Interpreting executive and lower-order error scores on the timed subtests of the Delis-Kaplan Executive Function System (D-KEFS) battery: Error analysis across the adult lifespan.
OBJECTIVE
The Delis-Kaplan Executive Function System (D-KEFS) is a battery of tests designed to measure executive functions (EF). Additionally, the D-KEFS contains lower-order tasks, designed to control for speed of visual scanning, sequencing, and verbal and graphomotor output. The construct and criterion validities of D-KEFS scores that are time-based are well established. However, the constructs measured by the D-KEFS error scores are poorly understood, making clinical interpretations of such scores difficult. This study examined the construct validity of D-KEFS errors committed on EF tasks and tasks designed to measure lower-order processes (i.e., non-EF tasks), across the adult lifespan.


METHOD
Participants were 427 adults (18-93 years) who completed the timed subtests of the D-KEFS. Four hundred two participants also completed the Push-Turn-Taptap (PTT; a separate measure of EF) to allow cross-validation.


RESULTS
General linear regressions showed that D-KEFS errors committed on the EF tests were associated with EF timed performance (assessed using the D-KEFS time-based scores and the PTT), but only among older adults. Importantly, errors committed on the D-KEFS tasks of lower-order processes were also associated with D-KEFS time-based EF performance, and this relationship held across the adult lifespan.


CONCLUSIONS
These findings suggest that among older adults EF errors on the D-KEFS can be interpreted as indices of EF, but such interpretations are not automatically warranted for younger adults. Additionally, errors committed on non-EF tasks contained within the D-KEFS battery can be interpreted as reflecting EF weaknesses across the adult lifespan.
['Suchy|Yana|Y|', 'Mullen|Christine M|CM|', 'Brothers|Stacey|S|', 'Niermeyer|Madison A|MA|']
D000293:Adolescent D000328:Adult D000368:Aged D000369:Aged, 80 and over D056344:Executive Function D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D009483:Neuropsychological Tests D011594:Psychometrics D011597:Psychomotor Performance D055815:Young Adult
errors Executive functioning construct validity accuracy processing speed