Influence of limb temperature on cutaneous silent periods
Language English Country Netherlands Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
24555925
DOI
10.1016/j.clinph.2014.01.018
PII: S1388-2457(14)00054-6
Knihovny.cz E-resources
- Keywords
- A-delta fiber, Cutaneous silent period, Nerve conduction, Physiology, Spinal reflex, Temperature,
- MeSH
- Action Potentials physiology MeSH
- Adult MeSH
- Extremities physiology MeSH
- Skin innervation MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Motor Neurons physiology MeSH
- Nerve Fibers, Myelinated physiology MeSH
- Sensory Receptor Cells physiology MeSH
- Neural Conduction physiology MeSH
- Median Nerve physiology MeSH
- Reflex physiology MeSH
- Sensory Thresholds physiology MeSH
- Body Temperature physiology MeSH
- Temperature MeSH
- Check Tag
- Adult MeSH
- Middle Aged MeSH
- Humans MeSH
- Young Adult MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
OBJECTIVE: The cutaneous silent period (CSP) is a spinal inhibitory reflex mediated by small-diameter afferents (A-delta fibers) and large-diameter efferents (alpha motoneurons). The effect of limb temperature on CSPs has so far not been assessed. METHODS: In 27 healthy volunteers (11 males; age 22-58 years) we recorded median nerve motor and sensory action potentials, median nerve F-wave and CSPs induced by noxious digit II stimulation in thenar muscles in a baseline condition at room temperature, and after randomly submersing the forearm in 42 °C warm or 15 °C cold water for 20 min each. RESULTS: In cold limbs, distal and proximal motor and sensory latencies as well as F-wave latencies were prolonged. Motor and sensory nerve conduction velocities were reduced. Compound motor and sensory nerve action potential amplitudes did not differ significantly from baseline. CSP onset and end latencies were more delayed than distal and proximal median nerve motor and sensory latencies, whereas CSP duration was not affected. In warm limbs, opposite but smaller changes were seen in nerve conduction studies and CSPs. CONCLUSION: The observed CSP shift "en bloc" towards longer latencies without affecting CSP duration during limb cooling concurs with slower conduction velocity in both afferent and efferent fibers. Disparate conduction slowing in afferents and efferents, however, suggests that nociceptive EMG suppression is mediated by fibers of different size in the afferent than in the efferent arm, indirectly supporting the contribution of A-delta fibers as the main afferent input. SIGNIFICANCE: Limb temperature should be taken into account when testing CSPs in the clinical setting, as different limb temperatures affect CSP latencies more than large-diameter fiber conduction function.
Department of Neurology Charles University 3rd Faculty of Medicine Prague Czech Republic
References provided by Crossref.org
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