ABSTRACT
This study provides observed base rates of low executive functioning test scores among healthy children and adolescents, stratifies those base rates by narrow intellectual functioning and age groupings, and provides normative classification ranges to aid the interpretation of performances on the Delis-Kaplan Executive Function System (D-KEFS) in clinical practice and research. Participants included 875 children and adolescents between 8 and 19 years old from the D-KEFS normative sample (48% male; 52% female). Among these participants, 838 had complete data and were included in the current study. The racial/ethnic composition of the sample was: White (73.7%), African American (12.4%), Hispanic (11.1%), and other racial/ethnic backgrounds (2.7%). The Overall Test Battery Mean (OTBM) and the prevalence of low scores at various clinical cut-offs were calculated for the 13 primary scores from the D-KEFS Trail Making Test, Verbal Fluency Test, and Color-Word Interference Test. The OTBM and base rates were also calculated separately for those scores reflecting executive functioning (n = 7) and processing speed (n = 6). Healthy children and adolescents commonly obtained low scores on the D-KEFS tests considered here. Younger age, lower estimated full-scale intelligence quotient, and more test scores interpreted were associated with a greater frequency of low scores. Clinicians and researchers are encouraged to consider these multivariate base rates when assessing and attempting to identify executive functioning impairment among children and adolescents with the D-KEFS.
Acknowledgments
Standardization data from the Delis-Kaplan Executive Function System (D-KEFS), © 2001 NCS Pearson, Inc., used with permission. All rights reserved. JEK is a Vanier Canada Graduate Scholar and thanks the Natural Sciences and Engineering Research Council of Canada for their support of his graduate studies. GLI notes that this work is related in part to the TBI Endpoints Development (TED) Initiative and a grant entitled Development and Validation of a Cognition Endpoint for Traumatic Brain Injury Clinical Trials (subaward from W81XWH-14-2-0176). MGB also notes that this work is related in part to his grant entitled Characteristics and Correlates of Intraindividual Variability in Executive Control Processes (Natural Sciences and Engineering Research Council of Canada; 418676-2012). BLB acknowledges funding from the Canadian Institutes for Health Research Embedded Clinician Researcher Salary Award.
Disclosure statement
Brian Brooks receives royalties for tests published by Psychological Assessment Resources, Inc. [Child and Adolescent Memory Profile (ChAMP, Sherman and Brooks, 2015), Memory Validity Profile (MVP, Sherman and Brooks, 2015), and Multidimensional Everyday Memory Ratings for Youth (MEMRY, Sherman and Brooks, 2017)]. He also receives royalties from a book that is cited in this manuscript (Pediatric Forensic Neuropsychology; Sherman & Brooks, 2012). James Holdnack is Senior Scientist with Pearson Assessment, which is the publisher for the Children’s Memory Scale (CMS; Cohen, 1997). Grant Iverson has received research support from test publishing companies including Psychological Assessment Resources, Inc. and CNS Vital Signs in the past (not in the past 5 years). He acknowledges unrestricted philanthropic support from ImPACT Applications, Inc. He receives royalties for one neuropsychological test (Wisconsin Card Sorting Test-64 Card Version).