Measuring quality of life in ALS/MND: validation of the WHOQOL-BREF.

The World Health Organization Quality of Life-BREF Scale (WHOQOL-BREF) is a generic QOL measure with four domains covering Physical, Psychological, Social and Environment. Providing the opportunity to contrast QoL with other conditions, or with population norms, the current study had three aims: 1) can the established domains of the WHOQOL-BREF be validated within a large ALS/MND population; 2) can a total score be validated and 3) can they provide interval level measurement? Data were obtained from the Trajectories of Outcomes in Neurological Conditions study. Internal construct validity was determined by fit of the data to the Rasch measurement model. 636 participants with ALS/MND were included. All domains, except the Social domain, showed satisfactory fit to the Rasch model. All were unidimensional, and showed no Differential Item Functioning by age, gender, or onset type. Finally, a total score was validated from a bi-factor perspective. The WHOQOL-BREF is valid for use in populations with ALS/MND and can be analyzed to yield interval level measurement: It offers a range of domains that reflect QOL, which can be used for parametric analysis and for comparison with other conditions or general populations, two advantages for its inclusion as a trial outcome measure and for observational studies.