Can we unmask features of spasticity during gait in children with cerebral palsy by increasing their walking velocity?
OBJECTIVE
Spasticity is a velocity dependent feature present in most patients with cerebral palsy (CP). It is commonly measured in a passive condition. The aim of this study was to highlight markers of spasticity of gastrocnemius and hamstring muscles during gait by comparing the effect of increased walking velocity of CP and typical developing (TD) children.


METHODS
53 children with spastic CP and 17 TD children were instructed to walk at self-selected speed, faster and as fast as possible without running. Kinematics, kinetics and electromyography (EMG) were collected and muscle length and muscle lengthening velocity (MLV) were calculated. To compare the data of both groups, a linear regression model was created which resulted in two non-dimensional gait velocities. A difference score (DS) was calculated between the high and low velocity values for both groups.


RESULTS
103 gait parameters were analyzed of which 16 had a statistically significant DS between TD and CP groups. The spastic gastrocnemius muscle presented at high velocity with a higher ankle angular velocity, plantar flexion moment, power absorption and increased EMG signal during loading response. The spastic hamstrings demonstrated at high velocity a delayed maximum knee extension moment at mid-stance and increasing hip extension moment and hip power generation. The hamstrings also presented with a lower MLV during swing phase.


CONCLUSIONS
A limited number of gait parameters differ between CP and TD children when increasing walking velocity, giving indirect insight on the effect of spasticity on gait.
Department of Orthopaedics, University Hospital Leuven, Belgium. Electronic address: anja.vancampenhout@uzleuven.be.
Anja
A
Van Campenhout
Clinical Motion Analysis Laboratory, University Hospital Leuven, Belgium.
Lynn
L
Bar-On
KU Leuven, Department of Mechanical Engineering, Leuven, Belgium.
Erwin
E
Aertbeliën
Clinical Motion Analysis Laboratory, University Hospital Leuven, Belgium.
Catherine
C
Huenaerts
Department of Orthopaedics, University Hospital Leuven, Belgium; KU Leuven, Department of Development and Regeneration, Leuven, Belgium.
Guy
G
Molenaers
Clinical Motion Analysis Laboratory, University Hospital Leuven, Belgium; KU Leuven, Department of Rehabilitation Sciences, Leuven, Belgium.
Kaat
K
Desloovere
D001696:Biomechanical Phenomena; D002547:Cerebral Palsy / Q000503:physiopathology*; D002648:Child; D004576:Electromyography; D005260:Female; D020233:Gait Disorders, Neurologic / Q000503:physiopathology*; D006801:Humans; D008297:Male; D009128:Muscle Spasticity / Q000503:physiopathology; D018482:Muscle, Skeletal / Q000503:physiopathology*; D016138:Walking / Q000502:physiology*
Cerebral palsy; Gait; Spasticity; Walking velocity