A first step towards objective grading of equine laryngeal function.

Area of Science:

• Veterinary Medicine
• Equine Science
• Diagnostic Imaging

Background:

• Veterinary disagreement in grading equine laryngeal function (LF) necessitates standardized diagnostic methods.
• Existing grading systems can be ambiguous, leading to inconsistent assessments.

Purpose of the Study:

• To develop and validate a diagnostic decision tree (DDT) for objective grading of resting equine laryngeal function (LF).
• To reduce ambiguity and improve consistency in LF grading among veterinarians.

Main Methods:

• Codified the Havemeyer grading system into a flowchart-based DDT.
• Used videoendoscopic examinations with unanimous LF grades from experienced observers to develop the DDT.
• Defined objective cut-off values for key parameters like left arytenoid cartilage (LAC) abduction duration and angle.

Main Results:

• The DDT provides a series of yes/no decisions to guide LF grade determination.
• Objective definitions were established for maintained full LAC abduction (≥0.2s) and partial abduction (≥45° vs <45°).
• The DDT offers a structured approach to LF assessment, potentially aiding computer-assisted grading.

Conclusions:

• The developed DDT offers a standardized, objective method for grading equine laryngeal function.
• Implementation of the DDT can enhance diagnostic consistency and reduce inter-observer variability.
• This tool serves as a foundational step towards automated laryngeal function assessment in horses.