New Audiology-Based Opportunities in the Management of the Dizzy or Balance-Disordered Patient

Introduction:

Recent developments in the health care industry are not only changing the way patients are being managed but, together with new clinical advancements, are opening the door to new practice opportunities. This is particularly true for providers seeking to add cost-effective management solutions for their patients with chronic dizziness and imbalance, and for those looking to expand their practice and increase revenues.

First, dizziness and balance disorders are receiving increased attention in the medical and popular press, especially as these problems relate to the economic and quality-of-life (QOL) impact of fall related injuries and disabilities in our aging population. In a recent article entitled 'Preventable Medical Injuries in Older Patients', for example, falling is cited as a major cause of injury and disability that can be prevented by recently developed disease management techniques¹.

Second, the American Academy of Otolaryngology-Head & Neck Surgery (AAO-HNS) has validated vestibular and balance retraining therapies by stating that 'balance retraining is a scientifically based and clinically therapeutic modality for the treatment of persistent dizziness and postural instability due to incomplete compensation after a peripheral vestibular or central nervous system injury.' In addition, the AAO-HNS has stated 'balance retraining therapy is a significant benefit for fall prevention in the elderly patient...suffering from multiple sensory and motor impairments.'²

Third, according to the Health Care Finance Administration's (HCFA) final ruling on payment policies, rehabilitation services can now be provided in a private practice under the direct supervision of a physician³.

Finally, recent developments in medical technologies provide the key to cost-effective medical management of dizziness and balance disorders. Medical devices are now available to aid the clinician in classifying patients not only in terms of their underlying pathology, but also their resulting functional impairments. The additional functional impairment information enables the clinician to customize an effective approach that combines traditional surgical and medical treatment options with newly developed rehabilitation methods. The integration of these three treatment approaches allows the clinician to minimize the impact of pathology and maximize the patient's functional performance abilities relative to the pathology.

For the office-based practice, appropriate classification allows the clinician to differentiate between patients who can be effectively managed in the office through vestibular and balance exercises, from those who require referral to a balance center for more comprehensive assessment and treatment approaches. In short, this is the most effective treatment pathway as it maximizes clinical outcomes and minimizes costs.

Classifying Patients with Balance Dysfunction: The Role of Pathology and Impairment Information

Impairments, functional limitations and disabilities are the manifestations of the underlying pathology, according to the World Health Organization (WHO) classification framework⁴. In patients with chronic vestibular and balance disorders, the basis of cost-effective medical management is the treatment plan that maximizes the patient's daily life capabilities by stabilizing the pathology and minimizing the underlying functional impairments. When a specific medically treatable pathology can be identified, the rehabilitation component is necessary to minimize the associated functional impairments. In these cases, impairment information is essential to design the rehabilitation component because functional manifestations of pathology vary considerably from one patient to the next due to the brain's unique adaptive response.

In many other cases a specific pathology that would account for the patient's problems cannot be identified. In these cases, the impairment information alone must be relied on to drive the treatment plan. Recent studies have reinforced the value of impairment information, even when a pathology diagnosis is made, and have shown that pathology diagnosis alone fails to provide the treatment plan in approximately one-third to one-half of patients^5,6.

Balance system impairments fall into three broad categories: (1) sensory inputs, (2) automatic (reflex) movement reactions to external balance disturbances, and (3) voluntary control of balanced movements. Office-based observational tests are available that can accurately determine whether a patient has functional limitations in their daily life balance and mobility activities. Examples of these include the tandem Romberg, quick turn, and gait tests. Observational tests, however, cannot identify the underlying impairments responsible for the patient's complaints and functional limitations in daily life. For example, imagine two patients who fall or sway excessively in response to external disturbances. In the first patient, instability may result from failure to sense the disturbance, while the second patient may sense the disturbance, but reacts with an uncoordinated movement.

Advances in computerized assessment technology have made it possible to quantify a wide range of balance and mobility impairments with easily interpreted graphic documentation of results. Quantified impairments include: organization of vestibular, somatosensory and visual sensory inputs to balance;coordination of automatic motor responses and movement strategies;coordination of voluntary motor responses;center of gravity alignment and weight bearing;and planning and coordination of weight transfers for mobility and function.

A recent cost-effectiveness study from the Baylor Schools of Public Health and Medicine demonstrated the importance of the impairment tests in the diagnostic work-up of patients with chronic dizziness and balance disorders⁷. This unique population study quantified the value of all the objective diagnostic technologies typically brought to bear on patients with chronic vestibular and balance system deficits. The study focused on the impact of the diagnostic information on the treatment plan and the resulting functional outcome, as well as relative costs of administering each test.

The Baylor study concluded Computerized Dynamic Posturography (CDP) is the most cost-effective assessment tool for managing the balance component. In reaching this conclusion, the study specifically recognized the critical value of impairment information in determining the most effective treatment plan.

There are growing numbers of outcome studies that provide further validation for the Baylor cost-effectiveness study. A key feature among these outcome studies is the use of new treatment designs in which impairment information provided by CDP is the primary driver of the treatment planning process^{8, 9}. These studies have shown that when treatment is customized to target the individual patient's pathology and impairments, outcomes are significantly improved over those achieved with generic approaches based on performance and/or site of lesion tests only⁵.

Additional Audiology-Based Opportunities for Management of Dizziness and Balance Disorders:

Office-based otolaryngologists and audiologists are familiar with chronic disorder management techniques for their hearing impaired patients (see Ear & Hearing August 2000 supplement). New techniques, now available for clinical management of vestibular balance and mobility disorders are similar, in many respects, to the management techniques used with hearing impaired patients.

In the hearing impaired patient, an audiology-based diagnostic work-up is necessary to define the type and degree of hearing loss and to rule out progressive, life-threatening, and/or complex pathology which may require referral to an otolaryngologist, or other physicians. In the vast majority of patients without acute problems, the patient is managed by the audiologist, focusing on the patient's underlying hearing impairment and prescription of the therapeutic means to maximize the patient's capabilities in daily life hearing activities.

This same management approach is applicable to a broad spectrum of patient populations with balance and mobility disorders. In essence, every patient with possible disequilibrium, functional mobility limitations, postural instability or other movement disorder, is an audiology-based management candidate. Additionally, the most common population with chronic balance disorders is the 60+ year old individual, the very same population with the highest incidence of chronic hearing impairments.

Fall Risk Identification/Reduction in the Elderly:

Falls in the 60+ year old population are prevalent, dangerous, and costly. Even falls that do not result in injury can have serious consequences¹⁰. Importantly, falls are not a normal part of aging. Current research indicates that elderly fallers are different than their healthy, age-matched counterparts^{11, 12, 13}. It has been suggested that dizziness may be a geriatric syndrome, similar to delirium and falling¹⁴. Some patients have medical diagnoses such as diabetes or Parkinson's disease which contributes to falling, but many have no diagnoses at all that would explain their falls. This is because they do not have a major problem focused to a single system that would 'earn' them a diagnosis. Instead, they often have many small problems across multiple systems, which interact to produce instability¹³.

As falls are not a normal part of aging, they are preventable to a large degree. Risk factors for falls have been identified and there are many screening tools available to determine the presence of balance and mobility disorders. While 'low-tech' or non-technology assessments provide a gross idea of who may be at risk, they do not identify impairments within specific body systems or the etiology of the problem. In addition, many of these tools are not sensitive to changes that may occur through interventions. Computerized assessments, on the other hand, provide a greater degree of sensitivity and can more accurately quantify balance disorders.

The computerized version of the modified Clinical Test for the Sensory Interaction on Balance (mCTSIB), when used in conjunction with the Limits of Stability (LOS) test, offers a test protocol for fall risk screening. In many respects, the combination of the mCTSIB and LOS parallel the sensory and motor components of the classic vestibular function test battery. The mCTSIB, like the caloric test and head-shake exam, tests the efficacy of sensory inputs to the balance system. The LOS test is similar to the ocular motility segment of the vestibular exam in that both confirm the patient's ability tofective voluntary movements for postural and ocular control, respectively.

The mCTSIB is a computerized version of the CTSIB or 'Foam and Dome' introduced by Shumway-Cook and Horak¹⁵ as an observational test version of the Sensory Organization Test (SOT) portion of CDP. The SOT is widely accepted as the 'gold standard' for assessment of sensory impairments to balance. The sensitivity of the mCTSIB has been shown to compare favorably with the SOT and is now widely accepted and used by clinicians interested in a first level assessment of balance disorders. With the mCTSIB, the original protocol has been modified by eliminating test 3 and 6, i.e. those involving the so-called 'Chinese lantern' or dome, and by adding a computerized forceplate to record and process body sway. Additional support for the clinical efficacy of the protocol in the assessment and management of the dizzy patient can be found in Weber and Cass¹⁶;Cass, et al¹⁷;and El-Kashlon, et al¹⁸.

The LOS protocol quantifies the maximum distance a person can intentionally displace their center of gravity (COG), i.e. lean their body in a given direction without losing balance, stepping, or reaching for assistance. The computerized assessment measures reaction times, movement speeds, distances, and coordination. The information is used to assess impairments in muscle weakness, range of motion, central control, and 'fear' factors related to the motor control of balance. The parameters reported in the LOS are significantly correlated with activities of daily living, i.e. getting out of bed, stair climbing and walking^{19, 20}.

Industrial Monitoring of Neurotoxic Effects:

The mCTSIB protocol has been shown to be an effective tool for monitoring the vestibular and proprioceptive function in workers exposed to significant levels of neurotoxins^{21, 22}. Researchers concluded that routine monitoring of workers would provide a baseline against which subtle neurotoxic effects could be assessed. In the event a change in a worker's balance is noted, the next logical step would be an immediate referral to a balance center equipped with the testing capabilities provided through CDP.

The Sensory Organization Test (SOT) component of CDP documents the patient's underlying dysfunction(s) in detail and objectively identifies abnormalities in the patient's use of the three sensory systems that contribute to postural control: somatosensory, visual and vestibular.

Conflict(s) in one or more senses generate responses in which a normal individual will suppress inaccurate inputs and select other, more accurate sensory systems to generate appropriate motor responses and postural strategies. In the presence of pathology(s), patients may display either an inability to make effective use of sensory systems or inappropriate responses, resulting in the use of inaccurate sense(s).

Worker's Compensation: Identification of Aphysiologic Sway:

Of equal importance in assessing workers with balance disorders, is the ability to differentiate those individuals with true balance problems from those exaggerating their problems for personal gain²³. In most cases of dizziness and/or imbalance the historical severity of the problem correlates with the physical and laboratory findings.

Occasionally, however, particularly in cases of head trauma, the mechanism and severity of injury are out of proportion to the physical or laboratory findings of posture and gait control. Distinguishing between normal, true physiological abnormalities, and exaggerated symptoms of balance dysfunction is an important element of the diagnostic work-up of dizziness and balance disorders, whether or not medical-legal issues are involved. For these instances, CDP has been found to be useful in documenting excessive or voluntary sway patterns as an indication of non-organic (aphysiologic) etiology²⁴. In fact, CDP is widely accepted as the definitive test for non-organic sway in normal subjects, patients, and suspected malingerers^{23, 25}.

Vestibular Rehabilitation:

Balance retraining/rehabilitation may include a traditional approach, as well as a technological component. Patients with imbalance/dizziness disorders often present with multifactoral impairments and functional limitations. A comprehensive balance retraining program must be able to address gait and mobility;sensory organization;and automatic and voluntary motor control.

The introduction of CDP coupled with advancements in vestibular/balance rehabilitation, has made management of the dizzy patient to a positive outcome all the more possible. Dizzy/unsteady patients who were previously referred on to other specialists, often resulting in a continuous and expensive cycle of referral, can now be cared for in the audiologist's or physician's office with excellent results.

The same clinical pathway used with hearing impaired patients can objectively identify patients with more complex balance/dizziness problems who merit additional consultation or referral to a physician, or a balance center.

By identifying and retaining appropriate cases for office-based management through a well-defined balance/vestibular rehabilitation program, the audiologist can significantly enhance patient outcomes and practice stature;develop new referral patterns to and from physicians and other professionals (i.e., physical therapists);and enhance the efficiency involved in addressing the patient's needs.

Summary:

Office-based otolaryngologists and audiologists are already familiar with the management of patients with chronic hearing impairments. The ability to address balance problems often associated with this patient population represents a tremendous opportunity for practice growth. The new technologies and accepted treatment modalities available today offer cost-effective solutions for patients who previously could not be helped. The addition of balance assessments and rehabilitation into the audiology-based practice can be rewarding as the new services not only enhance practice expansion (i.e. fall risk screening, medical legal cases), but also reinforce existing services.

For more information on this topic, Dr. Nashner may be contacted at www.onbalance.com, or can be phoned at 1-800-767-6744 (USA only), 1-503-653-2144.

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