Considerations in preparing a multicenter study: Lessons learned from the Epilepsy Monitoring Unit Comfort...

It is recommended to perform a pilot testing before conducting a validation study of a novel questionnaire. Pilot studies may serve different purposes. The aim of this study was to assess the feasibility of a multicenter validation study, to recruit additional study centers, and to undertake orientating descriptive item analysis of the 44-item Epilepsy Monitoring Unit (EMU) Comfort Questionnaire (EMUCQ).

During a six-month sampling period, the EMUCQ was administered to eligible EMU patients. The patients filled out the questionnaire at two time points. Additional centers were recruited in Germany and Austria, and ethics votes obtained. In descriptive item analysis central tendency, variability, item distribution and item difficulty were calculated.

A total of 44 EMU patients participated in the study. Eight additional EMUs agreed to join the planned validation study. Recruitment of the centers took four months. Another six months passed to obtain all the ethics votes. Floor and ceiling effects could be detected in 32 items. One item with the lowest median showed the low item difficulty. Another five items showed medians with the height of 6. In four items, high difficulty indices could be observed.

A good network has turned out to be very helpful while planning a multicenter study. Enough time must be scheduled, because obtaining an ethics vote may take quite a long time. No conclusive statements regarding item properties could be made as this was a feasibility study.