Executive function Patel Mar 21, 2013
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EXECUTIVE FUNCTION PART 2 DEVELOPMENT, DYSFUNCTION, APPROACH TO EVALUATION Puja Patel March 21, 2013 Development Know healthy brain development for better understanding of functional recovery and outcome in children with brain lesions PFC is especially vulnerable to brain lesions due to its extended developmental trajectory Adults rely on PFC; cognitive fnc less localized in children Development of executive skills progresses in spurts PFC Maturation Occurs in Growth Spurts Development of Foundational Executive Skills Selective attention Elements formed in first years of life Develops considerably between 2.5–6 years, ceiling effects by 6 years Another peak from 8–10 years of age; skills functioning reliably Less rapid improvement from 10 years to early adolescence Development of Foundational Executive Skills Inhibition Emerges as early as 7–8 months of age, but not consistently employed reflecting skill immaturity By age 4, signs of successful performance on simple and complex inhibition tasks Improves from age 5-8, particularly for tasks that combine inhibition and WM Complete by age 10; mastery by age 12 Development of Foundational Executive Skills WM Improvement during the preschool years By age 6 executive components sufficient to be used during complex tasks Linear increase from ages 4 to 14 and a leveling off between ages 14 and 15 across nearly all WM tasks examined Development of Foundational Executive Skills Planning Simple planning in children as young as 3 Greatest period of development between ages of 5-8 By age 7-11, strategic behavior and reasoning abilities leads to more organized and efficient planning Reach adult levels between the ages of 9-13 Improvements continue into early adulthood period Development of Foundational Executive Skills Shifting Preschoolers can shift between two simple response sets when demands on inhibition are reduced Inhibition and WM interrelated; prerequisites for successful shifting Ability to perform on complex shifting tasks improves from age 7-9 By middle adolescence, reaches adult-like levels Risky Behaviors in Adolescence Imbalance of development of prefrontal regions relative to subcortical regions (limbic system; involved in desire and fear) maximal during adolescence Executive dysfunction in the clinical setting EF is multi-dimensionalpresents in a variety of ways Lesions affecting the prefrontal-subcortical system can have delayed manifestations in children TBI in children vs adults EF still developing throughout childhood and adolescents, and children have fewer well established routines and skills to rely upon EF in Clinical Practice Neuropsychiatric Syndromes that involve Executive Dysfunction Autism Frontal brain tumors ADHD TBI Disruptive Behavioral Disorders Tourette syndrome Frontal Lobe Epilepsy Bipolar Disorder Fragile X syndrome Schizophrenia Williams syndrome Wilson’s disease PKU Fetal Alcohol syndrome Autism Deficits in communication, social interactions, presence of restricted interests and repetitive behaviors Related to WM and cognitive flexibility “stuck-in-set” perseveration, difficulty in the inhibition of a prepotent response and planning BUT may be preservation vs compensatory mechanismsresponse inhibition and WM intact ADHD Developmentally inappropriate symptoms of inattention, impulsivity and motor restlessness EF deficits: inhibitory control and suppression of overlearned responsesimpulsive sustained attentiondistractible WMforgetful, slow processors planning and organizing monitoring and regulating self-actionfail to modify behaviors Disruptive behavioral disorders (CD/ODD) Oppositional, aggressive, and antisocial behaviors fMRI shows underactivation of R-FOC (involved in sense of euphoria, uncontained responsiveness to impulses, behavioral disinhibition) compromised processing of reward cues Impaired inhibition after controlling for attention Response perseveration Frontal Lobe Epilepsy Impacts wide scale of cognitive domains; impaired EF and attention most frequent RFs unclear Age of onset, sz frequency, localization, ↑AEDs, duration Behavioral disturbances can be ictal, interictal, or postictal FL/executive dysfunction in up to 84% of children and adolescents with TLE! Wider anatomic and functional network connects temporal and FL Hypometabolism of prefrontal regions in TLE ? protection against epileptiform discharge propagation by FL function inhibition Approach to Evaluation Accurate diagnosis is basis for effective management plan Challenges of diagnosis Delayed manifestations Identifying threshold of childish behavior Comorbid LD or severe behavioral problems Approach to Evaluation Multidisciplinary approach Psychological Intelligence testing Personality assessment Behavioral observation Achievement testing Approach to Evaluation Neuropsychological: sensory processes, motor systems, attention and concentration, learning and memory, language, visuospatial processing, conceptual skills, executive functions EF assessment challenging Not easily measured in office setting Formal testing may not correlate to daily life Limitless opportunities for dysfunction Parents and teachers should describe problems in real word Multiple tests (Dr. Goldman) Approach to Evaluation Psychiatry Prefrontal EF impairment important feature of many psychiatric disorders listed in the DSM-IV Treat psychiatric symptoms vs EF deficits vs both Neurologic exam to r/o focal structural lesions, genetic/metabolic disorders Normal exam DOES NOT r/o prefrontal lesion Interventional Methods Delayed responding Increases time devoted to objective goal-setting, systematic screening for appropriate responses, response selection and enactment Plan-Execute-Repair (P-E-R) Thinking maps to aid organizational strategies Self talk to enhance skills related to inhibition, stress/anxiety, anger management, appropriate goal setting Self-regulated strategy development (SRSD) intervention model to enhance self-regulation and increase positive self-concept
