title: Pain rather than induced emotions and ICU sound increases skin conductance variability in healthy volunteers.
abstract: BACKGROUND
  Assessing pain in critically ill patients is difficult. Skin conductance variability (SCV), induced by the sympathetic response to pain, has been suggested as a method to identify pain in poorly communicating patients. However, SCV, a derivate of conventional skin conductance, could potentially also be sensitive to emotional stress. The purpose of the study was to investigate if pain and emotional stress can be distinguished with SCV.
  
  
  METHODS
  In a series of twelve 1-min sessions with SCV recording, 18 healthy volunteers were exposed to standardized electric pain stimulation during blocks of positive, negative, or neutral emotion, induced with pictures from the International Affective Picture System (IAPS). Additionally, authentic intensive care unit (ICU) sound was included in half of the sessions. All possible combinations of pain and sound occurred in each block of emotion, and blocks were presented in randomized order.
  
  
  RESULTS
  Pain stimulation resulted in increases in the number of skin conductance fluctuations (NSCF) in all but one participant. During pain-free baseline sessions, the median NSCF was 0.068 (interquartile range 0.013-0.089) and during pain stimulation median NSCF increased to 0.225 (interquartile range 0.146-0.3175). Only small increases in NSCF were found during negative emotions. Pain, assessed with the numeric rating scale, during the sessions with pain stimulation was not altered significantly by other ongoing sensory input.
  
  
  CONCLUSIONS
  In healthy volunteers, NSCF appears to reflect ongoing autonomous reactions mainly to pain and to a lesser extent, reactions to emotion induced with IAPS pictures or ICU sound.
authors.affiliation: Section for Anesthesiology and Intensive Care, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.|Department of Cardiothoracic Surgery and Anesthesiology, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: A C
authors.initials: AC
authors.lastname: Günther
authors.affiliation: Section for Anesthesiology and Intensive Care, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.|Department of Anesthesiology, Surgical Services and Intensive Care Medicine, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: A R
authors.initials: AR
authors.lastname: Schandl
authors.affiliation: Division of Social Sciences, Department of Psychology, Mid Sweden University, Östersund, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Berhardsson
authors.affiliation: Division of Social Sciences, Department of Psychology, Mid Sweden University, Östersund, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Bjärtå
authors.affiliation: Division of Social Sciences, Department of Psychology, Mid Sweden University, Östersund, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Wållgren
authors.affiliation: Division of Social Sciences, Department of Psychology, Mid Sweden University, Östersund, Sweden.
authors.forename: Ö
authors.initials: Ö
authors.lastname: Sundin
authors.affiliation: Marcus Wallenberg Laboratory, Department of Aeronautical and Vehicle Engineering, School of Engineering Sciences, Royal Institute of Technology, Stockholm, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Alvarsson
authors.affiliation: Unit of Biostatistics, Department of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Bottai
authors.affiliation: Section for Anesthesiology and Intensive Care, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.|Department of Anesthesiology, Surgical Services and Intensive Care Medicine, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: C-R
authors.initials: CR
authors.lastname: Martling
authors.affiliation: Section for Anesthesiology and Intensive Care, Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.|Department of Anesthesiology, Surgical Services and Intensive Care Medicine, Karolinska University Hospital Solna, Stockholm, Sweden.
authors.forename: P V
authors.initials: PV
authors.lastname: Sackey
mesh_terms: D000328:Adult; D004558:Electric Stimulation; D005260:Female; D005712:Galvanic Skin Response / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D007362:Intensive Care Units; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000503:physiopathology*; D013315:Stress, Psychological / Q000503:physiopathology*