Inter-rater Agreement for the Clinical Dysphagia Scale

Area of Science:

• Neurology
• Speech-Language Pathology
• Medical Diagnostics

Background:

• Dysphagia assessment is crucial for patient outcomes.
• The Clinical Dysphagia Scale (CDS) is a bedside tool for evaluating swallowing difficulties.
• Ensuring high inter-rater reliability is essential for consistent clinical application.

Purpose of the Study:

• To evaluate the inter-rater agreement of the Clinical Dysphagia Scale (CDS).
• To explore methods for enhancing the reliability and validity of the CDS.
• To compare CDS performance in stroke versus non-stroke patients.

Main Methods:

• Two independent raters assessed 67 subjects before video-fluoroscopic swallowing studies (VFSS).
• Inter-rater agreement was calculated for individual items and total scores using intraclass correlation coefficients (ICC) and Cohen's kappa (κ).
• Item subtraction and modification of rating criteria were tested to improve agreement and validity.

Main Results:

• Excellent overall inter-rater agreement was found for the total CDS score (ICC: 0.886).
• Four items showed less than excellent agreement; however, item subtraction did not improve overall reliability.
• Refining the 'history of aspiration' and 'lesion location' items significantly enhanced inter-rater agreement (ICC: 0.912, 0.888) and validity.

Conclusions:

• The Clinical Dysphagia Scale (CDS) demonstrates good reliability as a bedside swallowing assessment tool.
• Modifying specific items, particularly 'history of aspiration' and 'lesion location,' can improve the CDS's inter-rater agreement and validity.
• The CDS showed higher agreement and validity in stroke patients compared to non-stroke populations.