In 2018, Duke University investigators discovered that when the eyes move, the ears generate a tiny almost imperceptible murmur and the other way around. presently, following up on their first study, the scientists investigated if the faint audio impulses generated by the body parts, contained comprehensive information about eye movements.
Jennifer Groh, Ph.D., senior author of the new report said that, generally you can estimate the movement of the eyes, the position of the target that the eyes are going to look at, just from the recordings made with a microphone in the ear canal.
Groh and her team realized that they were able to find out the shape of the ear sound waveform, by examining where someone was looking. Presently Groh believes that these muffled sounds are created by eye movements to encourage the brain to tighten either middle ear muscles, which usually helps to attenuate loud sounds, or hair cells, which help to strengthen quiet sounds.
The sounds may even assist in enhancing individuals perceptions. The new discovery may presently lead to improved clinical tests for hearing.
Stephanie Lovich, a graduate student in psychology & neuroscience at Duke said, if each part of the ear contributes individual rules for the eardrum signal, then they could be used as a type of clinical tool to find out which part of the anatomy in the ear is nonfunctional.
To Analize sound signals, participants glanced at a green dot on a computer screen, then tracked it with their eyes while it disappeared and reappeared either up, down, left, right, or diagonally from its initial location. This provided Groh’s team with a varied set of sound signals produced when the eyes moved diagonally, vertically or horizontally,
The researchers then recorded the eye movements and the corresponding ear sounds allowing them to uncover the ear noises code and extrapolate where individuals were looking just by analyzing this series of murmurs.
Since a diagonal eye movement is just a horizontal component and vertical component, Co- Author David Murphy realized that you can take the two components and guess what they would be if you put them together, Lovich said adding that, in the opposite way, examining an oscillation can lead to anticipating that someone was looking 30 degrees to the left.
The next steps in the study consist of evaluating whether these ear sounds do indeed influence perception. This process needs investigating whether ear signals can effectively conduct a sound localization task.
Eye movements alter the relationship between the visual and auditory spatial scenes. Signals connected to eye movements affect neural pathways from the ear through auditory cortex and beyond, but how these signals contribute to computing the locations of sounds with respect to the visual scene is not clearly understood. At this point, we assessed the information contained in eye movement-related eardrum oscillations (EMREOs), pressure changes recorded in the ear canal which happens in conjunction with simultaneous eye movements. We show that EMREOs contain parametric information about horizontal and vertical eye displacement as well as initial eye position with respect to the head.
The parametric information in the horizontal and vertical directions can be showed as combining linearly and allowing accurate prediction of the EMREOs connected with oblique (diagonal) eye movements. Target location can also be inferred from the EMREO signals recorded during eye movements to those targets. We assume that the (currently unknown) mechanism underlying EMREOs could impose a two-dimensional eye-movement-related transfer function on any incoming sound, allowing subsequent processing stages to compute the positions of sounds in relation to the visual scene.
