AN INSTRUMENT TO MEASURE FUNCTIONAL STATUS OUTCOMES FOR DISORDERS OF EXCESSIVE SLEEPINESS

This article reports the development of the functional outcomes of sle ep questionnaire (FOSQ). This is the first self-report measure designe d to assess the impact of disorders of excessive sleepiness (DOES) on multiple activities of everyday living. Three samples were used in the development and psychometric analyses of the FOSQ: Sample 1 (n = 153) consisted of individuals seeking medical attention for a sleep proble m and persons of similar age and gender having no sleep disorder; samp les 2 (n = 24) and 3 (n = 51) were composed of patients from two medic al centers diagnosed with obstructive sleep apnea (OSA). Factor analys is of the FOSQ yielded five factors: activity level, vigilance, intima cy and sexual relationships, general productivity, and social outcome. Internal reliability was excellent for both the subscales (alpha = 0. 86 to alpha = 0.91) and the total scare (alpha = 0.95). Test-retest re liability of the FOSQ yielded coefficients ranging from r = 0.81 to r = 0.90 for the five subscales and r = 0.90 for the total measure. The FOSQ successfully discriminated between normal subjects and those seek ing medical attention far a sleep problem (T-157 = -5.88, p = 0.0001). This psychometric evaluation of the FOSQ demonstrated parameters acce ptable for its application in research and in clinical practice to mea sure functional status outcomes for persons with DOES. Thus, the FOSQ can be used to determine how disorders of excessive sleepiness affect patients' abilities to conduct normal activities and the extent to whi ch these abilities are improved by effective treatment of DOES.