Balance Disorders

To appropriately evaluate the balance system, we need to assess 3 modalities that help us maintain equilibrium. These 3 modalities are:

1) Vestibular System (inner ear)
2) Visual Information (eyes )
3) Somatosensory (muscles and central nervous systems of the body, including feet, legs, back, spinal cord, arms and the neck)

Information from these 3 modalities are controlled by the Cerebellum of the brain. The Cerebellum acts as the controller, or "the brakes" for the balance system, integrating information from the inner ears, eyes, and muscles of the body to provide effective feedback to help our bodies resist the forces of gravity to remain upright. Any false information from one or more of these balance modalities can cause a disturbance within the balance system, resulting in symptoms ranging from vertigo, (room spinning), lightheadedness, nausea, vomiting, or the worst scenario - falling.

Thus, evaluation of the balance system must involve a test battery that accurately assesses the Vestibular, Visual, and Somatosensory modalities, or inputs of balance. In essence, we are evaluating "reflexes" of this modality system that helps us maintain balance. The 2 reflexes we measure are Vestibulo-ocular Reflex, or the coordination between the Vestibular and Visual input systems, and the Vestibulo-Spinal Reflex, or the coordination of the Vestibular System and the Somatosensory System. The first of these reflexes, the Vestibulo-ocular, or the ability to maintain focus on visual targets during head motion, is perhaps the most vunerable of the reflexes, and usually the first to be affected by a balance disorder. This involves coordination of the eyes with the organ of balance, or the vestibular system, consisting of the vestibular nucleus, two fluid filled chambers called the utricle and saccule (the otolith organs), and 3 semicircular canals which actually control our eyes like string puppets and allow the eyes to maintain focus while the head is being tilted back, bent over, lying back, or rolling to the right or left.

The Vestibulo-ocular reflex can be easily evaluated via hearing examination and the use of a video camera, a testing procedure known as Video Oculography. By viewing the motion of the eyes in response to head movements and head angles, along with results from hearing examination, an inner ear pathologies such as Vestibular Neuritis, Meneire’s and Benign Paroxysmal Positional Vertigo (BPPV) can be easily detected. Once diagnosed, these inner ear disorders are easily be treated via Canal Repositioning Exercises and Maneuvers, Adaptation Exercises, and medical treatment.

The measurement of the Vestibulo-spinal reflex, or the "motor control" signals to the musculoskeletal system for postural control, is not as easy to evaluate. However, abnormalities of this reflex can cause the most detrimental affects to the balance system. Unsteadiness and difficulty with walking, especially on dynamic or uneven surfaces, can lead to falling, which could result in broken bones, internal bleeding, and even death. Thus, it is vital that a balance evaluation include examination of more musculature and motor control functions. Two segments of our test battery, the Vestibular Evoked Myogenic Potential (VEMP) test and the Functional Assessment With Stable and Foam Surfaces, allow us to gain invaluable information regarding the Vestibulo-spinal reflex, which greatly enhance our ability to accurately treat and rehabilitate balance disorders related to central or musculature functioning. Both of these evaluations are quick, painless, and extremely easy to perform in our office.

The Vestibular Evoked Myogenic Potential , or VEMP is a myogenic, or muscular response that occurs from high intensity acoustic stimuli. The VEMP actually measures myogenic potential from the Sternoclydomastoid muscle (SCM), which is located down each side of the neck. This large muscle branches to the otolith organs, or Utricle and Saccule, and also attaches to the inferior branch of the vestibular nerve and lower brainstem. An elicited response of the SCM muscle, either induced acoustically or with flexion of the muscle, is known as the VestibuloCollic Reflex. This reflex acts on the muscles in the neck to stabilize the head, especially with sudden unexpected events. The head also responds to movement sensed by the Saccule within the inner ear as well. Thus, the VestibuloCollic Reflex prevents our head from flopping around as we walk, run, bend over, and turn our bodies.

As previously mentioned, the VEMP is a quick, painless and easy evaluation. Electrodes are taped onto the SCM muscles and forehead, and insert earphones are placed into each ear canal for the sound stimulation. While lying in a supine position and head turned towards one side, sound is presented into the opposite ear from which the head is turned. The sound causes a reaction within the saccule of the inner ear, and the movement within this otolith organ results in the flexion of the SCM muscle, thus eliciting the VestibuloCollic Reflex, allowing for the evaluation of the inferior branch of the vestibular nerve and vestibular nuclei along with the Saccule of the inner ear. This measurement allows us to gain valuable information to rule out such pathologies as Menierearsquo's Disease, Vestibular Neuritis, Migraine Headaches, Multiple Sclerosis, Vestibular Schwannoma (small benign tumor located on the vestibular branch of the VIIIth nerve), Brainstem Stroke, Neurolabyrinthitis, and Superior Canal Dehiscence (perforation or lack of development of the Superior Semicircular Canal).

As you can see, the VEMP can also provide information about the Vestibulo-ocular reflex by assisting in the evaluation of Meniere’s and Labyrinthitis. However, it can provide vestibular information about the lower portion of the vestibular system that tradition balance testing is unable to accomplish. Thus, the VEMP has become an extremely valuable portion of the battery of balance tests performed in our office.

Functional Assessment using Stable and Foam Surface is a second evaluation of the Vestibulo-spinal reflex of the balance system. This quick evaluation includes four phases designed to evaluate a person’s dependence on vestibular, visual and somatosensory inputs in maintaining balance. These four phases include: 1) Romberg on Stable Surface (Standing with feet together on the floor); 2) Tandem Romberg on Stable Surface (stepping in place on floor); 3) Romberg on Foam Surface (Standing with feet together on a foam cushion); and 4) Tandem Romberg on Foam Surface (Stepping in place on foam cushion). During each phase, the patient is required to do each task with eyes opened, and then repeat task with eyes closed.

The purpose of this task is to evaluate the dependency on each sensory input by disturbing one or more of the sensory modalities (visual, vestibular, and somatosensory) needed for maintaining balance. Disturbing one or two of these modalities increases the dependence on another modality, thus increasing the challenge of each balance task. The visual modality is disturbed simply by closing the eyes. The brain can fix what it can see. But by closing your eyes, now the brain has to become more dependent on vestibular and somatosensory inputs to maintain balance and prevent falling. The task becomes even more challenging by disturbing not only vision but somatosensory input, which is accomplished by standing on the unstable foam surface. With eyes closed and standing or stepping on foam, the brain now becomes dependent on the vestibular input to maintain balance and upright posture.

By a "process of elimination" of the balance modalities, we can gain information about how dependent the individual is on the vestibular, somatosensory, and visual inputs to maintain balance. If a person can perform all tasks on stable and foam surfaces with eyes opened, but unable to perform one or more of these tasks with eyes closed, then it is suggested that the person may be experiencing a vestibular dysfunction causing the dizziness. However, if a person is unable to perform one or more tasks on stable and/or foam surfaces with eyes opened, then it can be suggested that the person may be suffering from more central causes of vertigo affecting the vestibulo-spinal input. Such pathologies include Multiple Sclerosis, Parkinson’s Disease, spinal cord deficiencies, Migraine Headaches, Mal de Debarquement (persistent sensation of swaying or rocking, usually following sea travel), Brainstem Stroke or other circulatory related disorders, and cerebellar deficiencies. Information from this evaluation can be extremely valuable in implementing medical treatment along with the most effective Vestibular Rehabilitation (Physical Therapy for balance dysfunction) and Fall Prevention to help that person rehabilitate and regain balance functioning.

As you can see, a balance evaluation includes a thorough battery of tests. However, a case history along with professional care, listening and understanding by our professionals is just as important as test results in helping you overcome the disruptive symptoms of your balance disorder. If you are suffering from symptoms of vertigo, lightheadedness, and even falling, give us a call. There IS something that can be done about your balance disorder!!!


Please contact Ear, Nose Throat & Allergy Specialists for an appointment today at 770-345-6600, or use our secure online appointment request.