Language-4
European Workshop on Cogni)ve Neuropsychology (EWCN) Bressanone 2018, January 21-26.
Distinctive error patterns on verb inflection in Basque speakers with aphasia and healthy adults. Arantzeta, M.1*, Webster, J.2, Laka, I.3, Martínez-Zabaleta, M.4, & Howard, D.2 1 Interna)onal Doctorate for Experimental Approaches into Brain and Language (IDEALAB), Universi)es of Groningen (NL), Newcastle (UK), Potsdam (DE), Trento (IT) & Macquarie University
Sydney (AU); 2 Centre for Research in Linguis)cs and Language Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom; 3 Department of Linguis)cs and Basque Studies, University of the Basque Country (UPV/EHU), Vitoria-Gasteiz, Spain. 4 Biodonos)a Health Research Ins)tute, San Sebas)an University Hospital, Donos)a-San Sebas)an, Spain. *Contact:
[email protected] Introduction:
Results:
Impaired morphosyntactic procecssing in agrammatic aphasia (PWA): •
PWA have difficulties establishing semantic relations between the verb and the constituents of the sentence.
•
These difficulties increase as a function of number of arguments required by the verb in their sentence production [1], even when they have preserved access at the single word level [2] . That is, the production of sentences such as (1) is less impaired than (2), and the latter is less impaired than (3). (1) The man falls. (2) The boy chaces the dog. (3) The postman gives a letter to the woman.
•
This pattern of deficit cannot be explained by the length effect of the sentence. Previous findings have shown that verbs with optional arguments are produced correctly less often than verbs with obligatory arguments [1]
Basque: Basque case morphology indicates thematic role: ergative case marks agents, absolutive marks themes and dative marks goals/beneficiaries. CASE
Erga8ve
Absolu8ve
Da8ve
Thema8c role
Agent
Theme
Beneficiary
Case morphology
-k
-ø
- (r)i
The lexical verb obligatorily agrees with ergative, absolutive and dative arguments in case, number and person, by means of agglutination. Mutil-a-k txakurr-a-ø boy-Det.sg-ERG dog-Det.sg-ABS The boy has seen the dog.
ikusi see
Mutil-e-k txakurr-a-ø ikusi boy.-Det.pl-ERG dog-Det.sg-ABS see The boys have seen the dog.
d-u-ø 3.p.sg. ABS-root-3.p.sg.ERG
d-u-te 3.p.sg. ABS-root-3.p.pl.ERG
Mutil-e-k txakurr-a-ri buztan-a-ø boy-Det.pl-ERG dog-Det.sg-DAT tail-Det.sg-ABS The boys have seen the tail of the dog.
ikusi see
di-o-te 3.p.sg. ABS-3.p.sg. DAT-3.p.pl.ERG
Research questions: • When we tease apart the role of lexical retrieval, what is the effect of argument structure in verb inflec)on abili)es of PWA and healthy speakers? • If any, what aspects of verb agreement (number, person and/or case) are affected by argument structure in PWA and healthy speakers? Methodology:
Figure 1: Response accuracy of the production of the verb auxiliary across the sentence conditions. PWA= people with aphasia; NBD= non-brain damaged
Table 1: Classification of production errors.
Group
Incorrect Neologism auxiliary
Synthe8c verb
Others (e.g., nouns, op8onal argument)
PWA
85.05%
7.73%
2.53%
4.64%
Age-matched NBD
100%
0%
0%
0%
Young NBD
100%
0%
0%
0%
PWA= people with aphasia; NBD= non-brain damaged
Participants:
Five individuals with mild agramma)c aphasia (x̄= 66 years, SD= 11) due to stroke were included in the study. Five age-matched NBD speakers (x̄= 69 years, SD= 8), and 13 young NBD speakers (x̄= 34 years, SD=2) formed two control groups. Experimental material: The experimental materials consisted of incomplete single sentences (i.e., Subject-Object(s)Verb) presented auditorily simultaneously with the presenta)on of a picture. Auxiliary type Intransi)ve Transi)ve Sentence condi8on ABS ABS-DAT ABS-ERG ABS-DAT-ERG N= 80 20 20 20 20 Experimental task: Sentence comple)on. Par)cipants had to complete the sentence using an auxiliary verb. amona-k aitona-ri partida-Ø irabazi… dio grandma-ERG grandpa-DAT match-ABS win has Grandma has won the match to grandpa Previsualiza8on linguis8c s8muli (♩) target (3000 ms)
Acknowledgements:
Figure 2: Distribution of verb inflection errors by participant group across sentence conditions. PWA= people with aphasia; NBD1= age-matched non-brain damaged participants; NBD2= young non-brain damaged participants.
Discussion: • PWA show significant difficul)es addressing polypersonal agreement, and hence, producing verb auxiliaries in Basque. • Verb agreement in Basque is directly affected by the difficulty hierarchy imposed by the argument structure. • The number of arguments involved in the verb agreement imposes increased demands on both PWA, and age-matched and young NBD speakers, in line with previous studies [1][3]. • The error paqern shown by PWA and NBD groups suggests that the inflec)onal breakdown happens at different processing levels. PWA show both impaired integra)on of thema)c roles into verb inflec)on and number agreement deficits. In contrast, NBD do not have difficul)es in seman)c processing, but they make errors exclusively at the syntac)c level, in which number agreement is assigned. References: [1] Thompson, et al. Aphasiology. (1997) 11:473-90 [2] Whitworth, et al. Aphasiology. (2015) 29:1426-47 [3] Thompson, et al. J. Cog. Neuroscience (2007) 19:1753-67
