The second exteroceptive suppression is affected by psychophysiological factors
Received 7 April 2008; received in revised form 18 November 2008; accepted 16 December 2008. published online 04 March 2009.
Abstract
Objective
The second exteroceptive suppression (ES2) is assumed to be an indicator of central antinociceptive processing, although some conflicting data have been produced. We examined the impact of experimentally induced psychophysiological conditions on the latency and duration of the ES2. Also, the association to the subjective evaluation of the painful electrical stimulation by which the ES2 is elicited was studied.
Methods
ES2 was assessed in 46 healthy volunteers running through four experimentally induced psychophysiological conditions: stress, relaxation, depressed mood, and heterotopic pressure pain. Conditions were presented in a repeated measure design in permuted sequences. Ten stimulation-recording sequences per condition were averaged. ES2 parameters were compared to a baseline condition and correlated to subjective pain perception.
Results
ES2 duration was found to be prolonged and ES2 latency to be shortened under the impact of relaxation and depressed mood. The subjective perception of the painful electrical stimulation was affected by the experimental conditions.
Conclusion
Data lend support to the hypothesis that the repeatedly observed limited stability of ES2 parameters might be caused by the variability of individual psychophysiological states. Against expectation, subjective pain perception is not systematically correlated with ES2 parameters. Thus it can be questioned whether the ES2 is directly associated with pain processing at all.
aInstitute of Medical Psychology and Medical Sociology, University Hospital of RWTH Aachen University, Aachen, Germany
bDepartment for Clinical Psychology and Psychotherapy, Institute of Psychology, University of Göttingen, Göttingen, Germany
cDepartment of Clinical Neurophysiology, Medical Faculty, University of Göttingen, Göttingen, Germany
Corresponding author. Institute of Medical Psychology and Medical Sociology, University Hospital of RWTH Aachen University, Pauwelsstraße 30, 52074 Aachen, Germany. Tel.: +49 241 8089003; fax: +49 241 80 33 89003.
ABSTRACT