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The importance of stimulus configuration for temporal summation of first and second pain to repeated heat stimuli
Author(s) -
Nielsen Jesper,
ArendtNielsen Lars
Publication year - 1998
Publication title -
european journal of pain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.305
H-Index - 109
eISSN - 1532-2149
pISSN - 1090-3801
DOI - 10.1016/s1090-3801(98)90031-3
Subject(s) - summation , stimulus (psychology) , audiology , nociceptor , stimulation , nociception , anesthesia , perception , radiant heat , medicine , psychophysics , psychology , neuroscience , cognitive psychology , materials science , receptor , composite material
Temporal summation of pain is suggested to be an important factor during various clinical conditions. Controversies exist as to whether temporal summation exists for A8 fibre‐mediated first pain. The aim of the present human experimental study was to investigate the importance of stimulus configuration (intensity, interpulse interval, location) for temporal summation of radiant (laser)‐ and contact‐heat‐induced pain. Consecutive stimuli were applied to the same or to adjacent skin locations. Both stimulation techniques evoked rapid temperature changes, which is an important parameter for recruitment of specific cutaneous nociceptors (Aδ and C fibres). Psychophysical thresholds and intensity ratings were used to assess the pain evoked by repeated stimuli applied to the hairy skin of nine volunteers. Inter‐pulse interval (IPI) and stimulus intensity were important and interrelated parameters for temporal summation of pain. An increase in IPI resulted in a decreased summation, whereas increased stimulus intensity resulted in increased summation. Brief heat pulses evoked both first and second pain, and summation of the different pain qualities was investigated. Taking the latency from stimulation to perception into consideration, we were able to differentiate and find summation of first (A8 fibre‐mediated) and second pain (C fibre‐mediated). Summation of first pain was more pronounced for high (38°C) than for low (30–32°C) baseline temperature.