Article

Previous studies have demonstrated the presence of intact axons
across a spinal cord lesion, even in those clinically diagnosed with complete
spinal cord injury (SCI).
These axons may allow volitional motor signals to be
transmitted through the injury, even in the absence of visible muscle
contraction. OBJECTIVE: To demonstrate the presence of volitional
electromyographic (EMG) activity below the lesion in motor complete SCI and to
characterize this activity to determine its value for potential use as a
neuroprosthetic command source. METHODS: Twenty-four subjects with complete (AIS
A or B), chronic, cervical SCI were tested for the presence of volitional
below-injury EMG activity. Surface electrodes recorded from 8 to 12 locations of
each lower limb, while participants were asked to attempt specific movements of
the lower extremity in response to visual and audio cues. EMG trials were ranked
through visual inspection, and were scored using an amplitude threshold algorithm
to identify channels of interest with volitional motor unit activity. RESULTS:
Significant below-injury muscle activity was identified through visual inspection
in 16 of 24 participants, and visual inspection rankings were well correlated to
the algorithm scoring. CONCLUSIONS: The surface EMG protocol utilized here is
relatively simple and noninvasive, ideal for a clinical screening tool. The
majority of subjects tested were able to produce a volitional EMG signal below
their injury level, and the algorithm developed allows automatic identification
of signals of interest.
The presence of this volitional activity in the lower
extremity could provide an innovative new command signal source for implanted
neuroprostheses or other assistive technology.

Langue : ANGLAIS