Visual, perceptual functions, and functional vision in children with unilateral cerebral palsy compared to children with neurotypical development.

AIM: To investigate visual (perceptual) function and functional vision in children with unilateral cerebral palsy (CP) and children with neurotypical development (NTD). METHOD: Fifty children with unilateral CP (mean age 11 years 11 months, SD 2 years 10 months, range 7-15 years; 27 males; 26 left-sided unilateral CP; Manual Ability Classification System [MACS] levels: I, 27; II, 16; III, 7) and 50 age- and sex-matched children with NTD participated in a cross-sectional study. Visual acuity, stereoacuity, and visual-perceptual functions were measured with standardized clinical tests. Functional vision was assessed in children with unilateral CP with the Flemish cerebral visual impairment questionnaire (FCVIQ). Group differences were investigated with Mann-Whitney U tests, Kruskal-Wallis tests, and the relative effect sizes r, η2 respectively. Correlations between visual assessments and the FCVIQ were investigated with Spearman's rank correlations. RESULTS: The total group of children with unilateral CP showed reduced visual acuity compared with children with NTD (p = 0.02, r = 0.23). Only children with left-sided unilateral CP scored lower than those with NTD on stereoacuity (p < 0.01, r = 0.36). Children with right/left-sided unilateral CP scored significantly lower than those with NTD on visual-perceptual functions (p = 0.001-0.02), with large effect sizes on visuomotor integration and visual closure (both r = 0.57). Children with unilateral CP classified in MACS level III showed significantly lower scores on visual-perceptual assessments than children classified in MACS level I. Stereoacuity and visual-perceptual functions negatively correlated with the FCVIQ, with the highest association with visual (dis)interest and anxiety-related behaviours. INTERPRETATION: Multi-level visual profiling is warranted in the clinical intake of children with unilateral CP to detect visual impairments that further compromise their level of functioning.

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.

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.

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.

Tyneside Pegboard Test for unimanual and bimanual dexterity in unilateral cerebral palsy: association with sensorimotor impairment.

AIM: We explored the psychometric properties of the recently developed Tyneside Pegboard Test (TPT) for unimanual and bimanual dexterity in children with unilateral cerebral palsy (CP) and investigated the impact of sensorimotor impairments on manual dexterity. METHOD: In this cross-sectional study, the TPT was assessed in 49 children with unilateral CP (mean age 9y 8mo, SD 1y 11mo, range 6-15y; 30 males, 19 females; 23 with right unilateral CP). All participants additionally underwent a standardized upper limb evaluation at body function and activity level. We investigated: (1) known-group, concurrent, and construct validity and (2) impact of sensorimotor impairments including spasticity, grip force, stereognosis, and mirror movements using analysis of covariance, Spearman's rank correlation (r), and multiple linear regression (R2 ) respectively. RESULTS: TPT outcomes significantly differed according to the Manual Ability Classification System (p<0.001, known-group validity). Relationships were found between the unimanual TPT tasks and the Jebsen-Taylor Hand Function Test (r=0.86-0.88, concurrent validity). Bimanual TPT tasks were negatively correlated with the Assisting Hand Assessment, ABILHAND-Kids, and Children's Hand-use Experience Questionnaire (r=-0.38 to -0.78, construct validity). Stereognosis was the main determinant influencing all tasks (p<0.001, R2 =37-50%). Unimanual dexterity was additionally determined by grip strength (p<0.05, R2 =8-9%) and mirror movements in the more impaired hand (p<0.05, R2 =4-8%). Bimanual dexterity was also explained by mirror movements in the more impaired hand (p<0.01, R2 =10-16%) and spasticity (p=0.04, R2 =5%). INTERPRETATION: The TPT is a valid test to measure unimanual and bimanual dexterity in unilateral CP. The results further emphasize the importance of somatosensory impairments in children with unilateral CP. What this paper adds The Tyneside Pegboard Test is valid for measuring unimanual and bimanual dexterity in unilateral cerebral palsy. Children with poorer manual ability show worse unimanual and bimanual dexterity. Stereognosis is the main predictor of both unimanual and bimanual dexterity. Stronger mirror movements in the more impaired hand result in worse bimanual dexterity.