Executive dysfunction

In psychology and neuroscience, executive dysfunction, or executive function deficit, is a disruption to the efficacy of the executive functions, which is a group of cognitive processes that regulate, control, and manage other cognitive processes. Executive dysfunction can refer to both neurocognitive deficits and behavioural symptoms. It is implicated in numerous psychopathologies and mental disorders, as well as short-term and long-term changes in non-clinical executive control. In psychology and neuroscience, executive dysfunction, or executive function deficit, is a disruption to the efficacy of the executive functions, which is a group of cognitive processes that regulate, control, and manage other cognitive processes. Executive dysfunction can refer to both neurocognitive deficits and behavioural symptoms. It is implicated in numerous psychopathologies and mental disorders, as well as short-term and long-term changes in non-clinical executive control. Executive dysfunction is not the same as dysexecutive syndrome, a term coined by Alan Baddeley to describe a common pattern of dysfunction in executive functions, such as deficiencies in planning, abstract thinking, flexibility and behavioural control. This group of symptoms, usually resulting from brain damage, tend to occur together. However, the existence of dysexecutive syndrome is controversial. Executive functioning is a theoretical construct representing a domain of cognitive processes that regulate, control, and manage other cognitive processes. Executive functioning is not a unitary concept; it is a broad description of the set of processes involved in certain areas of cognitive and behavioural control. Executive processes are integral to higher brain function, particularly in the areas of goal formation, planning, goal-directed action, self-monitoring, attention, response inhibition, and coordination of complex cognition and motor control for effective performance. Deficits of the executive functions are observed in all populations to varying degrees, but severe executive dysfunction can have devastating effects on cognition and behaviour in both individual and social contexts. Executive dysfunction does occur to a minor degree in all individuals on both short-term and long-term scales. In non-clinical populations, the activation of executive processes appears to inhibit further activation of the same processes, suggesting a mechanism for normal fluctuations in executive control. Decline in executive functioning is also associated with both normal and clinical aging. In aging populations, the decline of memory processes appears to affect executive functions, which also points to the general role of memory in executive functioning. Executive dysfunction appears to consistently involve disruptions in task-oriented behavior, which requires executive control in the inhibition of habitual responses and goal activation. Such executive control is responsible for adjusting behaviour to reconcile environmental changes with goals for effective behaviour. Impairments in set shifting ability are a notable feature of executive dysfunction; set shifting is the cognitive ability to dynamically change focus between points of fixation based on changing goals and environmental stimuli. This offers a parsimonious explanation for the common occurrence of impulsive, hyperactive, disorganized, and aggressive behaviour in clinical patients with executive dysfunction. Executive dysfunction, particularly in working memory capacity, may also lead to varying degrees of emotional dysregulation, which can manifest as chronic depression, anxiety, or hyperemotionality. Russell Barkley proposed a hybrid model of the role of behavioural disinhibition in the presentation of ADHD, which has served as the basis for much research of both ADHD and broader implications of the executive system. Other common and distinctive symptoms of executive dysfunction include utilization behaviour, which is compulsive manipulation/use of nearby objects due simply to their presence and accessibility (rather than a functional reason); and imitation behaviour, a tendency to rely on imitation as a primary means of social interaction. Research also suggests that executive set shifting is a co-mediator with episodic memory of feeling-of-knowing (FOK) accuracy, such that executive dysfunction may reduce FOK accuracy. There is some evidence suggesting that executive dysfunction may produce beneficial effects as well as maladaptive ones. Abraham et al. demonstrate that creative thinking in schizophrenia is mediated by executive dysfunction, and they establish a firm etiology for creativity in psychoticism, pinpointing a cognitive preference for broader top-down associative thinking versus goal-oriented thinking, which closely resembles aspects of ADHD. It is postulated that elements of psychosis are present in both ADHD and schizophrenia/schizotypy due to dopamine overlap. The cause of executive dysfunction is heterogeneous, as many neurocognitive processes are involved in the executive system and each may be compromised by a range of genetic and environmental factors. Learning and development of long-term memory play a role in the severity of executive dysfunction through dynamic interaction with neurological characteristics. Studies in cognitive neuroscience suggest that executive functions are widely distributed throughout the brain, though a few areas have been isolated as primary contributors. Executive dysfunction is studied extensively in clinical neuropsychology as well, allowing correlations to be drawn between such dysexecutive symptoms and their neurological correlates. Executive processes are closely integrated with memory retrieval capabilities for overall cognitive control; in particular, goal/task-information is stored in both short-term and long-term memory, and effective performance requires effective storage and retrieval of this information.