TABLE 1.

Group characteristics at the start of formal reading instruction

	Typical controls	At-risk children with typical reading outcomes	At-risk children with poor reading outcomes	MANOVA F(max df = 2,72)
General information
n	39 (21 f/18 m)	18 (7 f/11 m)	17 (9 f/8 m)
Age (in months)	66.62 ± 4.15	65.94 ± 3.21	68.47 ± 4.68	2.06
Nonverbal IQ	102.59 ± 9.68	99.56 ± 8.27	92.71 ± 10.02	5.21**b
Classification variables (initial screening)
Phonological awareness	10.77 ± 1.68	9.64 ± 1.82	8.52 ± 1.54	11.78***a
Rapid naming	105.41 ± 9.81	89.25 ± 11.09	87.07 ± 13.26	18.11***a
Letter-sound knowledge	107.90 ± 11.78	97.33 ± 13.90	91.00 ± 12.21	12.28***a
Letter identification	109.73 ± 8.14	102.00 ± 9.09	96.62 ± 8.81	15.69***a
Word identification	123.10 ± 28.43	100.39 ± 15.76	94.18 ± 13.76	13.02***a
Speech and language skills
Sentence comprehension	11.79 ± 3.67	11.78 ± 2.60	9.94 ± 2.61	2.05
Vocabulary	120.38 ± 14.59	114.39 ± 11.72	108.82 ± 14.71	3.04
Speech accuracy (%)	94.10 ± 4.29	91.55 ± 7.20	86.88 ± 6.63	7.95***c
Socioeconomic status
Mother’s educatione	18.92 ± 2.19	18.67 ± 2.12	15.53 ± 3.22	16.70***c
Father’s educatione	17.61 ± 3.57	17.47 ± 3.04	14.12 ± 3.14	7.67***c
Total parent education and occupationf	51.77 ± 9.25	50.94 ± 9.43	37.53 ± 11.32	15.49***c
Right-hemispheric superior longitudinal fasciculus (SLF)
Anterior segmentg	0.43 ± 0.06	0.44 ± 0.06	0.40 ± 0.08	2.79
Middle segmentg	0.42 ± 0.06	0.43 ± 0.05	0.41 ± 0.05	1.15
Posterior segmentg	0.43 ± 0.06	0.48 ± 0.05	0.43 ± 0.07	3.49*d

Note: Standardized scores provided unless otherwise specified;

^*p < .05,

^**p < .01,

^***p ≤ .001.

^aFDR-corrected post-hoc tests on a one-way ANOVA by group found that typical controls performed significantly better than at-risk children with typical and poor word reading skills; at-risk groups did not significantly differ.

^bFDR-corrected post-hoc tests on a one-way ANOVA by group found that typical controls performed significantly better than only at-risk children with poor word reading skills; at-risk groups did not significantly differ.

^cFDR-corrected post-hoc tests on a one-way ANOVA by group found that typical controls and at-risk children with typical reading skills performed significantly better than at-risk children with poor reading skills, typical controls did not significantly differ from at-risk children with typical reading skills.

^dFDR-corrected post-hoc tests on a one-way ANOVA by group found that at-risk children with typical reading skills showed significantly higher FA than at-risk children with both poor reading skills as well as typical controls, typical controls did not significantly differ from at-risk children with poor reading skills.

^eIndex for level of education from the Barratt simplified measure of social status (scale: 3–21)

^fBarratt simplified measure of social status (score based on parent education and occupation prestige out of 66)

^gFractional anisotropy values, which range on a scale from 0 to 1.