Double peak sensory responses: effects of capsaicin

Neurol Sci. 2007 Oct;28(5):264-9. doi: 10.1007/s10072-007-0833-x. Epub 2007 Oct 31.

Abstract

The aim of this study is to verify whether degeneration of skin receptors or intradermal nerve endings by topical application of capsaicin modifies the double peak response obtained by submaximal anodal stimulation. Five healthy volunteers topically applied capsaicin to the finger-tip of digit III (on the distal phalanx) four times daily for 4-5 weeks. Before and after local capsaicin applications, we studied the following electrophysiological findings: compound sensory action potential (CSAP), double peak response, sensory threshold and double peak stimulus intensity. Local capsaicin application causes disappearance or decrease of the second component of the double peak, which gradually increases after the suspension of capsaicin. Conversely, no significant differences were observed for CSAP, sensory threshold and double peak stimulus intensity. This study suggests that the second component of the double peak may be a diagnostic tool suitable to show an impairment of the extreme segments of sensory nerve fibres in distal sensory axonopathy in the early stages of damage, when receptors or skin nerve endings are impaired but undetectable by standard nerve conduction studies.

Publication types

  • Clinical Trial

MeSH terms

  • Administration, Cutaneous
  • Adult
  • Analysis of Variance
  • Capsaicin / administration & dosage*
  • Dose-Response Relationship, Radiation
  • Electric Stimulation* / methods
  • Evoked Potentials / drug effects*
  • Evoked Potentials / physiology
  • Evoked Potentials / radiation effects
  • Female
  • Humans
  • Male
  • Nerve Endings / drug effects
  • Reaction Time / drug effects
  • Reaction Time / radiation effects
  • Sensory System Agents / administration & dosage*
  • Sensory Thresholds / drug effects*
  • Skin / innervation

Substances

  • Sensory System Agents
  • Capsaicin