Verb and sentence production and comprehension in aphasia: Northwestern Assessment of Verbs and Sentences (NAVS)

Abstract

Background: Verbs and sentences are often impaired in individuals with aphasia, and differential impairment patterns are associated with different types of aphasia. With currently available test batteries, however, it is challenging to provide a comprehensive profile of aphasic language impairments because they do not examine syntactically important properties of verbs and sentences.

Aims: This study presents data derived from the Northwestern Assessment of Verbs and Sentences (NAVS; Thompson, 2011), a new test battery designed to examine syntactic deficits in aphasia. The NAVS includes tests for verb naming and comprehension, and production of verb argument structure in simple active sentences, with each examining the effects of the number and optionality of arguments. The NAVS also tests production and comprehension of canonical and non-canonical sentences.

Methods & procedures: A total of 59 aphasic participants (35 agrammatic and 24 anomic) were tested using a set of action pictures. Participants produced verbs or sentences for the production subtests and identified pictures corresponding to auditorily provided verbs or sentences for the comprehension subtests.

Outcomes & results: The agrammatic group, compared to the anomic group, performed significantly more poorly on all subtests except verb comprehension, and for both groups comprehension was less impaired than production. On verb naming and argument structure production tests both groups exhibited difficulty with three-argument verbs, affected by the number and optionality of arguments. However, production of sentences using three-argument verbs was more impaired in the agrammatic, compared to the anomic, group. On sentence production and comprehension tests, the agrammatic group showed impairments in all types of non-canonical sentences, whereas the anomic group exhibited difficulty primarily with the most difficult, object relative, structures.

Conclusions: Results show that verb and sentence deficits seen in individuals with agrammatic aphasia are largely influenced by syntactic complexity; however, individuals with anomic aphasia appear to exhibit these impairments only for the most complex forms of verbs and sentences. The present data indicate that the NAVS is useful for characterising verb and sentence deficits in people with aphasia.

Keywords: Agrammatic aphasia; Anomic aphasia; Comprehension; Production; Sentence; Verb.

Figures

Figure 1

Sample stimuli for the Verb Naming Test (VNT) by verb type. (a) one-argument verb (target verb: bark); (b) two-argument verb (target verb: tickle); (c) three-argument verb (target verb: read).

Figure 2

Sample stimuli for the Verb Comprehension Test (VCT) (from top left to bottom right, different verb distractor: grab and kiss; target: deliver; same verb distractor: throw).

Figure 3

Sample stimuli for the Argument Structure Production Test (ASPT). (3a) optional two-argument verb with two arguments (target: The man is washing the clothes); (3b) optional two-argument verb with one argument (target: The man is washing).

Figure 4

Sample stimuli for the Sentence Production Priming Test (SPPT) and Sentence Comprehension Test (SCT). (a) Sample stimulus for testing actives, passives, and subject and object extracted wh-questions (SWQ target: Who is chasing the dog?; OWQ target: Who is the cat chasing?); (4) Sample stimulus for testing subject and object relative clauses (SR target: Pete saw the cat who was chasing the dog; OR target: Pete saw the dog who the cat was chasing).

Figure 5

Mean percentage of correct verbs by type (one, two, and three arguments) for agrammatic and anomic participants (***p < .001, **p < .01, *p < .05). (a) Verb Naming Test (VNT) scores, (b) Verb Comprehension Test (VCT) scores. Agr = agrammatic; An = anomic.

Figure 6

Mean percent correct production of sentences with one-, two-, and three-argument verbs on the Argument Structure Production Test (ASPT) for agrammatic and anomic participants (***p < .001, **p <. 01). Agr = agrammatic; An = anomic.

Figure 7

Mean percentage of correct sentences by type for agrammatic and anomic participants (*p < .0042). (a) Sentence Production Priming Test (SPPT) scores; (b) Sentence Comprehension Test (SCT) scores. SWQ = subject extracted wh-question; SR = subject relative clause; OWQ = object extracted wh-question; OR = object relative clause; Agr = agrammatic; An = Anomic.