Validation of the Virtual MET as an assessment tool for executive functions.

The purpose of this study was to establish ecological validity and initial construct validity of a Virtual Multiple Errands Test (VMET) as an assessment tool for executive functions. It was implemented within the Virtual Mall (VMall), a novel functional video-capture virtual shopping environment. The main objectives were (1) to examine the relationships between the performance of three groups of participants in the Multiple Errands Test (MET) carried out in a real shopping mall and their performance in the VMET, (2) to assess the relationships between the MET and VMET of the post-stroke participant's level of executive functioning and independence in instrumental activities of daily living, and (3) to compare the performance of post-stroke participants to those of healthy young and older controls in both the MET and VMET. The study population included three groups; post-stroke participants (n = 9), healthy young participants (n = 20), and healthy older participants (n = 20). The VMET was able to differentiate between two age groups of healthy participants and between healthy and post-stroke participants thus demonstrating that it is sensitive to brain injury and ageing and supports construct validity between known groups. In addition, significant correlations were found between the MET and the VMET for both the post-stroke participants and older healthy participants. This provides initial support for the ecological validity of the VMET as an assessment tool of executive functions. However, further psychometric data on temporal stability are needed, namely test-retest reliability and responsiveness, before it is ready for clinical application. Further research using the VMET as an assessment tool within the VMall with larger groups and in additional populations is also recommended.