Post-mortem supravital skeletal muscle excitability for early post-mortem interval estimation: a scoping review and...

Area of Science:

• Forensic Science
• Physiology
• Pathology

Background:

• Early post-mortem interval (PMI) estimation relies on imprecise temperature-based methods and physical changes like rigor mortis.
• Current methods for early PMI estimation have significant limitations, with a recent validation showing only ~37% agreement.
• Post-mortem supravital skeletal muscle excitability has been explored as a potential adjunctive marker but evidence is fragmented.

Purpose of the Study:

• To map existing evidence on post-mortem supravital skeletal muscle excitability for early PMI estimation.
• To identify methodological requirements for a future prospective study on this topic.
• To evaluate electrical and mechanical stimulation of muscle as adjunctive tools for early PMI estimation.

Main Methods:

• A scoping review following JBI methodology and PRISMA-ScR guidelines.
• Searches conducted in PubMed/MEDLINE, Scopus, and Web of Science without date or language restrictions.
• Included 26 records, analyzing data across five streams: electrical excitability, mechanical reaction, compound method, structural artifacts, and animal models.

Main Results:

• Electrical muscle stimulation provided precise estimates (±2.7-2.85 h up to ~13 h) but required invasive instrumentation.
• Mechanical testing was field-deployable but operator-dependent and influenced by various factors.
• Incorporating muscle excitability into the compound method improved PMI interval accuracy in approximately two-thirds of cases.

Conclusions:

• Supravital muscle excitability is a promising adjunctive marker for early PMI estimation when used within a standardized compound method.
• It should not be used as a standalone determinant of the time of death.
• A prospective, minimally invasive study with standardized protocols and objective outcomes is recommended for validation.