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.
