Development and reliability of the revised Patterson Edema Scale

Abstract

Objective: The Patterson Edema scale was developed in 2007 to address the lack of a reliable, sensitive scale to measure laryngeal and pharyngeal oedema in patients with head and neck cancer. The objective of this study was to revise the existing Patterson scale to improve its reliability and utility.

Design: Prospective investigation.

Setting: Academic medical center.

Participants: Speech-Language Pathologists, Otolaryngologists, and Radiation Oncologists.

Main outcome measures: Ratings using the Revised Patterson Edema Scale.

Methods: A consensus group reviewed existing literature regarding the performance of the original Patterson scale and revised the existing scale in regard to items to be included and descriptors for each severity level. The scale was then utilised by 18 speech language pathologists from the US and UK with >2 years-experience working with dysphagia and dysphonia with endoscopy. Each SLP rated a total of eight parameters (epiglottis, vallecula, pharyngoepiglottic folds, aryepiglottic folds, arytenoids, false vocal folds, true vocal folds and pyriform sinuses) using the Revised Patterson Edema Scale. Feedback was solicited from raters regarding areas where clarity was lacking for further scale revision. Scale revisions were completed and additional ratings were completed by otolaryngologists, radiation oncologists and less experienced SLP providers to establish reliability across disciplines. Quadratic weighted Kappa values were obtained to establish interrater reliability.

Results: Feedback received from raters included suggestions for clarification of how to rate unilateral oedema, use of a standard task battery to visualise and rate structures consistently, and clarification of true vocal fold oedema rating parameters. Overall interrater reliability was established using quadratic weighted Kappa with good agreement noted for the epiglottis, vallecula, arytenoids and false vocal folds; moderate agreement noted for aryepiglottic folds, pharyngoepiglottic folds and pyriform sinuses; and fair agreement noted for true vocal folds.

Conclusions: The Revised Patterson Edema Scale demonstrates moderate-substantial interrater reliability for most parameters across multiple disciplines and experience levels, with the exception of the true vocal folds where agreement was fair. We believe the Revised Patterson Oedema Scale provides a reliable tool for clinicians and researchers to rate oedema in the supraglottic larynx and pharynx following treatment for head and neck cancer.

Keywords: flexible laryngoscopy; head and neck cancer; laryngeal edema; lymphedema.