One problem with BPPV is that the symptom complex can wax and wane, he said. Even if you don’t see it the first time, you’re obligated to look for it again. Just because it was in remission or symptoms were weak on one occasion doesn’t mean the patient doesn’t have it. If the history is compatible with BPPV, you’re obligated to look for it.
Explore This IssueApril 2006
Head Shaking Tests
In addition to these tests, there are three other tests people should do in the office, said Dr. Goebel. Those are the head impulse test, the head shake test, and dynamic visual acuity.
With the head impulse test, the patient shakes the head side to side and the doctor asks the patient to view a target to test whether the patient can keep his or her vision aligned on the target. The head impulse test detects damage to the vestibular system; if the gaze slips on both sides, both ears could be involved, Dr. Goebel said.
With the head shake test, the patient closes his or her eyes or puts on Fresnel lenses and shakes his or her head for 20 seconds, after which the clinician looks for nystagmus. This test can identify peripheral vestibular lesions, he said, noting that the eye will beat toward the better ear.
The dynamic visual acuity test (DVAT) involves the patient reading an eye chart. Then, with the patient reading the lowest line of best corrected vision with the head still, you shake the patient’s head and ask them to read, he said. They should still be able to read within three lines. If not, the vestibular system is not well timed, he said.
Dr. Goebel agreed with Dr. Soileau that these tests should be done along with the Dix-Halpike test. An update of this, the computerized DVAT, is in development, Dr. Goebel said.
The electronystagmography (ENG) and the videonystagmography (VNG) which document various changes in position and oculomotor tests, are considered the gold standard for assessing dizziness, yet I see patients who have had these tests but nothing has been found, Dr. Epley said. That’s because they only test a limited amount of pathology.
He added that the positions used may not be the triggering positions, and that clinicians need to be exhaustive in their use of positions in order to determine whether the patient has BPPV.
Dr. Soileau added that using VNG or Fresnel lenses enhances the physicians ability to observe the patient’s eye movements while doing this maneuver. Oftentimes this is relegated to the audiologist or physical therapist, and unfortunately, many neurootologist relegate this important part of the clinical exam to other assistants, he said.