Analysis of Alternative Light in the Detection and Visibility of Cutaneous Bruises

As submitted by the proposer: Problem Statement: Victims of violence often have cutaneous bruises latent or barely visible to the naked eye due to skin color, injury age, or depth. Unidentified injuries can cause a disparity in forensic investigations, leading to unsuccessful or lack of criminal prosecutions. An alternate light source (ALS) with short narrowband visible (NBV) or long ultraviolet (UV) spectrums may improve detection and visibility of cutaneous bruises. However, the limited research available is not definitive whether light absorption within these wavelengths results from bruising or artifact. Little is known how skin color affects bruise visibility using an ALS. We propose an innovative, randomized controlled trial (RCT) with the purpose of measuring the effectiveness of ALS in improving bruise detection and visibility over white light. We will also explore the effects of skin color, gender, localized fat/muscle and bruise size, mechanism, and color on specific wavelength performance over time. Partnership: This multisite study is a partnership between two U.S. universities. Subjects: Participants will include 156 healthy adults, ages 18-65 with equal sampling of six skin colors. Research Methods: This RCT will include a crossover design, randomizing the order of ALS and white light application for each bruise. Bruises will be created under controlled application of a paintball pellet and dropped weight to the upper and lower parts of one arm. Both bruised and non-bruised arms will be assessed for bruise visibility under white and alternate light nine times during the first 72 hours, 11 times the first week and a total of 21 times over four weeks. A smaller subset (n=30) of subjects will continue to have their bruises assessed for up to 8 weeks. Bruise visibility using wavelength peaks within UV (365nm) and NBV (415nm, 450nm, 475nm, 495nm, 515nm, 535nm) spectrums and filters (yellow, orange, red) will be examined. Spectrophotometric measures of skin and bruise color will be obtained along with digital photographs under each light source. Analysis: Statistical analysis will include sensitivity and specificity to assess bruise detection and general linear mixed models to examine the effect of bruise and subject characteristics on bruise visibility with specific wavelengths and filters. Products: Multiple scholarly products are projected from this study’s large dataset with dissemination plans in forensics, healthcare, and criminal justice fields. This study will increase our understanding of bruise visibility by ALS, guiding criminal justice policy and forensic practice with broad applications in clinical settings and future potential in deceased populations. Note: This project contains a research and/or development component, as defined in applicable law. ca/ncf