Dynamic stability in cerebral palsy during walking and running: Predictors and regulation strategies.

The postural control in cerebral palsy (CP) is often deficient and manifests in a variety of impairments. Consequently, maintaining balance and controlling posture is impeded and results in an increased cost of locomotion and higher risk of falls. The margin of stability is an established measure to quantify dynamic stability during gait. It can be facilitated to analyze impaired control mechanisms, but it is unknown if and how people with CP manage to control the margin of stability during a more demanding motor task, such as running. How do people with cerebral palsy regulate dynamic stability during walking and running? Children and adolescents with bilateral cerebral palsy (N = 117; 50 female, 67 male; age 11.0 ± 3.2) were retrospectively included. All underwent instrumented 3D gait analysis, walking and running barefoot at a self-selected gait speed. People with CP were compared to a control group of N = 25 typically developed (TD). Repeated measures ANOVAs were computed to analyze group differences and multiple linear regressions to identify predictors for the medio-lateral margin of stability. The medio-lateral margin of stability was significantly higher in the CP group and was statistically unchanged during running. Different adaptions when running were particularly observed in the lateral trunk lean and step width, which remained high in CP, whereas the TD increased the trunk lean and reduced their step width. Step width was the main predictor for the medio-lateral margin of stability in both gait conditions. Young people with cerebral palsy manage to maintain their medio-lateral margin of stability during walking and running, however, with significantly higher safety margins compared to typically developed. This conservative strategy may reflect an adaption to motor and postural control impairments.

Rethwilm R ，Böhm H ，Haase M ，Perchthaler D ，Dussa CU ，Federolf P ... -  《-》

How do children with bilateral spastic cerebral palsy manage walking on inclines?

Walking on inclined surfaces is an everyday task, which challenges stability and propulsion even in healthy adults. Children with cerebral palsy adapt similarly to inclines like healthy children do. However, how stability and propulsion in these subjects are influenced by different inclines remained unaddressed as of yet. The aim was to examine the feeling of safety, stability and propulsion of children with cerebral palsy when walking on inclines to gain insight into the challenges they might face on these conditions. Eighteen children with bilateral spastic cerebral palsy with gross motor function classification scale level I and II and nineteen healthy children underwent instrumented 3D gait analysis on level ground and on a 5° and a 10° incline. A mixed linear model was used to draw between and within group comparisons. Reduced lateral trunk sway, a relative lengthening of the lower limb at initial contact and a controlled walking speed were employed during downhill gait compared to level walking. Patients showed an increased sagittal ROM of trunk (3-4°) and pelvis (2-3°) and a decreased sagittal knee ROM (13°) compared to the typically developed children. During uphill gait, an insufficient increase of push-off power at the ankle (increase by 0.48 W/kg) was noted in children with CP, which appeared to lead to particularly shorter strides (about 0.1 m) in patients compared to healthy children (increase by 1.32 W/kg). Depending on inclination angle, children with cerebral palsy managed to walk on inclines in a controlled manner. The steeper the incline, the more the gait appeared to be affected: decreased feeling of safety, increased need for stabilising mechanisms for downhill gait and less sufficient uphill propulsion were seen. Helping these patients to attain better control during downhill gait and strengthening uphill gait mechanisms may support their participation in everyday life.

Yılmaz Topçuoğlu MS ，Krautwurst BK ，Klotz M ，Dreher T ，Wolf SI ... -  《-》

Kinematic adaptation and changes in gait classification in running compared to walking in children with unilateral spastic cerebral palsy.

Classification of sagittal gait patterns in unilateral spastic cerebral palsy (CP) provides direct implication for treatment. Five types are described: type 0 has minor gait deviation; type 1 has inadequate ankle dorsiflexion in swing; type 2 has inadequate ankle dorsiflexion throughout the gait cycle; types 3 and 4 have abnormal function of the knee and hip joint respectively. During gait analysis of children with unilateral spastic CP we observed frequently that a knee flexion deficit disappeared during running. That may have an impact on classification and treatment. Does the classification type change while running and how do patients' kinematics adapt to running? 64 children with unilateral spastic CP were classified using instrumented gait analysis for walking and running. The deviation of four parameters from typically developing children (TD) were used to distinguish between types: peak ankle dorsiflexion in swing for type 1, peak ankle dorsiflexion in stance for type 2, knee range of motion for type 3, and hip range of motion for type 4. A three-factor ANOVA for factors group (CP/TD), locomotion (walk/run) and limb side (in-/uninvolved) was conducted. The number of patients with type 1, 3 and 4 decreased considerably from walking to running, whereas, the number of type 0 and 2 patients increased. The ANOVA showed that three of four parameters of patients' pathologic limb adapt similarly to TD to running, except for the ankle dorsiflexion in stance. Running shows that there is a natural way to resolve abnormalities. Therefore, recommended treatments of hip and knee joint abnormalities based on the walking classification can be questioned and additional running analysis may be important for surgical decision making.

Krätschmer R ，Böhm H ，Döderlein L 《-》

Dynamic stability during walking in children with and without cerebral palsy.

Cerebral palsy (CP) is associated with a high risk of falling during walking. Many gait abnormalities associated with CP likely alter foot placement and center of mass (CoM) movement in a way that affects anterior or lateral dynamic stability, in turn influencing fall risk. Do children with CP demonstrate altered anterior or lateral dynamic stability compared to typically-developing (TD) children? In this case-control, observational study, we measured gait kinematics of two groups of children (15 CP, 11 GMFCS level I, 4 GMFCS level II; 14 TD; age 5-12) in walking conditions of a preferred speed, a fast speed, and a preferred speed while completing a cognitive task. For dominant and non-dominant limbs, the margin of stability (MoS), a spatial measure of dynamic stability, was calculated as the distance between the edge of the base of support and the CoM position after accounting for scaled velocity. Statistical comparisons of were made using mixed factorial ANOVAs. Post hoc comparisons were Sidak adjusted. The anterior MoS before foot strike and at mid-swing differed between each condition but not between groups. Based on the minimum lateral MoS, children with CP had more stability when bearing weight on their non-dominant limb compared to TD children. These differences were not apparent when on the dominant limb. This high-functioning group of children with CP exhibited a more conservative lateral stability strategy during walking when bearing weight with the non-dominant limb. This strategy may be protective against lateral falls. We observed no between-group differences in anterior stability. Because CP has been previously associated with impaired anterior balance reactions, and there was no observed compensation in anterior gait stability, this lack of group differences could contribute to a higher risk of falling in that direction.

Tracy JB ，Petersen DA ，Pigman J ，Conner BC ，Wright HG ，Modlesky CM ，Miller F ，Johnson CL ，Crenshaw JR ... -  《-》

Ability and stability of running and walking in children with cerebral palsy.

Many studies have examined how children with cerebral palsy (CP) manage to walk, but few have investigated running, yielding controversial results. The aim of this study was to quantitatively assess gait ability and its stability in children with hemiplegic CP while running and walking. A group of 20 children with spastic hemiplegia due to CP (CPG, 5.1 ± 2.3 years old), and a group of 20 children with typical development (TDG, 5.9 ± 2.6 years old) underwent a 10-m walking/running test with a wearable triaxial accelerometer fixed to their lower trunk. Spatiotemporal gait parameters, root mean squares of upper body acceleration, and related harmonic and symmetry ratios were computed. Differences in gait speed were significantly higher during running ( - 19% for CPG with respect of TDG) than during walking ( - 14%, p = 0.028). Conversely, no significant changes were observed in terms of gait stability, and the differences in terms of gait harmony along anteroposterior axis recorded during walking ( - 43%, p < 0.001) disappeared during running ( + 3%, p = 0.834). During running, children with CP are slower than children with TD, but their gait was not less stable, and the harmony of their anteroposterior movements was even more similar to TDG than during walking.

Iosa M ，Morelli D ，Marro T ，Paolucci S ，Fusco A ... -  《-》