Objective	Participants	Method	Results	Conclusions
Tannock et al.9 (Journal of Abnormal Child Psychology)	Investigate rapid automatized naming (RAN) and effects of stimulant medication in school-age children with ADHD with and without concurrent reading disorder (RD)	67 children with ADHD, 21 with ADHD + RD, and 27 healthy comparison children participated. All children were between 7–12 years of age, 80% of which were male In a second study, a subgroup (n = 47) of the total ADHD sample participated in an acute medication trial, 35 belonging to the ADHD group, 12 to the ADHD + RD group	The three groups were compared on: color naming speed, letter naming speed, phonologic decoding, and arithmetic computation In the medication trial, the subgroup of children completed several academic and cognitive measures as well as three of the RAN Tests: Colors, Letters, and Digits. Each child completed a randomized, placebo-controlled, cross-over trial with three single doses (10, 15, 20 mg) of methylphenidate. The active medication and placebo were administered in a double-blind manner each morning during a 1-week period. Testing under double-blind conditions commenced about 1 h after ingestion of medication and lasted for 2 h	Both ADHD groups were significantly slower in color naming than controls, but did not differ from one another, showing evidence of an association between deficits in color naming and ADHD that could not be attributed to the comorbidity with RD. Methylphenidate selectively improved color-naming speed but had no effect on the speed of naming letters or digits	The findings of color naming impairments in ADHD challenge the current assumption that naming speed deficits are specific to RD and also provide some support for the purported processing differences underlying color naming and letter naming, of which color-naming speed is improved by stimulant medication
Lawrence et al.10 (Journal of Attention Disorders)	Compare performance on both neuropsychological and real-life measures of executive function and processing speed	44 boys aged 6–12 years (mean age 9.7 years), 22 with a diagnosis of ADHD and 22 controls participated	Participants completed the Stroop Color-Word Test and Wisconsin Card Sorting Task (WCST), which were selected as neuropsychological measures, as well as route tasks in a videogame and at the zoo, which were used to index real-life measures	There were no group differences in executive function on the Stroop or zoo tasks The ADHD group was significantly slower in color naming on the Stroop, and also took more trials on the WCST to complete sorting cards according to the first category of color	Color naming and color processing deficits may exist in children with ADHD
Banaschewski et al.6 (Journal of Child Psychology and Psychiatry)	Investigate color perception and performance on a conventional neuropsychological task (Stroop Task) that requires speeded naming of colored stimuli in children with ADHD	27 children aged 8.0–13.0 years, consisting of 14 children with ADHD and 13 controls participated	Color discrimination ability was investigated using the Farnsworth-Munsell 100 Hue Test (FMT) Children completed the Stroop-Color-Word Task. Naming time and errors were recorded for three subtests separately: Stroop-Word, Stroop-Color, and Stroop-Color/Word	Children with ADHD committed more errors in blue–yellow axis in FMT. They were also slower in naming the colors of stimuli on both the Color and Color-Word conditions of the Stroop, but did not differ in naming speed on the Word condition, nor in Stroop interference	These findings indicate problems in the blue–yellow perception which may be accounted by retinal dopaminergic mechanisms in children with ADHD
Roessner et al.7 (J Neural Transm)	Examine color perception in ADHD and Chronic Tic Disorders (CTD) to clarify which factor (ADHD versus CTD) influences color vision parameters especially in the case of the comorbidity of ADHD + CTD	69 children aged 8.0–12.6 years, 14 with a diagnosis of ADHD, 22 with CTD, 19 with ADHD + CTD, 14 healthy controls	Color discrimination ability was investigated using the Farnsworth-Munsell 100 Hue Test (FMT) Participants also completed the Stroop-Color-Word Task. Naming time and errors were recorded for three subtests separately: Stroop-Word, Stroop-Color, and Stroop-Color/Word.	Color perception deficits were found for both main factors (ADHD and CTD), but there were no interaction effects A deficits on the blue–yellow compared to the red–green axis was detected for ADHD In the Stroop task only the ‘pure’ ADHD group showed impairments in interference control and other parameters of Stroop performance No significant correlations between any FMT variable and color naming in the Stroop task were found	Basic color perception deficits in both ADHD and CTD were suggested, and these deficits are additive in the case of comorbidity (ADHD + CTD) The influence of color perception deficits on Stroop task performance might be negligible
Silva and Frère8 (Biomedical Engineering Online)	Examine blue–yellow color discrimination in ADHD individuals using a virtual environment that is capable of quantifying the influence of red–green versus blue–yellow color stimuli on participant performance	20 ADHD and 20 control matched for age and gender participated (15–25 years, 17 men and 23 women)	An interactive computer game based on virtual reality was used. Within the game, the player must find and interpret hints scattered in different scenarios. In one version, hints and information boards were painted using red and green colors. In the second version, these objects were painted using blue and yellow colors. The ADHD group and control group were divided into subgroups and played either the red–green version or the yellow–blue version. The time spent to complete each task of the game was measured	Use of blue/yellow instead of green/red colors decreased the game performance of all participants. However, a greater decrease in performance was observed with participants with ADHD	Color influences the performance of executive tasks that require attention. ADHD participants were more influenced by blue–yellow than control group
Kim et al.5 (Journal of Optometry)	Evaluate color vision deficiency in adults with ADHD and the impact of everyday life	30 adults with ADHD and 30 controls matched for age and gender	Participants completed Visual Activities Questionnaire (VAQ) and performed Farnsworth-Munsell 100 Hue test (FMT) and A Quick Test of Cognitive Speed (AQT)	Adults with ADHD reported more visual activities problems on VAQ. They also committed more errors in FMT, particularly in Blue spectrum	Color vision problem, particularly in blue spectrum is replicated in adult with ADHD. A comprehensive research on mechanism underlying color vision deficit is warranted