Forensic scientists have to rely on their own subjective experience when asked to ascertain the age of contusions. Now, however, researchers in Norway have found a far more objective and precise method.
Scientists knew surprisingly little about how to tell the age of bruises before Lise Lyngsnes Randeberg and her colleagues at the Norwegian University of Science and Technology (NTNU) in Trondheim approached the issue.
Algorithms and light
Previous research has shown that forensic scientists are wrong roughly half the time when attempting to determine the age of bruises based on their visible colours. Such a high margin of error is unacceptable, so Norwegian researchers began searching for more reliable methods for dating bruises.
In a project that receives funding under the Research Council's open competitive arena for independent, researcher-initiated basic research projects, the NTNU researchers first studied various bruises using light, then they formulated algorithms for how a bruise progresses over time. The technology they applied is simple and common: a lamp illuminates the bruise, and a spectrometer measures the reflected light.
Entirely new model developed
The true breakthrough, however, came when the researchers worked out a model that predicts how a bruise will develop over time.
They were able to conduct controlled studies of bruise infliction -- thanks to willing volunteers from among NTNU's martial arts enthusiasts. A study was also carried out on older bypass operation patients taking blood-thinning medication. A third subject group comprised unconscious pigs under general anaesthesia.
"This allowed us to follow the development of a range of different contusions from the moment they were sustained," explains the NTNU associate professor. From these data the researchers created a model for bruise progression over time which enables them to determine the age of the bruises more reliably.
Seeking knowledge about bruising on children
Next, Professor Randeberg will be studying bruising on children, which develops differently from on adults. Knowledge within this area could be particularly important in cases of suspected child abuse.
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