Macrostructural and Microstructural Brain Lesions Relate to Gait Pathology in Children With Cerebral Palsy.

Background Even though lower-limb motor disorders are core features of spastic cerebral palsy (sCP), the relationship with brain lesions remains unclear. Unraveling the relation between gait pathology, lower-limb function, and brain lesions in sCP is complex for several reasons; wide heterogeneity in brain lesions, ongoing brain maturation, and gait depends on a number of primary motor functions/deficits (eg, muscle strength, spasticity). Objective To use a comprehensive approach combining conventional MRI and diffusion tensor imaging (DTI) in children with sCP above 3 years old to relate quantitative parameters of brain lesions in multiple brain areas to gait performance. Methods A total of 50 children with sCP (25 bilateral, 25 unilateral involvement) were enrolled. The investigated neuroradiological parameters included the following: (1) volumetric measures of the corpus callosum (CC) and lateral ventricles (LVs), and (2) DTI parameters of the corticospinal tract (CST). Gait pathology and primary motor deficits, including muscle strength and spasticity, were evaluated by 3D gait analysis and clinical examination. Results In bilateral sCP (n = 25), volume of the LV and the subparts of the CC connecting frontal, (pre)motor, and sensory areas were most related to lower-limb functioning and gait pathology. DTI measures of the CST revealed additional relations with the primary motor deficits (n = 13). In contrast, in unilateral sCP, volumetric (n = 25) and diffusion measures (n = 14) were only correlated to lower-limb strength. Conclusions These results indicate that the combined influence of multiple brain lesions and their impact on the primary motor deficits might explain a large part of the gait pathology in sCP.

Children with Spastic Cerebral Palsy Experience Difficulties Adjusting Their Gait Pattern to Weight Added to the Waist, While Typically Developing Children Do Not.

The prevalence of childhood overweight and obesity is increasing in the last decades, also in children with Cerebral Palsy (CP). Even though it has been established that an increase in weight can have important negative effects on gait in healthy adults and children, it has not been investigated what the effect is of an increase in body weight on the characteristics of gait in children with CP. In CP, pre and post three-dimensional gait analyses are performed to assess the effectiveness of an intervention. As a considerable amount of time can elapse between these measurements, and the effect of an alteration in the body weight is not taken into consideration, this effect of increased body weight is of specific importance. Thirty children with the predominantly spastic type of CP and 15 typically developing (TD) children were enrolled (age 3-15 years). All children underwent three-dimensional gait analysis with weight-free (baseline) and weighted (10% of the body weight added around their waist) trials. Numerous gait parameters showed a different response to the added weight for TD and CP children. TD children increased walking velocity, step- and stride length, and decreased double support duration with a slightly earlier timing of foot-off, while the opposite was found in CP. Similarly, increased ranges of motion at the pelvis (coronal plane) and hip (all planes), higher joint angular velocities at the hip and ankle, as well as increased moments and powers at the hip, knee and ankle were observed for TD children, while CP children did not change or even showed decreases in the respective measures in response to walking with added weight. Further, while TD children increased their gastrocnemius EMG amplitude during weighted walking, CP children slightly decreased their gastrocnemius EMG amplitude. As such, an increase in weight has a significant effect on the gait pattern in CP children. Clinical gait analysts should therefore take into account the negative effects of increased weight during pre-post measurements to avoid misinterpretation of treatment results. Overweight and obesity in CP should be counteracted or prevented as the increased weight has detrimental effects on the gait pattern.

Reliability of a novel, semi-quantitative scale for classification of structural brain magnetic resonance imaging in children with cerebral palsy.

AIM: To describe the development of a novel rating scale for classification of brain structural magnetic resonance imaging (MRI) in children with cerebral palsy (CP) and to assess its interrater and intrarater reliability. METHOD: The scale consists of three sections. Section 1 contains descriptive information about the patient and MRI. Section 2 contains the graphical template of brain hemispheres onto which the lesion is transposed. Section 3 contains the scoring system for the quantitative analysis of the lesion characteristics, grouped into different global scores and subscores that assess separately side, regions, and depth. A larger interrater and intrarater reliability study was performed in 34 children with CP (22 males, 12 females; mean age at scan of 9 y 5 mo [SD 3 y 3 mo], range 4 y-16 y 11 mo; Gross Motor Function Classification System level I, [n=22], II [n=10], and level III [n=2]). RESULTS: Very high interrater and intrarater reliability of the total score was found with indices above 0.87. Reliability coefficients of the lobar and hemispheric subscores ranged between 0.53 and 0.95. Global scores for hemispheres, basal ganglia, brain stem, and corpus callosum showed reliability coefficients above 0.65. INTERPRETATION: This study presents the first visual, semi-quantitative scale for classification of brain structural MRI in children with CP. The high degree of reliability of the scale supports its potential application for investigating the relationship between brain structure and function and examining treatment response according to brain lesion severity in children with CP.

Gait stability in children with Cerebral Palsy.

Children with unilateral Cerebral Palsy (CP) have several gait impairments, amongst which impaired gait stability may be one. We tested whether a newly developed stability measure (the foot placement estimator, FPE) which does not require long data series, can be used to asses gait stability in typically developing (TD) children as well as children with CP. In doing so, we tested the FPE's sensitivity to the assumptions needed to calculate this measure, as well as the ability of the FPE to detect differences in stability between children with CP and TD children, and differences in walking speed. Participants were asked to walk at two different speeds, while gait kinematics were recorded. From these data, the FPE, as well as the error that violations of assumptions of the FPE could have caused were calculated. The results showed that children with CP walked with marked instabilities in anterior-posterior and mediolateral directions. Furthermore, errors caused by violations of assumptions in calculation of FPE were only small (≈ 1.5 cm), while effects of walking speed (≈ 20 cm per m/s increase in walking speed) and group (≈ 5 cm) were much larger. These results suggest that the FPE may be used to quantify gait stability in TD children and children with CP.

Is interlimb coordination during walking preserved in children with cerebral palsy?

Arm movements during gait in children with cerebral palsy (CP) are altered compared to typically developing children (TD). We investigated whether these changes in arm movements alter interlimb coordination in CP gait. 3D gait analysis was performed in CP (diplegia [DI]: N = 15 and hemiplegia [HE]: N = 11) and TD (N = 24) children at preferred and fast walking speeds. Mean Relative Phase (MRP, i.e. mean over the gait cycle of the Continuous Relative Phase or CRP) was calculated as a measure of coordination, standard deviation of CRP was used as a measure of coordinative stability, and the sign of MRP indicated which limb was leading (for all pair combinations of the four limbs). In HE, coordination was significantly altered, less stable and a different leading limb was found compared to TD whenever the most affected arm was included in the studied limb pair. In DI, coordination deteriorated significantly when any of the two legs was included in the studied limb pair, and coordinative stability was significantly affected when any of the two arms was included. In almost all limb pair combinations, a different limb was leading in DI compared to TD. Increasing walking speed significantly improved coordination and coordinative stability of several limb pairs in DI. Coordination and limb-leading deficits were mostly linked to the affected limb. The compensating (non-affected) arm primarily affected coordinative stability, which underlines the importance of active arm movements in HE. Increasing walking speed may be used to improve interlimb coordination in DI.

Altered arm posture in children with cerebral palsy is related to instability during walking.

BACKGROUND: Toddlers learning to walk adopt specific 'guard' arm postures to maintain their balance during forward progression. In Cerebral Palsy (CP), the cause of the altered arm postures during walking has not been studied. AIM: To investigate whether the altered arm posture in children with CP is a compensation for instability during walking. METHODS: Vertical and horizontal hand position, and upper arm elevation angle in the sagittal plane were determined in eleven children with unilateral CP, fifteen children with bilateral CP using 3D gait analysis and compared to twenty-four TD children. A correlation analysis of these measures of arm posture to step width was made to examine the relationship between arm posture and instability. RESULTS: The hand position of children with CP was more elevated and anterior, and their upper arm was rotated more posterior than TD children. Children with unilateral CP held their most affected hand higher than their least affected. Increasing the speed accentuated the differences between groups for hand elevation. Step width correlated positively with horizontal hand position of the least affected arm in children with CP. CONCLUSION: Children with CP appear to rely on 'guard' arm postures as a compensation strategy to maintain balance while walking comparable to newly walking toddlers. Importantly, this pattern is seen on the least affected side. The substantially altered arm posture on the most affected side in children with unilateral CP, however, suggests that spasticity and associated movements are also important contributing factors.

Three-dimensional upper limb movement characteristics in children with hemiplegic cerebral palsy and typically developing children.

The aim of this study was to measure which three-dimensional spatiotemporal and kinematic parameters differentiate upper limb movement characteristics in children with hemiplegic cerebral palsy (HCP) from those in typically developing children (TDC), during various clinically relevant tasks. We used a standardized protocol containing three reach tasks (forwards, upwards, and sideways), two reach-to-grasp tasks (with objects requiring different hand orientations), and three gross motor tasks. Spatiotemporal (movement duration, trajectory straightness, maximum velocity, and timing of maximum velocity), as well as kinematic parameters (discrete angles and waveforms of the trunk, scapula, shoulder, elbow and wrist), were compared between 20 children with HCP (age 10.9 ± 2.9 years) and 20 individually age-matched TDC (age 10.9 ± 3.0 years). Kinematic calculations followed the recommendations from the International Society of Biomechanics. Results showed that children with HCP had longer movement durations, less straight hand trajectories, and lower maximum velocities compared to the TDC. Timing of maximum velocity did not differ between both groups. The movement pathology in children with HCP was highlighted by increased trunk movements and reduced shoulder elevation during reaching and reach-to-grasp. We also measured an increased anterior tilting and protraction of the scapula in children with HCP, although differences were not significant for all tasks. Finally, compared to the TDC, children with HCP used less elbow extension and supination and more wrist flexion to execute all tasks. This study reported distinct 3D upper limb movement characteristics in children with HCP and age-matched TDC, establishing the discriminative ability of the measurement procedure. From a clinical perspective, combining spatiotemporal and kinematic parameters may facilitate the identification of the pathological movement patterns seen in children with HCP and thereby add to a well-targeted upper limb treatment planning.

Probabilistic gait classification in children with cerebral palsy: a Bayesian approach.

Three-dimensional gait analysis (3DGA) generates a wealth of highly variable data. Gait classifications help to reduce, simplify and interpret this vast amount of 3DGA data and thereby assist and facilitate clinical decision making in the treatment of CP. CP gait is often a mix of several clinically accepted distinct gait patterns. Therefore, there is a need for a classification which characterizes each CP gait by different degrees of membership for several gait patterns, which are considered by clinical experts to be highly relevant. In this respect, this paper introduces Bayesian networks (BN) as a new approach for classification of 3DGA data of the ankle and knee in children with CP. A BN is a probabilistic graphical model that represents a set of random variables and their conditional dependencies via a directed acyclic graph. Furthermore, they provide an explicit way of introducing clinical expertise as prior knowledge to guide the BN in its analysis of the data and the underlying clinically relevant relationships. BNs also enable to classify gait on a continuum of patterns, as their outcome consists of a set of probabilistic membership values for different clinically accepted patterns. A group of 139 patients with CP was recruited and divided into a training- (n=80% of all patients) and a validation-dataset (n=20% of all patients). An average classification accuracy of 88.4% was reached. The BN of this study achieved promising accuracy rates and was found to be successful for classifying ankle and knee joint motion on a continuum of different clinically relevant gait patterns.

Arm swing during walking at different speeds in children with Cerebral Palsy and typically developing children.

Children with Cerebral Palsy (CP) have difficulties walking at a normal or high speed. It is known that arm movements play an important role to achieve higher walking speeds in healthy subjects. However, the role played by arm movements while walking at different speeds has received no attention in children with CP. Therefore we investigated the use of arm movements at two walking speeds for children with diplegia (DI) and hemiplegia (HE) as compared to typically developing (TD) children. Arm and leg swing lengths were determined in 11 HE children and 15 DI children and compared to 24 TD children using 3D gait analysis at their preferred and "as fast as possible" walking speeds. We found that TD children increased walking speed more than both CP groups. HE children showed larger arm swings on the non-hemiplegic compared to the hemiplegic side for both walking speeds. In contrast to TD or DI children, the HE group did not show an increase in arm swing length with increasing walking speed. Their leg swing length was larger on the non-hemiplegic than on the hemiplegic side but only at the preferred walking speed. The DI children exhibited smaller leg swings at both walking speeds. Since arm swing is used both by DI (to increase speed) and by HE children (to compensate for the reduced movement on the affected side) it is argued that these movements are important and should be allowed (or even encouraged) in gait training procedures (such as treadmill training).

Effect of dynamic orthoses on gait: a retrospective control study in children with hemiplegia.

Several positive influences of orthoses on gait in children with cerebral palsy have been documented, as well as some detrimental effects. Most importantly, push-off is decreased in orthoses, compromising a physiological third ankle rocker. The aim of this study was to evaluate the effect of three types of orthosis on gait in a homogeneous group of children. All orthoses aimed at improving push-off and normalizing the pathological plantarflexion-knee extension couple. Thirty-seven children (22 females, 15 males) with hemiplegia, aged 4 to 10 years (30 Gross Motor Function Classification System [GMFCS] Level I, six GMFCS Level II), walked barefoot and with orthoses being either Orteams (orthoses with the dorsal part containing 11 sleeves), posterior leafsprings (PLS), or Dual Carbon Fibre Spring ankle foot orthosis (AFOs; CFO: carbon fibre at the dorsal part of the orthosis). All orthoses were expected to prevent plantarflexion and allow dorsiflexion, thus improving first, second, and third rocker. The orthoses were compared through objective gait analysis, including 3D kinematics and kinetics. All orthoses successfully improved the gait pattern and only small differences were noted between the configurations of the different orthoses. The CFO, however, allowed a more physiological third ankle rocker compared with the Orteam/PLS. Although the PLS ensured the highest correction at the ankle around initial contact, the CFO created a significantly higher maximal hip flexion moment in stance. In general, the results of this study indicated a substantial functional flexibility of the CFO.

How can push-off be preserved during use of an ankle foot orthosis in children with hemiplegia? A prospective controlled study.

Several studies indicated that walking with an ankle foot orthosis (AFO) impaired third rocker. The purpose of this study was to evaluate the effects of two types of orthoses, with similar goal settings, on gait, in a homogeneous group of children, using both barefoot and shoe walking as control conditions. Fifteen children with hemiplegia, aged between 4 and 10 years, received two types of individually tuned AFOs: common posterior leaf-spring (PLS) and Dual Carbon Fiber Spring AFO (CFO) (with carbon fibre at the dorsal part of the orthosis). Both orthoses were expected to prevent plantar flexion, thus improving first rocker, allowing dorsiflexion to improve second rocker, absorbing energy during second rocker, and returning it during the third rocker. The effect of the AFOs was studied using objective gait analysis, including 3D kinematics, and kinetics in four conditions: barefoot, shoes without AFO, and PLS and CFO combined with shoes. Several gait parameters significantly changed in shoe walking compared to barefoot walking (cadence, ankle ROM and velocity, knee shock absorption, and knee angle in swing). The CFO produced a significantly larger ankle ROM and ankle velocity during push-off, and an increased plantar flexion moment and power generation at pre-swing compared to the PLS (<0.01). The results of this study further support the findings of previous studies indicating that orthoses improve specific gait parameters compared to barefoot walking (velocity, step length, first and second ankle rocker, sagittal knee and hip ROM). However, compared to shoes, not all improvements were statistically significant.