Po-Yi Chen1, Ya-Wen Jan2, Chien-Ming Yang3. 1. Department of Psychology University of Kansas, USA. 2. Sleep Research Center, Taipei Medical University Hospital, Taipei, Taiwan; Department of Psychology, National Chengchi University, Taipei, Taiwan. 3. Department of Psychology, National Chengchi University, Taipei, Taiwan; The Research Center for Mind, Brain, and Learning, National Chengchi University, Taipei, Taiwan. Electronic address: yangcm@nccu.edu.tw.
Abstract
OBJECTIVE: The purpose of this study was to examine whether the Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI) are valid outcome measures for Cognitive Behavioral Therapy for Insomnia (CBT-I). Specifically, we tested whether the factorial parameters of the ISI and the PSQI could remain invariant against CBT-I, which is a prerequisite to using their change scores as an unbiased measure of the treatment outcome of CBT-I. METHODS: A clinical data set including scores on the Chinese versions of the ISI and the PSQI obtained from 114 insomnia patients prior to and after a 6-week CBT-I program in Taiwan was analyzed. A series of measurement invariance (MI) tests were conducted to compare the factorial parameters of the ISI and the PSQI before and after the CBT-I treatment program. RESULTS: Most factorial parameters of the ISI remained invariant after CBT-I. However, the factorial model of the PSQI changed after CBT-I treatment. An extra loading with three residual correlations was added into the factorial model after treatment. CONCLUSIONS: The partial strong invariance of the ISI supports that it is a valid outcome measure for CBT-I. In contrast, various changes in the factor model of the PSQI indicate that it may not be an appropriate outcome measure for CBT-I. Some possible causes for the changes of the constructs of the PSQI following CBT-I are discussed.
OBJECTIVE: The purpose of this study was to examine whether the Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI) are valid outcome measures for Cognitive Behavioral Therapy for Insomnia (CBT-I). Specifically, we tested whether the factorial parameters of the ISI and the PSQI could remain invariant against CBT-I, which is a prerequisite to using their change scores as an unbiased measure of the treatment outcome of CBT-I. METHODS: A clinical data set including scores on the Chinese versions of the ISI and the PSQI obtained from 114 insomniapatients prior to and after a 6-week CBT-I program in Taiwan was analyzed. A series of measurement invariance (MI) tests were conducted to compare the factorial parameters of the ISI and the PSQI before and after the CBT-I treatment program. RESULTS: Most factorial parameters of the ISI remained invariant after CBT-I. However, the factorial model of the PSQI changed after CBT-I treatment. An extra loading with three residual correlations was added into the factorial model after treatment. CONCLUSIONS: The partial strong invariance of the ISI supports that it is a valid outcome measure for CBT-I. In contrast, various changes in the factor model of the PSQI indicate that it may not be an appropriate outcome measure for CBT-I. Some possible causes for the changes of the constructs of the PSQI following CBT-I are discussed.
Authors: Md Dilshad Manzar; Ahmed S BaHammam; Unaise Abdul Hameed; David Warren Spence; Seithikurippu R Pandi-Perumal; Adam Moscovitch; David L Streiner Journal: Health Qual Life Outcomes Date: 2018-05-09 Impact factor: 3.186