Abstract
The electrical and contractile properties of hand muscles in a selected population of quadriplegic subjects were studied intensively before and after EMG biofeedback. Spontaneously active motor units and units that could only be slowly and weakly activated were observed in these subjects, in addition to units that were voluntarily activated normally. This suggests a considerable overlap of surviving motor neurons to a single muscle that are below, near or above the level of a lesion. Despite the common occurrence of polyphasic potentials and other signs of neuromuscular reinnervation, the average twitch tension of single motor units in hand muscles of quadriplegic subjects was not significantly different from that in control subjects. Nor did it increase after biofeedback training that typically increased the peak surface EMG by a factor of 2-5 times. The percentage of spontaneously active units was also constant. The surface EMG may be increased during biofeedback by using higher firing rates in motor units that can already be activated, rather than by recruiting previously unavailable motor units.
| Original language | English |
|---|---|
| Pages (from-to) | 880-885 |
| Number of pages | 6 |
| Journal | Journal of Neurology, Neurosurgery and Psychiatry |
| Volume | 53 |
| Issue number | 10 |
| DOIs | |
| State | Published - Jan 1 1990 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Public Health, Environmental and Occupational Health
- Psychiatry and Mental health
- Neuroscience(all)
- Neuropsychology and Physiological Psychology
Cite this
Motor units in incomplete spinal cord injury : Electrical activity, contractile properties and the effects of biofeedback. / Stein, R. B.; Brucker, B. S.; Ayyar, D. R.
In: Journal of Neurology, Neurosurgery and Psychiatry, Vol. 53, No. 10, 01.01.1990, p. 880-885.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Motor units in incomplete spinal cord injury
T2 - Electrical activity, contractile properties and the effects of biofeedback
AU - Stein, R. B.
AU - Brucker, B. S.
AU - Ayyar, D. R.
PY - 1990/1/1
Y1 - 1990/1/1
N2 - The electrical and contractile properties of hand muscles in a selected population of quadriplegic subjects were studied intensively before and after EMG biofeedback. Spontaneously active motor units and units that could only be slowly and weakly activated were observed in these subjects, in addition to units that were voluntarily activated normally. This suggests a considerable overlap of surviving motor neurons to a single muscle that are below, near or above the level of a lesion. Despite the common occurrence of polyphasic potentials and other signs of neuromuscular reinnervation, the average twitch tension of single motor units in hand muscles of quadriplegic subjects was not significantly different from that in control subjects. Nor did it increase after biofeedback training that typically increased the peak surface EMG by a factor of 2-5 times. The percentage of spontaneously active units was also constant. The surface EMG may be increased during biofeedback by using higher firing rates in motor units that can already be activated, rather than by recruiting previously unavailable motor units.
AB - The electrical and contractile properties of hand muscles in a selected population of quadriplegic subjects were studied intensively before and after EMG biofeedback. Spontaneously active motor units and units that could only be slowly and weakly activated were observed in these subjects, in addition to units that were voluntarily activated normally. This suggests a considerable overlap of surviving motor neurons to a single muscle that are below, near or above the level of a lesion. Despite the common occurrence of polyphasic potentials and other signs of neuromuscular reinnervation, the average twitch tension of single motor units in hand muscles of quadriplegic subjects was not significantly different from that in control subjects. Nor did it increase after biofeedback training that typically increased the peak surface EMG by a factor of 2-5 times. The percentage of spontaneously active units was also constant. The surface EMG may be increased during biofeedback by using higher firing rates in motor units that can already be activated, rather than by recruiting previously unavailable motor units.
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U2 - 10.1136/jnnp.53.10.880
DO - 10.1136/jnnp.53.10.880
M3 - Article
C2 - 2266370
AN - SCOPUS:0025134740
VL - 53
SP - 880
EP - 885
JO - Journal of Neurology, Neurosurgery and Psychiatry
JF - Journal of Neurology, Neurosurgery and Psychiatry
SN - 0022-3050
IS - 10
ER -