Vestibular/Balance Services

At the University of Miami Ear Insitute there is state of the art equipment available to diagnose, treat, and assess the vestibular/balance system structures and their function. 

The equipment and tests available include:

Videonystagmography (VNG):

Asses the function of the horizontal semicircular canal, superior branch of the vestibular nerve and portions of the the central nervous system.

Rotary Chair:

Assesses the vestibulo-ocular reflex (VOR), the horizontal canal function in different frequencies (different from videonystagmography), the utricle function with the static and dynamic subjective visual vertical tests, central nervous system structures, and the superior branch of the vestibular nerve.

Posturography:

Sensory organization test: assesses the sensory input from the 3 systems (vestibular, visual and somatosensory) and the capacity to integrate the information from the 3 to help postural stability.  Motor control test: assesses the vestibulo spinal reflex.  

Vestibular evoked myogenic potential:

Assesses the function of the saccule and the inferior branch of the vestibular nerve.  

As every piece of equipment and sub-test is useful in identifying an abnormality of different structures within the vestibular system, it is essential to have a comprehensive evaluation.

With the results from these tests, the experts at the Ear Institute can determine if the symptoms (dizziness, vertigo, lightheadedness, disequilibrium, tinnitus, aural fullness) are produced because of a disorder or disease compromising the vestibular and balance organs. Additionally, they can objectively evaluate the improvement from the different treatment options, such as medicine or vestibular rehabilitation therapy.   With such state of the art equipment and professional expertise, patients with vestibular/balance problems from all over the world visit the University of Miami Ear Institute to get diagnosed and treated.

  

To better understand these available services, below is a brief description of the balance structures, their function, disorders and assessment. 

System of equilibrium:

Equilibrium is a complex function that requires accurate information from several sensory systems including: Vestibular, visual and somatosensory input.  

  

(www.control.lth.se/.../vestibular.html)

The vestibular system provides an internal reference, telling the brain where the head is in space, its direction of movement, and acceleration. It contributes up to two-thirds of the information needed to maintain equilibrium.

The visual system is an external reference telling the brain about the world outside.  Peripheral vision provides information about motion.

The somatosensory system provides external reference from tactile contact with surfaces (Receptor muscles in the ankle and the lower leg). Proprioceptor muscles in the neck also contribute information about head position.

The central nervous system (vestibular nuclei in the brainstem is the central integrator) integrates the sensory input from these 3 systems (vestibular, visual and somatosensory) and produces motor control responses. This motor control sends muscular output that goes to the eyes (vestibulo – ocular reflex) and to the spinal column (vestibulo-spinal reflex).  These reflexes help stabilize gaze and posture.

Vestibulo-ocular reflex graphic

 

(http://thalamus.wustl.edu/course/audvest.html)

Comparison of the various inputs allows the person to determine if they are moving or if the world is moving.    

 The vestibular system is located behind the hearing structures (cochlea) in the inner ear.

Ear structures        

                                  

(http://www.virtualmedicalcentre.com/anatomy.asp?sid=29&title=Ear#C1)

Inner ear/vestibular structures

 

(www.darwinismrefuted.com)

The vestibular system has different anatomic components:

The otolith organs are:  

Utricle and saccule, these are gravity detectors (linear acceleration)

Three semicircular canlas: 

  • Anterior, horizontal and posterior, these are sensitive to change in velocity (angular acceleration)
  

Some otologic diseases that can affect the vestibular system are:

  • Meniere's disease
  • Vestibular schwannoma/acoustic neuroma
  • Vestibular neuritis
  • Labyrinthitis
  • Superior canal dehiscence syndrome
  • Benign paroxysmal positional vertigo (BPPV)
  • Autoimmune inner ear disease
  • Herpes Zoster oticus
  • Ramsey hunt syndrome
  • Mal of Debarquement
 

These diseases have the following possible symptoms in common: Dizziness, vertigo, lightheadedness, disequilibrium, tinnitus (ringing and/or noises in the ear), hearing loss, aural fullness.

These diseases can also affect or compromise different structures from the vestibular system. The diagnosis, treatment and prognosis will be determined by the damaged structures within the vestibular system. Therefore, a comprehensive examination and expertise are imperative when diagnosing vestibular problems.