Vestibular and ocular motor disorders

A multidisciplinary team at Mayo focuses their practice and research on patients with dizziness, vertigo, vestibular disorders, and conditions affecting balance form a small multi–specialty group. Because the field of neurotology (or otoneurology) is defined primarily by the symptoms of the patients than by specific disease entities, experts in this area include all physicians whose disease interests may manifest as dizziness or imbalance. Such physicians include neurologists, neurotologic surgeons (otolaryngologists), audiologists, psychiatrists, and physical therapists, all of whom participate in the evaluation of patients.

Common conditions seen in this field include:

  • Positional vertigo
  • Meniere’s disease
  • Vestibular neuritis
  • Migraine–associated dizziness
  • Superior canal dehiscence
  • Vestibular schwannoma
  • Other central nervous system or general medical causes of imbalance and dizziness

Ocular motor disorders include conditions causing diplopia, nystagmus, impaired extraocular movements, abnormal saccadic or pursuit eye movements, and ptosis. The potential cause for such symptoms range from many different central nervous system disorders to cranial neuropathies, neuromuscular junction disorders, orbital muscle diseases, and vestibular disorders. Thus, patients with dizziness and vertigo frequently have ocular motor abnormalities.

Ongoing research

Current research at Mayo is focused on:

  • Developing specific clinical tests that help to evaluate the function of specific components within the vestibular system
  • Identifying evaluation tools that provide criteria to determine fall risks in all patients
  • Understanding the pathophysiological basis of certain eye movement disorders
  • Finding links between personality types, specific genes, and the risk for developing chronic dizziness

This research is done partly in collaboration with Dr. Staab in the vestibular lab.

Otology and neurotology

Otology is a specialty dedicated to the care of the ears, which includes the hearing and balance systems. The specialist who practices Otology has completed a five– or six–year residency in Otolaryngology, followed by one to two years of fellowship training in Otology. Neurotology is closely related to Otology, but adds the skill and training to evaluate parts of the brain and nervous system that are associated with hearing and balance in defining the cause of a patient’s symptoms. The training is usually obtained at the same time as the Otology training, although a surgeon may elect to only emphasize one or the other. Neurotologists operate on acoustic neuromas, glomus tumors, and other conditions found deep in the skull. The following are the most prevalent conditions in neurotology and otology:

Ear/Hearing disorders:

  • Progressive hearing loss (from early hearing loss to profound deafness)
  • Sudden hearing losses
  • Otosclerosis
  • Chronic ear infections (draining, cholesteatoma, ear canal infections)
  • Tumors of the ear canal or middle ear

Balance Disorders:

  • Positional vertigo
  • Meniere’s disease
  • Vestibular neuronitis
  • Migraine associated dizziness
  • Superior canal dehiscence
  • All other causes of imbalance and dizziness

Facial Nerve Disorders:

  • Facial nerve paralysis
  • Bell’s palsy
  • Ramsay–Hunt syndrome

Skull Base Tumors:

  • Acoustic tumors (vestibular schwannomas)
  • Meningiomas
  • All tumors affecting the ear, temporal bone, or posterior fossa

Ongoing research

Mayo Clinic researchers seek to define the physiology of the vestibular system, which informs the brain about the body's motion and orientation. The vestibular part of the inner ear contains receptors that gather information about the movement of the head. The brain combines this information with signals from the eye and from the sense of touch to assemble a perception of how the body is moving through space. Then, the body responds to this perceived movement with reflexes that maintain balance. Although much is known about the vestibular part of the inner ear, key aspects of how the vestibular receptors perceive, process and report essential information are still mysterious. Increasing the understanding of this process will have tremendous impact on quality–of–life of patients with vestibular disorders, who often suffer terrible discomfort from dizziness and vertigo.

The basic science research in this area focuses on the vestibulo–ocular reflexes, which move the eyes in response to motions of the head. This is done by studying the vestibular sensors and nerve cells that provide input to the reflexes; the eye movements in humans and animals with different vestibular disorders; the effects of electrical stimulation of vestibular sensors, using mathematical models to describe these reflexes; and the abnormalities of the brain's inability to compensate for vestibular disorders.

The questions driving this research often stem from interactions with patients in the clinic, so researchers and clinicians work closely together to translate scientific discoveries into advances in the diagnosis and treatment of patients.