Correlation between self-report questionnaire and mental chronometry measure of motor imagery ability in children with DCD versus TD children Presenter: Chu-Chun Cheng Advisor: Rong-Ju Cherng

Introduction -DCD Developmental coordination disorder (DCD) – Performance in daily life activities that require motor coordination (e.g. sports or handwriting) is substantially below that expected by age and IQ – The disturbance significantly interferes with academic achievements or activities of daily living – Is not due to a general medical condition – If mental retardation is present, motor difficulties must be in excess of those usually associated with it (APA, 1994 )

Introduction -DCD Prevalence – 5% to 8% of all school-aged children – Boy to girl 2:1 ratio (Sugden & Chambers, 1998) Internal modeling deficit theory – Internal models predict outcome of movement before slow sensorimotor feedback becomes available – Deficit leads to severely reduced motor control and learning ability (Maruff et al., 1999; Wilson et al., 2004; Wilson et al., 2001)

Introduction Forward internal models predict the future sensorimotor state (e.g., position, velocity) given the efferent copy of the motor command and the current state – For physically executed movement, noisy and delayed sensory feedback combined with forward internal model output provide accurate and precise state estimation – For mentally simulated movement, forward internal model output is the only basis for state estimation

Introduction -Motor Imagery Motor imagery- mental process during which a subject internally simulates a movement without any corresponding motor output Imagined and executed movements show – Same spatiotemporal characteristics – Obey same motor rules and biomechanical constraints – Trigger similar motor representations and share overlapping neural substrates

Introduction -Motor Imagery Motor imagery shown repeatedly to improve motor performance by mental training – Improves muscular force and arm kinematics – Reduces movement variability in locomotor tasks – Enhances service performance in volleyball players – Associated with changes in brain activation for both healthy individuals and stroke patients

Introduction -Motor Imagery Motor imagery should express motor properties pertaining to the action – Fitts’s law of speed-accuracy trade-off (Decety, Jeannerod & Prablanc, 1989; Sirigu et al., 1996) – Time course of actual & imagined action highly correlated for adults (Decety& Michel, 1989; Sirigu et al., 1996)

Introduction -Mental Chronometry Walking task, 5 yr olds vs. 7 yr olds Standard vs. informed condition 7 yr olds show expected time increase with harder task requirements (Molina et al., 2008)

Introduction -Motor Imagery Movement Imagery Questionnaire-Revised – Eight tasks – Two subscales: visual and kinesthetic – total score 56, range 4-28 on each subscale – Score imagery vividness on visual analogue scale (VAS) ranging from 1 (very hard to see/feel) to 7 (very easy to see/feel) – Good imaginers: score>39

Research Question Does score on MIQ-R indicating good imagery ability translate into better mental chronometry results on LE gross motor tasks for both children with DCD and TD children?

Hypothesis Children with DCD will have more variable and generally worse MI ability as measured by mental chronometry compared to TD children Children with DCD will have more variable scores on MIQ-R compared to TD children

Methods Participants – Elementary school children between 7-10 M-ABC-II > 20% M-ABC-II 5-15% PPVT-R test >20% TD group DCD group

Methods Assessment tool – Movement Assessment Battery for Children- Second Edition (Henderson, Sugden & Barnett, 2007) – For motor coordination – Age bands: 3-6, 7-10, and – Three components: manual dexterity (3), aiming & catching (2), and balance (3)

Methods Assessment tool – Peabody Picture Vocabulary Test-Revised ( 陸莉與劉鴻香， 2005) – For cognition – Age: 3-12 – 125 questions

Methods Procedure – MIQ-R administered first – Gross motor task (easy) 2 practice trials 1 run – Gross motor task (hard) 2 practice trials 1 run

Methods Setup- Easy

Methods -Easy Gross motor task (execution) – Clear verbal description of sequenced task – Jumping with both legs together – Stand on “0” platform, start task when hear *ding* sound Gross motor task (imagery) – Emphasize “feeling” the body going through the same movements but remain standing on “0” – Eyes open – Start imagining when hear *ding* sound – Hold main switch, press when feel body jump off “4”

Methods Setup- Hard

Methods -Hard Gross motor task (execution) – Clear verbal description of sequenced task – Jumping with both legs together on “1” & “2” – Step on “3”, Jump off small staircase on “4” with both legs – Stand on “0” platform, start task when hear *ding* sound Gross motor task (imagery) – Emphasize “feeling” the body going through the same movements but remain standing on “0” – Eyes open – Start imagining when hear *ding* sound – Hold main switch, press when feel body jump off “4”

Methods Data Analysis – 2 (Group: DCD vs. TD) by 2 (Condition: easy vs. hard) ANOVA – Pearson’s product moment correlation calculated between actual and imagined movement duration – Pearson’s product moment correlation calculated between individual MIQ-R score and individual actual/imagined correlation coefficient

Expected Results -TD children

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