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The effects of distraction on tooth-shock cerebral evoked potentials
THE EFFECTS OF DISTRACTIONON TOOTH-SHOCKCEREBRALEVOKED POTENTIALS. E.W. Howland*,5. Nichols*,O.C. Zelman* & C.S. Cleeland,(SPON:Charles S. Cleeland),Departmentof Neurology,Medical School, Universityof Wisconsin,Madison,WI 53792, USA. Aim of Investigation: Selectedwaves of the tooth-shockcerebralevoked potential(EP) are usually highly correlatedwith stimulationintensityand subjectivereportsof pain. This study examinesthe relationshipbetweenpain reportsand EP amplitudescollectedwhile subjectsare involvedin distractingtasks. A&hods: Volunteerswere asked to determinea range of stimulationfrom the lowest level producingpain to the greatestlevel that they could tolerate. Two stimulationvalues were chosen, 25% above the minimum of the range and 25% below the maximum of the range. These two levels of stimulationwere deliveredin blocks of 25 trials while subjectswere engaged in distractingmental tasks with two levels of difficulty. Additionally,baselinerecordingsat each level were recordedbefore and after the tasks. Pain ratingswere obtained from subjectsfollowingeach block of trials. Results: Approximatelyone half of the subjects'data have been analyzed. As expected, both pain ratings and EP amplitudessignificantlyincreasedwith increasedstimulusintensity. There was a trend for pain ratingsto decreasewith distraction. EP amplitudesdid not show the same decrease. In contrastto the reductionsin pain ratings,EP amplitudes were unaffectedby the distractiontasks. Conclusions: Althoughpain ratingsand EP amplitudesare usually closelycorrelated, distractionseems to reduce pain ratingswhile EPs remainedat the same amplitude. This disassociationbetween EP amplitudeand pain ratings suggeststhat behavioralmethods of pain control act on stages of pain perceptionnot involvedin creatingEPs.
EFFECT OF THERMAL-IMAGINATION ON EXPERIMENTAL PAIN USING A CONSTANT RADIANT HEAT. T."> K. ShimizuZ', and M. Ohyama", (SPON: H. Hayashi), Dept. of LPsychology, College of 'Medical Sciences, Tohoku University, Sendai, Miyagi, 980, Japan. of InveSm: The present study was aimed at studying the effect of thermal-imaginations on pain responses. Just prior to each trial the subject was exposed to one of the image cues which consisted of four thermal stimuli ranging from the ice-cold to the hot. The two of them were compatible with the heat stimulus and the others incompatible. Experimental pain was produced by a constant radiM&h&: ant heat of 200 mcal/sec/cm' delivered to the right dorsal forearm surface attached with black sticky patches. The time from heat presentation to releasing the key when the subject began to feel pain served as the measure of pain threshold. The subjects in the experimental group were asked to form the same image in their mind as the sensation produced by a cue given beforehand while the heat stimulus was being presented. As the cues were changed from the hot to ice-cold, Results: the thresholds we$e gradually elevated. Besides, the enhanced threshold was found to be obtained even in the posttest. The data on finger p&se volume recorded simultaneously differed from those on thresholds in that the imaginations in the test session had no effect on the pulse volume in the posttest. Conclusm: These results suggested that the threshold of pain response was altered by the image recalled, and that the incompatible images played a significant part in lessened pain sensitivity.
EFFECT OF THERMAL-IMAGINATION ON EXPERIMENTAL PAIN USING A CONSTANT RADIANT HEAT. T."> K. ShimizuZ', and M. Ohyama", (SPON: H. Hayashi), Dept. of LPsychology, College of 'Medical Sciences, Tohoku University, Sendai, Miyagi, 980, Japan. of InveSm: The present study was aimed at studying the effect of thermal-imaginations on pain responses. Just prior to each trial the subject was exposed to one of the image cues which consisted of four thermal stimuli ranging from the ice-cold to the hot. The two of them were compatible with the heat stimulus and the others incompatible. Experimental pain was produced by a constant radiM&h&: ant heat of 200 mcal/sec/cm' delivered to the right dorsal forearm surface attached with black sticky patches. The time from heat presentation to releasing the key when the subject began to feel pain served as the measure of pain threshold. The subjects in the experimental group were asked to form the same image in their mind as the sensation produced by a cue given beforehand while the heat stimulus was being presented. As the cues were changed from the hot to ice-cold, Results: the thresholds we$e gradually elevated. Besides, the enhanced threshold was found to be obtained even in the posttest. The data on finger p&se volume recorded simultaneously differed from those on thresholds in that the imaginations in the test session had no effect on the pulse volume in the posttest. Conclusm: These results suggested that the threshold of pain response was altered by the image recalled, and that the incompatible images played a significant part in lessened pain sensitivity.