As our eyes move, so do our eardrums
According to a recent study from North Carolina's Duke University, moving our eyes causes our eardrums to move, too. The scientists say that the finding may lead to a new understanding of hearing disorders, such as the difficulty that some people have with following a conversation in a crowded room.
Led by Prof. Jennifer Groh, the research team got 16 test subjects to sit in a darkened room and follow shifting LEDs with their eyes, without moving their heads. Those people also had tiny microphones placed in their ear canals, which were so sensitive that they could detect the vibrations made by the eardrums as they move back and forth.
It was found that as the peoples' eyes moved left or right, the eardrums correspondingly pointed in that same direction, with one side bulging inward at the same time the other side bulged outward. The larger the eye movement, the more pronounced the movement of the eardrums.
Interestingly, the eardrum vibrations actually started slightly before the eye movements. The researchers believe that this is because the motions of both the ears and the eyes are controlled by the same motor commands deep within the brain.
"The fact that these eardrum movements are encoding spatial information about eye movements means that they may be useful for helping our brains merge visual and auditory space," says David Murphy, a doctoral student in Groh's lab. "It could also signify a marker of a healthy interaction between the auditory and visual systems."
A paper on the research was recently published in the journal Proceedings of the National Academy of Sciences.
Source: Duke University