Dizziness and imbalance are complex and, often, multifactorial conditions that require skilled evaluation, sometimes by multiple health-care providers.
As audiologists, our role is largely diagnostic in nature. We are able to perform a variety of tests to help identify or rule out the site of lesion. Working in a collaborative team with physical therapists who are specifically trained in vestibular rehabilitation provides a comprehensive and dynamic approach to treating these patients.
We have the privilege to operate a multidisciplinary clinic of audiologists and physical therapists who are skilled in vestibular rehabilitation. As audiologists, we are able to benefit from the unique perspective that physical therapists bring to the table. Their focus is on improving function, with less emphasis on diagnostics. Our role in these patients’ care is outlined in the American Academy of Audiology’s Scope of Practice statement: “Audiologists also are involved in the treatment of persons with vestibular disorders. They participate as full members of the balance treatment teams to recommend and carry out treatment and rehabilitation of impairments of vestibular function” (2004).
“The goals of vestibular rehabilitation therapy (VRT) are to (1) enhance gaze stability, (2) enhance postural stability, (3) improve vertigo, and (4) improve activities of daily living,” according to Han et al (2011).
That is not to say that physical therapists are not interested in diagnoses or sites of lesion. In our experience, well-educated physical therapists who care for vestibular clients will take patient diagnosis and clinical findings into strong consideration when developing a treatment plan for their patients.
To outline the working clinical relationship between audiologists and physical therapists in practice, we would like to share a case study that demonstrates the clinical role that these two specialists bring to the care of vestibular patients.
Our patient is a 29-year-old, previously very healthy and active female, who presents with constant unsteadiness and disequilibrium with imbalance.
She had a four-day episode of sudden onset, severe, long-lasting vertigo that began two months prior to her appointment. She was seen by an urgent care facility, was prescribed meclizine, and was given home exercises for benign paroxysmal positional vertigo (BPPV).
Her symptoms decreased initially, but she continued to experience persistent dizziness and decreased balance. She was seen by her referring physician for an ear, nose, and throat (ENT) consultation and was reportedly diagnosed with vestibular labyrinthitis. Hearing assessment at her referring ENT revealed normal hearing sensitivity and speech understanding and type A tympanograms bilaterally.
Computerized Dynamic Posturography (CDP)
All patients in our clinic who are experiencing dizziness and imbalance are evaluated by an audiologist using CDP as part of a balance and vestibular assessment to determine function of visual, vestibular, and somatosensory balance systems. Impairments in balance can be a consequence of changes in the motor, sensory, and integrated aspects of motor control.
CDP results are used to establish a baseline of function and to determine if there is a sensory mismatch between the visual, vestibular, and somatosensory balance systems. The sensory mismatch contributes to the physical therapist’s determination of a treatment paradigm that will be used to address the patient’s dizziness and balance symptoms.
The Sensory Organization Test (SOT) portion of the CDP is used to assess the patient’s overall visual, vestibular, and somatosensory capabilities as they relateto balance.
The SOT revealed normal performance on conditions 1–3, which are performed on a stable surface (eyes open, eyes closed, and visual conflict, respectively). Her performance was abnormal on conditions 4–6, which are performed on an unstable surface (eyes open, eyes closed, and visual conflict, respectively).
This pattern is consistent with a somatosensory-vestibular mismatch (See FIGURE 1), indicating an over-reliance on the somatosensory system. Patients with somatosensory-vestibular mismatch are considered “surface dependent” and often complain of increased symptoms when their base of support is narrowed.
VNG testing is performed to identify peripheral and central vestibular deficits that may suggest disorders of the peripheral or central vestibular system.
The patient’s VNG test revealed left-beating nystagmus with a slow phase velocity (SPV) measuring six degrees/second in a supine position. Caloric testing revealed a right vestibular hypofunction (See FIGURE 2).
Identifying the presence of a peripheral weakness may influence the treatment plan made by the physical therapist to encourage compensation of the vestibular system. The patient was immediately scheduled for evaluation with physical therapy for vestibular rehabilitation and balance therapy.
Our therapy team worked with this patient during 40-minute sessions, two times a week for approximately 12 weeks, focusing on compensation strategies and sensory re-weighting for the patient’s vestibular hypofunction to address chronic dizziness and imbalance symptoms.
During therapy, the physical therapy team considered the patient’s current sensory-weighting strategies to develop a progressive treatment program. In this case, the patient’s CDP test revealed an over-reliance on somatosensory input. In other words, the patient was abnormally “surface dependent.”
Typical manifestations of a surface-dependent patient may include relying on touching a surface or assistive device with a hand while stepping up or stepping down stairs or curbs; taking short, shuffling steps and touching walls or other surfaces while walking.
The patient’s abnormal caloric findings (right hypofunction) are most likely the underlying pathology causing her symptoms and are consistent with her sudden onset of severe vertigo with residual balance symptoms.
In this case, the therapists worked with the patient to increase visual and somatosensory balance performance to compensate for abnormal vestibular function. They also completed vestibulo-ocular reflex (VOR) exercises to compensate/adapt the patient’s visual-tracking system to compensate for the hypofunction.
Upon completion of vestibular rehabilitation, a discharge CDP was completed by audiology to determine progress (See Figure 3). This indicates the progress after three months of therapy.
The discharge SOT indicated a significant improvement in functional balance performance and visual/vestibular function from the initial CDP evaluation three months prior. The outcomes of this test indicated normal functional balance for the patient’s age and height.
The collaboration between audiology and vestibular therapy professionals can result in excellent patient outcomes and a holistic approach to treating patients with dizziness and imbalance.
By combining skilled diagnostic testing with a structured vestibular rehabilitation program, patients with a variety of symptoms—including acute and chronic dizziness, imbalance, and high fall risk—can be treated effectively.
American Academy of Audiology. (2004) Scope of Practice. Audiol Today 15(3):44–45.
Han BI, Song HS, Kim JS. (2011) Vestibular rehabilitation therapy: review of indications, mechanisms, and key exercises. J Clin Neurol 7(4):184–196.