Minoru Toyokura1. 1. Department of Rehabilitation Medicine, Tokai University Oiso Hospital, 21-1 Gakkyo Oisomachi, Nakagun, Kanagawa 259-0198, Japan. toyokura@juno.dti.ne.jp
Abstract
OBJECTIVE: The aim of this study was to investigate the influence of stimulus intensity on the waveform of sympathetic skin response (SSR). The origin of the SSR waveform was discussed. METHODS: A total of 12 SSRs from palm skin were analyzed in 40 normal subjects. SSR was evoked by magnetic stimulation to the neck at 3 different intensities (10, 35, and 70% of the maximum output). The 3 stimuli were repeatedly applied in 4 separate sets. Waveforms were classified as either the P type, in which the positive component was larger than the negative one, or the N type, in which the negative component was larger than the positive one. Amplitude values of peak-to-peak, the first negative (N1), and subsequent positive (P1) components were compared among the 12 responses. RESULTS: When the stimulation was increased, the SSR size became larger. The P type SSR was most frequently found in the maximum stimulation. Strong stimulation generally produced a large P1. Only the N type SSR exhibited a large N1 response to the maximum stimulation. There was a significant, negative correlation between N1 peak duration (difference between the SSR onset and N1 peak latencies) and P1 amplitude. CONCLUSIONS: These results suggested that strong responses probably produced a P type SSR with a large P1 component. In this condition, a rapid change of potential from negative to positive prevented any correlation between N1 amplitude and the magnitude of the response. In the N type SSR, however, a large N1 was associated with a strong response. These findings can be explained by a newly presented theory on the neurophysiological origin of the negative and positive components, based on a model of equivalent current dipole dependent on the Na+ concentration gradient. SIGNIFICANCE: The present study provided some suggestions on the neurophysiological mechanism of SSR waveform.
OBJECTIVE: The aim of this study was to investigate the influence of stimulus intensity on the waveform of sympathetic skin response (SSR). The origin of the SSR waveform was discussed. METHODS: A total of 12 SSRs from palm skin were analyzed in 40 normal subjects. SSR was evoked by magnetic stimulation to the neck at 3 different intensities (10, 35, and 70% of the maximum output). The 3 stimuli were repeatedly applied in 4 separate sets. Waveforms were classified as either the P type, in which the positive component was larger than the negative one, or the N type, in which the negative component was larger than the positive one. Amplitude values of peak-to-peak, the first negative (N1), and subsequent positive (P1) components were compared among the 12 responses. RESULTS: When the stimulation was increased, the SSR size became larger. The P type SSR was most frequently found in the maximum stimulation. Strong stimulation generally produced a large P1. Only the N type SSR exhibited a large N1 response to the maximum stimulation. There was a significant, negative correlation between N1 peak duration (difference between the SSR onset and N1 peak latencies) and P1 amplitude. CONCLUSIONS: These results suggested that strong responses probably produced a P type SSR with a large P1 component. In this condition, a rapid change of potential from negative to positive prevented any correlation between N1 amplitude and the magnitude of the response. In the N type SSR, however, a large N1 was associated with a strong response. These findings can be explained by a newly presented theory on the neurophysiological origin of the negative and positive components, based on a model of equivalent current dipole dependent on the Na+ concentration gradient. SIGNIFICANCE: The present study provided some suggestions on the neurophysiological mechanism of SSR waveform.
Authors: Pedro Schestatsky; Josep Valls-Solé; João Costa; Lucia León; Misericordia Veciana; Márcia L Chaves Journal: Clin Auton Res Date: 2007-11-29 Impact factor: 4.435
Authors: Elisabeth Chroni; Andreas A Argyriou; Panagiotis Polychronopoulos; Vassiliki Sirrou Journal: Clin Auton Res Date: 2006-11-01 Impact factor: 4.435