Human balance is a complex, coordinated physiological process that keeps the body upright and stable. Maintaining equilibrium depends on continuous sensory input from three main systems: the visual system, the somatosensory system (proprioception from muscles and joints), and the vestibular system housed in the inner ear. The brainstem and cerebellum serve as the central processing unit, taking this information and sending signals to the eyes and muscles to make constant, automatic postural adjustments. A balance test, often referred to as a vestibular assessment, is a non-invasive diagnostic tool designed to evaluate the function of these interconnected systems. These tests help medical professionals pinpoint where a breakdown in the communication chain is occurring, providing objective data to determine the origin of a person’s unsteadiness.
Why Balance Assessment is Necessary
Patients are typically referred for a balance assessment when they experience persistent or recurrent symptoms indicating a problem with spatial orientation. The most common complaint is chronic dizziness, which can manifest as lightheadedness, faintness, or a floating sensation. Another major indicator is true vertigo, described as the illusion of motion or a spinning sensation of the self or the surrounding environment.
The assessment is also necessary when a patient reports unexplained falls, a staggering gait, or general instability while walking. Symptoms like nausea, vomiting, or blurred vision that accompany movement can point toward a balance disorder originating in the inner ear or the central nervous system. The assessment investigates conditions such as inner ear disorders (like Meniere’s disease or vestibular neuritis) and neurological conditions that affect the brain’s ability to process sensory input. By quantifying the degree of impairment, the tests help confirm a diagnosis and rule out non-vestibular causes of imbalance, such as cardiovascular or orthopedic issues.
Types of Balance Tests Performed
Balance assessments combine instrumented, objective measurements with simpler clinical evaluations to create a comprehensive functional profile. One common objective procedure is Videonystagmography (VNG), which uses infrared video goggles to track and record involuntary eye movements, known as nystagmus. The VNG battery includes tests of eye tracking and positional testing, often culminating in caloric testing. Caloric testing delivers warm and cool air or water into the ear canal, stimulating the balance organ to compare the function of the left and right ears separately.
Another objective method is Computerized Dynamic Posturography (CDP), which evaluates how a person uses their visual, vestibular, and somatosensory inputs to maintain stability. During CDP, the patient stands on a force-sensing platform that can move or tilt while the visual environment around them also moves. This procedure systematically removes or distorts sensory inputs, revealing whether the patient relies too heavily on vision or their body’s sensation of touch and pressure. Rotational Chair Testing is a specialized test involving a motorized chair that rotates in controlled patterns, assessing the coordination between the inner ear and the eyes in response to head movement.
The assessment frequently includes other specialized tests, such as Vestibular Evoked Myogenic Potentials (VEMP). VEMP measures sound-evoked muscle reflexes to check the function of the utricle and saccule, two specific organs within the inner ear. Simple bedside clinical tests are also routinely performed. The Romberg Test requires the patient to stand with feet together, first with eyes open and then closed, to see if removing visual input causes significant swaying. Tandem Gait, or heel-to-toe walking, is another common clinical test used to assess dynamic balance and gait stability.
Preparing for a Balance Test
Accurate test results depend on proper patient preparation, particularly concerning substances that can suppress the vestibular system. Patients are typically instructed to discontinue all non-essential medications that affect the nervous system for 24 to 48 hours before the test. This includes sedatives, tranquilizers, high-dose antihistamines, and medications used to control dizziness or motion sickness. Patients must consult their physician before stopping any prescribed daily medication, especially those for heart conditions, blood pressure, or seizures, which are generally continued.
Dietary restrictions are also advised, such as avoiding alcohol for 48 hours and discontinuing all caffeine intake for 24 hours prior to the appointment. This restriction includes coffee, tea, soda, and energy drinks, as stimulants can interfere with vestibular responses. Patients should wear comfortable, loose-fitting clothing, such as pants or shorts, since they may be required to move into various positions. Additionally, no facial or eye makeup should be worn, as it can interfere with the video goggles used to track eye movements during the VNG assessment.
Understanding the Results
The compilation of balance test data provides a comprehensive picture of the patient’s balance function, allowing the clinician to localize the source of the problem. A primary goal is to differentiate between a peripheral vestibular issue (originating in the inner ear) and a central issue (stemming from the brain or brainstem). For instance, certain patterns of nystagmus observed during VNG suggest an inner ear problem, while vertical or direction-changing nystagmus often points toward central nervous system involvement.
Posturography results help identify a patient’s specific sensory reliance, showing whether they struggle when visual or somatosensory cues are removed. The diagnosis informs the next steps in the patient’s care plan. This often involves a referral to a specialist, such as a neurologist or an otolaryngologist (ENT), for further investigation or treatment. Treatment frequently includes a referral for Vestibular Rehabilitation Therapy (VRT), which uses specific exercises to train the brain to compensate for inner ear deficits and improve stability.