Audiologists and the medical community are faced too often with the seemingly insurmountable task of successfully evaluating dizzy patients in the most efficient and cost-effective manner. This is seldom straightforward, as nearly one-third of people over age 75 are diagnosed with non-specific dizziness that is often secondary to multisystem dysfunction.¹

Because the skill set required to comprehensively evaluate the vestibular system is highly specialized, the idea of an audiologist who specializes in vestibular assessment is a concept that should be seriously considered and encouraged within our discipline. In a recent survey, the American Academy of Audiology estimated that approximately 17 percent of audiologists routinely perform some form of vestibular assessment,²with electro/videonystagmography (ENG/VNG) used much of the time.

However, in a retrospective study, Charles Stockwell reported that 61 percent of 2,584 dizzy patients exhibited normal ENG findings.³It is doubtful that all 61 percent had normal vestibular function; it is more likely that the ENG was insufficient to detect vestibular and/or balance dysfunction in some of these patients.

Therefore, it is imperative that we broaden our expertise and embrace an assessment beyond the traditional ENG/VNG. First, we must be well-trained in taking a first-rate vestibular and balance history; Kroenke et al. reported that a comprehensive medical history provided an accurate diagnosis of the patient's dizziness 76 percent of the time.⁴ dditionally, use of bedside tests to assess the vestibular -ocular, -spinal and -colic reflexes (VOR, VSR and VCR) can effectively supplement a working diagnosis until more objective measures can be obtained.

When bedside tests and a comprehensive history are inconclusive, referral for comprehensive objective assessment of vestibular and balance function should be routine. It is here that a strong working relationship with the multi-disciplinary balance team, including neurotologists and physical therapists, will prove invaluable. Think of it this way: When the audiologist identifies a more complex hearing loss, are not additional auditory measures warranted? We should approach vestibular/balance assessment in much the same way. It is our obligation and responsibility to understand the implications of each measure performed and to offer an interpretation and recommendations based on a well-constructed analysis and synthesis of the results.

It is clear that a rise in the number of balance-troubled patients lies ahead. In 1997, the National Institutes on Deafness and Other Communicative Disorders (NIDCD) estimated 12.5 million Americans over the age of 65 have a vestibular or balance disorder that impacts their daily functional capacity.⁵According to the U.S. Census Bureau, the projected number of U.S. citizens over the age of 65 will rise from approximately 40 million in 2010 to nearly 90 million by the year 2050.⁶These statistics are unsettling as the number of balance-troubled patients may approach 27 million by 2050.

There is, however, hope. Interest in vestibular assessment and management is extremely strong within the field of audiology. In a survey of doctoral students and recent graduates, vestibular education ranked third in "areas of interest in the field of audiology," behind diagnostics and hearing aids.⁷Moreover, vestibular testing ranked second in the area of "most-interest" if hands-on-training was to be offered at the annual professional conference. This is good news. Large numbers of patients with balance and vestibular disorders loom on the horizon, and we must prepare ourselves to be there, ready to take them on.

Christopher Zalewski, MA, is on staff at the National Institutes of Health. Contact him at zalewski@nidcd.nih.gov

References

1. University of Iowa Health Care. (2002). Comprehensive management of vestibular disorders. Currents, Spring 2002, Vol 3, No 2. Retrieved March 2004, from www.uihealthcare.com/news/currents/vol3issue2/03vertigo.html.

2. American Academy of Audiology. (2008). 2007 Academy membership demographics. Audiology Today, Vol 20 suppl, 46-47.

3. Stockwell, C. (May 2000). Incidence of ENG abnormalities. Insights in Practice, Clinical Topics in Otoneurology. ICS Medical.

4. Kroenke, K, Lucas, CA, Rosenberg, ML, Scherokman, B, Herbers, J, Wehrle, PA and Boggi, JO. (1992). Causes of persistent dizziness: A prospective study of 100 patients in ambulatory care. Annals of Internal Medicine, 117 (11): 898-904.

5. National Institute on Deafness and Other Communication Disorders, (1997). Facts Sheet, March, 1997.

6. U.S. Census Bureau statistics excerpted from 8-K SEC Filing; filed by GENTIVA HEALTH SERVICES INC on 2/3/2006. Retrieved March 2009, from http://sec.edgar-online.com/gentiva-health-services-inc/8-k-current-report-filing/2006/02/03/Section5.aspx

7. American Academy of Audiology. (2008). Doctoral students and recent graduates survey. Retrieved August 19, 2009, from www.audiology.org/education/students/SAA/Documents/StudentSurveyResults.pdf.