Inter-rater Agreement for the Clinical Dysphagia Scale

Abstract

Objective To investigate the inter-rater agreement for the clinical dysphagia scale (CDS). Method Sixty-seven subjects scheduled to participate in a video-fl uoroscopic swallowing study (VFSS) were preexamined by two raters independently within a 24-hour interval. Each item and the total score were compared between the raters. In addition, we investigated whether subtraction of items showing low agreement or modifi cation of rating methods could enhance inter-rater agreement without signifi cant compromise of validity. Results Inter-rater agreement was excellent for the total score (intraclass correlation coefficient (ICC): 0.886). Four items (lip sealing, chewing and mastication, laryngeal elevation, and reflex coughing) did not show excellent agreement (ICC: 0.696, 0.377, 0.446, and : 0.723, respectively). However, subtraction of each item either compromised validity, or did not improve agreement. When redefi ning 'history of aspiration' and 'lesion location' items, the inter-rater agreement (ICC: 0.912, 0.888, respectively) and correlation with new videofluoroscopic dysphagia score (PCC: 0.576, 0.577, respectively) were enhanced. Th e CDS showed better agreement and validity in stroke patients compared to non-stroke patients (ICC: 0.917 vs 0.835, PCC: 0.663 vs 0.414).