Bow and lean test reconsidered: anatomy, predictions, and a data visualization method for horizontal canal BPPV.

Area of Science:

• Neurology
• Otolaryngology
• Vestibular System Anatomy

Background:

• Lateralizing the affected side in horizontal canal benign paroxysmal positional vertigo (BPPV) presents diagnostic challenges.
• Current diagnostic methods often rely on anatomical models that inaccurately represent the horizontal canal's posteromedial segment.

Purpose of the Study:

• To compare diagnostic predictions based on hypothetical versus true horizontal canal anatomy.
• To demonstrate how the true anatomical model can differentiate between affected sides in horizontal canal BPPV.

Main Methods:

• Comparative analysis of predictive models based on hypothetical and actual horizontal canal anatomy.
• Simulation of roll maneuvers (supine to side-lying to prone) using the true anatomical model.
• Analysis of predicted nystagmus patterns for each affected side.

Main Results:

• Models based on hypothetical anatomy yield different predictions than those based on true anatomy.
• The true anatomical model predicts distinct nystagmus patterns for left vs. right horizontal canal BPPV during specific roll maneuvers.
• These distinct patterns allow for accurate lateralization of the affected side.

Conclusions:

• The true anatomical model of the horizontal canal is crucial for accurate BPPV diagnosis.
• A proposed roll maneuver utilizing the true anatomical model effectively lateralizes the affected side.
• This finding has significant implications for targeted BPPV treatment.