Photo: Nasser Nuri / Reuters
Scientists at the University of Utah explained the mechanism which causes the Tullio’s phenomenon — vertigo caused by loud or normal everyday sounds. According to the findings of researchers, the cause of the syndrome are false signals from the inner ear to the brain, resulting in occur uncontrolled movement of the eyes. This publication reports Science Alert.
It is known that a phenomenon that was first described by Italian biologist Pietro Tullio (Pietro and Tullio) in 1929, occurs due to the presence of defects (usually in the form of holes) in the middle or inner ear. Typically, this condition is caused by the gap (dehiscence) in the bony wall of the semicircular canals, which are tiny tubes in the inner ear filled with fluid (endolymph). The channels are part of the vestibular system, which is responsible for the correct perception of head movements and maintaining equilibrium.
Pietro Tullio discovered this condition when experimented on pigeons, drilling tiny holes in the tubes of the vestibular apparatus. However, it was later discovered that approximately two percent of people bone wall in the upper semicircular canal (MIC) has holes or is too thin at a rate of 0,67-0,38 mm. This disease is known as the syndrome of dehiscence bone wall of the upper semicircular canal (SDPC). The loud sounds of people SDPC feel dizziness, nausea, and they have nystagmus — oscillatory movements of the eyes high frequency. However, the exact mechanism linking dehiscence and dizziness was unknown.
In the new work, scientists conducted a computer simulation to simulate the movement of the endolymph in the semicircular canals and learned about the fish or frog Opsanus tau, in which the vestibular apparatus is similar to a human. It turned out that dehiscence contributes to the running of the mechanical waves in the liquid with a loud sound. These waves irritate the receptors of the inner ear, which, in turn, sent to the brain false signals about head rotation. Nystagmus occurs as a reflex, designed for visual stabilization, but in this case, when the head is actually fixed, it causes dizziness.
Video, photo All from Russia.