Robert A. Leark, Ph.D. Fellow, National Academy of Neuropsychology Associate Professor, Behavioral & Social Sciences

1. Theoretical Models of Explanation Robert A. Leark, Ph.D. Fellow, National Academy of Neuropsychology Associate Professor, Behavioral & Social Sciences Pacific Christian College, Fullerton, CA Vice President, Research & Development, UAD., Inc

2. Theoretical Models of Explanation • Multiple models of explanation for ADHD • Two have emerged as primary theories • Barkley & Gordon • Brown • Attention & executive functioning is multifaceted: difficult to map

3. Theoretical Models of Explanation • Recent Historical Models • Attention is not a unitary construct • Zubin (1995): attention conceptualized as having multiple components or elements • Psychiatric models:attention is process that controls the flow of information processing

4. Theoretical Models of Explanation • Recent Historical Models • Psychiatric models: 3 components of attention: • selectivity • capacity • sustained concentration • All of these must be sufficient enough to interfere with daily activities

5. Theoretical Models of Explanation • Recent Historical Models • Neuropsychologists typically conceptualize attention as: • selective processing • awareness of stimuli

6. Theoretical Models of Explanation • Recent Historical Models • Neuropsychologists use attention to refer to: • initiation or focusing of attention • sustaining attention or vigilance • inhibiting response to irrelevant stimuli (selective attention) • shifting of attention

7. Theoretical Models of Explanation • Riccio, Reynolds & Lowe (2001) summarize components of attention • Arousal/alertness • motor intention/initiation • Selective Attention • focusing of attention (inhibiting/filtering) • divided attention • encoding, rehearsal & retrieval • Sustaining attention/concentration • Shifting of attention

8. Theoretical Models of Explanation • Historical • Broadbent (1973) - capacity to take in information is limited, thus information not relevant needs to be filtered out. Information filtered out dependent upon stimulus characteristics (intensity, importance, novelty, etc.)

9. Theoretical Models of Explanation • Historical • 2nd model stresses arousal - here optimal arousal (alertness) is necessary for effortful, organized function (Hebb, 1958) • Pribram (1975) - arousal is short-lived response to stimulus. Arousal is the general state of the individual that allows for & effects attentional processing

10. Theoretical Models of Explanation • Historical • Mirsky (1987) proposed three factor model for attention • focusing of attention • sustaining of attention • shifting of attention

11. Theoretical Models of Explanation • Historical • Mirsky model • selective attention: part of process of focusing attention (level of distractibility if deficient) • Sustained attention: ability to maintain that focus over time • Shifting of attention: necessary for adaptation & inhibition

12. Theoretical Models of Explanation • Historical • Luria’s model • attention central to model • 2 attentional systems: reflexive & nonreflexive • reflexive: orienting response/appears early in development • nonreflexive: result of social learning/develops slower • limbic system & frontal lobe mediate attention

13. Theoretical Models of Explanation • Historical • Luria’s model • executive functions linked to mediating attention • executive functions: • self-direction • goal directedness • self-regulation • response selection • response inhibition

14. Theoretical Models of Explanation • Mesulam (1981): model similar to Luria’s • Model was specific to understanding phenomenon of hemiattention or hemineglect as result of brain damage • Attentional processes: reticular system, limbic system, frontal cortex & posterior parietal cortex

15. Theoretical Models of Explanation • Mesulam (1981) • Subcortical influences from limbic system, RAS & hypothalamus part of system matrix needed for control of attention • Frontal lobes influenced by & also influence the subcortical activity

16. Theoretical Models of Explanation • Historical • Summary: attention involves at least two separate neural systems • activation system: thought to be centered in left hemisphere & involved in sequential/analytic operations • arousal: thought to be centered in right hemisphere & involved in parallel or holistic processing & maintenance of attention

17. Theoretical Models of Explanation • Barkley & Gordon (1994,1997,1998,2001) • inattention emerges alongside a general pattern of impulsiveness & hyperactivity • deficits in self-control lead to secondary impairments in four executive functions

18. Theoretical Models of Explanation • Barkley & Gordon (1994,1997,1998,2001) • Nonverbal working memory - sensing to the self • verbal working memory - internalized speech • emotional/motivation self regulation - private emotion/motivation to the self • reconstruction or generativity - cover play & behavioral simulation to the self

19. Theoretical Models of Explanation • Barkley & Gordon (1994,1997,1998,2001) • basal ganglia • dopaminergic • disinhibition key factor to etiology

20. Theoretical Models of Explanation • Barkley & Gordon (2001) • ADHD is a longstanding, pervasive and chronically impairing consequence of poor inhibition and/or inattention • model is consistent with the DSM-Ivr criteria • symptoms occur prior to age 7

21. Theoretical Models of Explanation • Brown (1996) • etiology is on purely inattentive • stresses there has been an over-focus on disinhibition and an under appreciation of arousal, activation and working memory • onset of symptoms can occur after age 7

22. Theoretical Models of Explanation • Brown • ADHD criteria includes inattentive individuals who are not impulsive • “all inattention is ADD/ADHD” • ADHD is a suitable diagnosis for a broad range of symptoms • Brown’s rating scale: BADDS - modeled upon this theoretical approach

23. Theoretical Models of Explanation • Brown - ADD/ADHD is still an executive dysfunction of five clusters • organizing & activating to work • sustaining attention & concentration • sustaining energy & effort • managing affective interference • utilizing working memory & recall

24. Theoretical Models of Explanation • Key components of models • inattention is the king of all nonspecific symptoms (Gordon, 1995) • inattention can emerge as a feature from a variety of psychiatric & medical circumstances

25. Clinical Care • History - conception through current age • early life predictors • poor or inability to establish early life routines • motor hyperactivity at early age • ADHD is a diagnosis by exclusion: • low APGAR • hypoxia • central nervous system diseases

26. Issues in Clinical Care

27. Clinical Care • History • ADHD is a diagnosis by exclusion: • head injury/loss of consciousness • metabolic disorders • seizure disorders • apnea • other medical conditions • Other psychiatric conditions

28. Clinical Care • History • ADHD is a diagnosis by exclusion: • ADHD is diagnosed only when other disorders do not best account for the symptoms • symptoms may be same, etiology somewhat different (or unknown) • treatment may even be the same

29. Clinical Care • History • Problems with overlapping co-morbidity create need to be able to stick to DSM IV criteria: age 7 issue • May not be possible to determine if signs & symptoms might have been present (such as trauma-abuse cases) if such trauma had not occured

30. Clinical Care • Diagnostic procedures • Behavioral rating scales • Measure of sustained attention & impulse control • Medication follow-up

31. Clinical Care • Behavior Rating Scales • Child-Behavior Checklist (CBCL) • Parent Rating • Teacher Rating • Item pure scales: no item overlap

32. Clinical Care • Behavior Rating Scales • BASC (Reynolds & Kamphaus) • Ages 2 - 18 • Item pure scales: no item overlap • easy to administer • shorter: about 140 items

33. Clinical Care • Behavior Rating Scales • BASC (Reynolds & Kamphaus) • 2-6: parent/other ratings • 7-12: self rating parent rating teacher rating student observation guide

34. Clinical Care • Behavior Rating Scales • BASC (Reynolds & Kamphaus) • 13-18: self parent teacher student observation guide

35. Clinical Care • Behavior Rating Scales • BASC (Reynolds & Kamphaus) • New: ADHD predictor derived from discriminant function analysis using best predictors

36. Clinical Care • Behavior Rating Scales • Parent Ratings generally show more impairment for child than do Teacher Ratings • May want to use “blind” ratings from Teacher - where Teacher is unaware of use of medication • helpful with treatment follow up studies

37. Clinical Care Issues • Treatment Issues • Treatment consistent with theoretical models for ADHD? • NIMH Treatment Guidelines • Medication effective, data indicated medication alone more effective than • Medication & behavioral treatment • Behavioral treatment alone • Other modalities

38. Clinical Care Issues • Behavioral therapies • Treatment goal: improve/increase inhibition • Treatment strategies must be consistent with goal • Treatment strategies must be incorporated into family system • Often source of increase problems if family not stable • Noncompliance by parents

39. Clinical Care Issues • Newer treatment modalities • Neurofeedback • Issues:standardization of treatment • Length of treatment • Treatment cessation: maintenance of gains

40. Clinical Care • Treatment considerations • Stimulant medication is standard of care • NIMH revenue of ADHD studies suggested that • Stimulant medication alone better than stimulant medication and behavioral therapy, behavioral therapy alone or placebo.

41. Clinical Care • Treatment considerations • Medications • methylphenidate hydrochloride • Ritalin • Sustained Release • Concerta • Amphetamines • Adderall • Dexedrine

42. Clinical Care • Treatment considerations • Medication Issues • kg/mg - is this an appropriate method for titration? • Titration to cognitive measures produces an overall lower mean dosage than for behavioral measures • b.i.d. or t.i.d. • Dosage? • Time of day?

43. Clinical Care • Treatment considerations • Behavioral Treatment • home and classroom based intervention strategies • requires cooperation of parents & teachers • effective - but best when used with medication

44. Clinical Care • Treatment considerations • Family Therapies • Family system with behavioral interventions for child • Does require intact family system

45. Clinical Care • Treatment considerations • Stimulant medication is standard of care • NIMH revenue of ADHD studies suggested that • Stimulant medication alone better than stimulant medication and behavioral therapy, behavioral therapy alone or placebo.

46. Clinical Care Issues • Summary: treatment goals and plans need to be consistent with theoretical models of ADHD • Medication: ritalin, adderall, others

47. Clinical Care Issues • Summary: treatment goals and plans need to be consistent with theoretical models of ADHD • Medication: ritalin, adderall, others

48. Continuous performance tests

49. Grew out of need to provide for a measurement of attention and impulse control • Wanted actual measurement not behavioral attributes

50. Advances in electronics provided format • Historically, measures of sustained attention are intrical to the history of psychology • Study cited as the basis for the origin of cpts is: Rosvold, Mirsky, Sarason, Bransome & Beck (1956). A continuous performance test of brain damage. Journal of Consulting Psychology, 20, 3343-350.