Vestibular System Physiopatology

Abstract

The vestibular system plays a role in maintaining balance through head movements via the proprioceptive system. It is a sophisticated sensory system for detecting both angular and linear movements of the head. The semicircular canals are sensitive to angular movements of the head. When the head moves, the endolymph fluid within them also moves, causing deflection in the cupula. As a result of head movements, the membranous labyrinth moves towards the cupula. When the hair cells in the cupula bend towards the kinocilium, K⁺ channels open, leading to cell depolarization. Calcium channels then open in depolarized cells, resulting in the release of neurotransmitters (glutamate) into the synaptic cleft. Stimulation of afferent nerves transmits signals to the central nervous system. Otolith organs are sensitive to linear movements of the head. One of the most important functions of the vestibular system is to maintain balance. Additionally, it plays a role in ensuring visual clarity during sudden head movements, regulating postural posture, adjusting muscle tone, and providing autonomic reflexes. Pathologies affecting the vestibular system can arise due to various factors such as infection, injury, or aging, leading to disruptions in the balance system. These disruptions significantly impact patients' daily activities. The etiologies of vestibular disorders can be determined through multidisciplinary studies. Diseases leading to vestibular disorders sometimes manifest as severe vertigo or loss of balance. Other accompanying symptoms may include nausea, vomiting, a feeling of fullness in the ears, hearing loss, tinnitus, blurred vision, and a sensation of fainting. In diagnosing vestibular pathologies, medical history is crucial. Since vertigo accompanying these pathologies is a symptom, not a disease, providing detailed descriptions of the nature of dizziness can lead to appropriate diagnosis. Vertigo resulting from the disruption of this system is evaluated to determine whether it is of peripheral or central origin. This review evaluates types of peripheral vertigo, including benign paroxysmal positional vertigo, Meniere's disease, semicircular canal dehiscence, labyrinthitis, and perilymphatic fistula. The physiology of the vestibular system, general symptoms observed in vestibular pathologies, differential diagnostic tests, and their results have been evaluated.