Dix-Hallpike Maneuver

Anatomy and Physiology

The semicircular canals are integral components of the body's vestibular system, responsible for detecting angular or rotational movement. There are 3 membranous, interconnected tubes located within the temporal bone's bony labyrinth. Each semicircular canal contains endolymph. At the base of each canal is a bulbous expansion called the ampulla. Within the ampulla resides the crista ampullaris, a sensory receptor housing hair cells. The hair cells extend into the cupula, a gelatinous mass spanning the width of the ampulla.

During normal rotational movement of the head, the fluid endolymph remains relatively stationary while the canals and the cupula experience motion. The hair cells are mechanically stimulated by the resistance of the endolymph, causing mechanically gated ion channels to open, subsequently triggering an action potential indicating rotational movement.  

The semicircular canals are arranged along 3 perpendicular planes. The anterior and posterior canals lie in the vertical plane, designed to detect movement in the sagittal and coronal planes, respectively. The horizontal canal is positioned at a 30° angle from the horizontal plane, enabling it to detect movement to the left or right in the horizontal plane.[8] The semicircular canals work in conjunction with their partner canals on the head's contralateral side. The hair cells within the paired semicircular canals are oriented in opposite directions. When the head is turned, the receptors on one side are activated, while those on the other side are inhibited. Any angular movement tends to stimulate at least 2 pairs of canals if not all 3 pairs.

BPPV is thought to be caused by free-floating calcium carbonate crystals, called otoliths, within the semicircular canals. Gravity or changes in linear acceleration can dislodge an otolith, aberrantly displacing hair cells and resulting in a false sensation of movement with positional head changes. In BPPV, the posterior canal affects 85% to 95% of patients, while horizontal canal involvement accounts for 5% to 15% of cases.[9] Anterior canal BPPV is extremely rare.[10]

Indications

The Dix-Hallpike maneuver is indicated for patients with paroxysmal vertigo and when BPPV is considered in the differential. These patients experience vertigo in brief episodes lasting less than 1 minute, triggered by changes in head position and return to total normalcy between episodes. Although sensations of light-headedness or nausea might persist for longer than 1 minute, alternative diagnoses should be considered if the sense of movement continues beyond 1 minute.

Dizziness is a common complaint; serious causes must be considered and excluded first. Non-paroxysmal vertigo is likely caused by a vestibular syndrome or a central etiology, such as brainstem stroke.[11] Distinguishing between these causes requires a detailed medical history, a thorough neurological examination, and, when indicated, imaging such as a CT scan or MRI. Any neurological deficits, especially truncal ataxia, should raise concerns about a central cause and trigger further investigation. If the patient's history aligns with BPPV, the Dix-Hallpike maneuver is the preferred diagnostic test.[12][13]

Contraindications

The Dix-Hallpike maneuver involves hyperextending the neck; performing the maneuver should be avoided in patients with specific pathologies where rapid head and neck movements could be dangerous. Absolute contraindications to the Dix-Hallpike maneuver include cervical instability, acute neck trauma, cervical disc prolapse, Arnold-Chiari malformation, and vascular problems such as carotid sinus syncope, vascular dissection, and vertebrobasilar insufficiency. However, for patients without absolute contraindication but with impaired neck mobility, modified versions of the maneuver can be performed to evaluate for BPPV.[14]

Equipment

To perform the Dix-Hallpike maneuver effectively, an examination table that can recline horizontally is required. Additionally, specific equipment can be helpful if available. Frenzel goggles, which feature high-diopter lenses, limit patients' ability to visually fixate and magnify their eyes. This allows the clinician to better observe nystagmus, an essential indicator during the maneuver.[15] 

More advanced practitioners may use video electronystagmography (VNG) goggles, which utilize infrared light and cameras to record precise eye movements that may be challenging to detect with the naked eye.[1]

Personnel

A single practitioner can accomplish the Dix-Hallpike maneuver.[1] It is recommended to have nursing staff available to assist in moving the patient if necessary and to monitor the patient's condition, especially if the procedure induces severe nausea and emesis.

Preparation

Patients should be appropriately counseled on the steps involved in the Dix-Hallpike maneuver and the potential vertigo they may experience. In some cases, administering an antiemetic before initiating the maneuver can temporarily relieve any nausea or vomiting associated with vertigo induced by the procedure.[1]

Technique or Treatment

During the Dix-Hallpke maneuver, the patient sits upright on the examination table with extended legs. The clinician rotates the head 45° toward the ear that will be tested. The patient is then swiftly laid back down with the head hanging off the edge of the examination table. The patient’s neck should extend approximately 20° below the horizontal plane while the head maintains the initial 45° rotation. This position should be held for at least 30 seconds. Throughout this time, the clinician should closely observe the patient’s eyes for nystagmus.

In posterior canal BPPV, the characteristic nystagmus observed is torsional and up-beating. The vertical quick phase of the nystagmus is directed upward toward the forehead. In contrast, the torsional quick phase is directed downward with the upper pole of the eyes toward the tested ear.

Typically, there is a latency period of 2 to 5 seconds between completing the maneuver and the onset of nystagmus. However, in rare cases, a latency period of up to 40 seconds may be observed.[5] Classically, the duration of nystagmus associated with posterior canal BPPV is brief, lasting less than 1 minute, and it tends to fatigue with repetitive positional testing. Visual fixation can suppress the nystagmus associated with BPPV. If the patient is instructed to focus their eyes on a visible target for approximately 10 seconds, the nystagmus caused by BPPV should cease.

Suppose the Dix-Hallpike maneuver does not elicit nystagmus, but clinical suspicion remains high. In that case, the patient should recover for at least 1 minute before testing the other ear. In some cases, horizontal canal pathology may not be detected through the Dix-Hallpike maneuver alone. If there is a suspicion of horizontal canal involvement, a supine roll test can be performed to evaluate the condition further.[16][17]

Complications

During the Dix-Hallpike maneuver, it is common for patients to experience nausea and vomiting. To mitigate these symptoms, administering an antiemetic before the procedure can be helpful.[5] This preventive measure can help alleviate the potential discomfort associated with the maneuver and improve the overall patient experience.

Clinical Significance

The Dix-Hallpike maneuver is considered the gold standard for diagnosing posterior canal BPPV and is an integral component of the diagnostic criteria. However, evaluating the diagnostic utility of this test can be challenging. In the published literature, the sensitivity of the Dix-Hallpike maneuver for diagnosing posterior canal BPPV has been reported to range from 48% to 88%, while estimates of its specificity are currently lacking.[18] 

Despite these limitations, the Dix-Hallpike maneuver remains a low-cost and safe diagnostic tool that can easily transition into the Epley maneuver, a simple and non-invasive treatment for BPPV. Given the high recurrence rate of BPPV, providing relief to patients using this approach is highly desirable. Patients can also be instructed on performing the Epley maneuver at home to manage recurrences.[1][6][16]

Enhancing Healthcare Team Outcomes

Vertigo is a prevalent and distressing symptom that can significantly impact a patient's quality of life. Due to the diverse range of conditions associated with vertigo and its frequent co-occurrence with nonspecific symptoms like nausea, dizziness, and imbalance, determining the underlying cause can be challenging.

When the etiology of vertigo is uncertain, seeking a specialty consultation is appropriate. Patients presenting with nonparoxysmal vertigo or vertigo accompanied by neurological deficits, such as truncal ataxia, should not undergo the Dix-Hallpike maneuver. These associated findings are concerning for central etiologies and warrant further neurologic evaluation. Improving healthcare professionals' understanding of promptly evaluating and treating vertigo will lead to better patient outcomes. 

For patients with an appropriate history and a positive Dix-Hallpike test, a diagnosis of BPPV can be established without further testing.[5][9] Routine vestibular testing and radiographic imaging should not be ordered for patients who meet the diagnostic criteria for BPPV.[9] In the absence of additional vestibular signs or symptoms inconsistent with BPPV, vestibular testing and imaging are associated with low yield and may result in false-positive diagnoses. Moreover, they can accrue additional costs, prolong the diagnostic process, and delay appropriate treatment.

Once a diagnosis of BPPV is made, treatment options such as the Epley maneuver and vestibular rehabilitation can be considered. Strong evidence exists for using the Epley maneuver to treat posterior canal BPPV. A meta-analysis conducted by the Cochrane Collaboration concluded that the Epley maneuver was an effective treatment for BPPV, although there was a high likelihood of symptom recurrence.[6] 

Nurse practitioners, physician assistants, and physicians should be familiar with the Dix-Hallpike maneuver and the Epley maneuver.

Additionally, an interprofessional team approach involving collaboration among healthcare professionals can enhance the evaluation and care of patients with vertigo, leading to optimal patient outcomes.