Estimation of Early Postmortem Interval by Multiple Regression Analysis

Research Article

Austin J Forensic Sci Criminol. 2015; 2(5): 1044.

Estimation of Early Postmortem Interval by Multiple Regression Analysis

Saralaya PK*, Chandra YPG, Jayanth SH, Praveen S and Krishnan AG

Department of Forensic Medicine, M.S. Ramaiah Medical College, India

*Corresponding author: Pradeep K Saralaya, Department of Forensic Medicine, M.S. Ramaiah Medical College, MSRIT Post, MSR Nagar, Bangalore- 560054, India

Received: April 20, 2015; Accepted: November 20, 2015; Published: November 23, 2015


A multiple regression analysis using core body temperature and non temperature based postmortem changes were applied to 204 postmortem cases of within 24h Post Mortem (PM) interval, and non-temperature based postmortem changes like hypostasis and rigidity, were numerically categorized and used with core body temperatures as three statistical variables in the multiple regression analysis. The multiple regression analysis produced a multiple correlation coefficient values for core body temperature multiplication factor is -0.010, rigor mortis multiplication factor is 0.341, and for hypostasis multiplication factor is 0.674, and the constant factor is 0.423. Although assessments of non-temperature based PM changes are mostly subjective and have a wide variation, the present study demonstrated usefulness of non temperature based PM changes in the estimation of PM intervals.

Keywords: Postmortem Interval; Multiple Regression Analysis; Core Body Temperature; Rigidity; Hypostasis


Estimation of postmortem interval is an important goal in forensic medicine, the estimation of the time of death, also known as Post Mortem Interval (PMI), is of paramount importance for the police in their investigation when arriving at the scene of a questionable death. A precise determination of a victim’s time of death makes it possible to focus the investigation not only on a narrow time frame, but often also on a narrower range of suspects. This saves valuable time and resources in the critical early stage of the investigation [1]. The aim of the present work was to estimate the time since death using a scoring two postmortem changes; hypostasis, rigidity and analyzing the core body temperature with atmospheric temperature to create a regression equation to narrow down the wide variation in postmortem interval.

Materials and Methods

A one year prospective study was conducted at mortuary, Department of Forensic Medicine M.S. Ramaiah Medical College and teaching hospital Bangalore. Two hundred and four postmortem cases with known PM intervals were selected from the cases autopsied at our institution from the year 2011 to 2012. Clearance from ethical committee was obtained. Cases with known PM interval with in 24 hr are included in the study. Deaths which influence body temperature like drowning, burns, septicemia and early and old age group people are excluded from the study.

The development of rigidity, hypostasis were categorized, and each phase was designated with scores [1-4]. The PM rigidity was categorized into 4 phases according to its development and resolution. The hypostasis was categorized into 2 phases according to its appearance and movement by thumb pressure (Table 1).