The relationship between early literacy skills and speech-sound production in students with intellectual disability and communication difficulties: a cross-sectional study

Figures & data

Table 1. Participants were divided into subgroups according to diagnoses as reported by caregivers, and their used modes of augmentative and alternative communication.

	Only intellectual disability	Autism^a	Down syndrome^a	Cerebral palsy^a	Rare/unknown^a	Total
Number of students	19	33	25	11	28	116
Nonverbal communication	8	28	17	9	21	83
Manual sign	8	18	24	4	17	71
Pictorial support	12	22	17	8	19	78
Speech-generating device	4	7	4	2	4	21

Note: ^aDiagnostic categories besides intellectual disability. The category Nonverbal communication includes facial expressions, gestures, eye contact, and body movement. The category Pictures includes pictorial schedules, single pictures, picture communication boards, and pragmatic organized dynamic displays (PODD).

Table 2. Descriptive statistics and correlations between participants’ (n = 116) speech production – percentage phoneme correct, IQ, age, phonological awareness, and letter-sound knowledge.

Variables	M	SD	95% CI		1	2	3	4	5
			LL	UL
1. Percentage phoneme correct	66.5%	32.4%	60.5%	72.4%	–	.14	.13	.54**	.45**
2. IQ	48.8	13.3	46.4	51.3		–	–0.23*	.20*	.23*
3. Age	13.6	3.2	13.0	14.2			–	.29**	.24*
4. Phonological awareness	12.7	8.0	11.3	14.2				–	.60**
5. Letter-sound knowledge	6.3	2.5	5.9	6.8					–

Note. CI: confidence interval; LL: lower limit; UL: upper limit.

* p < .05.

** p < .01.

Table 3. Hierarchical multiple regression model with speech production PPC as dependent variable.

Variable	B	95% CI for B		SE B	β	R^2 adj	ΔR^2 adj	t	p
		LB	UB
Block 1						0.03	0.03
Constant	21.16	–16.61	58.93	19.07				1.11	.269
Age	0.005	0.00	0.01	0.003	0.17			1.85	.067
IQ	0.44	–0.01	0.90	0.23	0.18			1.94	.055
Block 2						0.29	0.26
Constant	30.73	–2.24	63.70	16.64				1.85	.067
Age	–0.001	–0.01	0.004	0.002	–0.04			–0.44	.662
IQ	0.01	–0.40	0.42	0.21	0.003			–0.04	.967
PA	1.77	0.94	2.59	0.42	0.43			4.25	<.001
LSK	2.72	0.02	5.42	1.36	0.20			2.00	.048

Note. CI: confidence interval; LB: lower bound; UB: upper bound; IQ: intelligence quotient, PA: phonological awareness; LSK: letter-sound knowledge.