Changes in electromyographic activity after botulinum toxin injection of the rectus femoris in patients with hemiparesis walking with a stiff-knee gait.
OBJECTIVE
This study was designed to evaluate the effects of botulinum toxin type-A (BoNTA) injection of the rectus femoris (RF) muscle on the electromyographic activity of the knee flexor and extensor and on knee and hip kinematics during gait in patients with hemiparesis exhibiting a stiff-knee gait.


METHODS
Two gait analyses were performed on fourteen patients: before and four weeks after BoNTA injection. Spatiotemporal, kinematic and electromyographic parameters were quantified for the paretic limb.


RESULTS
BoNTA treatment improved gait velocity, stride length and cadence with an increase of knee angular velocity at toe-off and maximal knee flexion in the swing phase. Amplitude and activation time of the RF and co-activation duration between the RF and biceps femoris were significantly decreased. The instantaneous mean frequency of RF was predominantly lower in the pre-swing phase.


CONCLUSIONS
The results clearly show that BoNTA modified the EMG amplitude and frequency of the injected muscle (RF) but not of the synergist and antagonist muscles. The reduction in RF activation frequency could be related to increased activity of slow fibers. The frequency analysis of EMG signals during gait appears to be a relevant method for the evaluation of the effects of BoNTA in the injected muscle.
GRCTH, EA4497, CIC-IT 805, CHU Raymond Poincaré, 92380 Garches, France. julien.boudarham@yahoo.fr
J
J
Boudarham
S
S
Hameau
D
D
Pradon
D
D
Bensmail
N
N
Roche
R
R
Zory
D000328:Adult; D000368:Aged; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D004576:Electromyography / Q000187:drug effects*; D005260:Female; D020233:Gait Disorders, Neurologic / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D007273:Injections, Intramuscular; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000503:physiopathology*; D009465:Neuromuscular Agents / Q000008:administration & dosage; D010291:Paresis / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology*; D004856:Postural Balance / Q000187:drug effects; D016896:Treatment Outcome
D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A
Co-activation; Continuous wavelet transform; Principal component analysis; Spasticity; Stroke