Electrical stimulation of innervated muscles has been investigated for many decades with alternations of high and low clinical interest in the fields of stroke, SCI rehabilitation, and sport sciences. Early work demonstrated that afferent fibers have lower thresholds and are usually activated first (therefore eliciting an H-reflex). In the case of nerve trunk stimulation, the order of recruitment is mostly conditioned by the axonal dimension and excitability threshold. In the case of muscle motor point stimulation, the spatial distribution of nerve branches plays a predominant role. Sustained stimulation produces a progressive increase of force that is often maintained in subsequent voluntary activation by stroke patients. This observation suggested a facilitation mechanism at the spinal and/or supraspinal levels. Such facilitation has been observed in healthy subjects as well, and may explain the generation of cramps elicited during stimulation and sustained for dozens of seconds after stimulation has been interrupted. The most recent interpretations of facilitation resulting from peripheral stimulation focused on pre- (potentiation of neurotransmitter release from afferent fibers) or post-synaptic (generation of “Persistent Inward Currents” in spinal motor neurons or interneurons) mechanisms. The renewed attention to these phenomena is once more increasing the interest toward electrical stimulation of the neuromuscular system. This is an opportunity for a structured investigation of the field aimed to resolving elements of confusion and controversy that still plague this area of electrophysiology.

Spinal involvement and muscle cramps in electrically-elicited contractions. / Merletti R; Botter A; Minetto MA. - In: ARTIFICIAL ORGANS. - ISSN 0160-564X. - 34(2010), pp. A45--. ((Intervento presentato al convegno 15th Annual Conference of the International FES Society tenutosi a Vienna, Austria nel Spetember 8-12, 2010.

Spinal involvement and muscle cramps in electrically-elicited contractions.

MINETTO, Marco Alessandro
2010

Abstract

Electrical stimulation of innervated muscles has been investigated for many decades with alternations of high and low clinical interest in the fields of stroke, SCI rehabilitation, and sport sciences. Early work demonstrated that afferent fibers have lower thresholds and are usually activated first (therefore eliciting an H-reflex). In the case of nerve trunk stimulation, the order of recruitment is mostly conditioned by the axonal dimension and excitability threshold. In the case of muscle motor point stimulation, the spatial distribution of nerve branches plays a predominant role. Sustained stimulation produces a progressive increase of force that is often maintained in subsequent voluntary activation by stroke patients. This observation suggested a facilitation mechanism at the spinal and/or supraspinal levels. Such facilitation has been observed in healthy subjects as well, and may explain the generation of cramps elicited during stimulation and sustained for dozens of seconds after stimulation has been interrupted. The most recent interpretations of facilitation resulting from peripheral stimulation focused on pre- (potentiation of neurotransmitter release from afferent fibers) or post-synaptic (generation of “Persistent Inward Currents” in spinal motor neurons or interneurons) mechanisms. The renewed attention to these phenomena is once more increasing the interest toward electrical stimulation of the neuromuscular system. This is an opportunity for a structured investigation of the field aimed to resolving elements of confusion and controversy that still plague this area of electrophysiology.
15th Annual Conference of the International FES Society
Vienna, Austria
Spetember 8-12, 2010
34
A45
-
Merletti R; Botter A; Minetto MA
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2318/75750
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