From the Guidelines
The Dix-Hallpike test is positive when it elicits vertigo and nystagmus in a patient, typically within 1-45 seconds after being rapidly moved from a sitting position to lying down with the head hanging 30 degrees below horizontal and turned 45 degrees to one side, as described by Bhattacharyya et al 1. The test is considered positive when the patient experiences vertigo and displays nystagmus, which typically has a latency period before appearing, increases in intensity, and usually lasts less than one minute.
- The nystagmus often has a rotatory component, with the top pole of the eye beating toward the affected ear.
- The vertigo and nystagmus may fatigue with repeated testing, but repeating the Dix-Hallpike maneuver to demonstrate fatigability is not recommended, as it may interfere with the immediate bedside treatment of BPPV 1. A positive Dix-Hallpike test confirms posterior semicircular canal BPPV, which occurs when otoconia become dislodged from the utricle and move into the posterior semicircular canal, causing abnormal fluid movement and inappropriate sensation of motion when the head position changes relative to gravity.
- The Dix-Hallpike maneuver is considered the gold standard test for the diagnosis of posterior canal BPPV, with a sensitivity of 82% and a specificity of 71% in specialty clinicians, as reported by Lopez-Escamez et al 1.
- However, the accuracy of the test may vary between specialty and nonspecialty clinicians, and a negative Dix-Hallpike maneuver does not necessarily rule out a diagnosis of posterior canal BPPV 1.
From the Research
Dix-Hallpike Test Positivity
The Dix-Hallpike test is positive when it elicits vertigo and nystagmus in a patient, indicating the presence of benign paroxysmal positional vertigo (BPV) 2. The test involves rapidly moving the patient from a sitting position to a "head hanging" position, where the patient's head is at least 10 degrees below horizontal 2.
Conditions for Positivity
The test is initially performed for the posterior semicircular canals, and if no vertigo or nystagmus is elicited, tests of the horizontal semicircular canals are performed by laying the patient on each side 2. The test can become positive if the patient is held in the head hanging positions and then left and right lateral positions, allowing the canaliths to collect 2.
Key Factors
Some key factors that can influence the positivity of the Dix-Hallpike test include:
- The type of nystagmus provoked by the test, such as geotropic or apogeotropic nystagmus 3
- The presence of bilateral nystagmus, which can indicate a more complex condition 3
- The parameters of positional nystagmus, such as vertical time course and velocity amplitude, which can affect the treatment efficacy 4
- The patient's age and comorbidities, which can impact the recurrence of BPV and the effectiveness of treatment 5
Diagnostic Accuracy
The Dix-Hallpike test has a sensitivity of 79% and a specificity of 75% for diagnosing posterior semicircular canal BPV 6. The test is considered the standard for diagnosing BPV, but alternative tests such as the side-lying test can be used in patients who are unable to move into the Dix-Hallpike test positions 6.
Treatment and Recurrence
The Canalith Repositioning Maneuver (CRM) is a common treatment for BPV, and the Dix-Hallpike test can be used to assess the effectiveness of the treatment 2, 5. However, the recurrence of BPV can vary depending on the patient's age, comorbidities, and the therapeutic techniques applied 5.