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ADHD and multitasking

ADHD and multitasking. Martha Bridge Denckla, MD. May 4, 2012. Definitions of “Multitasking”. Colloquial: more than one task accomplished simultaneously Cognitive science: more than one task between or among which there is rapid shifting or sequential interleaving.

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ADHD and multitasking

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  1. ADHD and multitasking Martha Bridge Denckla, MD. May 4, 2012

  2. Definitions of “Multitasking” • Colloquial: more than one task accomplished simultaneously • Cognitive science: more than one task between or among which there is rapid shifting or sequential interleaving

  3. Interleaving as Multitasking • In a sequence of stimulus-response tasks, response to stimulus #1 overlaps evaluation of stimulus #2 • Reading (most obviously when aloud) involves saying a word while “processing” the next word to the right • Thus fluent reading involves multitasking in the sense of interleaving

  4. Multitasking and Dual Task Performance (DTP) • Dual task performance does refer to simultaneous accomplishment of two tasks • DTP is an experimental probe into R/L hemispheric “shared processing space” • Example: Recite the alphabet while balancing a dowel on R hand’s index finger vs. L hand’s index finger

  5. Conclusions Drawn From DTP • Left hemisphere motor and language “shared processing space” results in greater slow-down of alphabet when R hand’s challenge is to balance the dowel than when Left • Note one “habitual/automatized” (alphabet) and one “novel” (balance dowel) task

  6. Types of Tasks, Multi- or Dual • Each task is established “habitual/automatized” (proverbial “walk and chew gum”) • One task is automatized, the other(s) require online processing, with relative degrees of novelty

  7. Driving With Multitasking • Experienced driver, very familiar route, listens to engrossing book on tape • Experienced driver, new route, misses an exit while listening to routine newscast • Now substitute for just listening the responses in conversation with passenger • Now conversation is on cell phone

  8. Inferring Various Combinations and Challenges • Motor habit, familiar visual environment, attention-grabbing audio-linguistic. MUST STILL REACT TO ALWAYS NOVEL TRAFFIC! • Adding novel response formulations in conversation, worse if passenger (or cell phone partner) doesn’t adjust to traffic • Texting while driving adds overt shift of visual attention plus spelling response

  9. Neuropsychological Concepts/Tests of Multitasking Exist Clinically • Executive Function involves “I-S-I-S” and the last 2, “Inhibit” and “Shift” are explicitly challenged • Color-Word Subtest of Delis-Kaplan Executive Function System • Continuous Performance Tests, including Go/No-Go

  10. Executive Function with ADHD • Diagnosis of ADHD is often associated with cognitive control deficit (synonym for executive dysfunction (EDF) • EDF features of inhibitory insufficiency and inefficient (slow/variable) response preparation are prominent if ADHD • Shifting more dysfunctional with Autistic Spectrum Disorder than with ADHD

  11. How Is Multitasking Performance with ADHD? • Lack of efficient response preparation impairs automaticity of one of dual tasks • Insufficient inhibition impairs allocation of attention to novel processing demands

  12. The Example of Reading Comprehension with ADHD • Despite good/adequate acquisition of basic skills (use of phonics, memory for sight words with ADHD) • Reading comprehension unexpectedly lags in many with ADHD by 4th grade • Suspect “processing speed” issue complicated by working memory deficit

  13. Center for Study of Reading Development (Project III) Addressed Reading Comprehension with ADHD • Analysis of Processing Speed and Working Memory in Experimental tasks • fMRI of Working Memory • aMRI/DTI of relevant brain connectivity • Electrophysiology of Multitasking

  14. “ADHD: A Matter of Timing” Joshua Ewen, MD Kennedy Krieger Institute/JHUSOM Spectrum 2012 ewen@kennedykrieger.org

  15. Collaborators and Thank-Yous KKI CSRD • Martha Denckla • Mark Mahone • Matthew Ryan • Lisa Ferenc • Priya Xavier JHU Psychological and Brain Sciences • Howard Egeth • Jeff Moher KKI Clinical Neurophysiology Laboratory • Balaji Lakshmanan

  16. Processing Speed in Real Life • Reading Fluency • Conversation • Sports, Video Games • Driving

  17. Conceptualization SR

  18. Conceptualization SR S Visual Proc Stimulus Eval “Cognitive Processing” Response Sel Response Exec R RT

  19. Slowed (and variable) processing speed in ADHD

  20. Processing Speed in ADHD • Well described • Reaction time (RT) tasks • Wodka et al, JCEN 2007 • Oculomotor tasks • Thaler et al, J Atten Disord 2011 • Nielsen & Wiig, Int J Psychiatry Clin Pract 2011. • Mahone et al,JAACAP 2009 • Hynd et al, J Learn Disabil 1989 • Clinical Measures • WISC-IV PSI (Coding and Symbol Search) • Mayes & Calhoun, J Atten Disord 2006 • Reading Fluency • Ghelani et al, Dyslexia 2004 • Willcutt et al, Am J Med Gen B 2007

  21. Which Stage of Processing is Slowed? • Response Execution(i.e., motor) • Doesn’t explain silent reading fluency • Stimulus Evaluation vs. Response Selection • “input-side” vs. “output side” S Visual Proc Stimulus Eval Response Sel Response Exec R RT

  22. Input-Side vs. Output-Side ? S Visual Proc Stimulus Eval Response Sel Response Exec R RT

  23. Psychological Refractory Period T1 T2 Stimulus Onset Asynchrony (SOA)

  24. PRP Visual Proc Stimulus Eval Response Sel RE Visual Proc Stimulus Eval Response Sel RE Visual Proc Stimulus Eval Response Sel RE Visual Proc Stimulus Eval Response Sel RE

  25. PRP Visual Proc Stimulus Eval Response Sel RE Long SOA Visual Proc Stimulus Eval Response Sel RE Short SOA

  26. PRP Marois & Ivanoff, Trends in Cog Sci2005

  27. PRP • “Central processing bottleneck” • Amodal

  28. Neurobiology of the PRP • Some evidence for subcortical contribution • Ivry et al, J Exp Psychol: Hum Percept Perform 1998 • Pashler er al, Neuroreport 1994 • Multiple frontal areas • Marti et al, NeuroImage 2012 • Marois et al, Psychol Res 2006 • Frontal-Parietal Networks • Hesselmann et al, NeuroImage 2011

  29. Individual Response Sel. Differences Visual Proc Stimulus Eval Response Sel RE Visual Proc Stimulus Eval Response Sel RE Visual Proc Stimulus Eval Response Sel RE Visual Proc Stimulus Eval Response Sel RE

  30. PRP in ADHD • 44 children (19 ADHD, 25 control), grades 4-8 • Evaluated PRP effect

  31. PRP: ADHD vs. Controls F(1,34) = 3.97, p = 0.05; ηp² = 0.11 Ewen et al, Dev Neuropsychol 2012

  32. PRP: ADHD vs. Controls • Conclusions: • Kids with ADHD have a higher cost for multi-tasking • This cost manifests in processing speed • This cost represents slowed response selection

  33. Input-Side vs. Output-Side S Visual Proc Stimulus Eval ? Response Sel Response Exec R RT

  34. P3 Source • Parietal association cortex • Picton, J Clinical Neurophysiol 1992 • Combined in PRP-inducing paradigm, inferior parietal—pre-central regions activate • Hesselmann et al, NeuroImage 2011

  35. Combining P3 and PRP:Independence of Two Effects Luck, Psychol Bulletin 1998

  36. No Significant Effect of SOA on P3 Latency

  37. Dual-Task P3 Results • No significant effect of diagnosis on P3 latency • P3 and PRP reasonably independent: • P3 latency predicted only 6% of PRP results • PRP (plus P3) predict reading fluency • ΔR2 = 0.27 • Majority of the effect from PRP • ADHD showed stronger PRP-fluency effect than controls

  38. Conclusions • Children with ADHD have slowed processing speed • Motor slowing is not a confound in some measures • Response Selection is slowed in ADHD • Increased costs for multi-tasking • Relationship to fluency • Stimulus Evaluation may be slowed, but perhaps not a key contributor

  39. Grant Support • P50 HD052121 (MBD; EMM) • K12 NS001696 (H. Singer) • K23 NS073626 (JBE) • Johns Hopkins ICTR • KKI IDDRC

  40. Implications of Ewen et al. • Multitasking involved in reading comprehension is inefficient with ADHD • Recapitulation: Fluency facilitates comprehension and itself depends on interleaving sequential response preparation with overlapping stimulus evaluation

  41. Multitasking in the Agenda of Daily Life (Difficult for Those with ADHD) • On scale of hours, switching and interleaving several strands of life • School (4-5 subjects)/Extracurricular/Home • Work (might be subdivided)/Family • “Covert” multitasking from middle school through life involves “cold” and “hot” cognition (skills/duties vs. social relations)

  42. Examples From My Own Experience As “DocMom” • Holding/bouncing baby, stirring pot of soup, talking on phone to patient • Dictating patients’ reports while sitting in car during sons’ soccer practices • Switching between patient reports and portions of research papers to meet deadlines of others to whom “owe” work • Note necessity of Working Memory to a multitasking agenda

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