Judit Druks

Nouns and verbs in the brain: A review of behavioural, electrophysiological, neuropsychological and imaging studies

In the past 30 years there has been a growing body of research using different methods (behavioural, electrophysiological, neuropsychological, TMS and imaging studies) asking whether processing words from different grammatical classes (especially nouns and verbs) engage different neural systems. To date, however, each line of investigation has provided conflicting results. Here we present a review of this literature, showing that once we take into account the confounding in most studies between semantic distinctions (objects vs. actions) and grammatical distinction (nouns vs. verbs), and the conflation between studies concerned with mechanisms of single word processing and those studies concerned with sentence integration, the emerging picture is relatively clear-cut: clear neural separability is observed between the processing of object words (nouns) and action words (typically verbs), grammatical class effects emerge or become stronger for tasks and languages imposing greater processing demands. These findings indicate that grammatical class per se is not an organisational principle of knowledge in the brain; rather, all the findings we review are compatible with two general principles described by typological linguistics as underlying grammatical class membership across languages: semantic/pragmatic, and distributional cues in language that distinguish nouns from verbs. These two general principles are incorporated within an emergentist view which takes these constraints into account.

Object and action picture naming in three- and five-year-old children

The objectives were to explore the often reported noun advantage in childrens language acquisition using a picture naming paradigm and to explore the variables that affect picture naming performance. Participants in Experiment 1 were aged three and five years, and in Experiment 2, five years. The stimuli were action and object pictures. In Experiment 1, action pictures produced more errors than object pictures for the three-year-olds, but not the five-year-olds. A qualitative analysis of the errors revealed a somewhat different pattern of errors across age groups. In Experiment 2 there was no robust difference in accuracy for the actions and objects but naming times were longer for actions. Across both experiments, imageability was a robust predictor of object naming performance, while spoken frequency was the most important predictor of action naming. The results are discussed in terms of possible differences in the manner in which nouns and verbs are acquired.

The treatment of object naming, definition, and object use in semantic dementia: The effectiveness of errorless learning

Background: Patients with semantic dementia are impaired in both object naming and, to a lesser extent, in object use (Bozeat, Lambon Ralph, Patterson, & Hodges, 2002a; Hodges, Graham, & Patterson, 1995). To date there have been relatively few studies examining the relearning of object names, and only one examining the relearning of object use. No study has examined relearning object naming, definition, and use simultaneously. Aims: To explore the relatedness of object naming, definition, and object use in semantic dementia; to explore whether or not therapy is effective; and to explore the effectiveness of errorless learning. Methods & Procedures: Two patients with mild to moderate semantic dementia and two matched control participants were tested in naming, defining, and demonstrating the use of 33 household objects. The quality of the definitions was rated as poor, adequate, or good by three independent raters. Three components of object use were examined: hold, orientation, and movement. The assessment was repeated with the patients following 3 weeks of therapy, and 1 month after completion of therapy. For the therapy objects were divided into individual trained and untrained sets based on familiarity and performance at initial assessment. Patients received therapy sessions twice weekly, and engaged in independent practice. During the therapy sessions, the researcher modelled the name, definition, and use of each item, which the patient then repeated. In the independent practice each patient watched a DVD in which she named and defined the object and used it correctly. Outcomes & Results: Patients were severely impaired on object naming and definition, but less so on object use. Both patients showed some improvement as a result of therapy, which was maintained at follow‐up in one case. Conclusions: The results show that relearning in semantic dementia is possible. Factors affecting the results and the interaction between lexical and conceptual impairments are discussed. An unexpected finding of the study was that patients performed better in verb production both in the preliminary tests and in object definition.

Selective Naming (and Comprehension) Deficits in Alzheimer's Disease?

The study addresses the issue of the selective preservation of verbs in Alzheimers disease (AD). Twenty three AD patients and age-matched controls named pictures of objects and actions and took part in a word-picture verification task. The results for picture naming revealed that both patients and controls were faster and produced more target responses for objects than actions. In the comprehension task, accuracy levels were comparable for nouns and verbs, but response times were longer for verbs. Although patients were more error prone and had longer latencies in both tasks than controls, the only qualitative difference in performance between the groups was in response to trials with semantically related foils in the word-picture verification task. Patients were particularly error prone in this condition. We conclude that the results do not provide support for the notion that verbs are selectively preserved in AD. They also do not provide conclusive evidence for claims that depressed naming and comprehension is (always) due to loss of semantic knowledge or inadequate access to semantic knowledge. Finally, we discuss the findings in relation to comparable investigations in patients with semantic dementia.

The crucial role of tense for verb production

The case of an aphasic patient whose spontaneous speech contains very few lexical verbs is reported. Instead of sentences with lexical verbs, the patient produces many (grammatical) copular constructions. He also substitutes lexical verbs with the copula. Although this results in ungrammatical utterances, by doing so, a resemblance of sentence structure and a degree of grammaticality of his utterances are preserved. Although the patient is more impaired in naming action than object pictures, it is unlikely that lexical retrieval difficulties are solely responsible for the paucity of lexical verbs in his speech. A series of tests revealed a profound deficit in producing tense marking inflections and in understanding their significance. We argue that the unavailability of tense features is the primary reason for the lack of lexical verbs in his speech. An alternative possibility, that the tense deficit interacts with the verb retrieval deficit, is also discussed. The patient has a complex lesion and language profile, with features associated with both Brocas and Wernickes aphasia. However, since the study focuses on his verb and tense deficits and the grammaticality of his utterances, issues that are often discussed in relation to agrammatic Brocas aphasia, the literature that is relevant to these topics and to Brocas aphasia is reviewed, despite the different diagnostic profile of the patient.

Morpho-syntactic and morpho-phonological deficits in the production of regularly and irregularly inflected verbs

Background: The background to the study is the debate in relation to the English regular/irregular past tense forms. Aims: The purpose of the investigation was the evaluation of the dual mechanism (DMT: Pinker, 1999; Marslen-Wilson & Tyler, 1997, 1998; Ullman, Corkin, Coppola, Hickok, Growdon, Koroshetz, et al., 1997) and connectionist single mechanism models (SMT: Bird, Lambon Ralph, Seidenberg, McClelland, & Patterson, 2003; Joanisse & Seidenberg, 1999; Patterson, Lambon Ralph, Hodges, & McClelland, 2001) through exploring the reading and oral production of regular and irregular past tense forms and other verbal and nominal inflections by a Brocas type aphasic and phonological dyslexic patient. Methods & Procedures: Eight experimental tasks are reported. Three involved the reading of stems and inflected verbs and nouns in differently organised lists, two involved the oral production of past tense verbs and plural nouns, and three explored the ability to distinguish between written verbs inflected with various affixes. Outcomes & Results: In reading randomly organised list of nouns, verb stems, and regular and irregular past tense forms the patient displayed dissociation between regular and irregular past tense forms as predicted by DMT. When the same items were presented in a list with present and past tense forms paired, and in the oral transformation task, the dissociation disappeared, and performance in regular and irregular past tense forms became comparable. There was a difference in the patients reading of plural nouns and progressive verbs, which was good, and of past tense forms and third person forms, which was impaired. The recognition/comprehension tasks revealed that the patient was aware of the presence of an affix, but he could not reliably distinguish between different affixes. Conclusions: Performance on regular/irregular past tense forms and the variable levels of performance in producing different regular inflections are in conflict with both DMT and SMT on a number of grounds. The task-related differences between randomly organised lists and paired present and past tense forms are accounted for by distinguishing between morpho-phonological and morpho-syntactic effects. It is argued that deficits confined to the production of regular past tense forms are morpho-phonological in nature, while deficits in both regular and irregular past tense forms originate in morpho-syntax. Since SMT and DMT are theories of morpho-phonological processes, they cannot account for the complex performance pattern presented by the patient in the present study and by other similar patients. The differences attested in the availability of differently affixed words and deficits in irregular past tense forms are only accountable at the level of morpho-syntax.

The syntax of single words: Evidence from a patient with a selective function word reading deficit

We describe the reading performance of a patient who has selective deficits for reading nonwords, function words, and morphologically complex words in isolation. His reading of highly abstract nouns and verbs, however, is relatively well preserved. He can recognise and comprehend the meaning of written function words, of derivational morphology, and of most inflectional morphology. We suggest that his deficit in reading grammatical morphemes is unrelated to his problems in reading nonwords and cannot be explained by their low semanticity and imageability. The patients speech is ungrammatical but is not devoid of grammatical morphemes and his reading of functional elements improves when these are presented within the context of sentences. We argue that syntactic information relevant to individual lexical items including information about how the word may potentially be used within a phrase must be accessed during single word reading tasks (e.g., Levelt, 1989). This is particularly difficult for function words due to their linguistic specification, which is different from that of lexical categories (Chomsky, 1995). Both linguistic theory and Garretts (e.g., 1982) model of sentence processing account for the patients improved reading of function words in the context of sentences.

Spared syntax and impaired spell-out: The case of prepositions

The present study deals with the impairment of prepositions, a somewhat neglected topic in aphasia research. It is the first to investigate the availability of all types of prepositions (i.e., spatial, temporal, other meaningful, subcategorized, syntactic prepositions, and particles) in a variety of comprehension and production tasks in one anomic aphasic and four Broca’s aphasic patients and healthy speakers. While the availability of spatial, temporal, or subcategorized prepositions has been investigated, other preposition types have never been studied before. The data revealed that prepositions were impaired in the patients, and that the degree of impairment differed for different types of prepositions. Three of the main findings are: first, meaningless prepositions were not the most vulnerable subcategory of prepositions in the patients. In fact, four of the five aphasic patients performed best on (meaningless) syntactic prepositions. Second, patients made few omissions and many substitution errors which were mostly within-category (a preposition was substituted by another preposition). Third, there was no difference in the performance of Broca’s and anomic aphasic patients. These results differ from those of previous studies (e.g., Bennis et al., 1983; Friederici, 1982). They found that (i) meaningful prepositions remained relatively well preserved in Broca’s aphasia, while meaningless subcategorized and/or syntactic prepositions were very impaired, (ii) that Broca’s aphasic patients tended to omit rather than substitute prepositions, and (iii) that patients of contrasting clinical profiles performed differently. The preservation of syntactic prepositions together with the large number of within-category substitutions (which indicate sensitivity to the grammatical class of prepositions) were interpreted to suggest that the preposition deficit of the patients is not due to syntactic impairments. Rather, a post syntactic deficit in selection of the correct preposition at spell-out – a construct in modern linguistic theory that links syntax with phonology – is put forward.

Syntactic predictions and asyntactic comprehension in aphasia: Evidence from scope relations

People with aphasia (PWA) often fail to understand syntactically complex sentences. This phenomenon has been described as asyntactic comprehension and has been explored in various studies cross-linguistically in the past decades. However, until now there has been no consensus among researchers as to the nature of sentence comprehension failures in aphasia. Impaired representations accounts ascribe comprehension deficits to loss of syntactic knowledge, whereas processing/resource reduction accounts assume that PWA are unable to use syntactic knowledge in comprehension due to resource limitation resulting from the brain damage. The aim of this paper is to use independently motivated psycholinguistic models of sentence processing to test a variant of the processing/resource reduction accounts that we dub the Complexity Threshold Hypothesis. According to this hypothesis, PWA are capable of building well-formed syntactic representations, but, because their resources for language processing are limited, their syntactic parser fails when processing complexity exceeds a certain threshold. The source of complexity investigated in the experiments reported in this paper is syntactic prediction. We conducted two experiments involving comprehension of sentences with different types of syntactic dependencies, namely dependencies that do not require syntactic prediction (i.e. unpredictable dependencies in sentences that require Quantifier Raising) and dependencies whose resolution requires syntactic predictions at an early stage of processing based on syntactic cues (i.e. predictable dependencies in movement-derived sentences). In line with the predictions of the Complexity Threshold Hypothesis, the results show that the agrammatic patients that participated in this study had no difficulties comprehending sentences with the former type of dependencies, whereas their comprehension of sentences with the latter type of dependencies was impaired.

Parallel deterioration to language processing in a bilingual speaker

The convergence hypothesis [Green, D. W. (2003). The neural basis of the lexicon and the grammar in L2 acquisition: The convergence hypothesis. In R. van Hout, A. Hulk, F. Kuiken, & R. Towell (Eds.), The interface between syntax and the lexicon in second language acquisition (pp. 197–218). Amsterdam: John Benjamins] assumes that the neural substrates of language representations are shared between the languages of a bilingual speaker. One prediction of this hypothesis is that neurodegenerative disease should produce parallel deterioration to lexical and grammatical processing in bilingual aphasia. We tested this prediction with a late bilingual Hungarian (first language, L1)–English (second language, L2) speaker J.B. who had nonfluent progressive aphasia (NFPA). J.B. had acquired L2 in adolescence but was premorbidly proficient and used English as his dominant language throughout adult life. Our investigations showed comparable deterioration to lexical and grammatical knowledge in both languages during a one-year period. Parallel deterioration to language processing in a bilingual speaker with NFPA challenges the assumption that L1 and L2 rely on different brain mechanisms as assumed in some theories of bilingual language processing [Ullman, M. T. (2001). The neural basis of lexicon and grammar in first and second language: The declarative/procedural model. Bilingualism: Language and Cognition, 4(1), 105–122].