Do gestures have a hand in verb retrieval? Investigation of iconic and non-iconic gestures in aphasia

Figures & data

Table 1. Demographic data and assessment results of individuals with aphasia (P1–P6)

IWA	P1	P2	P3	P4	P5	P6
Gender	F	M	M	M	M	M
Age	59	76	67	61	78	71
Handedness^1	Right	Right	Right	Left	Right	Right
L.Q.	+ 100	+ 100	+ 100	- 100	+ 100	+ 100
Time post-stroke (yrs; mths)	3;1	7;0/4;3	1;10	20;1	4;9	1;0
Aetiology^2	LCH	LCH	LCH	RCH	LCI	LCH
Hemiparesis^3	Right	No	Right	Left	Right	No
Limb apraxia
Pantomime-to-	41	46	45	49	36	54
command task^4
Verbs
Verb naming (n= 34)^5  Verb-picture verification (n = 34)^6 Level of impairment^7	14 23 Lexical-semantic	21* 31* Lexical-semantic/ phonological	27 24 Lexical-semantic	24 33 Phonological	5 4 Lexical-semantic	21* 31* Lexical-semantic/ phonological
Aphasia^8	Non-fluent	Fluent	Non-fluent	Non-fluent	Non-fluent	Fluent

Notes: ^aPremorbid handedness was measured using a German version of the Edinburgh Handedness Inventory (Oldfield, 1971); ^bLCH: Left cerebral haemorrhage, RCH: Right cerebral haemorrhage, LCI: Left cerebral infarction; ^cIWA with hemiparesis were not able to use their dominant hand for daily activities such as grabbing objects, eating, or writing. ^dPantomime-to-command task (Goldenberg et al., 2003; Goldenberg et al., 2007): maximum score: n = 55, cut-off: n = 45; bold indicates impairment; ^eRaw scores, n = 34, cut-off: n = 30 (2 SD below mean performance of control group), 20 healthy controls (16 female, 4 male): 25–65 years (M = 38.25 years; SD = 13.67); ^fRaw scores, n = 34, cut-off: n = 32 (2 SD below mean performance of control group), 20 healthy controls (15 female, 5 male): 25–69 years (M = 42 years; SD = 16.34), italics indicate performance within normal range, *indicates significant difference between verb naming and verb-picture verification task; ^gLexical-semantic: deficits in verb naming and verb-picture verification with no significant difference between the tasks, phonological: deficit in verb naming and normal performance in verb-picture verification, lexical-semantic/phonological: impairment in both tasks with significantly better results in the verb-picture verification task; ^hAccording to Aachen Aphasia Test (AAT; Huber et al., 1983) and/or clinical profile.

Table 2. Means and standard deviations (SD) of matched linguistic/psycholinguistic variables in the three sets of verbs

Verbs		Set 1 (n= 25)	Set 2 (n= 25)	Set 3 (n= 25)
Word length	No. of syllables	2.12 (0.60)	2.12 (0.60)	2.12 (0.44)
	No. of phonemes	5.16 (1.55)	5.24 (1.45)	5.00 (1.26)
	No. of phonemes (stem)	3.88 (1.17)	3.84 (1.14)	3.52 (0.71)
Transitivity^a		t + i = 11, t = 8, i = 6	t + i = 11, t = 8, i = 6	t + i = 11, t = 8, i = 6
Instrumentality^b		yes = 11, no = 14	yes = 11, no = 14	yes = 11, no = 14
Name relation to instrument^c		yes = 5, no = 6	yes = 5, no = 6	yes = 5, no = 6
Word frequency (dlex, norm. log.)		1.21 (0.78)	0.94 (0.57)	1.09 (0.93)
Age of acquisition (scale: 1–7)^d		2.63 (0.80)	2.62 (0.67)	2.57 (0.93)
Familiarity (concept) (scale: 1–5)^e		3.15 (1.11)	3.34 (1.05)	3.24 (1.14)
Imageability (scale: 1–5)^f		4.44 (0.42)	4.54 (0.31)	4.47 (0.38)
Naming agreement (%)^g		96.42 (4.48)	93.94 (6.98)	95.82 (6.93)

Notes: ^at: transitive verbs (verbs that require a direct object, e.g., to grab), i: intransitive verbs (verbs that do not take a direct object, e.g., to swim), t + i: transitive/intransitive (pseudo-transitive) verbs (verbs that can occur with and without a direct object, e.g., to eat); ^bInstrumental verbs refer to actions that require an object to be performed (yes: instrumental verb, e.g., to sew, no: non-instrumental verb, e.g., to wave); ^cName relation to a noun (the instrument) within the class of instrumental verbs (yes: name-related to instrument, e.g., to rake – a rake (not fully homophonous in German: verb = noun + n, e.g., Harke (noun: a rake) – harken (verb: to rake)), no: not name-related to instrument, e.g., to sweep – a broom; ^dRating study with 20 language-unimpaired people (female: n = 16, male: n = 4), M_age = 57.06 years; SD = 7.46 (age information missing in two people); 7-point scale: 1 = 1–2 years; 2 = 3–4 years; 3 = 5–6 years; 4 = 7–8 years; 5 = 9–10 years; 6 = 11–12 years; 7 = 13 years or older; due to missing data, means were calculated for 19 instead of 20 ratings for some verbs; ^eRating study with 20 language-unimpaired people (female: n = 13, male: n = 7), M_age = 60,16 years; SD = 9,67 (age information missing in one person); 5-point scale: 1 = very unfamiliar to 5 = very familiar; due to missing data, means were calculated for 19 instead of 20 ratings for some verbs; ^fRating study with 20 language-unimpaired people (female: n = 18, male: n = 2), M_age = 59,6 years; SD = 8,09; 5-point scale: 1 = very low imageable to 5 = very high imageable; due to missing data, means were calculated for 19 instead of 20 ratings for some verbs; ^g69 Language-unimpaired people (female: n = 60, male: n = 9), M_age = 21.45 years; SD = 3.24; three language-unimpaired individuals who performed greater than 2 standard deviations below group mean were excluded from analysis.

Figure 1. Sample pictures for verbs used in Experiment 1

Figure 2. Procedure of Experiment 1: Facilitation Study

Figure 3. Number of items retrieved (white)/not retrieved (grey) with iconic gesture, non-iconic gesture, and no gesture in the second naming attempt for each IWA (P1-P6).

Notes: The figure displays the results of the second naming attempts in all three conditions. Only items that could not be named in the first naming attempt were entered in the second naming attempt, e.g., P1: iconic gesture condition: n = 15 items, non-iconic gesture condition: n = 13 items, no gesture condition: n = 19 items; Lex.-sem. = lexical-semantic naming impairment, Phon. = phonological naming impairment, Lex.-sem./phon. = lexical-semantic/phonological naming impairment

Table 3. Overview of single-case statistics for iconicity ratings in IWA and language-unimpaired controls

Participant	P1	P2	P3	P4	P5	P6
n (iconic gestures)^a	15	8	7	7	22	6
Iconicity rating (mean; scale: 1–5)^b	3.00	3.18	3.43	2.90	1.44	4.65
Controlsnon-dominant hand (group average (SD); scale: 1–5)^c	3.64 (0.93)	3.22 (1.03)	4.30 (0.70)	3.47 (1.04)	3.80 (0.93)	3.58 (1.06)
t (Singlims_ES, e.g., Crawford et al., 2010)	−0.64	−0.04	−1.15	−0.51	−2.35	0.94
Two-tailed probability^d	.55	.97	.30	.63	.07	.39
Estimated % of normal population falling below individual’s score^d	27.60%	48.64%	15.10%	31.67%	3.28%	80.35%
Controlsboth hands (group average (SD); scale: 1–5)^e	4.06 (0.99)	3.69 (1.14)	4.19 (0.95)	3.80 (1.09)	4.22 (0.87)	4.21 (1.01)
t (Singlims_ES, e.g., Crawford et al., 2010)	−0.99	−0.41	−0.74	−0.76	−2.96	0.40
Two-tailed probability^d	.37	.70	.49	.48	.03	.70
Estimated % of normal population falling below individual’s score^d	18.35%	34.80%	24.61%	23.96%	1.58%	64.83%

Notes: ^aNumber of produced and rated iconic gestures in IWA; ^b5-point scale: 1 = non-iconic to 5 = very iconic; ^cRated iconicity in six language-unimpaired participants (non-dominant hand gesture). For each language-unimpaired participant (non-dominant hand gesture), the same number of iconic gestures as in the particular IWA was presented for rating (e.g., n = 15 gestures in P1, n = 15 gestures in each language-unimpaired participant). Subsequently, means for each gestured item and group averages were calculated; ^dSinglims_ES (e.g., Crawford et al., 2010); ^eRated iconicity in six language-unimpaired participants (both hand gesture). For each language-unimpaired participant (both hand gesture), the same number of iconic gestures as in the particular IWA was presented for rating. Subsequently, means for each gestured item and group averages were calculated.

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