Tohoku J. Exp. Med., 2010, 220(2)

Spectrophotometric Evaluation of the Age of Bruises in Children: Measuring Changes in Bruise Color as an Indicator of Child Physical Abuse

SOHTARO MIMASAKA,¹ MAKI OHTANI,¹ NAOHITO KURODA² and SHIGEYUKI TSUNENARI³

¹Department of Forensic Sciences, Akita University Graduate School of Medicine, Akita, Akita, Japan
²Department of Forensic Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Aomori, Japan
³Department of Forensic Medicine, Graduate School of Medical Science, Kumamoto University, Kumamoto, Kumamoto, Japan

Physical abuse of children is a severe social problem and is usually identified by the presence of bruises of various ages. The visual appearance of bruises is widely used to identify victims of abuse. Therefore, to objectively evaluate the age of bruises, we used a spectrophotometer to examine 86 bruises that occurred accidentally in healthy child volunteers, with consent from appropriate guardians. The bruise color was measured using a spectrophotometer and plotted using the CIE-L*a*b* color system, a method that expresses color numerically. The differences [Δ] in L* (lightness), a* (red and green content) and b* (yellow and blue content) color values relative to neighboring healthy/unbruised skin were measured for 7-10 days until the bruise disappeared. A characteristic pattern was observed in 21 bruises; ΔL* increased from the negative peak and returned to baseline, Δa* decreased from the positive peak to baseline, and Δb* increased above baseline and then slowly returned to baseline. The pattern of these color changes could be classified into three phases according to the time between bruising and the peak values for ΔL* (negative peak, 38.9 ± 19.5 hours), Δa* (positive peak, 37.6 ± 21.7 hours), and Δb* (negative and positive peak, 43.5 ± 18.7 and 132.6 ± 40.4 hours). Thus, spectrophotometric measurement of the color of bruises is helpful to estimate the approximate age of bruises and to distinguish between old and new bruises. This objective method could be introduced to clinical practice and social care to evaluate possible cases of child abuse.

keywords —— child abuse; bruise; spectrophotometer; tristimulus values; clinical forensic medicine