Presentation is loading. Please wait.

Presentation is loading. Please wait.

Martha Bridge Denckla, MD. May 4, 2012.  Colloquial: more than one task accomplished simultaneously  Cognitive science: more than one task between or.

Similar presentations


Presentation on theme: "Martha Bridge Denckla, MD. May 4, 2012.  Colloquial: more than one task accomplished simultaneously  Cognitive science: more than one task between or."— Presentation transcript:

1 Martha Bridge Denckla, MD. May 4, 2012

2  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  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  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  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  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  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  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  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  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  Lack of efficient response preparation impairs automaticity of one of dual tasks  Insufficient inhibition impairs allocation of attention to novel processing demands

12  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 4 th grade  Suspect “processing speed” issue complicated by working memory deficit

13  Analysis of Processing Speed and Working Memory in Experimental tasks  fMRI of Working Memory  aMRI/DTI of relevant brain connectivity  Electrophysiology of Multitasking

14 Joshua Ewen, MD Kennedy Krieger Institute/JHUSOM Spectrum 2012 ewen@kennedykrieger.org

15 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  Reading Fluency  Conversation  Sports, Video Games  Driving

17 S R

18 “Cognitive Processing” S Visual Proc Stimulus EvalResponse SelResponse Exec RRT

19

20  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  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 EvalResponse SelResponse Exec RRT

22 S Visual Proc Stimulus EvalResponse SelResponse Exec RRT ?

23 Stimulus Onset Asynchrony (SOA) T1T2

24 Response Sel Visual Proc Stimulus EvalResponse SelRE Visual Proc Stimulus EvalResponse SelRE Visual Proc Stimulus EvalResponse SelRE Visual Proc Stimulus EvalRE

25 Response Sel Visual Proc Stimulus EvalResponse SelRE Visual Proc Stimulus EvalRE Long SOA Short SOA

26 Marois & Ivanoff, Trends in Cog Sci 2005

27  “Central processing bottleneck”  Amodal

28  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 Response Sel Visual Proc Stimulus EvalResponse SelRE Visual Proc Stimulus EvalRE Response Sel Visual Proc Stimulus EvalResponse SelRE Visual Proc Stimulus EvalRE

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

31 Ewen et al, Dev Neuropsychol 2012 F (1,34) = 3.97, p = 0.05; η p ² = 0.11

32  Conclusions: 1. Kids with ADHD have a higher cost for multi-tasking 2. This cost manifests in processing speed 3. This cost represents slowed response selection

33 S Visual Proc Stimulus EvalResponse SelResponse Exec RRT ?

34  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 Luck, Psychol Bulletin 1998

36

37 1. No significant effect of diagnosis on P3 latency 2. P3 and PRP reasonably independent:  P3 latency predicted only 6% of PRP results 3. PRP (plus P3) predict reading fluency  Δ R 2 = 0.27  Majority of the effect from PRP  ADHD showed stronger PRP-fluency effect than controls

38 1. Children with ADHD have slowed processing speed 2. Motor slowing is not a confound in some measures 3. Response Selection is slowed in ADHD  Increased costs for multi-tasking  Relationship to fluency 4. Stimulus Evaluation may be slowed, but perhaps not a key contributor

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

40  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  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  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


Download ppt "Martha Bridge Denckla, MD. May 4, 2012.  Colloquial: more than one task accomplished simultaneously  Cognitive science: more than one task between or."

Similar presentations


Ads by Google