Determinants of spoken language comprehension in children with cerebral palsy

Figures & data

Table 1. Potential determinants of spoken language comprehension included in the study, ordered by level of the International Classification of Functioning, Disability, and Health for Children and Youth.

Body structures
Motor type (s110) Motor distribution (s110) Epilepsy (s110)	Spastic or non-spastic CP Unilateral or bilateral Absence or presence of epilepsy
Body functions
Intellectual functioning (b117) Speech functions (yes or no) (b320)	Any test or observational tool for cognitive functioning. Documented as: IQ < 70 or IQ ≥ 70. Speaking or non-speaking (less than five words).
Activities and participation
Speech production (d330) Communication (d350) Arm-hand functioning (d440, 445) Functional mobility (d450, 455, 460, 465) Language activities (d810)—telling stories by child	Viking Speech Scale (VSS); age ≥4;0 years Communication Function Classification System (CFCS) Manual Ability Classification System (MACS) Gross Motor Function Classification System (GMFCS) Whether the child can tell a story without or with the use of AAC: cannot do this, with help, always without help.
Demographic factors
Age Sex	Chronological age in months Boy or girl

CP: cerebral palsy; GMFCS: Gross Motor Function Classification System; MACS: Manual Ability Classification System; CFCS: Communication Function Classification System; VSS: Viking Speech Scale; AAC: Augmentative and Alternative Communication.

Table 2. Demographic and cerebral palsy-related characteristics of the participants.

Sample characteristics	Total cohort	Developmental stage	Developmental stage	Developmental stage
	18 months–8;11 years	Toddlers (18 months–3;11 years)	Preschool children (4;0–5;11 years)	Schoolchildren (6;0–8;11 years)
	n (%)	n (%)	n (%)	n (%)
Total	207 (100)	82 (40)	59 (29)	66 (32)
Age (in months)
Mean [SD]	60.11 [24.60]	35.84 [8.46]	60.49 [7.02]	90.38 [10.03]
Range	17–110	17–47	48–71	72–110
Sex
Boys	122 (59)	46 (56)	40 (68)	36 (55)
Girls	85 (41)	36 (44)	19 (32)	30 (45)
Use of AAC
No	123 (61)	44 (54)	37 (65)	42 (66)
Yes	80 (39)	38 (46)	20 (35)	22 (34)
Missing	4	0	2	2
Language comprehension outcomes
C-BiLLT raw scores*	n = 207 (100)	n = 82 (100)	n = 59 (100)	n = 66 (100)
*Maximum raw score = 87
Between developmental stages:
F = 36.484, p = 0.000
Range	0–84	0–68	1–74	2–84
Mean [SD]	48.45 [23.28]	35.65 [20.77]	49.23 [21.69]	64.16 [17.34]
Body structures
Motor type (s110)
Spastic	168 (86)	69 (89)	45 (85)	54 (84)
Non-spastic	27 (14)	9 (11)	8 (15)	10 (16)
Missing	12	4	6	2
Motor distribution (s110)
Unilateral	76 (37)	35 (43)	19 (33)	22 (33)
Bilateral	129 (63)	47 (57)	38 (67)	44 (67)
Missing	2	0	2	0
Epilepsy (s110)
No	141 (70)	65 (79)	35 (64)	41 (63)
Yes	61 (30)	17 (21)	20 (36)	24 (37)
Missing	5	0	4	1
Body functions
Intellectual functioning (b117)
IQ < 70	54 (30)	15 (19)	16 (31)	23 (45)
IQ ≥ 70	61 (34)	27 (35)	17 (33)	17 (33)
Not yet tested/estimated	65 (36)	36 (46)	18 (35)	11 (22)
Missing	27	4	8	15
Speech functions (no or yes) (b320)
No	39 (19)	20 (24)	14 (25)	5 (8)
Yes	166 (81)	62 (76)	43 (75)	61 (92)
Missing	2	0	2	0
Activities and participation
Speech production (d330)—VSS
Not yet specified (age below 4)	82 (40)	82 (100)	0 (0)	0 (0)
Age above 4, total	126 (100)		59 (100)	66 (100)
I	42 (37)		17 (33)	25 (40)
II	32 (28)		14 (27)	18 (29)
III	22 (19)		6 (12)	16 (26)
IV	17 (15)		14 (27)	3 (5)
Missing	12		8	4
Communication (d350)—CFCS
I	60 (31)	17 (23)	19 (35)	24 (36)
II	37 (19)	9 (12)	11 (20)	17 (26)
III	29 (15)	12 (16)	8 (15)	9 (14)
IV	51 (26)	21 (28)	16 (29)	14 (21)
V	8 (4)	5 (7)	1 (2)	2 (3)
Not yet specified	11 (6)	11 (15)	0 (0)	0 (0)
Missing	11	7	4	0
Arm-hand functioning (d440, 445)—MACS
I	33 (19)	12 (19)	10 (20)	11 (18)
II	57 (33)	17 (27)	16 (32)	24 (39)
III	42 (24)	8 (13)	16 (32)	18 (29)
IV	21 (12)	10 (16)	4 (8)	7 (11)
V	11 (6)	5 (8)	4 (8)	2 (3)
Not yet specified	11 (6)	11 (17)	0 (0)	0 (0)
Missing	32	19	9	4
Functional mobility (d450, 455, 460, 465)—GMFCS
I	53 (26)	23 (29)	14 (25)	16 (24)
II	53 (26)	18 (23)	15 (26)	20 (30)
III	27 (13)	10 (13)	8 (14)	9 (14)
IV	45 (22)	15 (19)	13 (23)	17 (26)
V	22 (11)	11 (14)	7 (12)	4 (6)
Not yet specified	2 (1)	2 (3)	0 (0)	0 (0)
Missing	5	3	2	0
Language activities (d810)—telling stories by child
Cannot do this	45 (32)	27 (46)	11 (29)	7 (17)
With help	61 (44)	23 (39)	17 (45)	21 (50)
Always without help	33 (24)	9 (15)	10 (26)	14 (33)
Missing	68	23	21	24

Missing: Information was not available. SD: standard deviation; AAC: Augmentative and Alternative Communication; GMFCS: Gross Motor Function Classification System; MACS: Manual Ability Classification System; CFC: Communication Function Classification System; VSS: Viking Speech Scale; C-BiLLT: Computer-Based instrument for Low motor Language Testing.

Figure 1. C-BiLLT raw score by age in months, filtered by GMFCS level.

Grouped scatterplot with on the y-axis C-BiLLT raw score (from 0 to 90, intervals of 10 points) and on the x-axis age in months (from 18 to 114, intervals of 6 months). TD norm data is showed with line graphs (up to the age of 84 months); the upper line is representing percentile 84, the middle line is representing percentile 50, and the lowest line is representing percentile 16. Scatters are grouped following the GMFCS level; level I is represented by a blue square, level II is represented by a red asterisk, level III is represented by a yellow diamond, level IV is represented by a purple plus, and level V is represented by a green multiplication sign.

Table 3. C-BiLLT performances per developmental stage and potential determinants.

C-BiLLT performances	Total cohort			Developmental stage			Developmental stage			Developmental stage
	18mo–8;11 years			Toddlers (18 months–3;11 years)			Preschool children (4;0–5;11 years)			Schoolchildren (6;0–8;11 years)
	n = 207 (100%)			n = 82 (100%)			n = 59 (100%)			n = 66 (100%)
	Average	Below average	p	Average	Below average	p	Average	Below average	p	Average	Below average	p
Total^a	82 (41)	120 (59)	0.560	29 (36)	52 (64)	0.528	22 (39)	35 (61)	0.953	31 (48)	33 (52)	0.506
Body structures
Motor type (s110)^b
Spastic	65 (83)	101 (89)	0.578	25 (89)	43 (88)	0.279	17 (85)	28 (85)	0.889	23 (77)	30 (91)	0.145
Non-spastic	13 (17)	13 (11)		3 (11)	6 (12)		3 (15)	5 (15)		7 (23)	3 (9)
Motor distribution (s110)^b
Unilateral	38 (46)	36 (30)	0.025	16 (57)	18 (34)	0.072	9 (41)	10 (29)	0.336	13 (42)	8 (24)	0.132
Bilateral	44 (54)	84 (70)		12 (43)	35 (66)		13 (59)	25 (71)		18 (58)	25 (76)
Epilepsy (s110)^b
No	67 (59)	71 (84)	0.001	22 (79)	41 (79)	0.961	20 (91)	15 (45)	0.001	24 (80)	15 (45)	0.005
Yes	47 (41)	14 (16)		6 (21)	11 (21)		2 (9)	18 (55)		6 (20)	18 (55)
Body functions
Intellectual functioning (b117)^c
IQ < 70	8 (15)	47 (38)	0.000	2 (7)	13 (27)	0.011	1 (6)	15 (49)	0.001	5 (21)	17 (71)	0.000
IQ ≥ 70	21 (40)	39 (31)		14 (52)	12 (24)		11 (61)	6 (19)		14 (58)	3 (13)
Not yet tested/estimated	24 (45)	39 (31)		11 (41)	24 (49)		6 (33)	10 (32)		5 (21)	4 (16)
Speech functions (no or yes) (b320)^b
No	4 (5)	35 (29)	0.000	1 (4)	19 (37)	0.006	1 (5)	13 (37)	0.005	1 (3)	4 (12)	0.185
Yes	78 (95)	85 (71)		27 (96)	33 (63)		21 (95)	22 (63)		30 (97)	29 (88)
Activities and participation
Speech production (d330)—VSS^c	n = 125 (100%)			n.a.
I	31 (58)	10 (16)	0.000				12 (60)	5 (16)	0.000	19 (61)	5 (17)	0.000
II	15 (28)	19 (31)					6 (30)	8 (26)		8 (26)	9 (31)
III	4 (8)	18 (29)					1 (5)	5 (16)		3 (10)	13 (45)
IV	3 (6)	15 (24)					1 (5)	13 (42)		1 (3)	2 (7)
Communication (d350)—CFCS^c
I	45 (56)	14 (14)	0.000	11 (43)	6 (16)	0.001	16 (73)	3 (9)	0.000	18 (58)	5 (15)	0.000
II	14 (17)	23 (22)		4 (15)	5 (14)		4 (17)	7 (21)		6 (19)	10 (30)
III	10 (12)	18 (17)		5 (19)	6 (16)		1 (5)	7 (21)		4 (13)	5 (15)
IV	11 (14)	41 (39)		6 (23)	15 (40)		1 (5)	15 (46)		3 (10)	11 (34)
V	1 (1)	8 (8)		0 (0)	5 (14)		0 (0)	1 (3)		0 (0)	2 (6)
Arm-hand functioning (d440, 445)—MACS^c
I	23 (32)	12 (13)	0.001	5 (26)	7 (21)	0.044	6 (30)	4 (13)	0.026	11 (35)	0 (0)	0.001
II	28 (38)	29 (32)		8 (42)	9 (28)		8 (40)	8 (27)		11 (35)	12 (41)
III	15 (21)	26 (28)		3 (16)	5 (15)		5 (25)	11 (37)		7 (23)	10 (34)
IV	4 (5)	17 (18)		3 (16)	7 (21)		0 (0)	4 (13)		1 (3)	6 (21)
V	3 (4)	8(9)		0 (0)	5 (15)		1 (5)	3 (10)		1 (3)	1 (3)
Functional mobility (d450, 455, 460, 465)—GMFCS^c
I	26 (33)	26 (22)	0.031	10 (39)	12 (24)	0.021	6 (27)	8 (23)	0.207	10 (32)	6 (18)	0.071
II	25 (31)	27 (23)		8 (31)	10 (20)		7 (32)	8 (23)		10 (32)	9 (27)
III	12 (15)	15 (13)		4 (15)	6 (12)		4 (18)	4 (11)		4 (13)	4 (12)
IV	14 (17)	31 (26)		4 (15)	11 (22)		4 (18)	9 (26)		6 (19)	11 (33)
V	3 (4)	19 (16)		0 (0)	11 (22)		1 (5)	6 (17)		1 (3)	3 (9)
Language activities (d810)—telling stories by child^c	n = 138 (100%)			n = 59 (100%)			n = 37 (100%)			n = 42 (100%)
Cannot do this	4 (7)	40 (53)	0.000	2 (9)	25 (66)	0.000	0 (0)	10 (48)	0.008	2 (8)	5 (29)	0.001
With help	32 (52)	27 (36)		13 (62)	10 (26)		10 (63)	7 (33)		9 (38)	11 (65)
Always without help	25 (41)	8 (11)		6 (29)	3 (8)		6 (37)	4 (19)		13 (54)	1 (6)
Demographic data
Sex^b
Boys	51 (62)	66 (55)	0.384	15 (54)	30 (57)	0.959	19 (86)	19 (54)	0.012	17 (55)	18 (56)	0.981
Girls	31 (38)	54 (45)		13 (46)	23 (43)		3 (14)	16 (46)		14 (45)	14 (44)

Percentile scores are provided for the C-BiLLT. Spoken language comprehension performance was based on percentile scores for children <7 years. A percentile score of <16 was defined as below average spoken language comprehension and a score ≥16 as average spoken language comprehension. Norm data for C-BiLLT is provided for <7 years. For children >7 years a raw score of >74 is considered as at least an age equivalent of >7 years (average). SD: standard deviation; AAC: Augmentative and Alternative Communication; GMFCS: Gross Motor Function Classification System; MACS: Manual Ability Classification System; CFC: Communication Function Classification System; VSS: Viking Speech Scale; C-BiLLT: Computer-Based instrument for Low motor Language Testing; n.a.: not applicable.

^aMann–Whitney U test.

^bFisher Exact test.

^cKruskal–Wallis test.

Table 4. Univariate analysis of determinants per developmental stage of spoken language comprehension (C-BiLLT raw scores).

Cohort	Total cohort			Developmental stage			Developmental stage			Developmental stage
Univariate analysis of determinants	18mo–8;11 years			Toddlers (18 months–3;11 years)			Preschool children (4;0–5;11 years)			Schoolchildren (6;0–8;11 years)
	B	95% CI for B	p	B	95% CI for B	p	B	95% CI for B	p	B	95% CI for B	p
Body structures
Motor type (s110) (ref = spastic)	−0.003	−0.018 to 0.012	0.671	−0.026	−0.046 to −0.005	0.015	0.013	−0.009 to 0.036	0.235	0.017	−0.007 to 0.042	0.164
Motor distribution (s110) (ref = unilateral)	−7.663	−14.269 to −1.056	0.023	−8.742	−17.821 to 0.336	0.059	−14.658	−26.325 to −2.991	0.015	−7.422	−16.533 to 1.689	0.109
Epilepsy (s110) (ref = no)	−8.068	−14.965 to −1.171	0.022	−2.893	−14.203 to 8.416	0.612	−19.564	−30.060 to −9.068	0.000	−15.965	−24.035 to −7.895	0.000
Body functions
Intellectual functioning (b117) (ref = IQ < 70)	−16.034	−23.221 to −8.847	0.000	−20.607	−30.984 to −10.231	0.000	−22.393	−33.855 to −10.932	0.000	−18.436	−27.233 to −9.639	0.000
Speech functions (no or yes) (b320) (ref = no)	35.213	28.639 to 41.788	0.000	30.679	22.447 to 38.911	0.000	31.453	20.973 to 41.934	0.000	31.844	17.716 to 45.972	0.000
Activities and participation
Speech production (d330)—VSS
I	Ref			n.a.			Ref			Ref
II	−5.225	−12.663 to 2.213	0.167				−5.605	−17.812 to 6.602	0.360	−4.252	−13.097 to 4.592	0.340
III	−17.902	−26.161 to −9.644	0.000				−21.010	−37.071 to −4.948	0.011	−18.646	−27.650 to −9.641	0.000
IV	−40.902	−49.738 to −32.066	0.000				−35.034	−47.241 to −22.826	0.000	−41.958	−59.043 to −24.874	0.000
Communication (d350)—CFCS
I	Ref			Ref			Ref			Ref
II	−7.685	−14.753 to −0.616	0.033	−3.895	−16.658 to 8.867	0.544	−10.574	−22.480 to 1.332	0.081	−10.457	−18.466 to −2.447	0.011
III	−11.752	−19.331 to −4.172	0.003	1.882	−9.790 to 13.555	0.748	−21.711	−34.955 to −8.466	0.002	−11.512	−21.186 to −1.838	0.021
IV	−24.819	−31.209 to −18.428	0.000	−11.499	−21.599 to −1.398	0.026	−35.586	−46.248 to −24.923	0.000	−20.671	−29.011 to −12.330	0.000
V	−53.907	−66.449 to −41.315	0.000	−35.518	−51.268 to −19.767	0.000	−64.211	−96.452 to −31.969	0.000	−65.457	−83.595 to −47.318	0.000
Arm-hand functioning (d440, 445)—MACS
I	Ref			Ref			Ref			Ref
II	−5.303	−13.657 to 3.051	0.212	−4.113	−16.057 to 7.831	0.492	−5.662	−21.812 to 10.487	0.484	−10.802	−21.987 to 0.382	0.058
III	−11.084	−19.986 to −2.181	0.015	−10.583	−25.043 to 3.876	0.148	−17.537	−33.687 to −1.388	0.034	−13.749	−25.554 to −1.943	0.023
IV	−23.874	−34.501 to −13.248	0.000	−10.983	−24.548 to 2.581	0.110	−28.350	−52.051 to −4.649	0.020	−35.169	−49.920 to −20.418	0.000
V	−39.848	−53.102 to −26.595	0.000	−35.983	−52.846 to −19.121	0.000	−38.850	−62.551 to −15.149	0.002	−31.955	−55.407 to −8.502	0.008
Functional mobility (d450, 455, 460, 465)—GMFCS
I	Ref			Ref			Ref			Ref
II	−3.077	−10.822 to 4.668	0.434	−8.056	−18.994 to 2.883	0.146	−1.648	−14.855 to 11.559	0.803	−4.234	−15.214 to 6.747	0.443
III	−4.173	−13.674 to 5.327	0.387	−5.200	−18.366 to 7.966	0.434	−6.839	−22.591 to 8.912	0.388	−2.312	−16.325 to 11.700	0.742
IV	−10.048	−18.091 to −2.004	0.015	−16.333	−27.869 to −4.789	0.006	−12.560	−26.249 to 1.128	0.071	−7.930	−19.202 to 3.342	0.164
V	−39.163	−49.227 to −29.099	0.000	−35.364	−48.105 to −22.622	0.000	−42.571	−59.023 to −26.120	0.000	−32.062	−50.153 to −13.972	0.001
Language activities (d810)—telling stories
Cannot do this	Ref			Ref			Ref			Ref
With help	31.345	24.376 to 38.315	0.000	26.043	16.457 to 35.630	0.000	37.259	26.729 to 47.788	0.000	18.000	5.706 to 30.294	0.005
Always without help	38.720	30.633 to 46.806	0.000	25.222	12.218 to 38.226	0.000	40.900	29.084 to 52.716	0.000	28.643	15.683 to 41.602	0.000
Demographic factors
Age (in months)	0.543	0.434 to 0.651	0.000	1.421	0.975 to 1.866	0.000	0.273	−0.558 to 1.104	0.513	0.182	−0.252 to 0.616	0.406
Sex (ref = boys)	−0.399	−6.957 to 6.159	0.905	2.463	−6.775 to 11.700	0.597	−17.474	−28.854 to −6.093	0.003	8.983	0.510 to 17.457	0.038

Ref: reference category; GMFCS: Gross Motor Function Classification System; MACS: Manual Ability Classification System; CFC: Communication Function Classification System; VSS: Viking Speech Scale; n.a.: not applicable.p < 0.05 is considered significant.

Table 5. Multivariable analysis of determinants per developmental stage of spoken language comprehension (C-BiLLT raw scores).

Multivariable analysis of determinants	Developmental stage
	Toddlers (18 months–3;11 years)
R square = 0.637	B	95% CI for B	p
Speech functions (no or yes) (b320)	21.805	12.446 to 31.164	0.000
Age (in months)	1.232	0.758 to 1.706	0.000
Communication (d350)—CFCS
I	Ref
II	−5.724	−14.786 to 3.339	0.211
III	−3.603	−12.133 to 4.926	0.401
IV	−4.231	−12.268 to 3.805	0.296
V	−23.543	−38.117 to −8.968	0.002
Motor type (s110)	−0.033	−0.059 to −0.008	0.011
Multivariable analysis of determinants	Developmental stage
	Preschool children (4;0–5;11 y)
R square = 0.820	B	95% CI for B	p
Language activities (d810)—telling stories
Cannot do this	Ref
With help	21.461	8.333 to 34.589	0.002
Always without help	21.734	7.059 to 36.410	0.005
Speech functions (no or yes) (b320)	15.709	2.370 to 29.047	0.023
Communication (d350)—CFCS
I	Ref
II	−4.946	−14.414 to 4.522	0.294
III	1.491	−15.919 to 18.900	0.862
IV	−13.297	−25.586 to −1.008	0.035
V	n.a.
Multivariable analysis of determinants	Developmental stage
	Schoolchildren (6;0–8;11 y)
R square = 0.807	B	95% CI for B	P
Communication (d350)—CFCS
I	Ref
II	−6.451	−14.034 to 1.133	0.092
III	3.629	−5.743 to 13.000	0.434
IV	16.909	−26.574 to −7.244	0.001
V	n.a.
Intellectual functioning (b117)	−7.642	−14.556 to −0.728	0.032
Arm hand functioning (d440, 445)—MACS
I	Ref
II	−9.679	−17.406 to −1.952	0.016
III	−13.507	−22.138 to −4.875	0.003
IV	−24.925	−38.011 to −11.840	0.001
V	−58.655	−77.334 to −39.976	0.000

Ref: reference category; GMFCS: Gross Motor Function Classification System; MACS: Manual Ability Classification System; CFC: Communication Function Classification System; VSS: Viking Speech Scale; n.a.: not applicable.

Data availability statement

The data that support the findings of this study are available from the corresponding author (EV), upon reasonable request.