Relations between executive function, language, and functional communication in severe aphasia

Figures & data

Table 1. Demographic data of participants, n = 47.

	Total sample (n = 47)	Verbal subgroup (n = 23)	Nonverbal subgroup (n = 24)	Difference between subgroups
Age, mean (range)	64 (26–86)	64 (26–86)	65 (39–85)	p = .856 ^a
Gender, n (%)				p = .813 ^b
Female	13 (27.7)	6 (26.1)	7 (29.2)
Male	34 (72.3)	17 (73.9)	17 (70.8)
Handedness, n (%)				p = .418^b
Right	40 (85.1)	19 (82.6)	21 (87.5)
Left	6 (12.8)	4 (17.4)	2 (8.3)
Ambidextrous	1 (2.1)	0	1 (4.2)
Education number of years, n (%)				p = .640 ^b
≤9 years	20 (42.6)	9 (39.1)	11 (45.8)
10–13 years	21 (44.7)	10 (43.5)	11 (45.8)
>13 years	6 (12.8)	4 (17.4)	2 (8.3)
Months post stroke, mean (range)	81 (6–340)	77.3 (6–270)	85.8 (8–340)	p = .710 ^a
Type of stroke, n (%)				p = .865 ^b
Ischaemic	30 (63.8)	15 (65.2)	15 (62.5)
Haemorrhagic	11 (23.4)	6 (26.1)	5 (20.8)
Both	5 (10.6)	2 (8.7)	3 (12.5)
Unknown	1 (2.1)	0	1 (4.2)
Number of strokes, n (%)				p = .813^b
One	34 (72)	17 (73.9)	17 (70.8)
Two or more^c	13 (28)	6 (26.1)	7 (29.2)
Severity of aphasia ASRS, n (%)				p < .001 ^b
0	4 (8.5)	0	4 (16.7)
1	23 (49.0)	5 (21.7)	18 (75.0)
2	20 (42.6)	18 (78.3)	2 (8.3)
Type of aphasia,^d n (%)				p = .006 ^b
Nonfluent	35 (74.5)	13 (56.5)	22 (91.7)
Fluent	12 (25.5)	10 (43.5)	2 (8.3)

^aMann–Whitney U-test.

^bPearson chi-square test.

^cOf which four (9%) in addition had minor damage to the right hemisphere.

^dRating of fluency according to Western Aphasia Battery (Kertesz, 2007).

Table 2. Results of the CLQT, raw scores for total sample and subgroups.

	Median raw score
Task (total possible score) (Criterion cut score 18–69 years, 70–89 years)	Total sample (n = 47), median raw score (interquartile range)	Verbal (n = 23), median raw score (interquartile range)	Non-verbal (n = 24), median raw score (interquartile range)	Difference between subgroups^a
Symbol cancellation (12) (11, 10)	10 (3–12)	11 (8–12)	4 (0.25–11)	U = 389.5 p = .014
Symbol trails (10) (9, 6)	6 (2–9)	8 (4–10)	2 (1–6)	U = 425 p = .001
Mazes (8) (7, 4)	4 (4–8)	7 (4–8)	4 (3.25–7)	U = 370 p = .033
Design generation (13) (6, 5)	3 (1–5)	5 (3–6)	2 (1–4)	U = 426.5 p = .001
CLQTtotal (43) (33, 25)	24 (11–32)	31 (24–32)	14.5 (7.25–25.5)	U = 440 p ≤ .001

^aMann-Whitney U test

Table 3. Results of the CLQT, transformed scores for total sample and subgroups, comparison to criterion cut scores.

Task (totalpossible score)	Total sample (n=47)		Verbal subgroup (n=23)		Non-verbal subgroup (n=24)
	Median transformed score (IQR)	No (%) below cut score	Median transformed score (IQR)	No (%) below cut score	Median transformed score (IQR)	No (%) below cut score
Symbol cancellation (12)	-1 (-7-1)	25 (53)	0 (-3-1)	9 (39)	-6 (-9.75-0)	16 (67)
Symbol trails (10)	-3 (-6-1)	31 (66)	1 (-4-1)	11 (48)	-5 (-7-2.25)	20 (83)
Mazes (8)	0 (-3-1)	18 (38)	0 (0-1)	4 (17)	-2 (-3-0)	14 (58)
Design generation (13)	-3 (-4-0)	33 (70)	-1 (-3-1)	12 (52)	-3.5 (-5- -2)	21 (88)
CLQTtotal (43)	-7 (-18 - -1)	37 (79)	-1 (-7 - 2)	14 (61)	-14 (-22 – -6.25)	23 (96)

Table 4. Results of the CAT, total sample, and subgroups.

	Median (interquartile range)
	Total sample n = 47	Verbal subgroup n = 23	Nonverbal subgroup n = 24	Difference between subgroups^b
Language comprehension (max 128)	73 (38–91)	91 (73–96)	39.5 (27–67)	U = 507 p < .001
Verbality index (max 99^a)	7 (0–30)	30 (17–47)	0 (0–3.75)	U = 552 p < .001^c
CAT total (max 406^a)	121 (55–212)	212 (153–230)	60.5 (30.25–96)	U = 545 p < .001

^aThis is the total predefined possible score. Additional scores can be obtained in the task of word fluency, where a maximum score is not defined. Median number of words produced for participants was 1 (interquartile range 0–4).

^bMann–Whitney U-test

^cThe group designation is based on VI scores, thus a significant difference between the groups in this variable is self-evident.

Table 5. Results of the ST and CETI, total sample, and subgroups.

	Median (interquartile range)
	Total sample n = 47	Verbal subgroup n = 23	Nonverbal subgroup n = 24	Difference between subgroups^a
Scenario Test (max 54)	37.5 (16–46)	44 (40–51)	17 (7–31)	U = 480.5 p < .001
CETI (max 100)	41.6 (30.9–56.7)	54.2 (42.8–62.1)	36.8 (26.7–41.1)	U = 459.0 p < .001

^aMann.Whitney U-test

Table 6. Total sample (n= 47) Spearman’s rank correlations between linguistic ability (LC, VI, CATtot) and executive functions (CLQT subtests and total score) p-values in parentheses. Significant correlations (p ≤ .01) are indicated in bold text.

	CLQTsc	CLQTst	CLQTm	CLQTdg	CLQTtot
LC	.45 (.001)	.61 (<.001)	.59 (<.001)	.60 (<.001)	.70 (<.001)
VI	.44 (.002)	.37 (.010)	.39 (.006)	.52 (<.001)	.55 (<.001)
CATtot	.47 (.001)	.45 (.001)	.46 (.001)	.58 (<.001)	.61 (<.001)

LC = language comprehension, VI = verbality index, sc = symbol cancellation, st = symbol trails, m = mazes, dg = design generation, tot = total

Table 7. Verbal (n= 23) and non-verbal (n= 24) subgroups. Spearman’s rank correlations between linguistic ability (LC, VI, CATtot) and executive functions (CLQT subtests and total score). P-values in parentheses. Significant correlations (p ≤ .01) are indicated in bold text.

		CLQTsc	CLQTst	CLQTm	CLQTdg	CLQTtot
Verbal	LC	.29 (.176)	.54 (.007)	.47 (.025)	.55 (.006)	.58 (.004)
	VI	.30 (.157)	−.26 (.222)	.06 (.774)	.33 (.127)	.23 (.297)
	CATtot	.39 (.067)	−.17 (.453)	.06 (.777)	.40 (.061)	.24 (.274)
Non-verbal	LC	.30 (.160)	.39 (.061)	.60 (.002)	.40 (.056)	.53 (.008)
	VI	.25 (.231)	.08 (.703)	.47 (.021)	.23 (.285)	.39 (.057)
	CATtot	.36 (.080)	.32 (.123)	.68 (<.001)	.42 (.039)	.58 (.003)

LC = language comprehension, VI = verbality index, sc = symbol cancellation, st = symbol trails, m = mazes, dg = design generation, tot = total

Table 8. Bivariate Spearman’s rank correlation coefficients of CLQTtot, LC, and VI with the ST and CETI. Total sample and subgroups. P-values in parentheses. Significant correlations (p ≤ .01) are indicated in bold text.

		Total sample (n = 46 for ST, n= 47 for CETI)	Verbal subgroup (n= 23)	Nonverbal subgroup (n= 23 for ST, n =24 for CETI)
ST	CLQTtot	.64 (<.001)	.34 (.113)	.71 (<.001)
	LC	.77 (<.001)	.48 (.020)	.63 (.001)
	VI	.77 (<.001)	.39 (.070)	.58 (.004)
CETI	CLQTtot	.42 (.004)	.20 (.360)	.29 (.172)
	LC	.44 (.002)	−.15 (.500)	.31 (.136)
	VI	.63 (<.001)	.16 (.468)	.57 (.004)

Table 9. Spearman’s partial rank correlation coefficients of CLQTtot, LC, and VI with the ST and CETI. Total sample and subgroups. P-values in parentheses. Significant correlations (p ≤ .01) are indicated in bold text.

		Total sample (n = 46 for ST, n = 47 for CETI)	Verbal subgroup (n = 23)	Nonverbal subgroup (n = 23 for ST, n = 24 for CETI)
ST	CLQTtot^a	.26 (.089)	.01 (.958)	.59 (.005)
	LC^b	.32 (.034)	.40 (.074)	.32 (.163)
	VI^c	.46 (.002)	.37 (.103)	.34 (.129)
CETI	CLQTtot^a	.18 (.245)	.33 (.141)	.10 (.649)
	LC^b	−.16 (.294)	−.33 (.140)	−.06 (.788)
	VI^c	.51 (<.001)	.12 (.594)	.49 (.021)

^acontrolling for LC and VI

^bcontrolling for VI and CLQTtot

^ccontrolling for LC and CLQTtot

Figure 1. Verbality index (maximum score 99) on all x-axes. Vertical lines indicating the cut off between the verbal (to the right) and the nonverbal subgroup (to the left). (a) Y-axis shows CLQT total raw score (maximum score 43). (b) Y-axis shows CAT language comprehension (maximum score 128). (c) Y-axis shows Scenario Test scores (maximum score 54). (d) Y-axis shows CETI scores (maximum score 100).

Kertesz, A. (2007). Western aphasia battery revised. San Antonio, TX: Pearson.

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