Time management EF
In our work, time management was found to be the second most significantly affected executive function in learning disability affecting 81% and also in the combined group (group III) affecting 90% of them.
This is similar to the results of a recent study by Sharfi K and Rosenblum (December 2016) on executive functions in learning disabilities which concluded that Deficits in initiation and emotional executive functions as well as organization in time abilities and emotional responses to impairments in organizing time. These deficits affected the quality of life of adults with LD [13].
Time management was also significantly affected in the ADHD group in 70% of children with no significant difference between affection in the three subtypes of ADHD. Also it was significantly affected in the combined group (ADHD and LD) in 81%, similar to the present results of Hosenbocus and Chahal [14] who found that many of the executive dysfunctions are found in children with ADHD including difficulties with priority and time management, planning and organization, initiating and completing tasks in a timely manner, difficulty shifting cognitive set, a high level of procrastination, forgetfulness, and poor working memory [14] (Figs. 1, 2, and 3).
Again, time management was significantly associated with other psychiatric comorbidities including most commonly nocturnal enuresis or delayed language was found in 81% of children, then mood and anxiety disorders in 78% of children and disruptive behavior disorders in 75% of children but with no significant association with epilepsy; this might be related to the compound effect of multiple comorbidities adding to a child disturbed mentality and cognition.
Problem solving (self-organization) EF
In the present study problem solving was the most significantly affected EF in learning disorder group before and after the exclusion of children with other psychiatric comorbidities affecting 81% of children. Also problem solving was significantly affected in combined group affecting 76% in agreement with the results found by Mccann [15] using the BRIEF-Parent report that children with dyslexia received significantly higher (reaching more clinical levels) scores than matched controls on the BRIEF Working Memory, Plan/Organize, and Monitor Scales [15].
Also, problem solving was related to other psychiatric comorbidities confirmed by multivariate regression analysis as a risk factor(OR = 3.98, CI 1.5–10.2) including epilepsy as it was affected in 100% of the epileptic children followed by disruptive behavior disorders in 67% of children and mood and anxiety disorders in 62% of them but no significant association with (nocturnal enuresis or delayed language). Similarly a study using standard performance-based neuropsychological measures (Wechsler Intelligence Scale for Children, Delis Kaplan Executive Functioning System, NIH Toolbox, Test of Everyday Attention for Children) and the Behavior Rating Inventory of Executive Functioning (BRIEF) comprised the multi-method assessment battery. Depending on the measure, 30% of adolescents with epilepsy had deficits in working memory, 17% in cognitive flexibility/problem solving, 6% in inhibition, and 18% in planning/ organization. Attention was a significant problem for 15% of adolescents with epilepsy [16].
This higher percent we found of problem solving executive dysfunction in case of comorbid epilepsy (100% compared by other studies (30-50%) may be explained by the fact that most of epilepsy cases referred to our child psychiatry clinic were of frontal lobe epilepsy subtype. There have been numerous reports of impaired executive functions in this population [17] referred for us for management of behavioral symptoms while other classical epilepsy subtypes are usually referred to our Epilepsy clinic. Also children with comorbid ADHD and epilepsy were not on antiepileptic; untreated epilepsy was proved in a study done on 247 untreated epileptic patient on 2012 to be related to more executive dysfunction (> 50% of untreated epileptic patients) [18]. Moreover, the fact that our study was done on children so those with early onset epilepsy which was proved by Black [19] on his study on 216 patient which proved that earlier onset was associated with higher executive function deficit.
Self-restraint EF (inhibition)
In our work, self-restraint was significantly affected in children with ADHD before and after exclusion of children with other comorbid psychiatric disorders affecting 93% of children (there was no significant difference in all EF affection between three subtypes of ADHD as found by previous studies [20] and 76% of children with combined (ADHD and LD) and this result repeated previous study findings and agrees with the body of research showing that executive dysfunction in the form of impaired response inhibition remains the most prominent cognitive theory of ADHD [21].
The present work also found that Self-restraint was not significantly affected in the children with LD affecting only 26% before excluding other comorbidities and only 20 % after excluding them. While recent research suggested that executive function skills, which include monitoring and manipulating information in mind (working memory), suppressing distracting information and unwanted responses (inhibition) and flexible thinking (shifting), play a critical role in the development of mathematics proficiency, this difference might be justified by the smaller sample size of math disorder in our study.
This study showed a significant association between self -restraint and other psychiatric comorbidities mainly disruptive behavior disorders to be affected in 87% of children then epilepsy to be affected in 78 % of children, and mood and anxiety disorders nocturnal enuresis to be affected in 68% and 66% respectively, this finding was similar to a study showing that oppositional defiant disorder (ODD)/ conduct (CD) but not ADHD was related to hot EF based on increased risky decision-making in the Iowa Gambling Task. ODD/CD was also independently related to aspects of cool EF independently of ADHD, namely slower speeds of inhibitory responding and increased intra-subject variability [22].
Self-motivation EF
The present work showed that self-motivation was significantly affected in the three groups affecting 73% of the combined group, 60% of the children with ADHD, and 57.5 % of children with LD.
Male sex was a significant risk factor for self-motivation executive dysfunction (OR = 0.3, CI 0.1–0.8), opposite to our finding. An Egyptian study by Amer et al. [23] showed that no robust differences in EF can be attributed solely to sex and that reading and metacognitive reading dysfunctions showed no gender difference; this difference can be explained by different sample size (60), different methodology using Wisconsin Card Sorting Test (WCST) and also that most of our sample were of the male gender.
Emotion regulation EF
The present study showed that emotion regulation was significantly affected in children with ADHD and children with combined ADHD and LD group affecting 73% of each; this finding might explain the emotional liability symptom associated with ADHD. One study [24] showed that 80% or more of adults with ADHD report significant levels of emotional liability, often severe, and causing impairments beyond that accounted for by inattention, hyperactivity or impulsivity and drug treatments for ADHD have all been shown to improve symptoms of emotional liability.
Moreover emotion regulation was significantly related to other psychiatric comorbidities which was found to be a risk factor for emotion regulation executive dysfunction (OR = 12, CI 3–46), this came as an answer for Surman’s question; Is Emotion liability in Adult ADHD due to Comorbidity? But could not answer it due to limited assessment of comorbidity contribution to emotional symptoms to date [25]. We assume based on the results of our study that the answer is Yes, as the emotion regulation executive dysfunction dropped after exclusion of children with other psychiatric comorbidities to be affecting only 37 % of ADHD only group and 30% of the combined group.
The psychiatric comorbidity which was most significantly affecting this EF was disruptive behavior disorders ( including ODD and Conduct disorder) to be present in 98% of them followed by mood and anxiety disorders affecting 92% of them then epilepsy affecting 89% of them and lastly those with history of (nocturnal enuresis or language delay) affecting 79% of them. Also some studies concluded that major depressive disorder (MDD) has been associated with executive dysfunction and related abnormal prefrontal ability while other others showed that the status of EF in anxiety disorders and in co-morbid depression and anxiety remain unclear [26].
Limitations of the study
The executive function assessment depended solely on parents reports using the Barkley Deficits in Executive Functioning Scale—Children and Adolescents (BDEFS-CA).