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PubMed1995

The breakdown of functional categories and the economy of derivation.

In this paper I argue that in a hierarchical structure of a sentence, the lower the position of the functional head and its projection, the more accessible they are to an agrammatic aphasic. The major empirical basis for this includes spontaneous speech data and an acceptability judgment experiment by Japanese agrammatic patients as well as the available French and Italian data. The previous cross-linguistic agrammatic data from verb second languages are also examined. The unified account for the status of functional categories in agrammatism is presented based on the principles of the Economy of the Minimalist framework (Chomsky 1994). Finally, the empirical consequences of agrammatic data for language acquisition are discussed.

Aphasia, Broca↗

PubMed1995

Functional categories in agrammatism.

This paper comments on Hagiwara's (1994b, this volume) proposals to account for the language deficits found in agrammatic aphasia, with special emphasis on Functional Categories (FCs). Some contemporary assumptions about FCs are reviewed focusing on their contentfulness, morphological features, and depiction as a heterogeneous set. This paper also discusses the view that the target of impairment in agrammatism constitutes a natural class. Treatment of FCs in their connection to chains and Lexical-Relatedness is discussed in terms of feature checking and morphological characteristics.

Aphasia, Broca↗

PubMed1995

Syntactic processing in aphasia.

In this report we comment upon subject selection and methodology, and we describe some recent studies of syntactic processing in aphasia. Our data show that, like neurologically intact subjects, Wernicke's patients reactivate moved constituents (instantiate coreference) at the site of their extraction (even for sentences that they do not understand). Broca's patients, by constrast, are shown not to create such syntactically governed links (even for sentences that they do understand). These data isolate the processing bottleneck in Broca's aphasia and more generally suggest that syntactic comprehension limitations can be traced to changes in cortically localizable resources that sustain lexical processing.

Aphasia, Broca↗

PubMed1995

The interpretation of sentence ambiguity in patients with unilateral focal brain surgery.

Interpretations of ambiguous sentences were studied in patients with unilateral anterior temporal lobectomy or selective amygdalo-hippocampectomy. The sentences represented lexical and syntactic ambiguities. In both left- and right-sided groups, regardless of type of surgery, total mean score on the test was below normal. Left-sided cases, regardless of type of surgery, provided significantly fewer alternative interpretations than right-sided cases. The results suggest greater left than right hemisphere specialization in both lexical and syntactic processing, but also suggest right hemisphere involvement in resolution of lexical ambiguity.

Adult↗

PubMed1996

Remediation of sentence processing deficits in aphasia using a computer-based microworld.

Byng (1988) has argued that some aphasic patients who show problems in sentence comprehension are unable to "map" a syntactic analysis of the sentence form onto the thematic roles specified by the verb or preposition in the sentence. In Byng's study, therapy aimed at improving the mapping process as applied to sentences containing locative prepositions led to improvements not only in the comprehension of such sentences but also in the comprehension of reversible verb sentences. In the present study, 14 aphasic patients were selected for having problems with sentence-picture matching involving reversible verb and preposition sentences. These problems were shown to be stable across three pre-intervention assessments. All assessments were computer-based and involved the matching of written sentences to pictures. A small vocabulary was used in assessment and therapy which involved a "microworld" of three characters (ball, box, and star) which could engage in a limited number of actions and could occupy a limited set of spatial relationships. Before therapy began, all the patients were given an assessment battery which included a 40-item Verb Test and a 40-item Preposition Test. The patients were then divided into two groups, A and B. Group A received two 1-hr sessions of therapy per week for 3 weeks aimed at improving the comprehension of verb sentences, then a second full assessment, followed by the same amount of therapy aimed at improving the comprehension of preposition sentences, and finally a third assessment. Group B received the preposition therapy first, followed by the verb therapy. The therapy involved the patient and therapist interacting with the computer, either assembling pictures to match written sentences ("picture-building mode") or assembling sentences to match pictures ("sentence-building mode"). Group A showed a classical "cross-over" treatment outcome. Performance on treated verb sentences improved during verb therapy and was retained when therapy switched to preposition sentences. Performance on treated preposition sentences was unaffected by verb therapy but improved when therapy switched to the processing of prepositions. Performance on untreated verb and preposition sentences showed a similar pattern, though the improvements observed were not as great. Improvement was also shown on a paper-based "Real World Test" which involved a wider range of more naturalistic sentences. Performance on a third aspect of sentence comprehension which the patients also had difficulty with, namely the comprehension of morphology, remained unchanged throughout, providing further evidence that the effects obtained were treatment-specific. The results of Group B were less clear cut. Comprehension of both verb and preposition sentences improved during the period that prepositions were being treated then remained static during verb treatment. Comprehension of morphology remained unchanged throughout. At the level of the individual patient, the majority of patients obtained higher scores on both the Verb Test and the Preposition Test after therapy, but only three patients showed improvements on both verbs and prepositions that were statistically significant. Six patients showed significant improvements on verbs but not prepositions while one showed the opposite pattern. Only three patients failed to show so much as a borderline improvement on either verbs or prepositions. Finally, seven of the patients returned for an additional assessment 5 months after completing the therapy. These patients, who had demonstrated significant improvements during the therapy, were shown to have maintained their improved comprehension skills.

Adult↗

PubMed1996

Verb comprehension deficits in probable Alzheimer's disease.

Studies of lexical comprehension in probable Alzheimer's disease (pAD) have focused almost exclusively on nouns. In the following preliminary study, we examined whether lexical comprehension for verbs is also impaired in 25 pAD patients. The semantic meaning of motion verbs, cognition verbs, and perception verbs was assessed with a triadic comparison task. Structural meaning associated with these verbs was evaluated by asking the patients to judge the coherence of sentence frames that accept these verbs naturally or awkwardly. We found that pAD patients are significantly impaired at identifying semantic relations among verbs. pAD patients also encountered significantly more difficulty judging the coherence of sentences than control subjects. Correlation and regression analyses demonstrated that semantic characteristics of verbs are projected from the verb's sentence frames in control subjects, but there was minimal evidence for such a structural-semantic relationship in pAD. We consider several possible explanations for our preliminary observations of an impairment that has consequences for processing both semantic and structural aspects of verb meaning.

Aged↗

PubMed1996

Comparison between oral and written spelling in Alzheimer's disease.

Written and oral spelling were compared in 33 patients with Alzheimer's disease (AD) and 25 control subjects. AD patients had poorer spelling results which were influenced by orthographic difficulty and word frequency, but not by grammatical word class. Lexical spelling was also more deteriorated than phonological spelling. Moreover, oral spelling was more impaired than written spelling in AD patients, whereas no difference was present between oral and written spelling of controls. Analysis of spelling errors showed that, for controls, errors were predominantly phonologically accurate in both spelling tasks. Significantly, AD patients produced more phonologically accurate than inaccurate errors in written spelling, whereas these errors did not differ in oral spelling. In contrast to controls who produced more constant than variable responses in oral and written spelling, AD patients made more variable responses (words correctly spelled in one task but incorrectly in the other) and they showed many instances of variable errors (different misspellings from one spelling task to the other). Two stepwise regression procedures showed that written misspellings were specifically correlated with language impairment, whereas oral spelling errors were correlated with attentional and language disorders. These results suggest that AD increases the attentional demands of oral spelling process as compared to written spelling. This dissociation argues, either for a unique Graphemic Buffer in which oral spelling requires more attentional resources than written spelling or for the hypothesis of separate buffers for oral and written spelling.

Aged↗

PubMed1997

The use of contextual information related to general world knowledge by right brain-damaged individuals in pronoun resolution.

This study investigated the ability of right brain-damaged individuals (RBD) to use contextual information to resolve ambiguous pronouns. Subjects were presented with sentence pairs and required to resolve the ambiguous pronoun in the second sentence. Contrary to the prevailing view that RBD patients have difficulty using contextual information to integrate language, the RBD group demonstrated a normal pattern of response, demonstrating a sensitivity to the pragmatic information contained in the leading sentence. They responded more quickly to sentences with a pragmatically constrained preferred referent than to those sentences for which there was no preferred referent. As well, they chose the preferred referent significantly more often than the non-preferred referent. These results suggest that RBD patients can use contextual information at the level of a minimal discourse (i.e., two sentences).

Adult↗

PubMed1997

Follow-up study of a right- and a left-hemispherectomized child: implications for localization and impairment of language in children.

Two hemispherectomized girls, one operated on the right, the other on the left, were followed from time of surgery until 9 and 10 years of age and compared with respect to course of language acquisition following surgery. At conclusion of follow-up, receptive and expressive language, phoneme perception and production, and sentence processing of the two hemispherectomized children were compared with those of two control groups of similar age, one developing language normally, the other language-impaired. The left-hemispherectomized child's abilities were similar to those of the language-impaired children; the right-hemispherectomized child's abilities resembled those of the language-normal children. Implications for localization of developmental anomalies in language-impaired children are discussed.

Brain↗

PubMed1997

The connectionist simulation of aphasic naming.

The simulation of language disorders using interactive activation (IA) networks and connectionist systems is discussed. An existing IA account of aphasic naming is described, in which two network parameters (decay rate and connection strength) are varied to fit the error production of an aphasic patient. Fairly similar results can be obtained through modification of additional parameters, including the so-called "shared weight increase factor" linking lexical and semantic units. This leads us to consider simulation of aphasic naming using connectionist networks which do not require explicit variation of network parameters. A modular connectionist architecture is presented, in which semantic-lexical and phonological knowledge are instantiated using self-organizing Kohonen maps, while connections between them are implemented using Hebbian networks; a linear connectionist network (Madaline) is used to simulate nonword repetition. The Hebbian connections are lesioned in order to reproduce the patient's naming errors.

Aphasia↗

PubMed1998

Conduction aphasia in a 3-year-old with a left posterior cortical/subcortical abscess.

A 3-year-old, right-handed girl developed a conduction-type aphasia following a second generalized seizure in the setting of a developing abscess involving left subcortical and cortical angular gyrus and arcuate fasciculus, and the posterior corpus callosum. The language disorder was fluent, characterized by age appropriate mean length of utterance and syntax, but with markedly reduced spontaneity of output, rapid rate of speech and mild dysarthria. Comprehension was relatively, but not completely spared. Naming, repetition, and reading (letters) were initially markedly impaired. Improvements in naming and repetition were associated with both literal and semantic paraphasias. Writing skills in the form of drawing were spared, but a mild apraxia to verbal command and imitation was initially present. Despite her young age, this child's fluent conduction aphasia and lesion localization were adult-like. Multimodal memory difficulties appeared to underlie what is best described as conduction aphasia.

Abscess↗

PubMed2000

Pitch and timing abilities in inherited speech and language impairment.

Members of the KE family who suffer from an inherited developmental speech-and-language disorder and normal, age-matched, controls were tested on musical abilities, including perception and production of pitch and rhythm. Affected family members were not deficient in either the perception or production of pitch, whether this involved either single notes or familiar melodies. However, they were deficient in both the perception and production of rhythm in both vocal and manual modalities. It is concluded that intonation abilities are not impaired in the affected family members, whereas their timing abilities are impaired. Neither their linguistic nor oral praxic deficits can be at the root of their impairment in timing; rather, the reverse may be true.

Adolescent↗

PubMed2001

The acquisition of complex predicates in japanese specifically language-impaired and normally developing children.

Japanese exhibits two different types of morphological processes. Some morphologically complex predicates are generated within the domain of the lexicon, whereas others are generated outside the domain of the lexicon. An elicited production task involving both types of complex predicates was administered to six Japanese children with specific language impairment (JSLI) and six children with normal language development (JNLD). The JSLI children experienced significant difficulty forming the lexicon-external complex predicates but much less difficulty with the lexicon-internal complex predicates while the performance of the JNLD children exhibited no such asymmetry. These preliminary results suggest that the deficit of SLI affects the ability to construct implicit procedural rules for morphology that are generated outside the lexicon while their lexical operations for morphology that are generated within the domain of the lexicon remain relatively unimpaired.

Child↗

PubMed2001

Functional categories and syntactic operations in (Ab)normal language acquisition.

This article argues in favor of the hypothesis that computational complexity determines order of acquisition of functional categories by normal children and patterns of impairment vs. relative preservation of these categories in children with Specific Language Impairment. Complexity is defined in terms of the properties of functional categories of the language the (ab)normal child is acquiring. The results of a study on present/past tense production and comprehension, carried out with children with and without Specific Language Impairment confirm the predictions of the computational complexity hypothesis. It is shown that it is easier to compute kernel functional categories than those that introduce further semantic modifications in the sentence.

Adolescent↗

PubMed2001

Comprehension of reversible relative clauses in specifically language impaired and normally developing Greek children.

This paper aims to investigate the syntactic comprehension of reversible relative clauses in a group of eight Greek children with specific language impairment (SLI) and two control groups of normally developing children matched on chronological and language age, respectively. An experiment using an acting out procedure was undertaken. Group analysis revealed that SLI children's performance is qualitatively different than that of both control groups. Interpreting the data, processes involved in syntactic comprehension are taken into consideration. It is claimed that processing demands impede SLI children's performance due to a deficit in their competence grammar.

Child↗

PubMed2001

Spoken language outcomes after hemispherectomy: factoring in etiology.

We analyzed postsurgery linguistic outcomes of 43 hemispherectomy patients operated on at UCLA. We rated spoken language (Spoken Language Rank, SLR) on a scale from 0 (no language) to 6 (mature grammar) and examined the effects of side of resection/damage, age at surgery/seizure onset, seizure control postsurgery, and etiology on language development. Etiology was defined as developmental (cortical dysplasia and prenatal stroke) and acquired pathology (Rasmussen's encephalitis and postnatal stroke). We found that clinical variables were predictive of language outcomes only when they were considered within distinct etiology groups. Specifically, children with developmental etiologies had lower SLRs than those with acquired pathologies (p =.0006); age factors correlated positively with higher SLRs only for children with acquired etiologies (p =.0006); right-sided resections led to higher SLRs only for the acquired group (p =.0008); and postsurgery seizure control correlated positively with SLR only for those with developmental etiologies (p =.0047). We argue that the variables considered are not independent predictors of spoken language outcome posthemispherectomy but should be viewed instead as characteristics of etiology.

Adolescent↗

PubMed2002

Lexical therapy and episodic word learning in dementia of the Alzheimer type.

The effect of a language therapy in a group of eight anomic mild patients (the Lexical Therapy group) was assessed by using a 5-month long Lexical Therapy in comparison with an occupational program used in a matched control group (AD; n = 8). The Lexical Therapy group benefited significantly from a language therapy as shown by the naming improvement postintervention. The improvement reached significance only for items that were included in the language therapy protocol and no significant generalization to untreated items was observed. In mild AD patients with anomia and no severe semantic impairment, a reinforcement of the relationship between the form of the object and the corresponding lexical label in episodic long term memory during language therapy may account for the observed lexical improvement.

Aged↗

PubMedDate not supplied

Verb-noun double dissociation in aphasic lexical impairments: the role of word frequency and imageability.

Neurolinguistic studies have provided important evidence regarding the organization of lexical representations and the structure of underlying conceptual knowledge; in particular, it has been shown that the retrieval of verbs and nouns can be damaged selectively. Dissociated lexical damage is proof of an independent mental organization of lexical representations and/or of the underlying processes. The aim of the present study is to estimate the rate of dissociated impairments for nouns and verbs on a large sample of mild to moderate aphasic patients and to investigate the mechanisms underlying such phenomena. In addition, the authors wished to verify to what degree the impairment for nouns and verbs is related to a specific type of language disorder. A confrontation naming task for verbs and nouns was administered to 58 aphasic patients. The major lexical (word frequency and age of acquisition) and semantic variables (familiarity and imageability of the underlying concept) were considered for each noun and verb used in the task. Verbs were distinguished by major functional classes (transitive, intransitive, and ergative verbs). The data collected from this task were analyzed twice: (i) as a group study comparison of major aphasic subgroups and (ii) as a multiple single case study to evaluate the differences on the naming of verbs and nouns and the effect of the lexical semantic variables on each individual patient. The results confirm the existence of dissociated naming impairments of verbs and nouns. Selective impairment of verbs is more frequent (34%) than that of nouns (10%). In many cases, the dissociated pattern of naming impairment disappeared when the effect of the concomitant variables (word frequency and imageability) was removed, but in approximately one-fifth of the cases the noun or verb superiority was preserved. Noun superiority emerged in five of six agrammatic patients. Both the naming of verbs (n = 9) or of nouns (n = 6) could be impaired selectively in fluent aphasic patients. The results lend support to the hypothesis of an independent mental organization of nouns and verbs, but a substantial effect of imageability and word frequency suggests an interaction of the naming impairment with underlying lexical and semantic aspects.

Aphasia, Wernicke↗