Psychometric Properties of the Arabic Version of Yale Global Tic Severity Scale (YGTSS)

Abstract

Introduction: Tic is a sudden, repetitive, nonrhythmic motor movement or vocalization including a separated group of muscles. Aim: Assess the validity and reliability of Arabic version of the Yale Global Tic Severity Scale (YGTSS). Methods: Methodological design was utilized to investigate Content Validity Index (CVI) reported by nine experts. Intra-class correlation coefficient ICC (Interrater and Intrarater Agreement) and Cronbach’s alpha reliability coefficients were addressed to investigate reliability. Results: CVI of clarity and relevance for each item ranged from 0.67 to 1. Predominance score of clarity and relevance was = 0.89 for most of items. Total CVI= 0.88. Cronbach’s alpha reliability coefficients for the Total Motor Tic Score =0.84, Total Vocal Tic Score =0.91, and Total Tic Score =0.80. ICC (Interrater agreement) of YGTSS regarding; motor tics, vocal tics, impairment and total severity score were (r= 0.72, 0.98, 0.88, and 0.97 respectively). ICC (Intra-rater agreement) of YGTSS regarding; motor tics, vocal tics, impairment and total severity score were = 0.96, 0.97, 1, and 0.96; respectively. Conclusion: The current Arabic Version is highly valid and reliable. Implications for Practice: Use of current Arabic version of YGTSS to assess severity of tics.