Overview of the Vestibular System
Vestibular System Examination and Evaluation
Patient Interview and History
Oculomotor and Vestibulo-ocular Reflex Assessment
Benign Paroxysmal Positional Vertigo
Recovery and Prognosis
Student Practice Activities
The vestibular system is a complex, highly integrated component of the nervous system that usually goes unnoticed until it is disturbed. Consider the person who goes on a ride at an amusement park feeling well but exits experiencing dizziness, unsteadiness, nausea, and difficulty with vision, concentration, and walking. In this instance, we intuitively identify that the person is experiencing “motion sickness” due to excessive stimulation from the ride. These are the same symptoms that people with vestibular disorders experience. According to the American Physical Therapy Association’s (APTA’s) Evidence-Based Clinical Practice Guideline for Peripheral Vestibular Hypofunction, 35.4% of adults in the United States seek medical attention for vestibular dysfunction, and the incidence increases with age. Vestibular rehabilitation is indicated for those with acute, chronic, unilateral, or bilateral vestibular hypofunction.1 This chapter presents an overview of the vestibular system and introduces entry-level outcome measures and interventions that address limitations/restrictions due to vestibular dysfunction.
OVERVIEW OF THE VESTIBULAR SYSTEM
The vestibular system makes up one of the seven special senses and is responsible for the awareness of body position in space, maintaining postural control against gravity, and coordinating head and eye movements. The pathways of the vestibular system are inextricably linked with all aspects of the postural control system. The otoliths and the semicircular canals detect the direction and rate of movement of the head in space, and the parieto-insular cortex processes this information for conscious awareness of body position.2 Visual information is used in conjunction with gaze stability from the vestibulo-ocular reflex (VOR) to interact with the environment. In addition, the vestibulospinal reflexes (VSR) cooperate with the somatosensory system to regulate postural tone and automatic postural responses (Fig. 14.1). As discussed in Chapter 10 Interventions to Improve Standing and Standing Balance Skills, the unique connections of the vestibular system allow it to regulate postural control under conditions in which somatosensory and visual information conflict or are inaccurate or unavailable.
Fundamental components of the vestibular system.
Overview of the Peripheral Vestibular System
The peripheral vestibular apparatus originates in the inner ear, adjacent to the cochlea, and lies deep within the temporal bone. It comprises the otoliths (the utricle and saccule), three semicircular canals, and the vestibular portion of the eighth cranial nerve (vestibulocochlear nerve). Each ear contains one set ...