A preliminary study of changes in scalp impedance during the early post-mortem period in rats.

An accurate and reproducible technique was used for estimation of scalp impedance (1 kHz) in each of eight rat cadavers, maintained at 9.0 +/- 0.7 degrees C, during the 1 to 144 hour post-mortem period. Scalp impedance increased non-linearly, and in a bimodal manner, between 24 and 144 hours post-mortem. The relationship between scalp impedance and post-mortem interval, and the degree of individual variation in the time course of impedance change, were such that scalp impedance is unlikely to be a suitable tool for estimation of time since death.