1. Introduction 
ttention Deficit Hyperactivity Disorder (ADHD) is a persistent pattern of inattention and/or hyperactive-impulsive behaviors. For its diagnosis, some symptoms must appear before the age of 12 years, although many cases are diagnosed years after the onset of symptoms. The disorder must be present in at least two fields, and the individual’s performance must be impaired in social, educational, or occupational settings, depending on the rate of growth. The symptoms do not occur exclusively during the course of a pervasive developmental disorder, schizophrenia, or other psychotic disorders, and are not better accounted for by another mental disorder (e.g. mood disorder, anxiety disorder, dissociative disorder, or a personality disorder) [1, 2]. The relationship between ADHD diagnosis education and its spread is evident. Diagnostic criteria for ADHD are influenced by factors related to education [3]. In fact, in the early conceptualization of ADHD as a minimal brain damage, emotion dysregulation is the core symptom along with its main symptoms [5]. After publication of the fifth edition of Diagnostic and Statistical Manual of Mental Disorders, emotional symptoms became manifestations of ADHD dependent on the diagnostic criteria [6].
Attention is an important component of emotional regulation [12]. Automatic biases in attention and difficulties in disengaging attention may be the important attention mechanisms in emotional regulation [13, 14]. Inefficient attentional biases (towards negative emotional information) may lead to unconscious, automatic and inflexible negative evaluations of a situation [12]. Attentional bias can cause a person to pay attention to the negative aspects of a situation. This causes the person to respond negatively to the situation, which makes it more difficult to activate positive or neutral assessments of the situation and regulate negative emotions. The ability to apply reassessment may depend on a person’s ability to overcome bias and self-assessment [14]. More bias in attention may increase the likelihood of distraction from the negative aspects of the situation, and the person may pay more attention to the more positive or neutral aspects of the situation, and may increase the person’s ability to positively assess the situation [15]. Due to the role of attention in emotion regulation, attention training may be a valuable intervention for improving emotion regulation [16]. In a review study by Wadlinger and Scakowitz, [12] it was reported that correction of attentional bias can directly modify the processes that are important in regulating attention [17].
Rehabilitation of cognitive deficits has attracted the attention of neuropsychologists for a long time. Interventions to improve or reduce cognitive deficits generally fall into three categories: A. Environmental interventions that provide situational support for impaired abilities; B. Interventions aimed at compensating for existing deficiencies; and C. Direct interventions aimed at improving the underlying cognitive processes and eliminating/reducing the defect itself. Direct interventions assume that attention al abilities are improved by providing structured opportunities to practice different aspects of attention. Treatment involves repeated exercises with a set of tasks that require attention at different levels. It is hypothesized that repeated activation and continuous stimulation of attention systems causes a change in cognitive capacity, which seems to indicate an underlying change in neuronal activity [18].
2. Materials and Methods
This is an experimental study with a pre-test, post-test, follow-up design with a control group. The study population consists of all students diagnosed with ADHD in 6-9th grades in schools located in District 7 of Tehran, Iran during 2017-2018. Of these, 24 (12 boys and 12 girls) were selected using a purposive sampling method and based on the entry and exit criteria. They were then randomly divided into experimental and control groups. Symptoms of ADHD were first diagnosed in school by a school counselor expert in psychology, and then a psychiatrist confirmed ADHD diagnosis. Entry criteria were: Diagnosis of ADHD and willingness to participate in the study, while the exit criteria were: organic disorder, psychotic disorder, mental retardation, and receiving medication or any concomitant psychological intervention. The computer-based cognitive rehabilitation therapy was presented at 20 sessions, each for 30 minutes.
3. Results
The results of within-group comparison showed the significant effects of study variables on both study groups over time. All of the study variables were significantly changed from the pre-test to the follow-up phases. The results of pairwise comparison in the experimental group showed a significant difference in the Difficulties in Emotion Regulation Scale (DERS) dimensions between pre-test and post-test scores (t=10.43, P=0.01), between pre-test and follow-up scores (t=10.22, P=0.01), and between post-test and follow-up scores (t=-5.19, P=0.01). There was no significant difference between the measurement phases in the control group (P>0.05). Regarding between-group comparison, results showed a significant difference in the post-test and follow-up scores of all DERS dimensions between the experimental and control groups which confirms the main hypothesis of our study. 
According to the ETA squared value which shows the effect size of the computer-based cognitive rehabilitation therapy, this intervention had a small effect on DERS dimensions of limited access to emotion regulation strategies (η2= 0.21) and lack of emotional clarity (η2= 0.27); a medium effect on dimensions of nonacceptance of emotional responses (η2= 0.43), difficulty engaging in goal-directed behavior (η2=34), and lack of emotional awareness (η2=0.41); and a large effect on the dimension of impulse control difficulties (η2= 0.55), and the overall DERS score (η2 = 0.84).
4. Conclusion
The present study aimed to improve the difficulty in emotional regulation of students with ADHD. Interventions related to ADHD usually focus on its cognitive neurological symptoms or secondary behavioral problems [55]. Although psychological interventions for ADHD vary in scope, they all tend to focus on correcting destructive or distracting behaviors. Several medications have been proposed for treating the emotional and behavioral difficulties of students with ADHD due to the high difficulty of emotion regulation and associated emotional/behavioral disorders. Almost half of the children in studies by Winterstein [57] and Rosen et al. [37] received one or more medications before the intervention. The concern may be because of long-term use of psychotropic drugs and their potential side effects including loss of appetite, sleep disorders, irritability, aggression, anxiety, tics, and seizures [28]. 
Although there is evidence that behavioral interventions are effective in improving the performance of children with ADHD in the presence of concomitant disorders [58], the main focus of these behavioral therapies is to reduce the disorder and increase behavioral flexibility rather than to improve difficulty in emotional regulation. The intervention in the present study was able to directly improve the emotional regulation abilities of children with ADHD. Therefore, the use of non-pharmacological methods such as computer-based cognitive rehabilitation therapy, which has been reported to have no side effects on children, is need for the treatment of ADHD.
Ethical Considerations
Compliance with ethical guidelines
The APA, IRPCO, and Helsinki Ethical Codes was considered in the this study. 
Funding
This study was extracted from the PhD. dissertation of first author approved by Islamic Azad University of Roudehen Branch.
Authors' contributions
All authors contributed equally in preparing all parts of the research.
Conflicts of interest
The authors declare no conflict of interest


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