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PubMed2006

Effect of semantic naming treatment on crosslinguistic generalization in bilingual aphasia.

PURPOSE: The effect of semantic naming treatment on crosslinguistic generalization was investigated in 3 participants with English-Spanish bilingual aphasia. METHOD: A single-subject experimental designed was used. Participants received semantic treatment to improve naming of English or Spanish items, while generalization was tested to untrained semantically related items in the trained language and translations of the trained and untrained items in the untrained language. RESULTS: Results demonstrated a within- and across-languages effect on generalization related to premorbid language proficiencies. Participant 1 (P1; equal premorbid proficiency across languages) showed within-language generalization in the trained language (Spanish) as well as crosslinguistic generalization to the untrained language (English). Participant 2 (P2) and Participant (P3) were more proficient premorbidly in English. With treatment in English, P2 showed within-language generalization to semantically related items, but no crosslinguistic generalization. With treatment in Spanish, both P2 and P3 exhibited no within-language generalization, but crosslinguistic generalization to English (dominant language) occurred. Error analyses indicated an evolution of errors as a consequence of treatment. CONCLUSIONS: These results are preliminary because all participants were not treated in both languages. However, the results suggest that training the less dominant language may be more beneficial in facilitating crosslinguistic generalization than training the more proficient language in an unbalanced bilingual individual.

Aphasia↗

PubMed1976

Semantic relations used by normal and language-impaired children at stage I.

Two-word utterances of four language-impaired children at Brown's Stage I level of linguistic development were compared with two-word utterances of four young normal children at the same linguistic level to determine any differences between the two groups in the use of a set of 10 basic semantic relations. Type-token ratios for each semantic relation were used to compare use of semantic relations between groups. A significant difference was obtained for only one relation, with the language-impaired group demonstrating greater diversity in the use of the introducer + entity relation than the normal group. The findings indicated that at Stage I level of linguistic development, the language-impaired children demonstrated a linguistic system no different than the system of normal Stage I children. The findings are discussed relative to possible cognitive and linguistic strategies involved in language acquisition. It is suggested that some language-impaired children rather than being deficient in their ability to understand and code the basic semantic relations demonstrate a deficit in the higher, more complex aspects of the linguistic coding system.

Child, Preschool↗

PubMed2004

[Semantic dementia: clinical profile and cognitive-neuropsychological relevance].

Semantic Dementia (SD) represents a rare variant of presenile primary degenerative diseases of "frontotemporal lobar degenerations" (FTLD). SD is characterized by anterior-temporal atrophy and a selective semantic deficit. Neuropsychological impairment either bears on fluent aphasia with marked naming and comprehension difficulties or on a disorder of object recognition or on both. Behavioural alterations such as stereotyped behaviour and change in food preference become prominent as the disease progresses and are interpreted as a correlative for the pathological spreading to frontal structures. Since SD is often misclassified as Alzheimer's disease (AD), but calls for a different management, diagnostic consensus criteria by Neary and colleagues are depicted. The neuropsychological profile is described in detail and complemented by a case report. Implications from the dissociation of disturbed memory systems of SD (semantic) and AD (episodic) for models of long-term memory are discussed in terms of connectivity in the medial temporal lobe. SD can contribute to a better understanding of the structure and organisation of the semantic system.

Cognition↗

PubMed1991

Influence of physical and semantic information in a categorisation task of fragmented forms.

Two experiments were carried out to investigate the influence of structural and semantic information in the categorisation of visual forms. In experiment 1 the stimuli were pairs of 'well structured' or 'poorly structured' fragmented forms differing in structural properties including convexity, collinearity, and closure of the elements, and in their 'nameability'. The influence of structural and semantic information was tested by means of a task involving the presentation to both visual hemifields separately of stimuli having within-category physical similarity. For well structured forms, subjects were asked to judge if two sequentially presented forms belonged to the same semantic category. For poorly structured forms, subjects were required to decide if two stimuli belonged to the same previously learnt category of forms. For the two types of stimuli, one category was composed of physically similar items, and the other was composed of physically dissimilar items. The results show a marked advantage for the category composed of physically similar forms when the stimuli are well structured but no differences between the two categories when the stimuli are poorly structured. This suggests a facilitation in the computation of global shape information for forms having collinear and closed elements. The only effect of semantic information was a tendency towards a right visual field advantage for same-category pairs of well structured forms. The pattern of results for well structured fragmented forms (experiment 1) and forms in which fragments had been joined in order to complete the contour (experiment 2) were similar, suggesting that structured incomplete forms can be processed in the same way as forms having a continuous contour. Hypotheses about the organisational processes of forms are proposed in the discussion.

Adult↗

PubMed2000

Can semantic knowledge influence motion correspondence?

Semantic factors are presumed to have little influence on motion perception. Two experiments examined the effects of an object's semantic identity on motion correspondence using the Ternus paradigm. Motion correspondence was not influenced by whether the object depicted is typically moving or stationary, but it was influenced by the way(s) in which an object's components typically move relative to one another: perceived correspondence differed depending on whether the motion tokens constituted the feet of a person walking or the wheels of a car. Apparently, semantic knowledge can influence motion correspondence, although such influence is weak and may be restricted to certain types of semantic information. The adaptive significance of such restricted influences is considered.

Adult↗

PubMed2004

From paragraph to graph: latent semantic analysis for information visualization.

Most techniques for relating textual information rely on intellectually created links such as author-chosen keywords and titles, authority indexing terms, or bibliographic citations. Similarity of the semantic content of whole documents, rather than just titles, abstracts, or overlap of keywords, offers an attractive alternative. Latent semantic analysis provides an effective dimension reduction method for the purpose that reflects synonymy and the sense of arbitrary word combinations. However, latent semantic analysis correlations with human text-to-text similarity judgments are often empirically highest at approximately 300 dimensions. Thus, two- or three-dimensional visualizations are severely limited in what they can show, and the first and/or second automatically discovered principal component, or any three such for that matter, rarely capture all of the relations that might be of interest. It is our conjecture that linguistic meaning is intrinsically and irreducibly very high dimensional. Thus, some method to explore a high dimensional similarity space is needed. But the 2.7 x 10(7) projections and infinite rotations of, for example, a 300-dimensional pattern are impossible to examine. We suggest, however, that the use of a high dimensional dynamic viewer with an effective projection pursuit routine and user control, coupled with the exquisite abilities of the human visual system to extract information about objects and from moving patterns, can often succeed in discovering multiple revealing views that are missed by current computational algorithms. We show some examples of the use of latent semantic analysis to support such visualizations and offer views on future needs.

Animals↗

PubMed2000

Statistical methods for characterizing similarities and differences between semantic structures.

This paper describes a variety of statistical methods for obtaining precise quantitative estimates of the similarities and differences in the structures of semantic domains in different languages. The methods include comparing mean correlations within and between groups, principal components analysis of interspeaker correlations, and analysis of variance of speaker by question data. Methods for graphical displays of the results are also presented. The methods give convergent results that are mutually supportive and equivalent under suitable interpretation. The methods are illustrated on the semantic domain of emotion terms in a comparison of the semantic structures of native English and native Japanese speaking subjects. We suggest that, in comparative studies concerning the extent to which semantic structures are universally shared or culture-specific, both similarities and differences should be measured and compared rather than placing total emphasis on one or the other polar position.

Analysis of Variance↗

PubMed2001

Preserved semantic access in global amnesia and hippocampal damage.

C.B., a right-handed 33-year-old man, presented with anterograde amnesia after acute heart block. Cognitive abilities were normal except for serious impairment of long-term episodic memory. The access to semantic information was fully preserved. Magnetic resonance showed high signal intensity and marked volume loss in the hippocampus bilaterally; the left and right parahippocampal gyrus, lateral occipito-temporal gyrus, inferior temporal gyrus, and lateral temporal cortex were normal. This case underlines that global amnesia associated with hippocampal damage does not affect semantic memory. Although the hippocampus is important in retrieving context-linked information, its role is not so crucial in retrieving semantic contents. Cortical areas surrounding the hippocampus and lateral temporal areas might guide the recall of semantic information.

Adult↗

PubMed2002

RT and non-RT methodology for semantic priming research with Alzheimer's disease patients: a critical review.

This paper provides a critical review of RT and non-RT methodology for the conduct of research on semantic priming in Alzheimer's disease (AD) compared to elderly normal (EN) individuals. The review is organized by type of semantic priming (or attribute-knowledge) paradigm. Theoretical as well as methodological issues are highlighted insofar as they are relevant to: (1) the design, conduct, and analysis of semantic priming experiments (and closely related types of experiments) with AD compared to EN participants, and (2) the interpretation of findings from these experiments. Recommendations are provided for further research involving semantic priming and related paradigms with AD and certain other neuropsychological populations.

Aged↗

PubMed2003

Memory for the perceptual and semantic attributes of information in pure amnesic and severe closed-head injured patients.

This study investigated the hypothesis that brain damaged patients with memory disorder are poorer at remembering the semantic than the perceptual attributes of information. Eight patients with memory impairment of different etiology and 24 patients with chronic consequences of severe closed-head injury were compared to similarly sized age- and literacy-matched normal control groups on recognition tests for the physical aspect and the semantic identity of words and pictures lists. In order to avoid interpretative problems deriving from different absolute levels of performance, study conditions were manipulated across subjects to obtain comparable accuracy on the perceptual recognition tests in the memory disordered and control groups. The results of the Picture Recognition test were consistent with the hypothesis. Indeed, having more time for the stimulus encoding, the two memory disordered groups performed at the same level as the normal subjects on the perceptual test but significantly lower on the semantic test. Instead, on the Word Recognition test, following study condition manipulation, patients and controls performed similarly on both the perceptual and the semantic tests. These data only partially support the hypothesis of the study; rather they suggest that in memory disordered patients there is a reduction of the advantage, exhibited by normal controls, of retrieving pictures over words (picture superiority effect).

Adolescent↗

PubMed2003

Differential impairment of person-specific knowledge in a patient with semantic dementia.

We report the case of ST, a 61-year-old gentleman of superior intelligence, who presented with a five-year history of slowly progressive word finding difficulty for proper names. MRI (magnetic resonance imaging) showed marked atrophy in the left anterior temporal lobe and SPECT (single photon emission computed tomography) demonstrated hypoperfusion in the left anterior and inferior temporal region. A detailed behavioral analysis of the integrity of his semantic system revealed naming deficits for both proper and common names. ST also showed severe impairments in person-specific semantic knowledge, but preservation of knowledge for famous places and common objects. ST's semantic knowledge deficit for people emerged whether he was tested with the faces or the names of famous individuals. Variables that affect name retrieval, such as familiarity, age of acquisition, and frequency of concept encounter, do not account for the selective impairment of person-specific knowledge evidenced by ST. Qualitative differences between the nature of knowledge representations for people and for common objects may underlie this effect. Disruptions in left temporal regions associated with semantic processing may be sufficient to produce a selective deficit in person-specific knowledge.

Attention↗

PubMed2003

The heterogeneity of category-specific semantic disorders: evidence from a new case.

We report a new case of category-specific semantic impairment, affecting living entities, in a patient with traumatic brain damage. In the present investigation we attempted to replicate as closely as possible the testing procedures which have been developed by Caramazza and Shelton (1998) to evaluate EW, a patient with a selective semantic disorder for the animal category. The results in our patient indicated a different performance profile, characterised by a more extensive semantic disorder for living entities, and by a more severe loss of specific visual rather than functional knowledge. These findings concur with other evidence indicating that category-specific semantic disorders are heterogeneous, reflecting different mechanisms of impairment, most likely associated with different neurobiological underpinnings.

Adult↗

PubMed1982

The effect of semantic relations on the memory deficit associated with Parkinson's disease.

Analysis of a series of verbal memory experiments reveals a systematic performance deficit in subjects with Parkinson's disease, relative to matched normal and right-hemisphere stroke controls, in both recall and recognition tasks. Parkinson patients benefit less from semantic recall cues; they find semantically mediated synonym detections particularly difficult; and they show reduced benefits from the introduction of semantically novel material in a recall task. Their recall is as well organized semantically as that of normal controls, but reduced in amount. Recognition deficits arise principally from increases in false positive responses.

Aged↗

PubMed1990

Facilitation of memory performance through induced semantic processing in survivors of severe closed-head injury.

This study examined whether survivors of severe closed-head injury (CHI) show a relative benefit in memory for words that are processed semantically versus words that are processed physically or acoustically. Sixteen long-term CHI patients and 14 demographically matched controls were administered a Levels of Processing paradigm involving detection of semantic (categorical), physical (letter), or acoustic (rhyme) features of to-be-remembered words. Semantic processing enhanced recognition memory and cued recall in the CHI patients, but the degree of facilitation was reduced relative to controls. The results indicate that attention to semantic features facilitates memory performance in survivors but may require greater cognitive effort. Implications for the remediation of memory impairments following CHI are discussed.

Attention↗

PubMed1985

The systematic use of semantic and acoustic processing by younger and older adults.

To examine age differences in semantic and acoustic processing, 80 older and 80 younger adults participated in an incidental learning study. The study compared free recall and semantic and acoustic cued recall performance after five orienting conditions. The younger adults performed better than the older adults, especially after acoustic orienting. Encoding specificity effects occurred at both age levels. The results indicated that both age groups performed better with semantic processing than acoustic processing, but that older adults relied on the semantic information far more than the younger adults.

Adult↗

PubMed1986

Adult age differences in visual word recognition: semantic encoding and episodic retention.

The present experiment examined adult age differences in semantic priming effects and subsequent episodic retention for visually presented words. Twenty-four young (18-22 years) and 24 older (58-74 years) adults participated. In a lexical decision task, each of the word targets was presented as the final item of a sentence context (i.e., a prime) that was either semantically congruous, incongruous, or neutral with regard to the target. The perceptual difficulty of the target was also varied. The semantic priming effects in lexical decision RT were equivalent in magnitude for the young and older adults. The RT data appeared to represent a generalized, age-related slowing in the speed of information processing. In unexpected tests of recall and recognition for the target words, the older adults performed significantly worse than the young adults. The present results indicate that age-related deficits in episodic memory are not accompanied by substantial changes in semantic encoding ability.

Adolescent↗

PubMedDate not supplied

Probing sensory and associative semantics for animals and objects in normal subjects.

Neuropsychological studies of patients with "category-specific" semantic memory disorders have fuelled a debate concerning the organisation of knowledge. In particular it has been suggested that the reported double dissociation between knowledge of animals and living things on the one hand, and objects on the other, reflects a more fundamental division of semantic representation into functional-associative and sensory-visual domains. The present study attempted to investigate whether there were systematic differences along these dimensions in normal subjects using a sentence-verification technique. It was found that response times were significantly longer for verification of statements concerning the sensory attributes of objects than for statements about their associative attributes. In the case of animals, there were no differences in response latency to associative or sensory statements. In the light of this previously unreported fractionation within verbal semantics, the possible consequences for models of semantic memory are discussed.

Adult↗

PubMedDate not supplied

Naming without knowing and appearance without associations: evidence for constructive processes in semantic memory?

This study describes a patient (SE) with temporal lobe injury resulting from Herpes Simplex Encephalitis, who displayed a previously unreported impairment in which his knowledge of associative and functional attributes of animals was disproportionately impaired by comparison with his knowledge of their sensory attributes (including their visual properties and characteristic sounds). His knowledge of man-made objects was preserved. A striking aspect of the present case was that the patient remained able to name many animals from their pictures, despite making gross errors in generating associative information about these same animals. This suggests that a semantic representation incorporating stored sensory knowledge may be sufficient for naming (at least for biological categories) and associative information may be unnecessary. Semantic knowledge may normally incorporate more information than is necessary for identification. SE's errors were found to be confabulatory and reconstructive in nature and it is argued that this aspect of his performance challenges passive conceptions of semantic memory couched in terms of a catalogue of stored representations. It is proposed that the patient's disorder affects a dynamic, constructive, and inferential component of his knowledge base, and that this component is sensitive to semantic category.

Anomia↗