In the present project, the investigators aim at proposing innovative ways of investigating spinal motoneuron hyperexcitability to counteract the associated impairments by using wide pulse high frequency neuromuscular electrical stimulation (WPHF NMES) in various populations. The investigators will use WPHF NMES contractions as a model to gain insights into the mechanisms underlying muscle cramps, restless legs syndrome or stroke-induced spasticity as there is evidence that they share common underlying mechanisms. The investigators will then use WPHF NMES as a training modality to improve plantar flexor neuromuscular function in stroke patients by taking advantage of their motoneuronal hyperexcitability.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
110
Plantar flexors will be stimulated with wide pulse high frequency neuromuscular electrical stimulation 3 times a week for 6 weeks
Bâtiment Synathlon, quartier UNIL-Centre
Lausanne, Switzerland
RECRUITINGChange in maximal voluntary contraction force
Change from baseline maximal voluntary contraction force after the six-week training period in stroke patients
Time frame: through study completion, an average of 8 weeks
Change in NMES-evoked force
Change from baseline NMES-evoked force after the six-week training period
Time frame: through study completion, an average of 8 weeks
NMES-evoked force
Comparison of NMES-evoked force in plantar flexor muscles between patients (prone to cramps or restless legs) and healthy volunteers
Time frame: through study completion, an average of 2 weeks
Change in estimates of persistent inward current (Delta F assessed with high-density surface electromyography and/ or the torque measured during vibration after the last bout of NMES)
Change from baseline estimates of persistent inward current after the six-week training period in stroke patients
Time frame: through study completion, an average of 8 weeks
Estimates of persistent inward current (Delta F assessed with high-density surface electromyography and/ or the torque measured during vibration after the last bout of NMES)
comparison of estimates of persistent inward current strength in plantar flexor muscles between patients (prone to cramps or restless legs) and healthy volunteers
Time frame: through study completion, an average of 8 weeks
Change in voluntary activation level and contractile properties of the plantar flexor muscles
Change from baseline voluntary activation level and contractile properties of the plantar flexor muscles after the six-week training period in stroke patients
Time frame: through study completion, an average of 8 weeks
voluntary activation level and contractile properties of the plantar flexor muscles
comparison of voluntary activation level and contractile properties of the plantar flexor muscles between patients (prone to cramps or restless legs) and healthy volunteers
Time frame: through study completion, an average of 2 weeks
change in spasticity at the ankle joint level for stroke patients
Change from baseline Ashworth scale score (minimal score 0, maximal score 4, a higher score means a worst outcome) after the six-week training period in stroke patients
Time frame: through study completion, an average of 8 weeks
10-m walking test (s)
functional test
Time frame: through study completion, an average of 8 weeks
6-min walking test (m)
functional test
Time frame: through study completion, an average of 8 weeks
time up and go test (s)
functional test
Time frame: through study completion, an average of 8 weeks
Change in spinal excitability in stroke patients
change from baseline soleus Hoffmann reflex amplitude after the six-week training period in stroke patients
Time frame: through study completion, an average of 8 weeks
Spinal excitability
comparison of soleus Hoffmann reflex amplitude between patients (prone to cramps or restless legs) and healthy volunteers
Time frame: through study completion, an average of 2 weeks
Cramp threshold frequency (CTF) for cramp-prone individuals
comparison between participants reporting muscle cramps and healthy volunteers
Time frame: through study completion, an average of 2 weeks
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