IMPACT OF EXECUTIVE FUNCTION DEFICIT ON ADHD COURSE AND PROGNOSIS
Mohammed Abd ElAziz ElHelali Ali;
Abstract
ADHD is one of the most prevalent behavioral disorders of childhood. The disorder is characterized by onset of age-inappropriate hyperactivity, impulsivity and inattentiveness before the age of 7 years.
ADHD is a relatively chronic disorder affecting many domains of major life activities. Around half of children with ADHD continue to have ADHD as adults. The symptoms have been shown to change with age (hyperactivity and impulsivity behavior decrease, while inattention increasingly becomes predominant).
The cause of most cases of ADHD is unknown; however, it is believed to involve interactions between biological and environmental factors.
Current models of ADHD suggest that it is associated with functional impairments in some of the brain's neurotransmitter systems, particularly those involving dopamine and norepinephrine. Their pathways, which project to the prefrontal cortex and striatum are directly responsible for modulating executive function (EF), motivation, and reward perception. The criteria for an EF deficit are met in 30–50% of children and adolescents with ADHD.
The prefrontal cortex (PFC) is subdivided into the medial frontal (anterior cingulate), and orbitofrontal areas which are involved in emotional behavior and have connections to the brain stem and limbic areas of the brain and the dorsolateral prefrontal cortex (DLPFC) provides the cognitive support to the temporal organization of behavior, speech, and reasoning.
Changes in the brain typically follow a cycle characterized by periods of active development followed by static periods. This cycling is sometimes referred to as “rises and falls” during development and occurs from infancy through young adulthood. EF also follows a developmental trajectory which is believed to parallel the development of the brain, specifically, the frontal lobes as it also follows the “rises and falls” pattern.
However, EF is a result of complex interactions between many areas of the brain, and thus, the frontal lobes do not equal a central executive system and represent only one functional category within the frontal lobes.
Also, many studies suggested that EF deficits are not necessarily unique to ADHD and they are not necessary or sufficient for a diagnosis of ADHD. In addition, when EF impairments are present in children with ADHD, they tend to be specific rather than global impairments, thus, considering that executive dysfunction is only a partial explanation of a comprehensive model of ADHD.
However, a potential flaw in the literature’s arguments is that “cold” EF psychometric measures (which are manifested under relatively de-contextualized, non-emotional, and analytical testing conditions) are the sole standard for evaluating EF.
Barkley’s, 2012 model integrates EF with larger important human endeavors (personality, ethics and morality, capacity for effective occupational and educational functioning, a preference for immediate gratification, emotional dysregulation, and an adverse impact on social reciprocity and cooperation) attempting to demonstrate why disorders of EF produce profound disturbances in human adaptive functioning across numerous major domains of daily life activities.
The expanded model explains why EF tests may be insufficient to capture deficits in EF because they focus on “cold” cognition rather than on the social purposes of the EF system, fail to evaluate the self-regulation of emotion and motivation, and do not capture the reciprocal relationship between EF and cultural scaffolding needed to operate at higher levels of EF as it occurs in human daily life activities.
Based on such a model, it is also evident that ADHD has to be an executive function deficit disorder (EFDD), not only because the neural networks of the prefrontal cortex (PFC) that give rise to the executive brain are deficient in
ADHD but also because the behavioral symptoms of ADHD are dimensions of EF in daily life (behavioral regulation and metacognition) even if such EF deficits are only evident in a minority of cases on “cold” cognitive test batteries that only partially evaluate the instrumental level of EF cognition.
ADHD is a relatively chronic disorder affecting many domains of major life activities. Around half of children with ADHD continue to have ADHD as adults. The symptoms have been shown to change with age (hyperactivity and impulsivity behavior decrease, while inattention increasingly becomes predominant).
The cause of most cases of ADHD is unknown; however, it is believed to involve interactions between biological and environmental factors.
Current models of ADHD suggest that it is associated with functional impairments in some of the brain's neurotransmitter systems, particularly those involving dopamine and norepinephrine. Their pathways, which project to the prefrontal cortex and striatum are directly responsible for modulating executive function (EF), motivation, and reward perception. The criteria for an EF deficit are met in 30–50% of children and adolescents with ADHD.
The prefrontal cortex (PFC) is subdivided into the medial frontal (anterior cingulate), and orbitofrontal areas which are involved in emotional behavior and have connections to the brain stem and limbic areas of the brain and the dorsolateral prefrontal cortex (DLPFC) provides the cognitive support to the temporal organization of behavior, speech, and reasoning.
Changes in the brain typically follow a cycle characterized by periods of active development followed by static periods. This cycling is sometimes referred to as “rises and falls” during development and occurs from infancy through young adulthood. EF also follows a developmental trajectory which is believed to parallel the development of the brain, specifically, the frontal lobes as it also follows the “rises and falls” pattern.
However, EF is a result of complex interactions between many areas of the brain, and thus, the frontal lobes do not equal a central executive system and represent only one functional category within the frontal lobes.
Also, many studies suggested that EF deficits are not necessarily unique to ADHD and they are not necessary or sufficient for a diagnosis of ADHD. In addition, when EF impairments are present in children with ADHD, they tend to be specific rather than global impairments, thus, considering that executive dysfunction is only a partial explanation of a comprehensive model of ADHD.
However, a potential flaw in the literature’s arguments is that “cold” EF psychometric measures (which are manifested under relatively de-contextualized, non-emotional, and analytical testing conditions) are the sole standard for evaluating EF.
Barkley’s, 2012 model integrates EF with larger important human endeavors (personality, ethics and morality, capacity for effective occupational and educational functioning, a preference for immediate gratification, emotional dysregulation, and an adverse impact on social reciprocity and cooperation) attempting to demonstrate why disorders of EF produce profound disturbances in human adaptive functioning across numerous major domains of daily life activities.
The expanded model explains why EF tests may be insufficient to capture deficits in EF because they focus on “cold” cognition rather than on the social purposes of the EF system, fail to evaluate the self-regulation of emotion and motivation, and do not capture the reciprocal relationship between EF and cultural scaffolding needed to operate at higher levels of EF as it occurs in human daily life activities.
Based on such a model, it is also evident that ADHD has to be an executive function deficit disorder (EFDD), not only because the neural networks of the prefrontal cortex (PFC) that give rise to the executive brain are deficient in
ADHD but also because the behavioral symptoms of ADHD are dimensions of EF in daily life (behavioral regulation and metacognition) even if such EF deficits are only evident in a minority of cases on “cold” cognitive test batteries that only partially evaluate the instrumental level of EF cognition.
Other data
| Title | IMPACT OF EXECUTIVE FUNCTION DEFICIT ON ADHD COURSE AND PROGNOSIS | Other Titles | تأثير نقص الوظائف اﻹجرائية على مجرى ومآل اضطراب نقص اﻹنتباه وفرط الحركة | Authors | Mohammed Abd ElAziz ElHelali Ali | Issue Date | 2014 |
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