Dizziness or vertigo is grouped into 2 main categories: peripheral vestibular disorders and central vestibular disorders. This week I will explain peripheral vestibular disorders. Stay tuned for next week's post about central vestibular disorders.
Peripheral vestibular disorders are caused by a dysfunction in the vestibular system in the inner ear or the corresponding neural pathways. Dizziness or vertigo can come from a variety of systems in the body or environmental sources. Some environmental factors include roller coasters, driving through hills, or as a side effect of some medications or alcohol use.
The vestibular system is comprised of the saccule, utricle, and semicircular canals. The saccule and utricle detect linear motion like going up and down in an elevator or forward and backward like in a moving car. The semicircular canals (horizontal, posterior, and anterior) detect rotational movement like bending forward, looking up, shaking our head yes or no or side to side. When the inner ear balance systems are working properly, the brain receives equal input that it can interpret and use to send out reflexes to stabilize our bodies, head, or eyes. These reflexes are used to keep us oriented in space, our head upright, and keep our eyes focused even if our bodies are moving. When there is a vestibular deficit in one ear, these systems are not in sync and send inconsistent messages to the brain creating a peripheral vestibular disorder. A peripheral vestibular disorder can be perceived as a spinning sensation or imbalance.
As audiologists, we have a full battery of vestibular tests to determine the function of each part of the vestibular system individually to identify if the inner ear vestibular systems are functioning well and in sync, or not, indicating a peripheral vestibular disorder. Peripheral vestibular disorders can often be treated with specific maneuvers or vestibular rehabilitation physical therapy.