariate. Using elastic-net regularized regression we investigated how graph metrics, lesion volume, lesion type, CST-wiring pattern and age predicted sensory-motor function. In both the whole brain and subnetworks, we observed a hyperconnectivity pattern in children with CDGM-lesions compared with PWM-lesions, with higher clustering coefficient (p = [<.001-.047], η p 2 =[0.09-0.27]), characteristic path length (p = .003, η p 2 =0.19) and local efficiency (p = [.001-.02], η p 2 =[0.11-0.21]), and a lower global efficiency with age (p = [.01-.04], η p 2 =[0.09-0.15]). No differences were found between CST-wiring groups. Overall, good predictions of sensory-motor function were obtained with elastic-net regression (R2  = .40-.87). CST-wiring pattern was the strongest predictor for motor function. For somatosensory function, all independent variables contributed equally to the model. In conclusion, we demonstrated the potential of structural connectomics in understanding disease severity and brain development in children with uCP.

A Critical View on Motor-based Interventions to Improve Motor Skill Performance in Children With ADHD: A Systematic Review and Meta-analysis.

OBJECTIVE: To map the effect of motor-based interventions on motor skills in children with ADHD. METHOD: A systematic literature search was performed in Pubmed, Web of Science, and the SCOPUS database (last search: October 30th 2022). Methodological quality was assessed using the PEDro-scale and the quality of evidence was determined with the GRADE-method. Meta-analysis was performed when at least five studies were available. RESULTS: Thirteen studies (7 RCTs) satisfied the inclusion criteria, five of which were eligible for meta-analysis. Only one of the included studies reached the low risk of bias threshold. Comparing different motor-based interventions to any non-motor control intervention showed large motor skill improvements (SMD = 1.46; 95% CI = [1.00;1.93]; I² = 47.07%). The most effective type of motor-based intervention and the optimal treatment parameters could not be determined yet. CONCLUSION: Motor-based interventions in general seem to improve motor skills in children with ADHD. Additional RCTs are needed to increase current low GRADE confidence.

Psychometric properties of functional postural control tests in children: A systematic review.

BACKGROUND: Postural control deficits are one of the most common impairments treated in pediatric physiotherapeutic practice. Adequate evaluation of these deficits is imperative to identify postural control deficits, plan treatment and assess efficacy. Currently, there is no gold standard evaluation for postural control deficits. However, the number of studies investigating the psychometric properties of functional pediatric postural control tests has increased significantly. OBJECTIVE: To facilitate the selection of an appropriate pediatric functional postural control test in research and clinical practice. METHODS: Systematic review following the PRISMA guidelines. PubMed, Web of Science and Scopus were systematically searched (last update: June 2022; PROSPERO: CRD42021246995). Studies were selected using the PICOs-method (pediatric populations (P), functional assessment tools for postural control (I) and psychometric properties (O). The risk of bias was rated with the COSMIN checklist and the level of evidence was determined with GRADE. For each test, the postural control systems were mapped, and the psychometric properties were extracted. RESULTS: Seventy studies investigating 26 different postural control tests were included. Most children were healthy or had cerebral palsy. Overall, the evidence for all measurement properties was low to very low. Most tests (95%) showed good reliability (ICC>0.70), but inconsistent validity results. Structural validity, internal consistency and responsiveness were only available for 3 tests. Only the Kids-BESTest and FAB covered all postural control systems. CONCLUSION: Currently, 2 functional tests encompass the entire construct of postural control. Although reliability is overall good, validity results depend on task, age and pathology. Future research should focus on test batteries and should particularly explore structural validity and responsiveness in different populations with methodologically strong study designs.

The impact of brain lesion characteristics and the corticospinal tract wiring on mirror movements in unilateral cerebral palsy.

Mirror movements (MM) influence bimanual performance in children with unilateral cerebral palsy (uCP). Whilst MM are related to brain lesion characteristics and the corticospinal tract (CST) wiring pattern, the combined impact of these neurological factors remains unknown. Forty-nine children with uCP (mean age 10y6mo) performed a repetitive squeezing task to quantify similarity (MM-similarity) and strength (MM-intensity) of the MM activity. We used MRI data to evaluate lesion type (periventricular white matter, N = 30; cortico-subcortical, N = 19), extent of ipsilesional damage, presence of bilateral lesions, and damage to basal ganglia, thalamus and corpus callosum. The CST wiring was assessed with Transcranial Magnetic Stimulation (17 CSTcontralateral, 16 CSTipsilateral, 16 CSTbilateral). Data was analyzed with regression analyses. In the more-affected hand, MM-similarity and intensity were higher with CSTbilateral/ipsilateral. In the less-affected hand, MM-similarity was higher in children with (1) CSTcontra with CSC lesions, (2) CSTbilat/ipsi with PVL lesions and (3) CSTbilat/ipsi with unilateralized lesions. MM-intensity was higher with larger damage to the corpus callosum and unilateral lesions. A complex combination of neurological factors influences MM characteristics, and the mechanisms differ between hands.

Reliable and Valid Robotic Assessments of Hand Active and Passive Position Sense in Children With Unilateral Cerebral Palsy.

Impaired hand proprioception can lead to difficulties in performing fine motor tasks, thereby affecting activities of daily living. The majority of children with unilateral cerebral palsy (uCP) experience proprioceptive deficits, but accurately quantifying these deficits is challenging due to the lack of sensitive measurement methods. Robot-assisted assessments provide a promising alternative, however, there is a need for solutions that specifically target children and their needs. We propose two novel robotics-based assessments to sensitively evaluate active and passive position sense of the index finger metacarpophalangeal joint in children. We then investigate test-retest reliability and discriminant validity of these assessments in uCP and typically developing children (TDC), and further use the robotic platform to gain first insights into fundamentals of hand proprioception. Both robotic assessments were performed in two sessions with 1-h break in between. In the passive position sense assessment, participant's finger is passively moved by the robot to a randomly selected position, and she/he needs to indicate the perceived finger position on a tablet screen located directly above the hand, so that the vision of the hand is blocked. Active position sense is assessed by asking participants to accurately move their finger to a target position shown on the tablet screen, without visual feedback of the finger position. Ten children with uCP and 10 age-matched TDC were recruited in this study. Test-retest reliability in both populations was good (intraclass correlation coefficients (ICC) >0.79). Proprioceptive error was larger for children with uCP than TDC (passive: 11.49° ± 5.57° vs. 7.46° ± 4.43°, p = 0.046; active: 10.17° ± 5.62° vs. 5.34° ± 2.03°, p < 0.001), indicating discriminant validity. The active position sense was more accurate than passive, and the scores were not correlated, underlining the need for targeted assessments to comprehensively evaluate proprioception. There was a significant effect of age on passive position sense in TDC but not uCP, possibly linked to disturbed development of proprioceptive acuity in uCP. Overall, the proposed robot-assisted assessments are reliable, valid and a promising alternative to commonly used clinical methods, which could help gain a better understanding of proprioceptive impairments in uCP, facilitating the design of novel therapies.

How can instructions and feedback with external focus be shaped to enhance motor learning in children? A systematic review.

AIM: This systematic review investigates the effectiveness of instructions and feedback with external focus applied with reduced frequency, self-controlled timing and/or in visual or auditory form, on the performance of functional gross motor tasks in children aged 2 to 18 with typical or atypical development. METHODS: Four databases (PubMed, Web of Science, Scopus, Embase) were systematically searched (last updated May 31st 2021). Inclusion criteria were: 1. children aged 2 to 18 years old; 2. Instructions/feedback with external focus applied with reduced frequency, self-controlled timing, and/or visual or auditory form as intervention, to learn functional gross motor tasks; 3. Instructions/feedback with external focus applied with continuous frequency, instructor-controlled timing, and/or verbal form as control; 4. performance measure as outcome; 5. (randomized) controlled studies. Article selection and risk of bias assessment (with the Cochrane risk of bias tools) was conducted by two reviewers independently. Due to heterogeneity in study characteristics and incompleteness of the reported data, a best-evidence synthesis was performed. RESULTS: Thirteen studies of low methodological quality were included, investigating effectiveness of reduced frequencies (n = 8), self-controlled timing (n = 5) and visual form (n = 1) on motor performance of inexperienced typically (n = 348) and atypically (n = 195) developing children, for acquisition, retention and/or transfer. For accuracy, conflicting or no evidence was found for most comparisons, at most time points. However, there was moderate evidence that self-controlled feedback was most effective for retention, and limited evidence that visual analogy was most effective for retention and transfer. To improve quality of movement, there was limited evidence that continuous frequency was most effective for retention and transfer. CONCLUSION: More methodologically sound studies are needed to draw conclusions about the preferred frequency, timing or form. However, we cautiously advise considering self-controlled feedback, visual instructions, and continuous frequency. TRIAL REGISTRATION: Registration: Prospero CRD42021225723. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021225723.

Test-Retest Reliability of a Static and Dynamic Motor Fatigability Protocol Using Grip and Pinch Strength in Children With Cerebral Palsy.

OBJECTIVE: The purpose of this study was to investigate the test-retest reliability, measurement error, and interpretability of new motor fatigability outcomes of grip and pinch strength for children with unilateral cerebral palsy (UCP). METHODS: Motor fatigability during grip and pinch strength was measured twice (within 48 hours) in both hands of 50 children (mean age = 11 years 2 months; 14, 31, and 5 children with Manual Ability Classification System levels I, II, and III, respectively) using a 30-second static and dynamic maximum exertion protocol. For static motor fatigability, the Static Fatigue Index (SFI) and mean force (Fmean) in the first (Fmean1) and last (Fmean3) 10 seconds were calculated. For dynamic motor fatigability, Fmean1, Fmean3, and the number of peaks in the first and last 10 seconds were calculated. RESULTS: For static motor fatigability, the intraclass correlation coefficients (ICCs) were moderate to high for Fmean1 and Fmean3 (0.56-0.88), and the SFI showed low to moderate reliability (ICC = 0.32-0.72). For dynamic motor fatigability, the ICCs were moderate to high for all outcomes (0.54-0.91). The standard error of measurement agreement and the smallest detectable difference agreement were large in all outcomes, except for the SFI in static motor fatigability. Details per age group are provided. In general, younger children (6-11 years old) showed lower reliability than older children (12-18 years old). CONCLUSION: Most outcome measures for static and dynamic motor fatigability of grip and pinch strength show moderate to high reliability in children with UCP, indicating that these tests can be used reliably to investigate the presence of motor fatigability in UCP, especially in older children. Standard error of measurement agreement and smallest detectable difference agreement indicated that these outcome measures should be interpreted with caution when evaluating change. IMPACT: Most of the proposed outcome measures for static and dynamic motor fatigability of grip and pinch are reliable in children with UCP and can be used for discriminative purposes.

The construct of balance control in primary school-aged children: Unidimensional and task-specific.

The aim of this study was to determine the dimensionality and task-specificity of balance control by investigating the relationships between different tasks and the degree to which these tasks belong to the same construct in primary school-aged children. Seventy-four South African children were randomly selected from a sample of convenience. They performed 18 different balance tasks that were grouped into four balance scales: the Performance and Fitness (PERF-FIT) static balance score, the PERF-FIT dynamic balance score, the PERF-FIT moving cans balance score and the Balance Sensory score. Spearman rank correlations were calculated between the scores. Principal component analysis (PCA) was used to investigate the number of factors within the construct. Moderate to good correlations were found between: i) PERF-FIT Moving cans balance score and the Balance Sensory score (r = 0.605, p < 0.001); ii) PERF-FIT static balance score and the PERF-FIT Moving cans (r = 0.586, p < 0.001); iii) PERF-FIT static balance score and the Balance Sensory score (r = 0.541, p < 0.001). All other correlations were low to fair. The PCA revealed one component. The three PERF-FIT items (moving cans-, static- and dynamic balance score) and the Balance Sensory score explained 59.4% of the variance of total balance performance.

Test-retest reliability of static and dynamic motor fatigability protocols using grip and pinch strength in typically developing children.

Upper limb motor fatigability is an important debilitating factor for activities of daily living in clinical pediatric populations. However, the reliability of fatigability protocols in these populations is currently unknown. Therefore, the current study investigates test-retest reliability of a static and dynamic motor fatigability protocol for grip and pinch strength in typically developing children (TDC). Eighty-nine TDC (35 boys, 54 girls; mean age 10 years 11 months) used a grip and pinch dynamometer for static (sustained) and dynamic (repeated) contractions during 30s. For static motor fatigability (SFI), mean (Fmean) and SD (Fvar) of force were calculated, and for dynamic motor fatigability, F mean and number of peaks (Npeaks) were calculated. Intraclass correlation coefficients (ICC) were calculated. ICCs of F mean in static and dynamic motor fatigability were high (ICC: 0.94-0.96 and 0.91-0.98). ICCs were moderate to high for F var (ICC: 0.67-0.85). The SFI showed moderate ICCs (ICC: 0.69-0.77). ICCs were moderate to high for N peaks (ICC: 0.78-0.91).Conclusion: The results suggest that static and dynamic motor fatigability in for grip and pinch can be used reliably in TD children aged 6-18 years. What is Known: •Psychometric properties of motor fatigability protocols using grip and pinch in children are lacking. •Motor fatigability in grip and pinch is an important debilitating symptom in multiple neurologic populations. What is New: •Static fatigability can be investigated using a 30-s maximum sustained grip strength protocol in children. •Dynamic fatigability can be investigated using a 30-s maximum repeated grip strength protocol in children.