Psychometric analysis of the short form UCLA Loneliness Scale (ULS-8) in people with Parkinson's disease

• Published in: Parkinsonism & related disorders Vol. 135; p. 107828
• Main Authors: Subramanian, Indu, McDaniels, Bradley, Zhou, Kaiqi, Mischley, Laurie K.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2025
• Subjects: Aged; CFA; Factor Analysis, Statistical; Female; Humans; Loneliness; Loneliness - psychology; Male; Middle Aged; Parkinson Disease - psychology; Parkinson's disease; Prospective Studies; Psychiatric Status Rating Scales - standards; Psychometrics - methods; Psychometrics - standards; Quality of life; Quality of Life - psychology; Reproducibility of Results; Loneliness; Parkinson's disease; Quality of life; CFA
• ISSN: 1353-8020; 1873-5126; 1873-5126
• DOI: 10.1016/j.parkreldis.2025.107828

Loneliness has recently been shown to be associated with worse motor and non-motor scores and Quality of Life (QOL) in people with Parkinson's disease (PWP), although a validated measure for use in this population has not yet been validated. The goal of this study was to assess the factor structure and structural validity of the UCLA Loneliness Scale (ULS-8) in a sample of PWP. The dataset was split randomly into two halves: the first for exploratory factor analysis (EFA) using bivariate correlation, the Kaiser-Meyer-Olkin (KMO) test, and Bartlett's test of sphericity, and the second for confirmatory factor analysis (CFA) to validate the factor structure identified by EFA. Exploratory factor analysis (EFA) on the first subset of 384 subjects identified a clear two-factor structure, supported by strong KMO (.90) and Bartlett's test of sphericity (χ2 = 94.234, df = 6, p < .01) results, suggesting the data were appropriate for factor analysis. Confirmatory factor analysis (CFA) on the second subset confirmed the two-factor structure with satisfactory model fit indices, validating the structural integrity of the scale. Correlation results indicated that one item (“I am an outgoing person”) should be excluded from the analysis, resulting in a 7-item instrument. The results of this psychometric validation study confirm the reliability and preliminary validity of a revised 7-item version of the ULS-8 scale for assessing loneliness in PWP. This study provides evidence for its utility in both clinical and research settings to assess and address loneliness effectively. •Cross-sectional studies have evidenced the relationship between loneliness and quality of life for people with Parkinson's disease.•No instruments to assess loneliness have been validated in people with Parkinson's disease.•Exploratory and confirmatory analyses provide evidence to support a modified, 7-item version of the 8-item UCLA Loneliness Scale (ULS-8) in PWP.•Clinically, the results of this study provide healthcare providers with a valuable tool to identify individuals at risk for loneliness, prompting timely interventions.