Confirmatory Factor Analysis of the Portuguese Version of the Arousal Predisposition Scale

Abstract

The Arousal Predisposition Scale (APS) is an instrument aimed to assess individual differences in self-reported arousability, specifically physiologically arousal. Besides, it is a scale frequently used in stress and sleep-related researches. The principal purpose of this study is to determine the factor structure of the APS through confirmatory factor analysis (CFA) and to test the goodness-of-fit of one- and two-factor models. A sample of 341 undergraduate medical students of both genders aged 17 to 25 years was enrolled. Beyond the APS, the participants also filled out the Portuguese versions of the Pre-Sleep Arousal Scale (PSAS), Ford Insomnia Response to Stress Test (FIRST) and the Neuroticism scale of Eysenck Personality Inventory (EPI) for concurrent validity purposes. From the studied solutions, a modified two-factor model (F1 = emotional reactivity and F2 = trait anxiety) achieved the better fit to the data. The Portuguese version of the APS was also significantly correlated with measures of neuroticism, insomnia, sleep reactivity to stress, and cognitive and somatic arousal. The two-factor modified model appears to display a superior fit to the data, supporting a scoring model of the APS according to two different factors as suggested by a previous research on the Portuguese version. This study supports reliability and validity indicators of the APS and its use in research and applied settings.