Dimensionality of the Pittsburgh Sleep Quality Index: a systematic review

Abstract

BackgroundThe Pittsburgh Sleep Quality Index (PSQI) dimensionality is much debated, with the greatest number of reported factor structures. Therefore, this review appraised the methodologies of studies investigating the factor structure of the PSQI.Material and methodsMEDLINE, PsycInfo, AJOL, BASE, Cochrane Library, Directory of Open Access Journals (Lund University), CINAHL, and Embase were searched systematically to include articles published till 23rd March, 2018. The articles with the objective of factor analysis of the PSQI (20 articles) or with a major section on the same subject (25 articles) were included. There was no limitation about participant characteristics. Descriptive analysis of articles for measures of the suitability of the data for factor analysis, details of the exploratory factor analysis (EFA) and details of the confirmatory factor analysis (CFA) was performed.ResultsThe analysis used by the majority did not employ the simplest scheme for interpreting the observed data: the parsimony principle. Other shortcomings included under- or non-reporting of sample adequacy measures (11 out of 45 articles), non-use of EFA (20 out of 45 articles), use of EFA without relevant details, non-use of CFA (11 out of 45 articles), and use of CFA without relevant details. Overall, 31 out of 45 articles did not use either EFA or CFA.ConclusionWe conclude that the various PSQI factor structures for standard sleep assessment in research and clinical settings may need further validation.Trial registrationNot applicable because this was a review of existing literature.

Psychometric Properties of the Athens Insomnia Scale in Occupational Computer Users

“…The principal axis factoring method of factor extraction, along with Promax rotation (Kaiser normalization), was used in EFA. According to standard practices, multiple methods of factor retention, namely, the cumulative variance explained rule (>40%), Kaiser's criteria (eigenvalue ≥1), Scree test and the robust parallel analysis based on minimum rank were used [20]. A parallel analysis with minimum rank was performed using Factor 10.8.04, and MS Excel was used to generate the graph from the tabular outcome.…”

“…In brief, comparative CFA was performed on these models; model-A: 1-factor (Soldatos et al [16]; Gomex-Benito et al [21]), model-B: 2-factor model (Chung et al [22]; Yen et al [23]), model-C: 2-factor (Okajima et al [24]) and model-D: 3-factor model (EFA finding in this study). According to recommended norms, fit indices from multiple categories were used [20,25]. Three absolute fit indices, i.e., Akaike's information criterion (AIC), goodness-of-fit index (GFI), and χ 2 , χ 2 /df, were used.…”

“…A non-centrality-based index, namely, the comparative fit index (CFI) was employed. Additionally, a relative fit index called Bollen's incremental fit index (IFI) was also used [20,25]. For χ 2 /df, a value equal or less than 3 indicated an acceptable fit [26].…”

“…For χ 2 /df, a value equal or less than 3 indicated an acceptable fit [26]. For, each of these, i.e., CFI, IFI, and GFI a value equal to or above 0.95 indicated excellent fit, while a value equal to or above 0.90 indicated acceptable fit [20,26]. A non-significant χ 2 -test was taken as suggestive of absolute fit [20,26].…”

Efficacy and Safety of Electro-Acupuncture (EA) on Insomnia in Patients with Lung Cancer: Study Protocol of a Randomized Controlled Trial

“…As the most rigorously validated sleep healthy assessment tool, PSQI is a self-rated questionnaire used to assess sleep quality and disturbance over a 1-month time interval. It consists of 24 items to be rated, 19 of which are self-reported and 5 of which are required secondary feedback from a room or bed partner [18]. The seven components are subjective sleep quality, sleep latency, sleep duration, habitual sleep e cacy (SE), sleep disturbance, use of sleeping medication, and daytime dysfunction.…”