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Pain Research and Management
Volume 16 (2011), Issue 1, Pages 10-12
http://dx.doi.org/10.1155/2011/873103
Original Article

Exploring the Association Between Pain Intensity and Facial Display in Term Newborns

Martin Schiavenato,1,2 Meggan Butler-O’Hara,3 and Paul Scovanner4

1University of Rochester School of Nursing, University of Rochester, Rochester, New York, USA
2Department of Biomedical Engineering, University of Rochester, Rochester, New York, USA
3Department of Pediatrics, Division of Neonatology, University of Rochester, Rochester, New York, USA
4School of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida, USA

Copyright © 2011 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

BACKGROUND: Facial expression is widely used to judge pain in neonates. However, little is known about the relationship between intensity of the painful stimulus and the nature of the expression in term neonates.

OBJECTIVES: To describe differences in the movement of key facial areas between two groups of term neonates experiencing painful stimuli of different intensities.

METHODS: Video recordings from two previous studies were used to select study subjects. Four term neonates undergoing circumcision without analgesia were compared with four similar male term neonates undergoing a routine heel stick. Facial movements were measured with a computer using a previously developed ‘point-pair’ system that focuses on movement in areas implicated in neonatal pain expression. Measurements were expressed in pixels, standardized to percentage of individual infant face width.

RESULTS: Point pairs measuring eyebrow and eye movement were similar, as was the sum of change across the face (41.15 in the circumcision group versus 40.33 in the heel stick group). Point pair 4 (horizontal change of the mouth) was higher for the heel stick group at 9.09 versus 3.93 for the circumcision group, while point pair 5 (vertical change of the mouth) was higher for the circumcision group (23.32) than for the heel stick group (15.53).

CONCLUSION: Little difference was noted in eye and eyebrow movement between pain intensities. The mouth opened wider (vertically) in neonates experiencing the higher pain stimulus. Qualitative differences in neonatal facial expression to pain intensity may exist, and the mouth may be an area in which to detect them. Further study of the generalizability of these findings is needed.