Attention-deficit /hyperactivity disorderevaluation and diagnosis

A practical approach

Dev PaedsDev Paeds21.07.200721.07.2007

Attention deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed biological-behavioral disorder of childhood.Prevalence -6% to 9% of school-aged children. M>F

Persistence of symptoms in 60% to 80% of these children as they become adolescents.

HistoryHistory1918 – George still observed an influenza pandemic with 1918 – George still observed an influenza pandemic with extreme hyperactivity in children and termed it as MBD. extreme hyperactivity in children and termed it as MBD.

In mid-1970s, largely through the work of researchers like neuro-psychologist Virginia Douglas, the core symptoms of ADHD have been considered to be problems with attention, impulse control, and hyperactivity

Uncertainty remains about whether ADHD represents the dysfunctional end of a continuum of normal temperamental characteristics or whether it represents a discrete qualitatively different biological or psychological entity

1998 NIH agreed that ADHD is separate clinical entity.

EtiologyEtiologyAttention deficit/hyperactivity disorder can be conceptualized as a cluster of behaviors that are the final common pathway for a number of heterogeneous biopsychosocial problems and brain developmental processes.

Because of this heterogeneity, no single factor can be considered the cause.

Brain dysfunctionIn the 1960s, the concept of MBD evolved, associating impairments in perception, conceptualization, language, memory, and the control of attention,impulses, or motor activities with functional problems in the central nervous system

This concept was positive in that it focused attention on brain mechanisms and away from the prevalent view that ADHD was caused by poor parenting.

Anatomical lesions

Singlele-photon emission computed tomography (SPECT) studies have shown cerebral hypoperfusion in the striatum and hyperperfusion in sensory and sensorimotor areas.

Recent studies have shown the right frontal anterior lobes to be decreased 6% to 8% with asymmetry in volume and the caudate nucleus to be compromised in children with ADHD compared with controls.

MRI - found smaller brain volumes in all regions in children with ADHD (independent of whether thechildren had taken stimulant medication).Preliminary fMRI studies have shown adolescents with ADHD to demonstrate decreased activity in several right hemispheric areas, including the right frontal region, and increased activity in some subcortical areas, particularly the right insula and left caudate nucleus during a task of visual inhibitory control .

QEEG activity during an attentional load task, with increased slow cortical activity (mainly over the frontal areas) and decreased fast cortical activity.

This pattern indicates a different arousal level in children with ADHD, and suggests a delay in functional cortical maturation.

Genetics and biochemical alterationsGenetics and biochemical alterations

ADHD relatives are at five times higher risk.ADHD relatives are at five times higher risk.

There is strong evidence that the catecholamines dopamine (DA) and norepinepherine (NE) are components in the pathopysiology of ADHD and in clinical response to stimulants.

DA D4 transporter gene implicated in ADHD. Presence of this gene produces a blunted intracellular response to DA.

1.5 times more frequency in individuals with ADHD than in the general population.Lack – results in increased DA availability at the synapse resulting in hyperactivity.

The role of NE in the pathophysiology of ADHD also is being considered.

Researchers have suggested that an overactivity of the locus ceruleus may result in hyperactivity and irritability, and that subsequent down-regulation of frontal lobe alpha2a receptors may lead to poor concentration and working memory deficits.

Deficits in neuropsychological functioning

ADHD children encounter similar problems to those individuals with frontal lobe deficits (abnormalities in executive functions).

Alterations of executive function are associated with difficulties with organizing, planning, attending, controlling impulsive response and setting maintenance.

Disordered adaptation theory

In ancestral environments, when foraging was necessary, response readiness likely may have included a high motor activity, hypervigilant, rapid, novel-stimulus seeking style that is no longer adaptive, particularly to present lifestyles, including school.

This model suggests that some individuals may retain these traits because of a lag in remodeling our genome.

Behavioral inhibition theory

Barkley has proposed a model that identifies behavioral inhibition as the major core deficit in ADHD.

In this theory, the ability to inhibit behavior includes being able to delay gratification and not respond immediately to a stimulus, the ability to interrupt ongoing responses, and to remain focused on a thought or action in the presence of a distractor.

This behavioral inhibition is postulated to have a direct effect on blocking immediate motor responses, allowing time for four major executive functions to operate effectively.

These executive functions includea. nonverbal working memory (such as having a

sense of time, hindsight,forethought, and self-awareness)

b. internalization of speech (including description,reflection, instructions, and reading comprehension),

c.self-regulation of affect / motivation /arousal (social perspective taking, objectivity, and self-regulation of goal-directed actions)

d. reconstitution (analysis, synthesis, syntax and fluency of behavior, and goal-directed creativity).

DiagnosisDiagnosisThere is no definitive diagnostic test for ADHD, it remains a behavioral diagnosis.

DSM IV of the American Psychiatric Association, which is a descriptive diagnostic classification system, remains the most widely accepted diagnostic tool for ADHD

Requirement for diagnosis

Onset of symptoms occurs before age 7.symptoms present for 6 months or longerSymptoms should be pervasive across two or more major life settings (like home and school)The frequency and severity are greater than those of children at a compatible developmental age.symptoms cause significant impairment in functioning. Out of the nine symptoms listed for each dimension, six are required to be present before a diagnosis is made.

InattentionInattention

Often fails to give close attention to details or makes careless mistakes in schoolwork, work, or other activities Often has difficulty sustaining attention in tasks or play activities Often does not seem to listen when spoken to directly Often does not follow through on instructions, and fails to finish schoolwork or duties in the workplace (not because of oppositional behavior or failure to understand the instructions)

Often has difficulty organizing tasks and activities Often avoids, dislikes, or is reluctant to engage in tasks that require sustained mental effort (such as schoolworkor homework) Often loses things necessary for tasks or activities (eg, toys,school assignments, pencils, books, or tools) Often easily distracted by extraneous stimuli Often forgetful in daily activities

Hyperactivity

a. Often fidgets with hands or feet or squirms in seatb. Often leaves seat in classroom or in other situations in which remaining seated is expectedc. Often runs about or climbs excessively in situations in which it is inappropriate (in adolescents, may be limited to subjective feelings of restlessnessd. Often has difficulty playing or engaging in leisure activities quietlye. Often ‘‘on the go’’ or often acts as if ‘‘driven by a motor’’f. Often talks excessively

Impulsivitya. Often blurts out answers before questions have been completeb. Often has difficulty awaiting turnc. Often interrupts or intrudes on others (eg, butts into conversations or games)

CategoriesCategoriesCombined type -adolescents predominantly

Predominantly inattentive type

Predominantly hyperactive–impulsive type

Functional ImpairmentFunctional ImpairmentFamily relationships, peer status and social skills, academic achievement, self-esteem and self perception and accidental injuries.

Disabilities in these areas can be pervasive,severe, and debilitating.

Parents of children with ADHD experience greater stress, cope less adaptively, display more negative behavior toward their children and have more marital discord than parents of children without ADHD .

Children with ADHD are more likely to experience peer disapproval at extremely high levels and often are rejected by peers after only brief interactions.

ASSESSMENTASSESSMENT

AAP recommends six steps AAP recommends six steps Primary care clinicians should initiate an evaluation for ADHD in a child 6 to 12 years old who presents with inattention, hyperactivity, impulsivity, academic underachievement or behavior problems.

Recommendation 1Recommendation 1

Screening questions. Screening questions. – 1. How is your child doing in school?– 2. Are there any problems with learning that you or the

teacher have seen?– 3. Is your child happy in school?– 4. Are you concerned with any behavioral problems in

school, at home, or when your child is playing with friends?

– 5. Is your child having problems completing classwork or homework?

Recommendation 2Recommendation 2The diagnosis of ADHD requires that a child meet DSM-IV criteria.

A critical part of the diagnostic process is that the clinician must ask about or have parents fill out DSM-based checklists that include all of the 18 behaviors.

Equally important, the behaviors should be endorsed as occurring ‘‘often’’ (or ‘‘usually’’or ‘‘frequently’’).

Ascertaining the duration of symptoms is crucial.

Recommendation 3Recommendation 3Evidence directly obtained from parents or caregivers.

Use of scales that screen for multiple behavioral and developmental problems (broadband scales) is not recommended in the diagnosis of children for ADHD

Recommendation 4Recommendation 4

Information from the child’s teacher or other school personnel who have observed the child in the classroom may be obtained from a verbal narrative, telephone calls, written narrative, and rating scales.

Recommendation 5

Evaluation of the child with ADHD should include assessment for coexisting conditions. Coexisting conditions refer to specific clinical diagnoses with symptoms that may mimic ADHD or be associated with ADHD

Recommedation 6Recommedation 6Evidence-based studies do not support

the routine use of other diagnostic testsLaboratory tests Imaging studies.

ThankyouThankyou