OUTER EAR TEMPERATURE AND TIME OF DEATH

From a research sample of 138 corpses, divided into four subgroups of ambient storage temperature (0-5 degrees C, 6-10 degrees C, 11-15 degr ees C and 16-23 degrees C) four linear regression formulae of actual v ersus estimated post-mortem interval were obtained ('interval' formula e) using a single outer ear temperature measurement on both sides. Thi s method showed the best correlation coefficient among five other meth ods previously proposed for time of death determination (rectal temper ature, vitreous K+, CSF K+, blood log Na+/K+ and log Cl-), however its results were less accurate than those obtained with a multivariate eq uation combining several of the above mentioned methods. Eventually an equation expressing time of death (TOD) as a function of outer ear te mperature (OE T-o) and ambient temperature was also established from t he whole research sample ('global' formulae), On a different sample of 141 corpses the regression formulae ('interval' and 'global') for the outer ear temperature were compared to three methods based on a singl e rectal temperature measurement ('rule of thumb' 1 and 2, Henssge nom ogram) and therefore useful at the scene; the results of all methods w ere compared within the four subgroups of ambient temperature as well as in three subgroups of different post-mortem interval lengths (<7 h, <10 h, <15 h), In all cases the outer ear temperature formulae provid ed better results than the rectal temperature methods (especially Hens sge nomogram and rule of thumb 1). Moreover they did not show any post -mortem plateau which was present in almost 30% of cases when rectal t emperature was measured in corpses kept at ambient temperature above 1 5 degrees C. Our results show that outer ear temperature measurement i s the method which provides the best simplicity/quality ratio and shou ld therefore be proposed for use at the scene when conditions are simi lar to those of our experiment (within buildings). A software equipped thermometer is required in order to use in each case the appropriate formula and confidence interval.