Enhanced spinal excitation from ankle flexors to knee extensors during walking in stroke patients.
OBJECTIVE
It is still unclear to what an extent altered reflex activity contributes to gait deficit following stroke. Spinal group I and group II excitations from ankle dorsiflexors to knee extensors were investigated during post-stroke walking.


METHODS
Electrical stimulation was applied to the common peroneal nerve (CPN) in the early stance, and the short-latency biphasic excitation in Quadriceps motoneurones was evaluated from the Vastus Lateralis (VL) rectified and averaged (N=50) EMG activity in 14 stroke patients walking at 0.6-1.6 km/h, and 14 control subjects walking at 3.2-4.8 and at 1 km/h.


RESULTS
The second peak of the CPN-induced biphasic facilitation in VL EMG activity, which is likely mediated by group II excitatory pathways, was larger on the paretic side of the patients, as compared to their nonparetic side or control subjects, whatever their walking speed.


CONCLUSIONS
The spinal, presumed group II, excitation from ankle dorsiflexors to knee extensors is particularly enhanced during post-stroke walking probably due to plastic adaptations in the descending control.


CONCLUSIONS
This adaptation may help to stabilize the knee in early stance when the patients have recover ankle dorsiflexor functions.
UPMC Univ Paris 06, ER 6, F-75005, Paris, France.
V
V
Achache
D
D
Mazevet
C
C
Iglesias
A
A
Lackmy
J B
JB
Nielsen
R
R
Katz
V
V
Marchand-Pauvert
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000842:Ankle / Q000294:innervation* / Q000503:physiopathology; D004558:Electric Stimulation; D004576:Electromyography; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D007717:Knee / Q000294:innervation* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation* / Q000503:physiopathology; D010543:Peroneal Nerve / Q000502:physiology; D020127:Recovery of Function; D013116:Spinal Cord / Q000503:physiopathology*; D020521:Stroke / Q000503:physiopathology*; D016138:Walking / Q000502:physiology*