Verbal short-term memory deficits in Down syndrome: phonological, semantic, or both?

Table 2 Means (SDs), marginal mean (SEs) and effect sizes (η^2p) on experimental tasks testing the phonological hypothesis

	DS Mean (SD)	Control Mean (SD)	Condition Marginal Mean (SE)	Effect size (η^2p) for Group, Condition & Interaction
Phonological Similarity Task
Span
Similar Condition	2.08 (0.65)	2.61 (0.58)	2.35 (0.10)	Group η^2p = 0.32; Condition η^2p = 0.36;
Dissimilar Condition	2.36 (0.68)	3.50 (1.00)	2.93 (0.14)	Interaction η^2p = 0.14
Group Marginal Mean (SE)	2.22 (0.15)	3.06 (0.15)
Proportion Correct
Similar Condition	0.51 (0.17)	0.57 (0.18)	0.54 (0.03)	Group η^2p = 0.08; Condition η^2p = 0.35;
Dissimilar Condition	0.54 (0.20)	0.69 (0.21)	0.61 (0.03)	Interaction η^2p = 0.20
Group Marginal Mean (SE)	0.53 (0.04)	0.63 (0.04)
Nonword Discrimination Task ^{a, b}
2-syllable Proportion Correct	0.69 (0.11)	0.88 (0.13)	0.78 (0.03)	Group η^2p = 0.66; Syllable η^2p = 0.13;
3-syllable Proportion Correct	0.65 (0.14)	0.76 (0.18)	0.70 (0.04)	Interaction η^2p = 0.17
4-syllable Proportion Correct	0.51 (0.15)	0.86 (0.11)	0.69 (0.03)
5-syllable Proportion Correct	0.59 (0.13)	0.63 (0.17)
Group Marginal Mean (SE)	0.62 (0.02)	0.83 (0.02)

^an = 11 in each group
^b Group marginal mean and syllable effect size reported are for 2–4 syllable nonwords only, given that neither group performed above chance on the 5-syllable nonwords

ISSN: 1866-1955