Infrared tympanic thermography as a substitute for a probe in the evaluation of ear temperature for post-mortem interval determination: a pilot study

Reported methods which have been used to measure tympanic temperatures on cadavers up to now are quite invasive. They involve the use of a probe which can perforate the tympanic membrane and frequently causes bleeding from the ear. For this reason a non traumatic method for estimating tympanic temperature should be applied. Infrared tympanic thermometry seems to be a plausible option. Reliability of infrared tympanic thermometry (ITT) has been largely assessed on living individuals but only one author up to now has assessed its applicability for post-mortem interval determination. Thus the authors set out to test the difference between ear temperatures taken with a probe vs. ITT, differences between left and right ear and reproducibility of measurements of ITT. The aim of the study was to verify whether ITT could be a plausible option for measuring ear temperature for PMI estimation. Ear temperatures were taken on 25 cadavers (15 males, 10 females). Temperatures were taken alternately by similarly trained personnel by two technical methods (Checktemp 1 thermocouple probe and First Temp Genius infrared thermometer) for a total of 93 measurements. Statistical analysis of the data was performed using SAS statistical software. The range of temperature measured was from 20 to 28 degrees C, statistical analysis revealed no differences within the two technical methods, both for right and left ear (ITT: 22.33+/-0.35 vs. probe: 23.08+/-0.25; P=0.087). The study shows the ITT method can be considered as a possible alternative to the probe for measuring ear temperative and further studies should be considered.