Executive Function Part 2 Development, Dysfunction, Approach to Evaluation

EXECUTIVE FUNCTION PART 2DEVELOPMENT, DYSFUNCTION, APPROACH TO EVALUATION

Puja PatelMarch 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 immaturityBy age 4, signs of successful performance on simple and complex inhibition tasksImproves from age 5-8, particularly for tasks that combine inhibition and WMComplete by age 10; mastery by age 12

Development of Foundational Executive Skills

WM Improvement during the preschool yearsBy age 6 executive components sufficient to be used during complex tasksLinear 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

PlanningSimple planning in children as young as 3Greatest period of development between ages of 5-8By age 7-11, strategic behavior and reasoning abilities leads to more organized and efficient planning Reach adult levels between the ages of 9-13Improvements continue into early adulthood period

Development of Foundational Executive Skills

Shifting Preschoolers can shift between two simple response sets when demands on inhibition are reducedInhibition and WM interrelated; prerequisites for successful shiftingAbility to perform on complex shifting tasks improves from age 7-9By 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

Autism Frontal brain tumors

ADHD TBI

Disruptive Behavioral Disorders

Frontal Lobe Epilepsy

Tourette syndrome Fetal Alcohol syndrome

Bipolar Disorder Fragile X syndrome

Schizophrenia Williams syndrome

Wilson’s disease PKU

Neuropsychiatric Syndromes that involve Executive Dysfunction

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 approachPsychological

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