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Electromyographic test to differentiate mild diplegic cerebral palsy and idiopathic toe-walking
J F Policy1, L Torburn, L A Rinsky
1Department of Orthopaedic Surgery, Children's Hospital, Oakland, California, USA.
Insights
Electromyography can differentiate children with cerebral palsy (CP) from those with idiopathic toe-walking (ITW). Gastrocnemius coactivation during specific muscle tests helps distinguish these conditions.
Area of Science:
- Pediatrics
- Neurology
- Biomedical Engineering
Background:
- Idiopathic toe-walking (ITW) and spastic diplegic cerebral palsy (CP) can present with similar gait abnormalities.
- Differentiating between ITW and mild CP is crucial for appropriate treatment and management.
- Understanding underlying neuromuscular mechanisms is key to accurate diagnosis.
Purpose of the Study:
- To investigate if obligatory coactivation patterns during voluntary muscle contractions can distinguish children with mild spastic diplegic CP from those with ITW.
- To identify specific electromyographic (EMG) signatures associated with each condition.
Main Methods:
- Surface EMG recordings of quadriceps and gastrocnemius muscles in 8 children with mild CP, 8 with ITW, and 8 controls.
- EMG data collected during resisted knee extension, isometric quadriceps contraction (quad set), and active plantarflexion.
- Passive range of motion measurements, including popliteal angle, were also assessed.
Main Results:
- No significant difference in range of motion between CP and ITW groups, except for a larger popliteal angle in the CP group.
- Gait analysis revealed premature gastrocnemius firing in the swing phase for both CP and ITW groups compared to controls.
- Significantly higher gastrocnemius coactivation during resisted knee extension (86%) and quad set (86%) in the CP group compared to ITW (20%, 35%) and controls (0.4%, 3%).
Conclusions:
- EMG testing during resisted knee extension and quad set can effectively differentiate mild spastic diplegic CP from ITW.
- Gastrocnemius coactivation during these specific voluntary contractions is a key distinguishing feature.
- This EMG-based approach offers a valuable tool for clinical diagnosis.
Abstract:
The purpose of this study was to determine whether children with mild spastic diplegic cerebral palsy (CP) could be differentiated from those with idiopathic toe-walking (ITW) based on an obligatory coactivation during voluntary contraction of the quadriceps or gastrocnemius. Twenty-four subjects participated in this study, eight children with mild spastic diplegia CP, eight with ITW, and eight age-matched controls. Measurements included passive range of motion and surface electromyographic recordings of the lateral quadriceps and lateral gastrocnemius. Electromyographic recordings were obtained during resisted knee extension with knee flexed 30 degrees, isometric quadriceps contraction with knee extended (quad set), active plantarflexion, and during gait. The range-of-motion values were not different between the CP and ITW subjects, with the exception of the popliteal angle, which was greater in subjects with CP, with an overlap in values. Gait electromyography showed premature firing of gastrocnemius in swing in both groups of subjects compared with controls. During resisted knee extension and quad set, the mean duration of gastrocnemius coactivation in subjects with CP was high: 86% and 86% compared with 20% and 35% for the subjects with ITW and 0.4% and 3% for controls, respectively. Voluntary plantarflexion did not consistently elicit coactivation of the quadriceps. The results suggest that electromyographic testing of resisted knee extension and quad set to identify gastrocnemius coactivation can help differentiate patients with mild CP from those with ITW.
