Otoacoustic Emission (OAE) Background


The ear acts as a biological microphone. Its most basic function is to sense incoming acoustic stimuli from the world around us and convert that mechanical information into electrical information which travels via the auditory nerve to the central nervous system. Thus, it might seem a bit surprising that a healthy ear actually produces and emits sound (which can be measured via a microphone in the ear canal). These sounds are called otoacoustic emissions (OAEs) and can arise either spontaneously or by an evoking external stimulus. These emissions are generated in the inner ear (cochlea) and are presumably a result of the mechano-electro and electro-mechano transduction mechanisms responsible for converting sound into neural impulses. Since the cochlea is encased in very hard bone and the sensory structures are highly sensitive (thus easily subject to damage), direct physiological observation of the inner ear is difficult. There is however a great variation in the anatomical structure of the inner ear between mammals and non-mammals. Our approach is to use that dichotomy to our advantage such that the comparison of OAEs between mammals and non-mammals can help shed light on the properties and dynamics of the underlying generation mechanisms without invasively damaging or inadvertently affecting them.

Current Research Questions