title: The effect of stimulation technique on sympathetic skin responses in healthy subjects.
abstract: The aim of this study was to collect normative data for sympathetic skin responses (SSR) elicited by electrical stimulus of the ipsilateral and contralateral peripheral nerves, and by magnetic stimulus of cervical cord. SSRs were measured at the mid-palm of both hands following electrical stimulation of the left median nerve at the wrist and magnetic stimulation at the neck in 40 healthy adult volunteers (mean age 52.2 +/- 12.2 years, 19 males). The onset latency, peak latency, amplitude and area were estimated in "P" type responses (i.e., waveforms with a larger positive, compared to negative, component). SSR onset and peak latency were prolonged when the electrical stimulus was applied at the contralateral side (i.e., the SSR recorded in the right palm P < 0.001). The onset latency was similar on both sides during cervical magnetic stimulation. However, peak latency was faster on the left side (P < 0.03). Comparison of electrical and magnetic stimulation revealed that both the onset and peak latency were shorter with magnetic stimulation (P < 0.001). The latency of a SSR varies depending on what type of stimulation is used and where the stimulus is applied. Electrically generated SSRs have a longer delay and the delay is prolonged at the contralateral side. These factors should be taken into account when interpreting SSR data.
authors.affiliation: Dept of Neurology, Laboratory of Clinical Neurophysiology, University of Patras Medical School, 26504, Rion-Patras, Greece. echroni@yahoo.com
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Chroni
authors.forename: Andreas A
authors.initials: AA
authors.lastname: Argyriou
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Polychronopoulos
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Sirrou
mesh_terms: D000328:Adult; D000368:Aged; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008280:Magnetics; D008297:Male; D008875:Middle Aged; D011930:Reaction Time / Q000502:physiology; D012867:Skin / Q000294:innervation*; D012879:Skin Physiological Phenomena; D013564:Sympathetic Nervous System / Q000502:physiology*