Article

Hoffman (H) reflexes were elicited from the soleus muscle during treadmill
walking in 21 spastic paretic patients. The soleus and tibialis anterior muscles
were reciprocally activated during walking in most patients, much like that
observed in healthy individuals.
The pattern of H-reflex modulation varied
considerably between patients, from being relatively normal in some patients to a
complete absence of modulation in others. The most common pattern observed was a
lack of H-reflex modulation through the stance phase and slight depression of the
reflex in the swing phase, considerably less modulation than that of normal
subjects under comparable walking conditions. The high reflex amplitudes during
periods of the step cycle such as early stance seems to be related to the
stretch-induced large electromyogram bursts in the soleus in some subjects. The
abnormally active reflexes appear to contribute to the clonus encountered during
walking in these patients. In three patients who were able to walk for extended
periods, the effect of stimulus intensity was examined. Two of these patients
showed a greater degree of reflex modulation at lower stimulus intensities,
suggesting that the lack of modulation observed at higher stimulus intensities is
a result of saturation of the reflex loop. In six other patients, however, no
reflex modulation could be demonstrated even at very low stimulus intensities.

Langue : ANGLAIS

Tiré à part : OUI