Attention Deficit Hyperactivity Disorder A Neuro-Anatomical Approach to diagnosis and treatment Damon Lipinski, Ph.D. Clinical Psychologist Center for Pediatric Neuropsychology
What is Attention? Different capacities or processes to respond to and shift from specific information present in our environment Necessary for awareness and memory Necessary to maneuver in our environment Necessary for auditory and visual processing
History of ADHD First described over 100 years ago Childhood disorder (boys) hyperactivity or hyperkinesis disorder of childhood (Still 1902) In the 1960s minimal brain damage or minimal brain dysfunction (Clemens 1966) Major shift in 1970s with concept of attention (Douglas 1972)
Prevalence
Levels of Explanation & Research: Evidence for a Biological Basis Subjective Level Diagnostic Criteria and parent questionnaires Neurological Correlates Examination of brain functioning through study of anatomy, neurochemistry, EEG, functional imaging, genetics, comparative anatomy Objective Constructs Clinical Neuropsychology: Objective measures done from a neuro-anatomical perspective
Diagnosis of ADHD DSM-IV ADHD - Predominantly Inattentive Type Fails to give close attention to details or makes careless mistakes Has difficulty sustaining attention Does not appear to listen Struggles to follow through on instructions Has difficulty with organization Avoids or dislikes tasks requiring sustained mental effort Loses things. Is easily distracted Is forgetful in daily activities
Diagnosis of ADHD DSM-IV ADHD - Predominantly Hyperactive/Impulsive Type Fidgets with hands or feet or squirms in chair Has difficulty remaining seated Runs about or climbs excessively Difficulty engaging in activities quietly Acts as if driven by a motor Talks excessively Blurts out answers before questions have been completed Difficulty waiting or taking turns Interrupts or intrudes upon others
Anatomical Imaging Studies Total brain volume Prefrontal volume Caudate volume Globus pallidus Retrocallosal regions Gray matter in frontal gyrus; retrosplenial cortex Corpus callosum Cerebellar volume Cerebellar vermis
Neurochemistry ADHD cognitive impairments associated with too little dopamine in the prefrontal cortex Hyperactivity associated with too much dopamine in striatum
Functional Imaging Studies Functional Magnetic Resonance Imaging (fmri) findings: Greater activation in the control group compared with the ADHD group during mental rotation Striatum Prefrontal Cortex Anterior Cingulate Cortex
Functional Imaging Studies Positron Emission Tomography (PET) Comparison Global metabolism reduced in ADHD
Genetics and ADHD Molecular Genetics Associations of ADHD with variations in certain genes Family & Twin studies: Higher incidence among 1 st and 2 nd degree relatives of affected individuals Parents and Siblings of those with the disorder are 3-5 times more likely to have the disorder Children of ADHD adults are 10 times more likely to have the disorder 50-80% concordance rate in monozygotic twins 33% concordance rate in dizygotic twins
Neuro-Anatomical Model of Attention - Mirsky et. al (1991) The Focus-Execute element represents the ability to select target information from an array for enhanced processing and is thought to be localized to the inferior parietal, superior temporal, and striatal regions The Sustain element represents the capacity to maintain focus and alertness over time and is assigned to the reticular formation of the brain stem and the thalamus The Shift element represents the ability to change attentive focus in a flexible and adaptive manner and is claimed to be localized to the prefrontal cortex
Attention over Time Focused Attention Sustained Attention Shifting Attention
Focused Attention Spatially selective speeded detection tasks (e.g., visual orienting tasks - Posner, 1980) Selective report of one visual object from amongst many - Cancellation Test Selective listening to attend to one voice or sound among many sounds (e.g., attending to a conversation with many other people talking in the background)
Vigilance & Sustained Attention Vigilance requires constant monitoring for signal occurrence Sustained attention is required once selection has occurred and further processing is necessary to complete task Both involve goal maintenance over time Related to arousal levels
Shifting Attention The ability to change attentive focus May have difficulty switching from one activity to another May have difficulty problem solving May have difficulty with perseveration
Attention over Space Associated with right posterior parietal lesions May neglect the left side of a page. May neglect the left side of a word or sentence resulting learning disability. May bump into walls to their left. Simultanagnosia-inability to see more than one object concurrently.
Modality Specific Attention Deficits Attention Deficits can affect just the Auditory system or just the Visual system Auditory Inattention can be a component of Central Auditory Processing Disorder Visual Inattention can be a component of Visual Processing Disorder and Dyslexia
Comorbidity of ADHD - Children Oppositional Defiant Disorder Conduct Disorder Mood Disorders (unipolar/bipolar) Anxiety Disorders Learning Disorders
Comorbidity of ADHD - Adults 5-66% of children persist with ADHD into Adulthood Overall prevalence 3-5% Anxiety Disorders (female) Mood Disorders (female) Antisocial Disorders Alcohol/Drug Dependence
Possible Causes Brain Injury Neurochemical Changes Genetic Factors Prenatal Risks Use of cigarettes or alcohol Complications during pregnancy Exposure to environmental toxins (Lead, PCBs) Other (less scientifically rigorous) Too much TV Sugar Caffeine Food colorings & additives Poor home life / Bad parenting Poor schools
Conclusions A major challenge for the clinician is to find the specific component of attention that is affected in each child and offer pharmacological, cognitive, and behavioral remediation. There is a tendency to treat all children with this Disorder the same. Analysis of the differences seen between children may aid in determining which type of medication will most effective.
Treatment Options Medication Individual Behavioral Therapy Social Skills Training Support Groups Family Therapy & Parenting Skills Training: Simple Behavioral Interventions
Pharmacological Options Psychostimulants (examples given in brackets) Methylphenidate (Ritalin) Dextroamphetamine (Dexadrine) Mixed Salts of Amphetamine (Adderol) Pemoline (Cylert) Antidepressants Tricyclic Antidepressants (Norpramin) Selective Serotonin Reuptake Inhibitors (Zoloft) Bupropion (Wellbutrin) Venlafaxine (Effexor) Other Agents MOAI s ( α- Noradrenergic agonists (e.g. Clonidine) β- Blockers (Propranalol) Atomoxetine (Strattera)
Home and School Modifications Set up a regular routine for homework. Try to schedule homework for the same time & place each day. When they are working on homework, schedule regular breaks for activity every 10 or 15 minutes. Offer rewards for doing homework. Give non-judgmental, constructive feedback.
Modifications continued Provide high interest books and materials to increase motivation to learn. Use assignment book or sheets that the teacher can sign to prevent confusion about assignments. Regular communication between home and school may be necessary for the first several months of school. Often kids with ADHD benefit from classroom accommodations to complete work. Talk to the teacher to see if they need more time, a quiet place to work, or shorter assignments to be successful.
Sleep Hygiene for Children Napping appropriate to age Avoid stimulants Consistent routine Establish a relaxing setting Quiet, dark and cool bedroom Do not go to bed hungry Keep fluids to a minimum Go to bed when drowsy but still awake NO TV, VIDEOGAMES IN BED!