Table 1.
All behavioral measures are listed as standard scores. In each child, we examined non-verbal IQ with a common IQ test for children (Kaufman Brief Intelligence Test, 2nd Edition (KBIT-2)). Reading and reading-related skills were examined through rapid automatized naming (RAN/RAS Numbers and Letters) (Wolf & Denckla, 2005), phonological processing (Comprehensive Test of Phonological Processing (CTOPP), Elision and Memory for Digits) (Wagner, Torgesen, & Rashotte, 1999); silent word reading fluency (Test of Silent Word Reading Fluency (TOSWRF)) (Mather, Hammill, Allen, & Roberts, 2004); speeded single word and nonword reading (Test of Word Reading Efficiency (TOWRE), Sight Word Efficiency and Phonemic Decoding Efficiency) (Torgesen, Wagner, & Rashotte, 1999); and reading comprehension (Woodcock Reading Mastery Test-Revised (WRMT-R), Passage Comprehension). To examine key components of executive function, we used the Delis-Kaplan Executive Function System (D-KEFS), which is a standardized battery of tests often used to study children with ADHD (Stern & Morris, 2013; Wodka et al., 2008a; Wodka et al., 2008b). In line with Stern and Morris (2013), who studied the discrimination of ADHD and RD in college-level adults, we focused the psychometric analysis on three subtests: Trail Making (TM), which measures flexibility of task execution; Verbal Fluency (VF), which assesses fluent productivity; and Color-Word Interference (CWI), which assesses verbal inhibition. For each group, the mean, standard deviation and all corresponding statistical values (F & p-values) are displayed.
| Dimension | Test | Description | TYP | RD | ADHD | COM | ANOVA | Post hoc t tests | |
|---|---|---|---|---|---|---|---|---|---|
| Mean±SD | F-value | p-value | corrected for multiple comparisons | ||||||
| reading related measures |
RAN Numbers | automized naming of numbers | 114.2 ±10.4 | 91.4 ±26.4 | 99.7 ±8.8 | 86.3 ±29.5 | 3.5 | 0.022 | TYP > RD,ADHD,COM; ADHD > COM |
| RAN Letters | automized naming of letters | 112.7 ±10.8 | 82.2 ±24.2 | 97.2 ±9.7 | 85.0 ±26.6 | 5.7 | 0.002 | TYP > RD,ADHD,COM; ADHD > RD,COM | |
| CMIDDLEP Elision | comprehensive test of phonological processing | 11.9 ±2.0 | 8.4 ±3.5 | 9.9 ±3.5 | 9.6 ±1.8 | 3.4 | 0.026 | TYP > RD,ADHD,COM | |
| CTOPP Memory for Digits | repetition of numbers | 11.0 ±1.2 | 8.6 ±2.2 | 10.8 ±2.42 | 8.2 ±1.2 | 4.1 | 0.011 | TYP,ADHD > RD,COM | |
| TOSWRF | word reading fluency | 109.2 ±19.4 | 92.9 ±12.6 | 100.0 ±13.4 | 91.9 ±8.4 | 3.9 | 0.014 | TYP > RD,COM; ADHD > COM | |
| TOWRE Sight Word Efficiency | sight word reading efficiency | 115.1 ±10.1 | 87.9 ±14.2 | 104.6 ±15.8 | 94.9 ±13.7 | 10.4 | <.001 | TYP > RD,COM; ADHD > RD | |
| TOWRE Phonemic Decoding E. | non-word reading efficiency | 110.0 ±10.9 | 89.9 ±10.5 | 102.3 ±18.0 | 95.6 ±14.4 | 4.2 | 0.011 | TYP > RD,COM; ADHD > RD | |
| WRMT-R | passage reading comprehension | 111.2 ±6.5 | 95.6 ±10.1 | 99.4 ±18.3 | 96.8 ±7.8 | 4.4 | 0.008 | TYP > RD,ADHD,COM | |
| executive function tasks |
TM Letter Sequencing | visual search, sequencing and flexibility | 12.6 ±2.2 | 8.5 ±3.2 | 9.6 ±3.2 | 10.9 ±2.5 | 4.3 | 0.012 | TYP > RD, ADHD |
| TM Number Letter Sequencing | visual-motor sequencing task and flexibility | 13.0 ±1.5 | 9.1 ±3.0 | 8.9 ±4.5 | 9.4 ±4.6 | 3.4 | 0.028 | TYP > RD, ADHD, COM | |
| VM Category Switching | ability to fluently generate words of two categories | 12.5 ±3.1 | 9.2 ±3.6 | 9.8 ±1.8 | 8.4 ±3.8 | 3.6 | 0.021 | TYP > RD, ADHD, COM | |
| CWI Color Naming | measure of basic naming | 12.8 ±2.2 | 8.6 ±2.8 | 9.2 ±3.9 | 10.1 ±3.4 | 4.1 | 0.01 | TYP > RD, ADHD, COM | |
| CWI Word Naming | measure of basic reading | 12.9 ±1.4 | 8.6 ±3.0 | 9.3 ±2.6 | 9.7 ±1.9 | 7.4 | <.001 | TYP > RD, ADHD, COM | |
| CWI Interference | verbal inhibition (traditional Stroop task) | 13.4 ±1.5 | 7.7 ±3.2 | 9.4 ±3.6 | 9.2 ±4.5 | 6.1 | 0.001 | TYP > RD, ADHD, COM | |
| CWI Inhibition/Switching | measure of inhibition and cognitive flexibility | 12.2 ±1.8 | 8.4 ±2.1 | 9.5 ±2.3 | 8.7 ±3.4 | 4.6 | <.001 | TYP > RD, ADHD, COM | |
| IQ | KBIT-2 Matrices | non-verbal IQ test | 113.1 ±11.1 | 104.9 ±9.8 | 106.1 ±19.7 | 101.6 ±14.8 | 1.4 | 0.264 | n.a. |
| Chi-Square test | |||||||||
| Gender | (females/total) | 7/15 | 8/15 | 4/15 | 2/5 | X2 2.4 |
p 0.493 |
n.a | |