Development of Differential Diagnosis Scale Items for Adductor Spasmodic Dysphonia and Evaluation of Clinical Availability

ABSTRACT

BACKGROUND AND OBJECTIVES@#The purpose of this study was to develop the differential diagnosis scale containing items from adductor spasmodic dysphonia (ADSD) to muscle tension dysphonia (MTD) and the determine clinical utility of newly developed items.MATERIALS AND METHOD: The four parts of pitch, redirected phonation, automatic speech and voiced sound were selected for analyzing the characteristics of ADSD in the literature. One part of tense voiceless sound was developed according to the Korean manner of articulation. The content validity was evaluated based on 5 scales (1–5 point) analysis from 30 experts. One hundred patients (50 ADSD and 50 MTD) were recorded in reading a sentence and sustained phonation. The two speech language pathologist evaluated recorded voices through a blind test using 4 scales (0–3 point) for newly developed items.@*RESULTS@#As a result of verifying the content validity of items with experts, it was identified that the differentiated items were valid with 4.2 out of 5. Through the differential diagnosis between two groups according to the items, the correlation between sub-domains and total scores was shown as higher than 0.710. The result of analyzing the reliability on each diagnosis domain was 0.840–0.893, which showed the internal consistency of items was great. Newly developed five parts of ADSD were significantly higher than those of MTD with strong correlation (p<0.01). The reliability among the evaluators was analyzed as high with 0.892.@*CONCLUSION@#In this study, the differential diagnosis scale of ADSD was revealed as having validity and reliability. It is considered that it will be useful for differentiating ADSD and MTD in the clinical field.