Coimbra sleep activation scale (C-SAS): Psychometric properties in insomniacs

Abstract

Hyper-arousal processes are believed to have an important role in the pathophysiology of primary insomnia, and are also a maintaining factor in co-morbid insomnia. Our purpose is to present the psychometric proprieties of a Portuguese instrument developed to access arousal in insomnia, originated from vast clinical experience, which may be useful in clinical practice: the Coimbra Sleep Activation Scale (C-SAS). A clinical sample was collected consisting of 100 selected participants (60 M and 40 F), 22–72 years-old (M = 45.14, DP = 12.54), followed at a Sleep Medicine Centre, that did not fulfill criteria for a sleep disorder other than insomnia, and with no missing answers on the self-reported measures. The C-SAS is composed by 31 items, each one rated on a 5-point Likert scale, reported to the last month. The Insomnia Severity Index scale (ISI) was used to assess the severity of the insomnia. Cronbach’s alpha for the C-SAS was.921, indicating a robust internal consistency. All items, except one, contributed to the internal consistency as shown by alpha values excluding each item. Corrected item-total correlations ranged from.29 to.69. An exploratory factor analysis using Varimax rotation and visual inspection of the Scree plot, yield four meaningful factors explained 51.53% of the total variance. A moderate significant correlation was found between C-SAS and ISI scores ( r = .298, p < 0.01), suggesting that, although sleep activation is associated with insomnia severity, the two sleep measures have some independence. The results of the present study, albeit preliminary, suggest an adequate validity and internal consistency of the C-SAS in a clinical sample of insomniacs. However, future psychometric studies are needed in order to expand our knowledge about its validity and reliability using other samples. Insomniac patients followed at the Sleep Medicine Centre of Coimbra University Hospital Centre (CHUC).