What Happens When the Vestibular Apparatus Is Damaged?

Dizziness and vertigo are two of the most common symptoms causing a patient to visit their physician. Many patients present because of a recent fall. Their unsteadiness may be associated with other signs and symptoms, some of which can be acute or chronic.

The overall incidence of dizziness, vertigo, or imbalance can affect as much as 10% of the population with that rate skyrocketing to 40% over age 40. The incidence of falling can approach 25% in those over 65.

There are two main reasons for dizziness, vertigo, or imbalance: central or peripheral. Central causes mean the patient has a central nervous system problem such as migraine. The majority of patients suffer because of disturbances within the inner ear which is a peripheral cause.

The inner ear and the vestibular system apparatus

The inner ear is composed of the cochlea which acts to process sound. Next to the cochlea is the vestibular system. Both the cochlea and vestibular system are housed in a bone called the otic capsule; a part of the skull called the petrous portion of the temporal bone.

The vestibular system is the control center for balance. It is the only system in our body that works at full throttle to keep up with its main task of maintaining balance. Other systems in our body work to produce or create, not to keep us at status quo. For example, we know when our hearing is working because we hear something.

The vestibular apparatus consists of 5 distinct organs. There are 3 semicircular canals which are a set of mutually orthogonal sensors, meaning they are at right angles to each other. One way to imagine the semicircular canals is to picture 3 sides of a box meeting at each corner so they cover all 3 dimensions or the x, y and z axes of height, width, and depth.

The semicircular canals specify the direction and amplitude of any rotation of our head. We have 2 sets of 3 canals so there are functional pairs covering forward-backward, left-right, and any other combination of movement. When we move one semicircular canal is excited and the opposite one is inhibited.

The other two vestibular apparatus organs are the utricle and saccule. The utricle senses motion in the horizontal plane. The saccule senses motion in the sagittal plane or up and down.

All 5 of these organs send information to the vestibular nuclei of the brain. The information is generated from movement of special fluids and tiny nerve cells called hair cells within the vestibular apparatus. The complexity of the vestibular system lends it to be vulnerable to disruption or damage.

Most common causes of peripheral and central vertigo

The most common reasons for peripheral dizziness, vertigo, or imbalance include BPPV (benign positional vertigo, vestibular neuronitis, Meniere’s disease, and immune-mediated inner ear disease.

The most common cause of central dizziness is migraine or vestibular migraine. Other central causes may include demyelination such as found in multiple sclerosis, acoustic tumors, and brainstem or cerebellar vascular lesions.

Here we will discuss peripheral causes of vertigo, particularly the most common one, BPPV. Meniere’s disease which will be covered in another article since it is more elusive and treated differently.

The vestibular apparatus doesn’t work or is damaged

Dizziness includes light-headedness, unsteadiness, motion intolerance, imbalance, floating, or a tilting sensation. Vertigo is a subtype of dizziness defined as the perception of movement caused by asymmetric input to the vestibular system.

Vertigo is usually indicative of true inner ear disease, whereas dizziness may be a result of a host of other issues such as cardiovascular, system, or central nervous system abnormalities.

The history of vertigo is critical. Episodic vertigo may be associated with nausea or a viral infection or it can be associated with head or body position changes as in benign positional vertigo (BPPV).

There are many tests your doctor can do to determine the precise cause of the vertigo. Surprisingly, a simple hearing test may offer immediate clues as to reasons for the vertigo since the hearing and vestibular apparatus are so closely related and may suffer equal disruption.

There are numerous potential inner ear problems. Some pathologies relate to disruption of the inner ear fluids which can result from changes in its chemistry. In the case of benign positional vertigo (BPPV), there may be small crystals that form within the inner ear fluids, and these can cause changes in how the nerve cells transmit information to the brain by delaying movement of the cells.

Diagnosis and treatment

Fortunately, most cases of dizziness or vertigo are short-lived and disappear as quickly as they arrive. In the diagnostic approach, it is always necessary to make sure an underlying cause such as high blood pressure is treated first.

If there is no obvious underlying cause, acute dizziness and vertigo is typically managed with medications that suppress the vestibular apparatus, antiemetics or antinausea medications, or antiviral medications. Vestibular suppressants should only be used for a few days since they can hinder the brain’s natural compensation.

The brain’s natural compensation is vital to improvement, particularly when dealing with BPPV. Many patients can hasten this process with vestibular rehabilitation.

Vestibular rehabilitation can be used acutely by having the doctor perform certain exercises and movements in the office. These are called Epley maneuvers. Many patients say their symptoms are relieved immediately. It is important to understand these Epley maneuvers should be performed by your doctor only.

At home, you can be given a series of vestibular exercises that are safe to do on your own. In some cases, a physical therapist can assist. It is important to be sure the patient does not have any biomedical problems such as with their back or neck before these vestibular exercises are undertaken. Other balance training can be useful as well such as tai chi.

The key to vestibular rehabilitation is consistency and diligence. Most stable and non fluctuating peripheral vestibular disorders can be treated long term without medications. Medications are reserved for the immediate symptoms only.