Biological: Genetics

Question 1

Significant co-morbidity with ADHD (50%) suggesting shared genetic aetiology

Answer 1

Barkley (1990)

Question 2

Barkley (1990)

Answer 2

Significant co-morbidity with ADHD (50%) suggesting shared genetic aetiology.

Question 3

Behaviour-genetic study using questionnaire-based measures of DCD and ADHD

Answer 3

Martin, Piek & Hay (2006)

Question 4

Martin, Piek & Hay (2006)

Answer 4

Behaviour-genetic study using questionnaire-based measures of DCD and ADHD

Question 5

Martin, Piek & Hay (2006) PARTICIPANTS

Answer 5

Parents (mostly mothers) of 5-16yr 1285 Australian twin pairs

Question 6

Martin, Piek & Hay (2006) QUESTIONNAIRES

Answer 6

ADHD: Australian Twin Behaviour Rating Scale (ATBRS)

ADHD: Strengths and Weaknesses of ADHD Symptoms and Normal Behaviour Scale (SWAN)

Developmental Coordination Disorder Questionnaire (DCDQ)

Question 7

DCDQ Questions

Answer 7

Asks parents to rate their child in relation to other children of the same age i.e “Throws a ball in a controlled and accurate fashion”

Question 8

Martin, Piek & Hay (2006) FINDINGS: Estimated heritability of DCD

Answer 8

0.69

Question 9

Martin, Piek & Hay (2006) FINDINGS: Common genetic effects (Ratings of inattention & …)

Answer 9

DCDQ ratings of movement control (0.72)

DCDQ ratings of of handwriting quality (0.66)

Question 10

Limitations of Martin, Piek & Hay (2006)

Answer 10

1. No clinical observation
2. Same parent rated both twins=overestimate similarity of MZ=inflated heritability
3. How much time does mother spend with child?
4. No mention of whether any of the twins were premature/low birth weight (also a biological risk factor)

Question 11

Strengths of Martin, Piek & Hay (2006)

Answer 11

1. Only used twins with determined zygocity: Twin questionnaire which has good agreement with blood/genetic markers (McGuffin et al, 1994)
2. DCDQ good internal consistency and construct validity