Abstract
METHODS
In this international validation study, we evaluated the EORTC IADL-BN32 questionnaire on several psychometric properties in a large sample of patients with a primary or metastatic brain tumour. We administered the 32-item questionnaire three times: at 'baseline', after 2 weeks and after 3 months. Procedures were in accordance with EORTC Quality of Life Group module development guidelines.
CONCLUSION
Overall, the EORTC IADL-BN32 questionnaire exhibited adequate to excellent psychometric properties. Cross-cultural validity and responsiveness should be further explored.
RESULTS
In total, 326 patients participated in the study. A bifactor scale structure showed satisfactory model fit measures, with five multi-item scales and two single items, and an IADL sum score. The internal consistency of the multi-item scales ranged from good to excellent (range Cronbach's α: 0.86-0.97). We found significant differences in scale scores between patients with and without neurocognitive impairments or complaints, supporting the construct validity. Initial cross-cultural validity analyses showed indications of item response biases for certain items. Analyses indicated moderate to good test-retest agreement (intraclass correlation coefficient > 0.70) between baseline and the 2-week follow-up assessment for all but one scale. Deterioration of EORTC IADL-BN32 scale scores were consistent with clinically relevant deterioration on other functional measures with small to large effect sizes, however, subgroup sample sizes were small.
BACKGROUND
Neurocognitive impairments are common in patients with a brain tumour, and may negatively impact on functioning in daily life, particularly on instrumental activities of daily living (IADL). The EORTC IADL-BN32 questionnaire was developed to measure IADL in this patient population.