Don’t Let Dizziness Throw Off Your Life’s Balance
Dizziness or loss of balance, sometimes referred to as vertigo, is the second most common complaint that doctors hear. According to the National Institutes of Health, dizziness will occur in 70 percent of Americans at some point in their lives. Whether the dizziness is fleeting or chronic may indicate how serious the potential health risks are to you as an individual.
Equilibrium disorders typically fall into two categories:
- Acute attacks of dizziness, vertigo, or a general loss of balance that may last a few seconds or a few hours
- A persistent sense of imbalance, unsteadiness, or what some people refer to as a loss of sure-footedness
Although you may feel helpless when you’re hit with a dizzy spell, there’s plenty of hope for these balance problems. Proper diagnosis and treatment options have been enhanced over the last decade, making dizziness a much easier problem to resolve.
Why Am I Losing My Balance?
To help balance your body, your brain requires input from your inner ear, your eyes, and your body to determine where it is in relation to other objects. Your brain takes this information to determine what movements your body should make based on what’s going on around you. If any one of the several parts of this complicated system does not work properly, a loss of sure-footedness or problems with movement coordination can take place.
The natural aging process may affect these senses, as well as the central nervous system’s ability to interpret and react to them quickly. Physicians commonly hear complaints that patients can see a curb or step but aren’t able to react quickly enough to keep their balance. With proper diagnosis and therapeutic exercises, like balance retraining, many older adults can return to a more active lifestyle.
VNG is the most common test battery administered to people with dizziness, vertigo, or imbalance. This highly advanced piece of equipment utilizes infrared video cameras to record eye movements. Subtle eye movements are measured in order to evaluate signs of vestibular dysfunction or central neurological problems. Various tracking tasks (including gaze stabilization) in the presence and absence of head movements are also assessed. This may require manipulating the head and body in different positions to induce certain vertiginous symptoms. Caloric testing, the final component of the VNG, assesses a specific portion of the vestibular system through administering warm and cool air into the ear canal. The subtests composing the VNG test battery are described further in detail below.
Ocular motor Testing
The common goal of all eye movements is to facilitate a clear and stable view of the environment. Patients will be asked to track visual targets consisting of different patterns and/or with their head in varying positions. The following ocular motor sub-systems will be assessed during the VNG and provide diagnostic information about the central vestibular and neuropthamologic connections within the brain.
- Saccade Testing:
- Smooth Pursuit:
- Gaze Stability:
the ability to move the eyes in a rapid single movement to re-fixate a target of interest onto the fovea (most sensitive part of the retina) for clear viewing. This brings images of objects of interest rapidly onto the fovea.
holds the image of a small moving target on the fovea; aids optokinetic responses to stabilize gaze during sustained head rotation
the ability to maintain gaze stable without the generation of other eye movements while looking straight ahead, up, down, left, and right.
holds images steady on the retina during sustained head rotation
This documents the presence of static positional nystagmus. Findings are used for differential diagnosis of BPPV and other peripheral vestibular deficits versus central nervous system impairment. The patient will be required to move their body/head into different positions within their range of motion as eye movements are recorded.
The ear canals will be individually stimulated via air irrigation at different temperature gradients. This will produce vestibular responses that will be interpreted through eye movements.
The following procedures may be included on an individual basis in order to provide a comprehensive balance assessment:
Canalith Repositioning Maneuver (CRM, also known as the Epley Maneuver)
The goal of CRM is to move displaced, free-floating otoconia (calcium carbonate crystals) from the sensitive area of the semicircular canal into their proper resting position. This will stop the false signals and symptoms that are being experienced (which is typically a spinning-sensation that lasts a few seconds). Depending on the individual and underlying cause of how the crystals were displaced, the procedure may need to be repeated to completely alleviate all symptoms.
GANS Sensory Organization Performance (SOP) Test
This provides qualitative information on whether an equilibrium dysfunction exists, and highlights if such deficit is more peripheral or central in nature. The patient will be asked to stand and maintain their center of gravity under varying conditions. This functional balance assessment hence exposes any sort of weakness in the following areas: inner ear- related, visually-related, and somatosensory-related.
Dynamic Visual Acuity Test
This test is a measure of gaze stability during head movement, which helps identify individuals who may have a deficit of the vestibular system. Visual acuity is first measured with the head still (static visual acuity, SVA) and then with the head in motion (horizontally or vertically) at a fixed speed.
Vertebral Artery Test
This test assesses collateral blood supply to the brain while compromising the vertebral artery circulation. It is a test of cervical positional tolerance versus arterial patency when examining dizzy patients.
Cervical Vertigo Test
The neck interacts with other types of vertigo. Neck input may be used as sensory input to assist in stabilizing vision. This can be easily demonstrated by eliciting ocular nystagmus from vibration of the neck in individuals who are otherwise well compensated.
Vestibulo-ocular reflex (VOR)
The purpose of the VOR is to maintain the location of a viewed image on the foveala of the retina during active head motion. The vestibular system provides information regarding head movement so that compensatory eye movements may be produced to avoid slippage of the image from this area. This will be measured by stimulating the vestibular system and measuring the eye movement responses throughout various subtests.