Chapter 21: Vestibular Disorders

LEARNING OBJECTIVES

INTRODUCTION

Physical therapists are likely to encounter patients with vestibular disorders in a variety of clinical settings, including the emergency department. At an incidence of 5.5%, dizziness in the United States affects more than 15 million people each year.¹ The reported prevalence of dizziness as a medical symptom in community-dwelling adults varies based on subjects’ age, sex, and definition of the complaint (1% to 35%).² Dizziness is among the most common complaints adults report to their health-care providers, and prevalence increases with age.³ A cross-sectional study of emergency department visits for dizziness found that otologic/vestibular pathology was the number one cause (32%).⁴ Among community-dwelling adults, it has been suggested that nearly one-third of the U.S. population has a vestibular disorder.^5,6 Patients who experience dizziness report a significant disability that reduces their quality of life.^7,9 Furthermore, it has been reported that greater than 70% of patients with initial complaints of dizziness will not have a resolution of symptoms at a 2-week follow-up. Of patients with persistent dizziness, 63% reported recurrent symptoms continuing beyond 3 months.¹⁰

Cawthorne¹¹ and Cooksey¹² were the first clinicians to advocate exercises for persons suffering from dizziness and vertigo. It has been only within the last three decades, however, that our knowledge of vestibular function and related disorders has profoundly changed rehabilitation approaches. Once an accurate diagnosis involving the vestibular pathways has been made, activity limitations are minimized and progression toward disability can be prevented. Evidence suggests that an individualized approach to vestibular rehabilitation is important for a better outcome.

The peripheral vestibular system serves as the primary focus of this chapter because it is the most common origin of patient signs and symptoms. The physical therapist, however, must recognize patterns of signs and symptoms from a central pathology as well. With an appreciation of the complexity of the vestibular system coupled with an understanding of tests to measure its function, the reader will be able to discern anomalies of the system and begin to formulate effective rehabilitation strategies.

ANATOMY

Peripheral Vestibular System

The three primary functions of the peripheral vestibular system are (1) stabilizing visual images on the fovea of the retina during head movement to allow clear vision; (2) maintaining postural stability, especially during movement of the head; and (3) providing information used for spatial orientation.

Semicircular Canals