Diagnostic Test for Benign Paroxysmal Positional Vertigo
The Dix-Hallpike maneuver is the gold standard test that confirms the diagnosis of posterior canal BPPV, which is the most likely diagnosis in this patient. 1
Clinical Presentation Confirms BPPV
This patient's presentation is classic for posterior canal BPPV:
- Brief episodes of vertigo (lasting about a minute) triggered by sudden head movements like rolling over in bed are pathognomonic for BPPV 1
- Nausea accompanying the spinning sensation is a common associated symptom 1
- Absence of auditory symptoms (no tinnitus or hearing loss) and no neurological signs (no facial numbness) effectively rule out other vestibular disorders like Meniere's disease or acoustic neuroma 1
The Dix-Hallpike Maneuver: Procedure and Interpretation
The test involves positioning the patient supine with the head extended 20 degrees off the examination table edge, then rapidly turning the head 45 degrees to one side while observing for characteristic nystagmus. 1, 2
Positive Test Criteria
A positive Dix-Hallpike maneuver demonstrates all of the following features:
- Torsional (rotatory) upbeating nystagmus appearing after a latency period of 5-20 seconds 1, 3
- Vertigo and nystagmus that crescendo then resolve within 60 seconds from onset 1, 3
- The nystagmus has a crescendo-decrescendo pattern, beginning gently, increasing in intensity, then declining 1
Diagnostic Accuracy
The Dix-Hallpike maneuver has a sensitivity of 82% and specificity of 71% among specialty clinicians, with a positive predictive value of 83% 1, 2. However, the negative predictive value is only 52% in primary care settings, meaning a negative test does not rule out BPPV 1.
Testing Algorithm
Perform the Dix-Hallpike maneuver bilaterally (testing both the right and left sides) to determine which ear is affected 1, 2. The affected ear is the one in the dependent position when nystagmus is elicited 1.
If Dix-Hallpike is Negative
If the Dix-Hallpike test is negative but clinical suspicion remains high, perform a supine roll test to evaluate for lateral semicircular canal BPPV, which accounts for 10-15% of BPPV cases 1. The supine roll test involves rotating the patient's head 90 degrees to each side while supine and observing for horizontal nystagmus 1.
Important Clinical Caveats
Warn the patient before testing that the maneuver will provoke intense vertigo and possibly nausea, which typically subsides within 60 seconds 2. This counseling improves patient cooperation and reduces anxiety 2.
Exercise caution in patients with significant vascular disease, cervical stenosis, severe kyphoscoliosis, limited cervical range of motion, Down syndrome, severe rheumatoid arthritis, or morbid obesity, as these conditions may affect safety 1, 2. For patients with physical limitations, special tilting examination tables may be necessary 1.
If the initial test is negative but clinical suspicion remains high, repeat the Dix-Hallpike maneuver at a separate visit to avoid false-negative results 1. The test can be falsely negative due to factors including the speed of head movements, time of day, and angle of the occipital plane 1, 2.
No Imaging Required
Normal medical imaging such as CT scans, MRI, or laboratory testing cannot confirm BPPV 1. The diagnosis is purely clinical, based on the characteristic nystagmus elicited during positional testing 1.