The Flinders Fatigue Scale: preliminary psychometric properties and clinical sensitivity of a new scale for measuring daytime fatigue associated with insomnia.
OBJECTIVE
To evaluate the psychometric properties and clinical significance of a new scale for measuring daytime fatigue associated with insomnia: The Flinders Fatigue Scale (FFS).


METHODS
The 7-item FFS was used in two separate studies. Study 1 was an on-line validation study involving 1093 volunteers (mean [SD] age = 38.6 [14.7] y, 626 poor sleepers, 467 good sleepers) in a cross-sectional design; Study 2 investigated the clinical sensitivity of the FFS on 113 insomnia patients (mean [SD] age = 48.3 [15.0] y) in response to a 5-week cognitive-behavior therapy for insomnia (CBT-I) program.


RESULTS
The FFS had an internal consistency of 0.91; it comprised a single factor, accounting for 67% of the total variance. Poor sleepers in Study 1 scored significantly higher than good sleepers on the FFS (p < 0.0001). In Study 2, significant reductions in FFS scores were found in response to CBT-I (p < 0.0001). These reductions in fatigue correlated with improvements on subjective sleep parameters (all p < 0.0001). The FFS showed good discriminant validity with the Epworth Sleepiness Scale.


CONCLUSIONS
The Flinders Fatigue Scale is a brief, clinically sensitive measure with strong psychometric properties.
Gradisar
Michael
M
School of Psychology, Flinders University, Adelaide, South Australia. grad0011@flinders.edu.au
Lack
Leon
L
Richards
Hayley
H
Harris
Jodie
J
Gallasch
Julie
J
Boundy
Michelle
M
Johnston
Anna
A
D000328:Adult; D015928:Cognitive Behavioral Therapy; D003430:Cross-Sectional Studies; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis* / Q000523:psychology / Q000628:therapy; D005221:Fatigue / Q000175:diagnosis* / Q000523:psychology / Q000628:therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011594:Psychometrics / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D007319:Sleep Initiation and Maintenance Disorders / Q000175:diagnosis* / Q000523:psychology / Q000628:therapy; D013021:South Australia; D011795:Surveys and Questionnaires; D016896:Treatment Outcome