Pupillary response to noxious electrodermal stimulation in varying conditions of intensity, delay and information.
Item
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Title
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Pupillary response to noxious electrodermal stimulation in varying conditions of intensity, delay and information.
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Identifier
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AAI9417476
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identifier
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9417476
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Creator
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Iglesias, Irmgard Isabel.
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Contributor
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Adviser: Gad Hakerem
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Date
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1994
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Neuroscience | Psychology, Physiological
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Abstract
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The pupillary response to noxious and non-noxious electrodermal stimulation at four intensity levels was studied in 24 paid volunteers, under conditions of information about intensity, information about delay, and after four, five, eight and nine second delays.;Pupil diameter size was recorded every 20 milliseconds during a three second period, starting at stimulus onset. Ratings of the pain experience using a 12 item scale were also recorded.;As expected, higher intensity noxious stimuli resulted in significantly larger changes in pupil size and higher intensity ratings. Both measures accurately reflected the stimulus intensity levels. The pupillary response was concluded to be an accurate indicator of the pain experience and a viable method in pain measurement.;Information about intensity and, or, delay was expected to influence the subjects' perception of stimulus intensity and to result in smaller responses because of the association between uncertainty and anxiety. Shorter delays were expected to result in smaller responses because of their association with better predictability.;Neither Delay, nor Information about Intensity or Delay, nor Order resulted in significant differences. However, a relative chronicity effect of Intensity Information was suggested because responses at the initial sessions were in the opposite direction as those of latter sessions.;The lack of significant differences due to Delay was explained in part by an information processing component believed to contribute to pupil size increases following short delays. Hypothetically, these increases offset the larger pupil dilations expected after longer delays.;Discriminability and response criteria were obtained from pain ratings data through Signal Detection Analysis. Discriminability was significantly higher when low intensity pairs of stimulus intensities were compared, and response criteria were significantly lower when high intensity pairs were compared. Neither Delay Information, nor Intensity Information nor Delay were found to significantly affect these responses. Further post-hoc analyses on sex reflected some subtle differences on these measures but due to uneven sample sizes data are inconclusive, but suggestive.;Conclusions arrived at from pupillary data were consistent with discriminability data, adding validity to the use of pupillometry in pain research.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
