A summary of “An Abbreviated Diagnostic Maneuver for Posterior Benign Paroxysmal Positional Vertigo”, Michael, P.,  et al (2016).

 

 

The authors of this article report that canalothiasis (free floating otoconia) of the posterior canal is the most common single cause of vertigo.  Treatments are easy, inexpensive, safe and effective, yet people wait months to years without proper diagnosis and treatment. The authors theorize that this may be due to the difficulty (perceived or real) of performing the Dix-Hallpike maneuver, which requires and examination table and the patient being placed in the supine head hanging position at least twice.

They offer an alternative to the Dix-Hallpike maneuver that does not require an examination table. In this abbreviated modification of the Dix-Hallpike, the patient in seated in a sturdy chair with a back. The patient sits on the front edge of the chair, turns their head to the side being examined, and leans back extending their head over the back of the chair. No video goggles or Frenzel lenses are used in the study, as the authors wanted to measure the utility of this maneuver in a typical primary care practice setting.  (Editors note: Nystagmus associated with posterior canal BPPV is visible to the naked eye).

Patient with suspected BPPV first underwent the abbreviated version, then came back on another day to undergo the traditional Dix-Hallpike maneuver. This removed the impact of a fatigued response related to repeated stimulation on the same day.

In this study, a positive response on the abbreviated maneuver was compared to a positive response on a traditional Dix-Hallpike with the benefit of video goggles. In the abbreviated maneuver, a positive response included nystagmus and/or unilateral symptoms triggered by the maneuver. For the traditional Dix-Hallpike, only a nystagmus response was considered positive.

Findings: 

When using the criteria of nystagmus or unilateral symptoms on the abbreviated maneuver, it was 80% predictive of a positive traditional Dix-Hallpike. When only considering the presence of nystagmus on the abbreviated maneuver, it was 50% predictive.  Of those with unilateral symptoms, but no visible nystagmus on the abbreviated maneuver, 30 of 31 patients had a positive Dix-Hallpike on follow up. Of those patients in the study with a history suspicious for BPPV, but no nystagmus or unilateral symptoms on the abbreviated maneuver, none had a positive Dix-Hallpike.

The authors state that the abbreviated maneuver “showed fair sensitivity (80%) and high specificity (96%)” when considering either triggered nystagmus and/or unilateral positional subjective dizziness or vertigo to be the diagnostic criteria for suspected (posterior canal) pc-BPPV.

Opinion:

These results are both logical and impressive. This technique needs to be studied and independently verified, but I think it holds great promise as part of a movement to improve the diagnostic efficiency in the Emergency Department and Primary Care setting.

 

 

 

 

BPPV (Benign Paroxysmal Positional Vertigo) is the most common cause of vertigo and dizziness complaints. It is generally easily treated once identified, as long as it happens to affect the posterior canal. In fact, it seems that many people are self diagnosing and going to the internet for home treatment instructions. Many physicians are sending people home with exercises for suspected BPPV, assuming that posterior canal BPPV is the source of the patient’s complaint, most often without having performed any exam for BPPV.

A few years ago, I did a post here regarding published statistics associated with BPPV. Among other disturbing statistics, I posted this: “ Despite the high incidence of BPPV, testing for positional vertigo is still rare (<10%) in the primary care setting (Polensek, 2008).” In a large study regarding management of dizzy patients seen in the Emergency Department, only 4% of patients complaining of dizziness underwent positional testing that may identify BPPV. Frankly, given the high incidence of BPPV in the general population, and the over 90% preponderance of posterior canal involvement, I can understand the reasoning behind this. Working at a large university medical center/teaching hospital, we tend to see the patients that do not respond positively to this approach, so our viewpoint may be skewed. We see many patients with less easily treated variations of BPPV, and some with positional vertigo due to worrisome brain and brainstem pathology. Basically, if they got better doing the home exercises, they don’t make an appointment with us.

BPPV can occur in any of the three semi-circular canals, and treatment differs depending on the involved canal. The offending canal can be identified with a positive positional test, based on the pattern of eye movements (nystagmus) seen during the episode of vertigo. Always keep in mind that a negative test does not rule out BPPV as the source of the patient’s complaint. As noted above, occasionally we see nystagmus pointing to dysfunction in the brainstem (of course our suspicions can only be confirmed through imaging of the brain and neurology examination).

Where am I going with all this? The Dix-Hallpike exam is a quick, simple, effective test to identify nystagmus that can help the examiner determine the cause of the vertigo complaint, yet it seems that it is still not part of the routine exam for dizziness. My next post will review a recently published study examining this issue, and offering some suggestions to hopefully increase the percentage of dizzy patients being offered positional testing.