In the world of vestibular testing, the Videonystagmography (VNG) is the gold standard for testing vestibular function. However, as a physical therapist evaluating and treating patients with vestibular dysfunction, I was curious to see how my examination techniques stacked up against this gold standard. I dove into researching my question: "just how reliable is bedside vestibular testing?" That's when I came across "Office Vestibular Tests: a battery approach to guide the diagnosis of dizzy patients" by Nadia Kamal, Hesham Taha, & Eman Galal (2011).
To briefly summarize the article:
- 35 participants were included:
- all complained of vertigo/dizziness
- all had confirmed unilateral vestibular insult
- First, a VNG and a VEMP was performed on all of the patients
- A VNG tests for Horizontal semicircular canal and/or superior vestibular nerve lesions with central vestibular connections
- A VEMP tests for information for saccular involvement and/or inferior vestibular nerve involvement
- After undergoing a VNG and VEMP, the study ran a proposed battery of tests on each participant the same day
- "The proposed battery of office vestibular tests was performed and evaluated independently for every patient by a different examiner who was blind to the results of the laboratory tests conducted by the other examiners."1
- Results:
- The sensitivity of the battery was 77% for identifying vestibular disorders
- The proposed battery of tests can identify and site the side of peripheral vestibular lesions
I would say 77% is pretty good! Especially since the proposed battery includes only a handful of tests that can be performed in the office setting. Here is what Kamal et al performed in their battery:
-Ocular Motility
-Smooth Pursuits
-Saccades
-Head Thrust/Heave
-Fukuda Step Test
-Gaze Stabilization (with and without fixation)
-Head Shake
-Dix-Hallpike and Roll Tests
Having this information made me feel more confident in my testing when a VNG has not been performed, or may not be a viable option for the patient. In some cases, a VNG may be too invasive or too intense for vestibular patients. Especially those who have increased anxiety/fear of vertigo or vomit easily. These patients may lose faith in their doctor or therapist, and avoid getting help or treatment out of fear of making their symptoms worse again.
This patient gave two thumbs up during his bedside vestibular evaluation with infrared video-ocuolography (IVOG) goggles.
A VNG is still a great test to have and remains the gold standard. A VNG is especially useful when a patient's bedside evaluation yields mixed results.
Other tests that may be performed in a Vestibular Examination not mentioned above include (but are not limited to):
- Musculoskeletal screens (of cervical spine and LE strength)
- Tuning fork tests (Weber/Rinne)
- A simple hearing screen
- Somatosensory Testing (sensation/proprioception)
- Coordination Testing (rapid alternating movements)
- mCTSIB and/or Rhomberg Test
- Functional Gait Assessment
- Dynamic Visual Acuity
- Cover/Uncover and Cover/Cross cover testing
- Convergence
- VOR Cancellation
- Slow VOR
- Hyperventilation Test
- Valsalva Test
- Mastoid Vibration Test
- Bow and Lean Test
- Computerized Dynamic Posturography (CDP)
References:
1. Kamal, Nadia, Hesham Taha, and Eman Galal. "Office vestibular tests: A battery approach to guide the diagnosis of dizzy patients." Audiological Medicine 9.2 (2011): 79-84.
(http://www.tandfonline.com/doi/abs/10.3109/1651386X.2011.580584)