Kate Cameron1, Paul Williamson1, Michelle A Short2, Michael Gradisar3. 1. School of Psychology, Flinders University, South Australia, Australia. 2. School of Psychology, Flinders University, South Australia, Australia; Centre for Sleep Research, University of South Australia, South Australia, Australia. 3. School of Psychology, Flinders University, South Australia, Australia. Electronic address: michael.gradisar@flinders.edu.au.
Abstract
STUDY OBJECTIVES: To clinically validate the Flinders Fatigue Scale (FFS) as a brief measure of daytime fatigue, and to derive cut-off scores to classify fatigue severity. METHOD: The FFS was administered to 439 adult volunteers from the general population, 292 adults with insomnia, 132 adults with Obstructive Sleep Apnoea (OSA) and 66 adults with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME), together with the Fatigue Severity Scale (FSS) and the Epworth Sleepiness Scale (ESS). RESULTS: A factor analysis revealed a single factor solution for the seven-item scale (67% of total variance), although a better fit was obtained for a modified six-item version (75% of total variance). Group FFS scores varied in accordance with theorised fatigue levels, with CFS/ME and insomnia samples reporting significantly higher fatigue than OSA and volunteer samples. Good convergent validity was established with the FSS for volunteer (r = 0.67) and CFS/ME samples (r = 0.61). Excellent discriminant validity with the ESS was observed for the insomnia (r = -0.08) and CFS/ME groups (r = 0.03), while a small-to-moderate correlation was found within the volunteer sample (r = 0.29). Cut-off scores were identified to categorise borderline (13-15), moderate (16-20) and severe (≥21) fatigue. CONCLUSIONS: The FFS is a reliable and valid instrument to quantify subjective daytime fatigue. Sensitivity and specificity analyses indicate scores that best discriminate insomniacs and CFS/ME populations from a non-clinical population. However, it is proposed that the data can also be used to indicate the severity of fatigue by reference to these first two groups.
STUDY OBJECTIVES: To clinically validate the Flinders Fatigue Scale (FFS) as a brief measure of daytime fatigue, and to derive cut-off scores to classify fatigue severity. METHOD: The FFS was administered to 439 adult volunteers from the general population, 292 adults with insomnia, 132 adults with Obstructive Sleep Apnoea (OSA) and 66 adults with Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME), together with the Fatigue Severity Scale (FSS) and the Epworth Sleepiness Scale (ESS). RESULTS: A factor analysis revealed a single factor solution for the seven-item scale (67% of total variance), although a better fit was obtained for a modified six-item version (75% of total variance). Group FFS scores varied in accordance with theorised fatigue levels, with CFS/ME and insomnia samples reporting significantly higher fatigue than OSA and volunteer samples. Good convergent validity was established with the FSS for volunteer (r = 0.67) and CFS/ME samples (r = 0.61). Excellent discriminant validity with the ESS was observed for the insomnia (r = -0.08) and CFS/ME groups (r = 0.03), while a small-to-moderate correlation was found within the volunteer sample (r = 0.29). Cut-off scores were identified to categorise borderline (13-15), moderate (16-20) and severe (≥21) fatigue. CONCLUSIONS: The FFS is a reliable and valid instrument to quantify subjective daytime fatigue. Sensitivity and specificity analyses indicate scores that best discriminate insomniacs and CFS/ME populations from a non-clinical population. However, it is proposed that the data can also be used to indicate the severity of fatigue by reference to these first two groups.
Authors: Alice Y Tu; Megan R Crawford; Spencer C Dawson; Louis F Fogg; Arlener D Turner; James K Wyatt; Maria I Crisostomo; Bantu S Chhangani; Clete A Kushida; Jack D Edinger; Sabra M Abbott; Roneil G Malkani; Hrayr P Attarian; Phyllis C Zee; Jason C Ong Journal: J Clin Sleep Med Date: 2022-03-01 Impact factor: 4.062
Authors: Y Laurisa Arenales Arauz; Gargi Ahuja; Ype P T Kamsma; Arjan Kortholt; Eddy A van der Zee; Marieke J G van Heuvelen Journal: Biology (Basel) Date: 2022-08-19