Content Validity and Intra-Inter Reliability of the Turkish Version of the Murray Secretion Scale

In healthy individuals, secretions are typically managed through reflexive swallowing or coughing. Impairments in sensory or motor function, however, may hinder laryngo-pharyngeal clearance, leading to hypopharyngeal secretion accumulation and compromised swallowing safety. This study aimed to translate the Murray Secretion Scale into Turkish (MSS-TR) and to evaluate its content validity and inter- and intra-rater reliability. The primary goal was to determine whether the Turkish version of the scale is a reliable and valid tool for clinical use in assessing pharyngolaryngeal secretion severity during fiberoptic endoscopic evaluation of swallowing (FEES).

The study involved a multi-step process: (1) translation and back-translation of the original Murray Secretion Scale, (2) expert review to establish content validity using the Content Validity Index (CVI) and (3) reliability testing using 40 FEES recordings assessed by four experienced speech-language therapists. Intra-rater reliability was evaluated via the Wilcoxon signed-rank test and Kendall's τ_b, while inter-rater reliability was assessed using Fleiss' Kappa and percentage agreement.

Content validity was confirmed with a CVI of 0.86 for the overall scale, with the highest agreement (CVI = 1.00) for the most severe score category. Intra-rater analyses showed no significant differences between repeated evaluations (p > 0.05) and demonstrated high ordinal consistency (Kendall's τ_b: 0.933-1.000). Inter-rater reliability was substantial to almost perfect for all score levels, with Fleiss' Kappa values ranging from 0.634 to 0.862 across sessions. The overall percentage agreement among raters was 94.4%. However, grade 2 on the MSS-TR showed slightly lower levels of compliance, indicating potential clinical uncertainty in this category.

The MSS-TR showed strong content validity and high intra- and inter-rater reliability, supporting its use as a standardized instrument in Turkish clinical practice. These data indicate that the scale can reliably evaluate secretion severity during swallowing assessments, aiding clinical decision-making in dysphagia management. Additional research is necessary to investigate how it applies across various patient populations and clinical settings.

What is already known on this subject The Murray Secretion Scale (MSS) is a widely used tool for assessing the severity of secretions during fiberoptic endoscopic evaluation of swallowing (FEES). Before this study, a Turkish version of the MSS with verified content validity for use in Turkish-speaking clinical settings did not exist. Standardized secretion severity ratings improve consistency in dysphagia evaluation and allow consistent reporting across studies and clinical environments. Consistent assessment of mid-range secretion levels may be challenging and could necessitate clinician training and calibration. What this paper adds to existing knowledge This study introduces the first Turkish translation and cultural adaption of the MSS (MSS-TR), addressing the lack of a standardized tool for assessing secretion severity among Turkish-speaking clinicians. The MSS-TR shown strong content validity and high intra- and inter-rater reliability, supporting its application as a reliable clinical and research tool during FEES. Findings suggest that moderate secretion severity (Grade 2) may present significant issues for clinical interpretation, highlighting the importance for clinician training and calibration in the use of the scale. The validated Turkish version of the MSS aims to improve standards in dysphagia evaluation, support clinical decision-making and facilitate international comparison of FEES-based research results. What are the potential or actual clinical implications of this work? The MSS-TR enables a systematic assessment of secretion severity in Turkish FEES practice, improving documentation and supporting clinical decision-making in dysphagia management. Routine use of MSS-TR may improve communication among clinicians and institutions, as well as support training, standardization and quality assurance procedures. A validated MSS-TR supports international comparison and multi-centre FEES research through standardized secretion reporting.