Review of recent studies and issues regarding the P300-based complex trial protocol for detection of concealed information.

In this review, the evolution of new P300-based protocols for detection of concealed information is summarized. The P300-based complex trial protocol (CTP) is described as one such countermeasure (CM)-resistant protocol. Recent lapses in diagnostic accuracy (from 90% to 75%) with CTPs applied to mock crime protocols are summarized, as well as recent enhancements to the CTP which have restored accuracy. These enhancements include 1) use of performance feedback during testing, 2) use of other ERP components such as N200 in diagnosis, 3) use of auxiliary tests, including the autobiographical implicit association test, as leading to restored diagnostic accuracy, and 4) a study of the mechanisms underlying CMs. A novel, doubly efficient version of the CTP involving presentation of two probes in one trial is described as a new way to improve accuracy to levels above 90% in mock crime situations. Finally, a thorough analysis of the legal issues surrounding use of the CTP in U.S. is given.