Diagnostic utility of the Key Search Test as a measure of executive functions.

Background: Executive function deficits are commonly observed in many clinical populations, highlighting the importance of appropriate diagnostic tools to screen for these deficits. Most neuropsychological tests of executive function, however, are time-consuming and difficult to administer in the case of moderate to severe cognitive decline. The aim of the present study was to examine whether the Key Search Test, a short and easy to administer test, is a useful indicator of executive function deficits in a study sample with a diagnosis of cognitive impairment.
Methods: Participants consisted of elderly people visiting the memory clinic at the department of geriatrics of a university medical center (n= 140) and of elderly controls (n= 37). Next to the Key Search Test, other executive function tests and a memory test were administered.
Results: Low to moderate correlations were found between the Key Search Test and other executive function tests. Furthermore, although the Key Search Test discriminated significantly between intact and impaired executive function (AUC = 0.677, P < 0.001), sensitivity and specificity were low and no optimal cut-off point could be determined.
Conclusion: The Key Search test might not be an appropriate measure of executive functions in cognitively impaired individuals.
(© 2010 The Authors. Psychogeriatrics © 2010 Japanese Psychogeriatric Society.)