Qualitative aspects of developmental language impairment relate to language and literacy outcome in adulthood

Figures & data

Table 1. Mean (standard deviation) age and age range of participants at initial testing (T1) and at follow‐up (T2). Also included is information about which study the participants took part in at T1

	Specific language impairment (SLI) (n = 18)	Pragmatic language impairment (PLI) (n = 7)	Autism spectrum disorder (ASD) (n = 11)	Typical (n = 12)
Age at T1	11;11 (3;0)	9;7 (2;3)	10;2 (3;2)	11;2 (2;10)
Range	6;1–15;7	7;0–13;9	6;2–15;11	7;0–15;7
Age at T2	24;8 (4;4)	22;3 (5;4)	21;9 (4;0)	21;6 (3;2)
Range	16;5–31;0	16;2–28;9	16;1–28;9	18;0–28;9
Study cohort
A	8 M	2 M	1 M	–
B	–	1 M	1 M	–
C	1 M	1 F	4 M	1 M, 3 F
D	2 M, 5 F	–	1 M	3 M, 5 F
E	1 M	2 M	2 M	–
F	1 M	1 M	2 M	–

Note: M, male; F, female.

Table 2. Mean (standard deviation) performance of the four groups on the battery of cognitive and language tests at follow‐up. Only statistically significant differences are presented

Domain	Assessment	Specific language impairment (SLI) (n = 18)	Pragmatic language impairment (PLI) (n = 7)	Autism spectrum disorder (ASD) (n = 11)	Typical (T) (n = 12)	Degrees of freedom (d.f.)	F	p	Partial eta^2	Statistical significant differences
Non‐verbal IQ	WASI (ss)	97 (16.95)	105.71 (16.58)	103.36 (19.35)	118.5 (8.61)		4.45	0.008	0.23	SLI<T
Structural language	Goldman–Fristoe (n errors)	4.06 (3.11)	1.43 (1.81)	1.64 (2.16)	0.67 (1.44)		5.64	0.001	0.28	SLI<T
	BPVS‐II (rs)	130.06 (13.68)	127.43 (14.79)	122.73 (21)	146.08 (6.67)		5.53	0.003	0.27	(ASD = SLI)<T
	TROG‐E (ss)	82.77 (13.57)	90.43 (24.33)	95.54 (11.56)	102 (4.35)		5.17	0.003	0.26	SLI<T
Narrative	Initial telling (ss)	88.00 (25.53)	99.14 (25.56)	89.18 (18.95)	104.5 (16.48)		1.64	0.19	0.1	No differences
	Delayed telling (ss)	90.39 (24.95)	101.71 (25.66)	82.82 (11.88)	107.33 (17.68)		3.14	0.04	0.18	ASD<T
	Comprehension (ss)	92.06 (20.98)	79.14 (36.97)	86.64 (22.61)	106.42 (15.74)		2.47	0.08	0.14	No differences
	MLUw (ss)	93.39 (16.33)	102.71 (22.57)	98 (26.88)	93.5 (18.59)		.44	0.23	0.03	No differences
Phonological awareness	Spoonerisms (n correctly transformed)	10.56 (9.57)	19.29 (6.94)	17.36 (10.01)	22.5 (1.73)		5.75	0.002	0.28	SLI<T
Verbal short‐term‐memory	Non‐word repetition (rs)	24.55 (11.33)	36.42 (3.82)	33.90 (8.79)	41.08 (3.42)		9.93	<0.001	0.4	SLI<(PLI = ASD = T)
	Sentence repetition (rs)	19.11 (5.67)	23.71 (3.59)	22.18 (4.73)	29.16 (2.52)		11.83	<0.001	0.45	(SLI = ASD)<T
Pragmatic language ^a	Structural language composite (SLC) (rs)	24 (12.96)	12.57 (8.77)	25.36 (13.94)	0.6 (1.07)		11.8	<0.001	0.48	T<(ASD = SLI)
	Pragmatic language composite (PLC) (rs)	19.29 (9.28)	21.29 (11.21)	37.27 (10.93)	0.5 (0.85)		28.66	<0.001	0.69	T<(SLI = PLI)<ASD
	Structural–pragmatic mismatch (rs)	4.36 (6.83)	−7.71 (8.92)	−11.91 (10.66)	0 (0.92)		11.5	<0.001	0.44	(ASD = PLI)<SLI

Notes: rs, Raw scores; ss, standard scores.

^aSLI = 14; PLI = 7, ASD = 11, Typical = 10. A high score denotes impairment.

Figure 1 Scatterplot showing the relationship between the structural language composite(SLC) and the pragmatic language composite (PLC) of the Communication Checklist — Adult (CC‐A). Higher scores on each index indicate greater deficit.

Table 3. Mean performance (standard deviation) of the specific language impairment (SLI), pragmatic language impairment (PLI), autism spectrum disorder (ASD), and typical (T) groups on the battery of literacy tests. Only statistically significant differences are presented

Assessments	SLI (n = 18)	PLI (n = 7)	ASD (n = 11)	T (n = 12)	F	p	Partial eta^2	Statistical significant differences
OSCCI spelling test (n words spelt correctly)	22.94 (9.66)	30 (9.68)	27.45 (7.23)	36 (3.38)	6.58	<0.01	0.31	SLI<T
TOWRE real word (ss)	72.22 (5.8)	79.14 (7.9)	83.36 (14.36)	94.75 (10)	13.32	<0.01	0.48	(SLI, PLI, ASD)<T; SLI<ASD
TOWRE non‐word (ss)	68.72 (14.61)	86.39 (7.13)	91.18 (18.76)	98.17 (14.44)	10.85	<0.01	0.43	SLI<(T = PLI = ASD)
Proof reading (n errors correctly identified)	5.44 (3.09)	8.43 (4.28)	7.73 (3.1)	9.58 (1.88)	4.85	<0.01	0.25	SLI<T
Proof reading (time, seconds)	111.46 (33.1)	77.21 (27.12)	83.46 (15.68)	66.68 (21.28)	7.87	<0.01	0.35	SLI<(T = PLI = ASD)
Non‐word passage (n errors)	21.94 (10.15)	13.29 (11.34)	20.5 (21.95)	6.67 (3.75)	3.8	<0.05	0.21	(SLI = ASD)<T
Non‐word passage (time, seconds)	126.89 (49)	77.99 (37.07)	69.64 (41.63)	59.07 (13.59)	8.9	<0.01	0.38	SLI<(T = PLI = ASD)

Table 4. Change in linguistic ability over time

		T2
		Poor	Fair	Good
T1	Poor	11 SLI; 5 ASD, 1 PLI	1 SLI, 1 PLI; 4 ASD	2 SLI, 1 PLI, 1 ASD
	Fair	3 SLI, 2 PLI	1 PLI, 1 Typical	1 SLI, 1 PLI, 1 Typical
	Good	1 ASD	2 Typical	8 Typical

Note: ASD, autism spectrum disorder; PLI, pragmatic language impairment; SLI, specific language impairment.

Table

	Cohort
	A	B	C	D	E	F
Research	Analysis of conversational ability in language impairment	Analysis of conversational ability in PLI	Analysis of conversational ability in language impairment	Electrophysiological study of auditory processing in SLI	Behavioural investigation of borderlands of SLI and Autism	Behavioural investigation of borderlands of SLI and Autism
Reference	Adams and Bishop (1989)	Bishop et al. (1994)	Bishop et al. (2000)	McArthur and Bishop (2004)	Bishop and Norbury (2002)	Norbury et al. (2004)
Assessments at T1	Non‐verbalBlock Design and Picture Completion subtests of WISC‐RLinguisticWISC‐R‐VCTROGMLUPragmaticTeacher report	Non‐verbalRCPMLinguisticBPVSITPAPragmaticTeacher reportPrecursor to CCC	Non‐verbalRCPMLinguisticCELF‐R‐RSBPVSMLUPragmaticTeacher reportPrecursor to CCC	Non‐verbalRSPMLinguisticBPVS‐IICELF‐R‐RSTLC‐RSPragmaticNot assessed	Non‐verbalRCPMLinguisticBPVS‐IITROG‐2CELF‐R‐RSPragmaticCCC	Non‐verbalWASI PIQLinguisticBPVS –IICELF‐III‐CDCELF‐III‐RSPragmaticTeacher and/or clinician reportCCC‐2
Specific language impairment (SLI) diagnosis	Based upon teacher and researcher judgement	Not recruited	Scored 1 SD below the mean on at least one linguistic testScoring ⩽10 on CCC precursor	Scoring more than 1 SD below the age‐expected level on at least two linguistic tests	Scored 1 SD below the mean on at least one linguistic testScoring>132 on pragmatic composite of CCC	Standard scores more than –1.25 SD below the mean on two of the three linguistic tests
Pragmatic language impairment (PLI) diagnosis	Based upon teacher and/or researcher judgement	Initially identified by teachers, researchers and/or cliniciansScoring ⩾12 on CCC precursor	Initially identified by teachers, researchers and/or cliniciansScoring ⩾12 on CCC precursor	Not recruited	Scoring<133 on pragmatic composite of CCC	Teacher and/or clinician judgement of significant pragmatic difficultiesConfirmed via CCC‐2

Notes: All participants had a non‐verbal IQ within the normal range. The measures used as an index of ability at T1 are shown in bold.

BPVS, British Picture Vocabulary Scale (Dunn et al.1982); BPVS‐II, British Picture Vocabulary Scale — Second Edition (Dunn et al.1997); CCC, Children's Communication Checklist (Bishop 1998); CCC‐2, Children's Communication Checklist — Second Edition (Bishop 2003); CELF‐R‐RS, Recalling Sentences Subtest from the Clinical Evaluation of Language Fundamentals — Revised (Semel et al.1987); CELF‐III‐CD, Concepts and Directions Subtest from the Clinical Evaluation of Language Fundamentals — Third Edition (Semel et al.1995); CELF‐III‐RS, Recalling Sentences Subtest from the Clinical Evaluation of Language Fundamentals — Third Edition (Semel et al. 1995); ITPA, Illinois Test of Psycholinguistic Ability — Revised Edition (Kirk et al.1968); MLU, mean length of utterance; PLI, pragmatic language impairment; RCPM, Raven's Coloured Progressive Matrices (Raven et al.1986); RSPM, Raven's Standard Progressive Matrices (Raven et al.1992); SLI, specific language impairment; TLC‐RS, Recreating Sentences Subtest from the Test of Language Competence — Expanded Edition (Wiig and Secord 1989); TROG, Test for Reception of Grammar (Bishop 1989); WASI PIQ, Wechsler Abbreviated Scales of Intelligence — Performance IQ (Wechsler and Chen 1999); WISC‐R, Wechsler Intelligence Scales for Children — Revised (Wechsler 1974); and WISC‐R‐VC, Verbal Comprehension Subtest of the Wechsler Intelligence Scales for Children — Revised (Wechsler 1974).

Table

Severity ratings
T1: Cohorts A, C, D, E, F = good, within normal limits on the three linguistic tasks administered; fair, within normal limits on two tasks; and poor, within normal limits on one or no tasks. Cohort B = good, within normal limits on the two tasks administered; fair, within normal limits on one; and poor, within limits on no task.
T2: Good: within normal limits on the BPVS‐II (raw score ⩾134), TROG‐E, MLUw and memory for sentences task from the NEPSY; fair, within normal limits on three of these tasks; poor, within normal limits on two or less of these tasks.

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