A Portable Auditory Steady-State Response Evoked Potentials Unit for Fast Screening of Aquatic Mammals

The screening of stranded or rehabilitated aquatic mammals´ auditory capabilities is a vital diagnosis. A portable battery-operated screening tool is presented, which enables, together with the collection of species related auditory characteristics, a rapid diagnosis of hearing impairment in rehabilitation centers and on stranding sites. Acoustic stimulation is achieved with a piezoelectric ceramic that can transduce sound either by skin-contact using a polyurethane suction cup or an acoustically transparent cushion when on stranding sites and in rehabilitation facilities, or more conventionally from a few meters distance to the subject in a pool. The difficulty raised by interferences from greater voltage stimulation signals onto microvoltage EEG was overcome by complete analog decoupling of high and low voltage signal conditioning stages and Faraday shielding. System portability and the integration of a wideband (>150kHz) steady-state response evoked potentials system should shorten acquisition times significantly and provide fast complementary information on the animal sensory health even in emergency situations.