Using Bioacoustical Methodologies to Evaluate Equine Hearing Capabilities and Cognition.

摘要

The field of Bioacoustics is an emerging field of science that investigates various aspects of animal audiology and communication. More recently, audiological means have been used to evaluate the cognitive abilities of animals using event related brain potentials (ERP's). The Mismatch Negativity (MMN) component of the ERP is considered a cognitive neuroelectric phenomenon since it is generated in the area of the cortex that is responsible for evaluating sound stimuli including the ability to discriminate. Such discrimination produces a negative-going waveform with a relative latency of about 150-250 msec when elicited with auditory stimuli in human adults. The MMN response is elicited by use of the oddball paradigm in which two different tones are presented in pseudo-random order. The purpose of this study was to determine if elicitation of the MMN is achievable in the horse by use of current equipment in a non-clinical setting such as a barn. During the course of this experiment, it became obvious that the major challenge was the excessive amount of noise that inundated the waveforms thereby making any specific waves even remotely discernible. Attempts were made to improve the signal-to-noise ratio (SNR) by modifications to the testing unit and the addition of several in-line and digital filters. However, even with these modifications, the MMN response still could not be identifiable within the noise of the waveforms. Therefore, the matter of whether or not the horse elicits a MMN response should be revised to if it is even feasible to elicit a MMN response in these animals.