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 ... -  《-》

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 ... -  《-》

Subthreshold electrical noise alters walking balance control in individuals with cerebral palsy.

Sensory deficits in individuals with cerebral palsy (CP) play a critical role in balance control. However, there is a lack of effective interventions that address sensory facilitation to improve walking balance. Stochastic Resonance (SR) stimulation involves delivering sub threshold noise to improve balance in patients with sensory deficits by enhancing the detection of sensory input. To investigate the immediate effects of SR on walking balance in individuals with and without CP. Thirty-four participants (17 CP, 17 age-and sex-matched typically developing controls or TD) between 8 and 24 years of age were recruited. SR stimulation was applied to the muscles and ligaments of ankle and hip joint. An optimal SR intensity during walking was determined for each subject. Participants walked on a self-paced treadmill for three trials of two minutes each using a random order of SR stimulation (SR) and no stimulation (noSR) control conditions. Our primary outcome measure was minimum lateral margin of stability (MOS). Secondary outcome measures include anterior MOS before heelstrike and spatiotemporal gait parameters. We performed two-way mixed ANOVAs with group (CP, TD) as between-subject and condition (noSR, SR) as within subject factors. Compared to walking without SR, there was a small but significant increase in the lateral and anterior MOS with SR stimulation, implying that a larger impulse was needed to become unstable, in turn implying higher stability. Step width and step ength decreased with SR for the CP group with SR stimulation. There were no significant effects for other spatiotemporal variables. Sub threshold electrical noise can slightly improve walking balance control in individuals with CP. SR stimulation, through enhanced proprioception, may have improved the CP group's awareness of body motion during walking, thus leading them to adopt a more conservative stability strategy to prevent a potential fall.

Sansare A ，Reimann H ，Crenshaw J ，Arcodia M ，Verma K ，Lee SCK ... -  《-》

Obstacle Crossing During Gait in Children With Cerebral Palsy: Cross-Sectional Study With Kinematic Analysis of Dynamic Balance and Trunk Control.

Balance problems are common in children who have cerebral palsy (CP) but are active and ambulant. Control of the whole-body center of mass is critical in maintaining dynamic stability during challenging mobility tasks, such as clearing an obstacle while walking. The objective of this study was to compare trunk and lower limb kinematics and center-of-mass control in children with CP and those in children with typical development during obstacle crossing. This was a cross-sectional study. Thirty-four children who were 5 to 17 years of age (17 with CP and 17 with typical development) and matched in age and height completed 2 gait trials involving crossing a 10-cm obstacle. Three-dimensional kinematic and kinetic data were captured with a general-purpose 3-dimensional motion tracking system and forceplates. Trunk data were captured with a validated model. All children cleared the obstacle with similar hip and knee kinematics, step length, and single-support duration. In children with CP, step width was increased by 4.81 cm, and center-of-mass velocity was significantly slower at lead limb toe-off (0.31 m/s) and during lead limb clearance (0.2 m/s). Children with CP showed altered trunk and pelvis movement, characterized by significantly greater pelvic obliquity, pelvic tilt, and trunk rotation throughout the task, increased lateral trunk lean during lead limb crossing (3.7°), and greater sagittal trunk movement as the trail limb crossed (5.1°). The study was not powered to analyze differences between children with diplegia and those with hemiplegia. Children with CP required greater adjustments at the trunk and pelvis to achieve successful obstacle crossing. The increase in trunk movement could have been compensatory for reduced stability distally or for a primary problem reflecting poor proximal control. The findings suggest that rehabilitation should focus on both proximal trunk control and distal stability to improve balance.

Malone A ，Kiernan D ，French H ，Saunders V ，O'Brien T ... -  《-》