Evoked response study tool: a portable, rugged system for single and multiple auditory evoked potential measurements.

Although the potential of using portable auditory evoked potential systems for field testing of stranded cetaceans has been long recognized, commercial systems for evoked potential measurements generally do not possess the bandwidth required for testing odontocete cetaceans and are not suitable for field use. As a result, there have been a number of efforts to develop portable evoked potential systems for field testing of cetaceans. This paper presents another such system, called the evoked response study tool (EVREST). EVREST is a Windows-based hardware/software system designed for calibrating sound stimuli and recording and analyzing transient and steady-state evoked potentials. The EVREST software features a graphical user interface, real-time analysis and visualization of recorded data, a variety of stimulus options, and a high level of automation. The system hardware is portable, rugged, battery-powered, and possesses a bandwidth that encompasses the audible range of echolocating odontocetes, making the system suitable for field testing of stranded or rehabilitating cetaceans.