s134 RELATIONSHIP BETWEEN FACIAL EXPRESSION AND SELF REPORT OF

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196 Video ENTAL PAIN. L. LFesche!, S.F. Dworkidy2, and A.C.N. Sun 3:30

Departments of Oral Medicine, "PsychiatryandBehav 5th Ave Rm ioral Sciences, Univ. of Washington, Seattle, WA 98195 USA

Particular discrete facial expressions are recognized as expressionc of

specific emotions in all human cultures. This study sought to validatepre- viously identified facial expressions of pain by determining their relation

to traditional self report pain measures in clinical acute pain patients. Fourteen dental patients with acute pathologic pain completed the McGill

Pain Questionnaire (MPQ), visual analog (VA) scales of pain aversiveness and intensity, state and trait anxiety scales, a dental fears scale, and were videotaped as part of our routine experimental protocol. Videotapes were

coded for the movement of individual facial muscles by two coders using the

anatomically based, comprehensive and highly reliable Facial Action Coding

System. Individual muscle movements occurring simultaneously were grouped into"clusters"or facial expressions on the basis of a computer algorithm.

Expressions previously reported to be facial expressions of pain were

shown by 8 of the 14 subjects. These behaviors occurred at a rate of about

Z/min. andlasted an average of 0.75 (+0.7l)sec. Subjects who showed these

expressions reported higher pain intensity (mean of 46.9,x.29.7 for those

who showed no pain expressions), as well as higher MPQ sensory (15.2 vs.Y.31

affective (3.1 F. l.O)and total scores (26.5 vs.14.7). Clinicians' VA

ratings of the patients' pain were also higher for the group showing facial

expressions of pain than for those who showed none (40.5~~. 24.8). State

and trait anxiety and dental fears did not differ in the two groups. The previously identified facial expressions are valid indicators of pain

under the conditions described. They are specific to pain, rather than

anxiety, may be recognized by clinicians and hold promise as measures of

pain. (Supported by NIH (NIDR) Grant No. DE06219.1