Processing of mass/count information in Alzheimer's disease and mild cognitive impairment

This study examines the processing of a specific linguistic distinction, the mass/count distinction, in patients suffering from Alzheimer's disease (AD) and mild cognitive impairment (MCI). Fourteen AD and 10 MCI subjects were tested using a sentence grammaticality judgement task where grammaticality violations were caused by determiner-noun mismatches, as well as a sentence-picture matching task to assess their ability to access mass and count readings of dual nouns. Considerable heterogeneity was observed within each subject group, and performance across groups was almost identical. It is concluded that a combination of linguistic and attentional and/or learning factors are responsible for the range of impairments; specifically, a subset of subjects exhibit no linguistic nor attentional/learning impairment, another subset exhibit only an attentional and/or learning impairment but no linguistic impairment, and a third subset (comprising more than half of the subjects included in this study) exhibit a linguistic impairment. It is postulated that the latter group have difficulty processing sense extensions in metonymous nouns. It is further claimed that, at least within the limits of the study, language impairments can be of the same severity and nature across AD and MCI subjects.     

Dissociations and associations of performance in syntactic comprehension in aphasia and their implications for the nature of aphasic deficits

Sixty-one pwa were tested on syntactic comprehension in three tasks: sentence-picture matching, sentence-picture matching with auditory moving window presentation, and object manipulation. There were significant correlations of performances on sentences across tasks. First factors on which all sentence types loaded in unrotated factor analyses accounted for most of the variance in each task. Dissociations in performance between sentence types that differed minimally in their syntactic structures were not consistent across tasks. These results replicate previous results with smaller samples and provide important validation of basic aspects of aphasic performance in this area of language processing. They point to the role of a reduction in processing resources and of the interaction of task demands and parsing and interpretive abilities in the genesis of patient performance.     

A study of syntactic processing in aphasia I: behavioral (psycholinguistic) aspects

This paper presents the results of a study of syntactically based comprehension in aphasic patients. We studied 42 patients with aphasia secondary to left hemisphere strokes and 25 control participants. We measured off-line, end-of-sentence, performance (accuracy and reaction time) in two tasks that require comprehension--enactment and sentence-picture matching--and in grammaticality judgment, with whole sentence auditory presentation. We also used sentence-picture matching and grammaticality judgment as tasks in two self-paced listening studies with the same patients to measure on-line performance. In each task and presentation format, we presented sentences that tested the ability to assign and interpret three structural contrasts chosen to examine different basic syntactic operations: actives and passives, subject and object extracted relative clauses, and reflexive pronouns and matched sentences without these elements. We examined these behavioral data to determine patterns of impairment in individual patients and in groups of patients, using correlational analyses, factor analyses, and analyses of variance. The results showed that almost no individual patients had stable deficits referable to the ability to interpret individual syntactic structures, that a variety of structural features contributed to sentence processing complexity both on-line and off-line, that correct responses were associated with normal on-line and errors with abnormal performance, and that the major determinant of performance is a factor that affected performance on all sentence types. The results indicate that the major cause of aphasic impairments of syntactically based comprehension are intermittent reductions in the processing capacity available for syntactic, interpretive, and task-related operations.     

Processing of mass/count information in Alzheimer’s disease and mild cognitive impairment

This study examines the processing of a specific linguistic distinction, the mass/count distinction, in patients suffering from Alzheimer’s disease (AD) and mild cognitive impairment (MCI). Fourteen AD and 10 MCI subjects were tested using a sentence grammaticality judgement task where grammaticality violations were caused by determiner–noun mismatches, as well as a sentence–picture matching task to assess their ability to access mass and count readings of dual nouns. Considerable heterogeneity was observed within each subject group, and performance across groups was almost identical. It is concluded that a combination of linguistic and attentional and/or learning factors are responsible for the range of impairments; specifically, a subset of subjects exhibit no linguistic nor attentional/learning impairment, another subset exhibit only an attentional and/or learning impairment but no linguistic impairment, and a third subset (comprising more than half of the subjects included in this study) exhibit a linguistic impairment. It is postulated that the latter group have difficulty processing sense extensions in metonymous nouns. It is further claimed that, at least within the limits of the study, language impairments can be of the same severity and nature across AD and MCI subjects.     

The Sum and Substance of It: The Appreciation of Mass and Count Quantifiers in Parkinson′s Disease

We performed three experiments in order to determine whether patients with Parkinson′s disease (PD) have a sentence comprehension impairment. In the first experiment, we found that nondemented PD patients were impaired at matching a short sentence containing a mass or count quantifier (e.g., "Point to the jar with many") with one of four pictures. Patients erred by pointing to the incorrect mass or count type of substance, but pointed correctly to the large or small amount of a substance in the picture. In the second experiment, we asked the same PD patients to judge short sentences containing mass or count nouns modified by mass or count adjectives (e.g., *"The glass contains many milk"). PD patients were significantly impaired at detecting errors in the agreement between a noun and a quantifying adjective and errors in the appropriate use of the plural associated with a noun. A sentence completion task was performed in order to determine whether patients impaired on both sentence-picture matching and sentence judgment tasks are also compromised in their expression of quantifiers. Some patients impaired on both tasks also had difficulty expressing quantifiers, and it is these patients who may have difficulty performing grammatical computations. Other patients were selectively impaired in their sentence-picture matching or their sentence judgments, suggesting a performance deficit concerned with a particular task. We conclude that sentence comprehension impairments in PD are multifactorial in nature.     

Syntactic and semantic contributions to sentence comprehension in agrammatism

Five aphasic subjects, who demonstrated agrammatic speech, and eight control subjects were presented with a sentence-picture matching task in which the factors of syntactic complexity, semantic reversibility, and sentence plausibility were independently varied. A subset of the sentences was patterned after that presented by A. Caramazza and E. Zurif (1976, Brain and Language, 5, 572-583) who concluded that Broca's aphasics rely on semantic constraints instead of syntactic information for sentence comprehension. Our aphasic subjects showed the same pattern of performance on this subset of sentences. However, the results from the full set of sentence materials we tested show that the aphasic subjects could perform some sentence level syntactic analyses, even when syntactic information conflicted with semantic constraints. The aphasic subjects correctly interpreted most active and passive sentences. They failed, however, to assign thematic roles and adjectives in center-embedded relative sentences, and instead relied on nonsyntactic information. These results show that both semantic and syntactic information contributed to sentence comprehension in the aphasic subjects we tested, in contrast to previous claims that syntactic and semantic processes are completely dissociated in this population.     

Pronoun comprehension in aphasia: a comparison of three languages

The research reported here investigated the effect of phonological and syntactic factors on the processing of pronouns by aphasics. The comprehension of these "closed-class" elements was studied in three different languages: French, Dutch, and German. The cross-linguistic design made it possible to vary phonological status (clitic/nonclitic) and phrasal category (noun phrase/prepositional phrase) as well as grammatical relation (direct/indirect object) while keeping class membership (closed class) and meaning constant. A sentence-picture matching task was given to 20 German-speaking, 16 Dutch-speaking, and 14 French-speaking aphasics, half of each language group being classified as agrammatic Broca's and half as paragrammatic Wernicke's aphasics. The results suggest that Broca's aphasics' limitations in retrieving pronouns, and therefore other closed-class elements, are not a function of either phonological status, phrasal category, or grammatical relation. These subjects' observed high level of performance on pronouns in language comprehension appears due to the kind of semantic and syntactic information they encode. Our findings indicate that a more refined distinction than closed class vs. open class is necessary.     

A study of syntactic processing in aphasia II: neurological aspects

This paper presents the results of a study of the effects of left hemisphere strokes on syntactically-based comprehension in aphasic patients. We studied 42 patients with aphasia secondary to left hemisphere strokes and 25 control subjects for the ability to assign and interpret three syntactic structures (passives, object extracted relative clauses, and reflexive pronouns) in enactment, sentence-picture matching and grammaticality judgment tasks. We measured accuracy, RT and self-paced listening times in SPM and GJ. We obtained magnetic resonance (MR) and 5-deoxyglucose positron emission tomography (FDG PET) data on 31 patients and 12 controls. The percent of selected regions of interest (ROIs) that was lesioned on MR and the mean normalized PET counts per voxel in ROIs were calculated. In regression analyses, lesion measures in both perisylvian and non-perisylvian ROIs predicted performance. Patients who performed at similar levels behaviorally had lesions of very different sizes, and patients with equivalent lesion sizes varied greatly in their level of performance. The data are consistent with a model in which the neural tissue that is responsible for the operations underlying sentence comprehension and syntactic processing is localized in different neural regions in different individuals.     

Verb deficits in Alzheimer's disease and agrammatism: implications for lexical organization

This study examined the nature of verb deficits in 14 individuals with probable Alzheimer's Disease (PrAD) and nine with agrammatic aphasia. Production was tested, controlling both semantic and syntactic features of verbs, using noun and verb naming, sentence completion, and narrative tasks. Noun and verb comprehension and a grammaticality judgment task also were administered. Results showed that while both PrAD and agrammatic subjects showed impaired verb naming, the syntactic features of verbs (i.e., argument structure) influenced agrammatic, but not Alzheimer's disease patients' verb production ability. That is, agrammatic patients showed progressively greater difficulty with verbs associated with more arguments, as has been shown in previous studies (e.g., Kim & Thompson, 2000; Thompson, 2003; Thompson, Lange, Schneider, & Shapiro, 1997), and suggest a syntactic basis for verb production deficits in agrammatism. Conversely, the semantic complexity of verbs affected PrAD, but not agrammatic, patients' performance, suggesting "bottom-up" breakdown in their verb lexicon, paralleling that of nouns, resulting from the degradation or loss of semantic features of verbs.     

The Understanding of Word Definitions in School-Age Children

This study investigated children’s understanding of unfamiliar noun and verb definitions in tasks that were manipulated for syntactic and semantic properties of definitions. The study was also designed to examine the relation between understanding word definitions and the skills of syntactic awareness and making inferences. A total of 117 children over three upper elementary grades (3, 4, 5) participated in the study. The definitional tasks were presented in multiple choice format, with each definition followed by four context sentences. In the syntactic/semantic condition, which included nouns and verbs, the context sentences were manipulated for syntactic and semantic properties. In the semantic condition, which included only nouns, the context sentences were manipulated only for semantics. All children also completed a syntactic awareness task and a making inferences task. Results indicated that children did not make significant grade improvements in the semantic task, but did so in the syntactic/semantic task, suggesting the dependence of syntactic cues on definitional understanding. Findings further suggested that inferencing and syntactic awareness are important to children’s ability in understanding a definition for an unfamiliar word and to integrating that meaning into a context sentence.     

Evaluating the semantic categories hypothesis: The case of the count/mass distinction

It is often claimed that grammatical categories are initially acquired via their semantic properties. In the case of the count/mass distinction, semantic correlations should predispose the child to acquire the count/mass subcategories as a distinction between names for objects vs. substances. This proposal is tested in three experiments. The first two experiments with 3- to 5-year-olds employ a word-learning paradigm in which semantic and syntactic cues are either in conflict, in accord or in isolation. Results demonstrate that syntactic cues are clearly the most effective and predominate over semantic cues as a basis for subcategorization. The third experiment with 2- to 5-year-olds demonstrates that children do not miscategorize nouns whose semantic properties are either inappropriate or indeterminate. Thus, for example, they do not tend to miscategorize a term such as “furniture” which is a mass noun yet denotes a class of objects. These results suggest that the count/mass distinction is not acquired via an object/substance distinction although semantic properties of quantification are probably important for the acquisition process.     

Lexical access in younger and older adults: the case of the mass/count distinction.

Although lexicosemantic deficits are not typically seen in older adults, some studies indicate that age-related changes in semantic processing may occur. We had groups of older and younger adults perform speeded lexical decision on mass (e.g., honey), count (e.g., car), and dual nouns, which may be either mass or count (e.g., lamb). Singular dual nouns engendered significantly faster response times in older adults than mass and count nouns, whereas younger adults manifested similar response times to count and dual nouns. These results point toward a three-way distinction in the lexicon between mass, count, and dual nouns. Older adults appear to treat a larger set of nouns as dual than do younger adults. This may be due to awareness of the mass/count ambiguity present in a greater number of lexical items, as a result of their greater linguistic experience. Alternatively, in order to conserve processing resources, older adults may not activate mass/count information when recognizing a dual noun unless a mass or count reading is forced by context.     

Hemispheric differences for semantically and phonologically primed nouns: A tachistoscopic study in normals

Normal individuals performed two matching tasks. In one task, semantic processing, synonyms had to be recognized. Half the stimuli were picturable and half were nonpicturable nouns. In this task, recognition of picturable synonyms was found to have hemifield symmetry, whereas recognition of nonpicturable synonyms yielded a left-hemisphere superiority, indicating that semantic matching itself did not reveal equal performance of both hemispheres. It is concluded that picturable synonyms might be recognized either by processes of visual imagery, which pertain to right-hemisphere function, or by their phonological or phonic features, which are processed by the left hemisphere. The other task, shown in previous research to exhibit a left-hemisphere superiority, was to decide if two nouns (homophones) were equally pronounced. Here a distinct left-hemisphere advantage was revealed.     

Sentence Comprehension Deficits in Alzheimer''s Disease: A Comparison of Off-Line vs. On-Line Sentence Processing

Two studies explored whether sentence comprehension impairments in Alzheimer's disease (AD) are due to deficits in syntactic processing or memory. Study 1 used a picture-pointing sentence comprehension task to measure the final outcome of comprehension in an off-line fashion. It showed the comprehension of 30 patients with AD to be impaired, but suggested that the deficits could not be attributed solely to syntactic impairments. Study 2 investigated the effects of memory on sentence comprehension by comparing off-line (grammaticality judgment) with on-line (cross-modal naming) language processing in 11 AD and 9 control subjects. The results revealed impaired performance in the off-line task but normal performance in the on-line task using the same sentences. Performance on the off-line task correlated with independent measures of verbal working memory. These data are used to argue that sentence comprehension impairments are related to verbal working memory deficits in AD.     

基于语义错觉效应的句子加工探索

“语义错觉效应”是指读者在加工某些语义违例句子时,会暂时性地产生语义合理错觉,而只有通过继续加工或者再加工才能辨别出错误的现象,在脑电成分上表现为没有出现N400效应,却出现P600效应。“语义错觉效应”对传统的句子加工理论模型以及N400和P600的特异性功能意义提出了质疑。研究者在讨论此效应的基础上提出了多个句子加工模型,各模型对语义和句法加工的过程进行了探索,对语义和句法通道的关系做出了新的阐述,并对N400和P600的功能意义做出了新的解读。目前研究对N400功能的解释存在语义整合观和词汇激活观的分歧,而对P600功能的解释则从传统的句法功能转换到了更宽泛的加工过程。未来研究应关注词汇语义关系和跨语言差异,以期进一步揭示句子加工的认知及神经机制。     

To watch, to see, and to differ: an event-related potential study of concreteness effects as a function of word class and lexical ambiguity

Electrophysiological techniques were used to assess the generalizability of concreteness effects on word processing across word class (nouns and verbs) and different types of lexical ambiguity (syntactic only and combined syntactic/semantic). The results replicated prior work in showing an enhanced N400 response and a sustained frontal negativity to concrete as compared with abstract nouns. The effect of concreteness on the N400 generalized to all word class and ambiguity conditions, whereas the frontal effect was present for all word types except for the syntactically and semantically ambiguous items when these were used as verbs. The seemingly dissociable ERP effects of concreteness at frontal and central/posterior electrode sites revealed by these data suggest that concreteness may impact multiple aspects of neurocognitive processing.     

句法和语义在汉语简单句理解中的作用

两个实验探讨句法和语义在汉语简单句加工中的作用及其相互关系。实验一采用施事判断任务,发现句法作用与语义可逆性的作用都很显著;实验二采用快速句子判断任务,发现句法作用是主要的,语义可逆性无显著作用;两个实验都发现句法与语义可逆性之间的交互作用不显著。这些结果表明：（１）在汉语简单句理解的过程中句法因素的作用是主要的,语义因素的作用是次要的,只要当实验任务更多地强调语义分析时,语义因素才有显著的作用。     

Sensitivity to inflectional morphology in agrammatism: investigation of a highly inflected language

We present the results of a study with six Serbo-Croatian-speaking agrammatic patients on a test of inflectional morphology in which subjects judged whether spoken sentences were grammatical or ungrammatical. Sensitivity to two kinds of syntactic features was investigated in these aphasic patients: (1) subcategorization rules for transitive verbs (which must be followed by a noun in the accusative case; intransitive verbs can be followed by nouns in other noun cases); (2) sensitivity to the inflectional morphology marking noun case. The test items consisted of three-word sentences (noun-verb-noun) in which verb transitivity and appropriateness of the case inflection of the following noun were manipulated. Results of the grammaticality judgment task show that both syntactic properties are preserved in these patients.     

Differences in Noun and Verb Processing in Lexical Decision Cannot be Attributed to Word Form and Morphological Complexity Alone

It has been suggested that the effect of word category in noun and verb processing reflects typical word class properties, which can be characterized in terms of semantic as well as syntactic and morphological features. The present study is aimed at differentiating and discussing the relative contribution of these aspects with a main focus on syntactic and morphological processing. Experiment 1 established a processing advantage for nouns in German visual lexical decision, using nouns denoting biological and man-made objects as compared to transitive and intransitive verbs. Experiment 2 showed that the noun advantage persisted even when the morphological differences between word categories were reduced by using identical suffixes in nouns and verbs. Overall results suggest that the processing differences cannot be reduced to variables such as frequency, word form, or morphological complexity. Reaction time differences between transitive and intransitive verbs strengthen the role of syntactic information. In line with previous accounts the observed effects are discussed in terms of a category-specific combination of linguistic parameters.     

句子加工中核心名词动物性效应及其认知机制

动物性核心名词在语言认知中有着重要的作用.基于句子产生和句子理解两方面的研究表明,句式选择、语态运用、词序排列、论元建构、格标记使用及从句加工等诸多方面都显著的受到句中核心名词动物性的影响.就该效应的来源及其作用机制,生命性名词表征特异性理论、词汇概念通达可及性层级理论、动物性名词句法突出性特征理论、基于频率分布的语言经验理论从不同的方面进行了分析.最后,就名词动物性效应的存在本质、作用机理以及文化和语境的影响等方面展开了评价和展望.