Wide-pulse-high-frequency neuromuscular electrical stimulation in cerebral palsy
Résumé
OBJECTIVE: The present study assesses whether wide-pulse-high-frequency (WPHF) neuromuscular electrical stimulation (NMES) could result in extra-force production in cerebral palsy (CP) patients as previously observed in healthy individuals. METHODS: Ten CP and 10 age- and sex-matched control participants underwent plantar flexors NMES. Two to three 10-s WPHF (frequency: 100Hz, pulse duration: 1ms) and conventional (CONV, frequency 25Hz, pulse duration: 50μs) trains as well as two to three burst-like stimulation trains (2s at 25Hz, 2s at 100Hz, 2s at 25Hz; pulse duration: 1ms) were evoked. Resting soleus and gastrocnemii maximal H-reflex amplitude (Hmax) was normalized by maximal M-wave amplitude (Mmax) to quantify α-motoneuron modulation. RESULTS: Similar Hmax/Mmax ratio was found in CP and control participants. Extra-force generation was observed both in CP (+18±74%) and control individuals (+94±124%) during WPHF (p\textless0.05). Similar extra-forces were found during burst-like stimulations in both groups (+108±110% in CP and +65±85% in controls, p\textgreater0.05). CONCLUSION: Although the mechanisms underlying extra-force production may differ between WPHF and burst-like NMES, similar increases were observed in patients with CP and healthy controls. SIGNIFICANCE: Development of extra-forces in response to WPHF NMES evoked at low stimulation intensity might open new possibilities in neuromuscular rehabilitation.