title: Assessment of bruise age on dark-skinned individuals using tristimulus colorimetry.
abstract: BACKGROUND
  Studies on the ageing of bruises have been reported on Caucasians or individuals of fair ethnicity. This study focuses on bruise changes in dark-skinned individuals using tristimulus colorimetry for forensic analysis in such individuals.
  
  
  METHODS
  Eighteen subjects of South Indian or Sri-Lankan ethnicity were recruited. Subjects were bruised using a vacuum pump and then daily colour measurements were taken of the bruise using a tristimulus colorimeter. The L*a*b* readings were recorded of a control area and of the bruise until it disappeared. Two Caucasians were used for comparison.
  
  
  RESULTS
  This study showed that, using colorimetry, bruises on dark-skinned individuals can be measured and analysed even if the bruises are unclear visually. As the bruise is beneath the skin, the colour difference ΔL*, Δa* and Δb* were calculated. All values showed a trend, indicating that the L*a*b* measuring technique is a reliable method to analyse bruises on dark-skinned individuals. Comparisons of Asian subjects and Caucasian subjects were performed. The largest difference was seen in the b* value. Statistical analysis showed that ΔL* colour difference was the most consistent (95% CI -4.05 to -2.49) showing a significant difference between days 1-4 and 5-8.
  
  
  CONCLUSIONS
  Objective assessment of bruises on dark-skinned individuals using the L*a*b* method of measuring gave reproducible results. Furthermore, the study showed that the yellowing of a bruise cannot be seen or measured with a tristimulus colorimeter on dark-skinned individuals due to the pigmentation of the skin. With further studies and more subjects, the age of bruises could potentially be assessed for use in forensic analysis.
authors: Queen Mary University of London, London, UK. ha06080@qmul.ac.uk
authors: D
authors: D
authors: Thavarajah
authors: P
authors: P
authors: Vanezis
authors: D
authors: D
authors: Perrett
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People; D003124:Colorimetry / Q000379:methods*; D003288:Contusions / Q000473:pathology*; D005260:Female; D049429:Forensic Pathology; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D012880:Skin Pigmentation; D013053:Spectrophotometry; D013188:Sri Lanka; D044465:White People; D055815:Young Adult