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PubMed1994

[The Repertory Grid as a research instrument in inpatient psychotherapy. Possibilities of semantic construct analysis in patients with psychogenic pain].

The Repertory Grid Technique provides a differential analysis of individual constructs ("hypotheses"), by which we structure the perception of our environment. In our study we investigated 35 psychogenic chronic pain patients at beginning and end of inpatient psychotherapy, whether semantic changes occurred in their construct system. We analysed these semantic changes using a categorial system, which was developed by Landfield (1971). This categorial system consists of 22 different categories, at which a rating system (by use of a manual) evaluates the appropriate semantic attachment of constructs of an individual repertory grid to these categories. Our study shows that contrary to our expectation psychogenic pain patients comparatively often described themselves with constructs, which expressed direct social interactions or emotions. However, this finding must be interpreted with some reservation, as our patient group probably is not representative for most of the chronic pain patients, which usually are hardly to motivate for inpatient (respectively outpatient) psychotherapy. Finally we investigated the semantic changes of the construct system during the course of inpatient psychotherapy--here we assume that the conceptualization of own theory guided categories will provide more clinically relevant or perspective results compared to the original category system of Landfield.

Adult↗

PubMed1997

Attention and Semantic Priming: A Review of Prime Task Effects

The single-word semantic priming paradigm is a tool for investigating how and when word meaning (semantic) activation occurs during visual word recognition. The prime task effect refers to the elimination of the typically robust semantic priming effect by a nonsemantic prime task (e.g., subjects search the prime word for a letter). The purpose of this paper is to provide a tutorial review of the literature examining the prime task effect. Understanding the nature of this effect has implications for delineating how selective attention modulates evidence for semantic activation during word reading. These implications are outlined. Additionally, speculations for how these issues of selective attention relate to awareness are offered.

Journal Article↗

PubMed1998

Rationale and design considerations for a semantic mediator in health information systems.

Rapid development of community health information networks raises the issue of semantic interoperability between distributed and heterogeneous systems. Indeed, operational health information systems originate from heterogeneous teams of independent developers and have to cooperate in order to exchange data and services. A good cooperation is based on a good understanding of the messages exchanged between the systems. The main issue of semantic interoperability is to ensure that the exchange is not only possible but also meaningful. The main objective of this paper is to analyze semantic interoperability from a software engineering point of view. It describes the principles for the design of a semantic mediator (SM) in the framework of a distributed object manager (DOM). The mediator is itself a component that should allow the exchange of messages independently of languages and platforms. The functional architecture of such a SM is detailed. These principles have been partly applied in the context of the HELIOS object-oriented software engineering environment. The resulting service components are presented with their current state of achievement.

Computer Communication Networks↗

PubMed1985

The prediction of semantic consistency in self-descriptions: characteristics of persons and of terms that affect the consistency of responses to synonym and antonym pairs.

Subjects described themselves, using an alphabetically ordered list of 191 trait adjectives, which included sets of synonyms and antonyms, half of each type more difficult than the other half. Subjects were randomly assigned to one of two experimental conditions. In one condition, each adjective was listed with its dictionary definition; in the other condition, only the adjectives were listed. All subjects were administered a battery of demographic, cognitive, and personality measures. We analyzed both the relative consistency elicited by different pairs of terms and the individual differences in semantic consistency displayed by different sorts of subjects. Although the provision of definitions served to increase consistency (especially for the difficult antonyms), it did not decrease the range of consistency values across either synonym or antonym pairs. And, although interpair differences in semantic consistency were as difficult to predict in this study as in previous ones, individual differences were highly predictable. The implications of our many findings are discussed in the context of various hypotheses about semantic inconsistency in self-reports.

Adolescent↗

PubMed1988

Nonspecificity of semantic impairment in dementia of Alzheimer's type.

Two psychometric tests designed to evaluate "verbal fluency" and "naming" as a measure of semantic memory were presented to 18 patients with Alzheimer's-type dementia, 16 other patients with multi-infarct dementia, and 14 age-matched control subjects. The diagnosis of multi-infarct dementia and Alzheimer's-type dementia was based on the commonly accepted criteria of the Diagnostic and Statistical Manual of Mental Disorders, ed 3. Although the patients with Alzheimer and multi-infarct dementias, respectively, suffered from a comparable degree of dementia (as determined by the Mini-Mental State examination), semantic memory was not specifically impaired in Alzheimer's-type dementia as opposed to multi-infarct dementia. In contrast semantic memory was correlated with the degree of dementia in both disease entities.

Aged↗

PubMed1999

Functional magnetic resonance imaging of neural activity related to orthographic, phonological, and lexico-semantic judgments of visually presented characters and words.

Functional magnetic resonance imaging was used to investigate neural activity during the judgment of visual stimuli in two groups of experiments using seven and five normal subjects. The subjects were given tasks designed differentially to involve orthographic (more generally, visual form), phonological, and lexico-semantic processes. These tasks included the judgments of whether a line was horizontal, whether a pseudocharacter or pseudocharacter string included a horizontal line, whether a Japanese katakana (phonogram) character or character string included a certain vowel, or whether a character string was meaningful (noun or verb) or meaningless. Neural activity related to the visual form process was commonly observed during judgments of both single real-characters and single pseudocharacters in lateral extrastriate visual cortex, the posterior ventral or medial occipito-temporal area, and the posterior inferior temporal area of both hemispheres. In contrast, left-lateralized activation was observed in the latter two areas during judgments of real- and pseudo-character strings. These results show that there is no katakana "word form center" whose activity is specific to real words. Activation related to the phonological process was observed, in Broca's area, the insula, the supramarginal gyrus, and the posterior superior temporal area, with greater activation in the left hemisphere. These activation foci for visual form and phonological processes of katakana also were reported for the English alphabet in previous studies. The present activation showed no additional areas for contrasts of noun judgment with other conditions and was similar between noun and verb judgment tasks, suggesting two possibilities: no strong semantic activation was produced, or the semantic process shared activation foci with the phonological process.

Adult↗

PubMedDate not supplied

Expressive semantic deficit in the productive language of males with fragile X syndrome.

Eleven males with fragile x syndrome [fra(X)] between the ages of 6 and 41, with an average communication age of 4 years 4 months and 11 normally developing 4 year old boys were administered a sentence completion task that assessed expressive semantic competence. The fra(X) males produced significantly more semantic errors than the normally developing 4 year children. Additionally, it was shown that sentences which could be correctly completed by a wider choice of words affected fra(X) males more than the nondisabled children. These 2 results suggest that the expressive semantic system is an area of specific deficit in fra(X) males.

Adolescent↗

PubMed2004

Simultaneous event-related potential and near-infrared spectroscopic studies of semantic processing.

Near-infrared optical topography (NIROT) signals and event-related potentials (ERPs) were measured simultaneously during a semantic processing task to evaluate the ability of these techniques to detect hemodynamic and electrophysiologic responses generated by semantic anomalies and to compare these results to earlier independent functional magnetic resonance imaging (fMRI) and ERP measurements. Candidate brain regions were first identified from activations detected by NIROT during a simple block-design task (in this case reading sentences vs. passive viewing), and defined regions (corresponding to Broca's and Wernicke's areas) were used for guiding the localization of optodes and electrodes for recording during tasks involving semantic anomalies. In five of six subjects, ERP measurements showed the characteristic N400 wave, whereas event-related NIROT showed results that agreed with previous fMRI studies. There were transient hemodynamic signals recorded in specific optodes that corresponded to activation in Broca's area, but slightly anterior to the region activated during the simple reading task, and in Wernicke's area, but slightly inferior to that for the simple reading task. A between-subject correlation of the ERP and NIRS data was also employed to identify areas of activation. The highest correlations were obtained in Broca's area, centered more anterior than for the reading task and in Wernicke's area, slightly inferior to that for the reading task. This study confirms that event-related studies are feasible using NIROT and produce results similar to those obtained with fMRI. Even though the spatial resolution is lower in NIROT than in fMRI, small differences in the locations of activation centers could be detected with NIROT. This, together with the feasibility of simultaneous ERP recording, makes NIROT attractive as a new approach to studying language function in healthy subjects as well as in those with functional abnormalities.

Adult↗

PubMed2005

Processing lexical semantic and syntactic information in first and second language: fMRI evidence from German and Russian.

We introduce two experiments that explored syntactic and semantic processing of spoken sentences by native and non-native speakers. In the first experiment, the neural substrates corresponding to detection of syntactic and semantic violations were determined in native speakers of two typologically different languages using functional magnetic resonance imaging (fMRI). The results show that the underlying neural response of participants to stimuli across different native languages is quite similar. In the second experiment, we investigated how non-native speakers of a language process the same stimuli presented in the first experiment. First, the results show a more similar pattern of increased activation between native and non-native speakers in response to semantic violations than to syntactic violations. Second, the non-native speakers were observed to employ specific portions of the frontotemporal language network differently from those employed by native speakers. These regions included the inferior frontal gyrus (IFG), superior temporal gyrus (STG), and subcortical structures of the basal ganglia.

Adult↗

PubMed2007

Neural correlates of semantic and morphological processing of Hebrew nouns and verbs.

Neuropsychological evidence regarding grammatical category suggests that deficits affecting verbs tend to localize differently from those affecting nouns, but previous functional imaging studies on healthy subjects fail to show consistent results that correspond to the clinical dissociation. In the current imaging study, we addressed this issue by manipulating not only the grammatical category but also the processing mode, using auditory presentation of Hebrew words. Subjects were presented with verbs and nouns and were instructed to make either a semantic decision ("Does the word belong to a given semantic category?") or a morphological decision ("Is the word inflected in plural?"). The results showed different patterns of activation across distinct regions of interest. With respect to grammatical category effects, we found increased activation for verbs in the posterior portion of the left superior temporal sulcus, left dorsal premotor area, and posterior inferior frontal gyrus. In each of these regions, the effect was sensitive to task. None of the ROIs showed noun advantage. With respect to task effects, we found a semantic advantage in left anterior inferior frontal gyrus, as well as in left posterior middle temporal gyrus. The results suggest that cerebral verb-noun dissociation is a result of localized and subtle processes that take place in a set of left frontal and temporal regions, and that the cognitive and neural processes involved in analyzing grammatical category depend on the lexical characteristics of the stimuli, as well as on task requirements. The discrepancy between functional imaging and patient data is also discussed.

Acoustic Stimulation↗

PubMed2002

Semantic knowledge in patient H.M. and other patients with bilateral medial and lateral temporal lobe lesions.

We investigated the effects of damage to the medial temporal lobe (MTL) and anterolateral temporal cortex on semantic knowledge. We studied eight male controls, two patients with lesions limited to the hippocampal formation, three postencephalitic patients with extensive MTL lesions and variable damage to the lateral temporal cortex, and patient H.M. (whose lesion is limited mostly to the MTL, but who also has minimal damage to the anterolateral cortex). On 13 tests of semantic memory, patients with lesions limited to the hippocampal formation performed similarly to controls. Postencephalitic patients were mildly to moderately impaired on most tests. Patient H.M.'s performance was impaired on only a few tests and was less severely impaired overall than the three postencephalitic patients. A ranking of test scores showed a direct relationship between impairment and the extent of damage to lateral temporal cortex. These findings, and related findings from other studies, point to the importance of anterolateral temporal cortex for semantic knowledge. Patient H.M. performed uniquely in certain respects. For example, when providing definitions of objects, he made many grammatical errors. In contrast, the other patients with large MTL lesions made no more errors than those made by controls. Considering that H.M.'s lesion, both medially and laterally, is less extensive than the lesions in these other patients, it appears unlikely that his shortcomings in language production are related to his temporal lobe lesion.

Aged↗

PubMed2005

Failure to acquire new semantic knowledge in patients with large medial temporal lobe lesions.

We examined new semantic learning in two profoundly amnesic patients (E.P. and G.P.) whose lesions involve virtually the entire medial temporal lobe (MTL) bilaterally. The patients were given five tests of semantic knowledge for information that could only have been acquired after the onset of their amnesia in 1992 and 1987, respectively. Age-matched and education-matched controls (n = 8) were also tested. On tests of recall, E.P. and G.P. each scored 10% correct on a test of 20 easy factual questions (controls = 90%), 2% and 4% correct on 55 questions about news events (controls = 85%), and 0% and 4% correct on a test of 24 famous faces. On three tests of recognition memory for this same material, the patients scored at chance levels. Similarly, the patients were unable to judge whether persons who had been famous for many decades were still living or had died during the past 10 years (E.P. = 53%; G.P. = 50%; controls = 73%; chance = 50%). Lastly, neither patient E.P. nor patient G.P. could draw an accurate floor plan of his current residence, despite having lived there for 10 years and 1 year, respectively. The results demonstrate that the capacity for new semantic learning can be absent, or nearly absent, when there is virtually complete damage to the MTL bilaterally. Accordingly, the results raise the possibility that the acquisition of conscious (declarative) knowledge about the world cannot be supported by structures outside the MTL, even with extended exposure. Published 2004 Wiley-Liss, Inc.

Aged↗

PubMed1994

Semantic processing of pictures and spoken words: evidence from event-related brain potentials.

Semantic associations between pictures and their verbal referents were assessed in a reaction time (RT) experiment where pictures and words acted both as primes and targets. Behavioral RTs and accuracy were recorded from 20 adult subjects along with the event-related brain potentials (ERPs) recorded from two midline and 10 lateral electrode sites. Behavioral effects were inconclusive, but the ERPs to target stimuli varied as a function of whether the priming stimulus was semantically related or unrelated to the target. The ERPs elicited to unrelated picture targets and unrelated word targets were more negative than their related counterparts and fit the characteristics of the N400 during all but the initial phase of differential processing. The differences in scalp distribution in the initial phases appear to reflect the processing of nonidentical sensory-specific mechanisms; the common later peak activity reflects the processing of a single common semantic processor.

Adolescent↗

PubMed1998

Chronic electrical stimulation of the left ventrointermediate (Vim) thalamic nucleus for the treatment of pharmacotherapy-resistant Parkinson's disease: a differential impact on access to semantic and episodic memory?

Thalamotomy for medically refractory Parkinson's disease (PD) is considered to be efficacious and relatively safe. Because a minority of patients experience decrements in language and memory (often mild and transient) after thalamotomy, chronic thalamic deep brain stimulation (DBS) might be a safer treatment given its reversibility and the modifiability of stimulation parameters. Two preliminary studies support the relative cognitive safety of unilateral DBS of the ventral intermediate (Vim) thalamic nucleus, but it is unclear whether possibly subtle changes in language and memory represent effects of "microthalamotomy" or of stimulation per se. This report provides preliminary data concerning effects of left thalamic stimulation on information processing speed, semantic memory (verbal fluency and visual confrontation naming), and verbal episodic memory in a patient with PD. In addition to being evaluated before and 3 and 6 months after surgery, the patient was tested 18 months after surgery either on or off medications and with the stimulator turned either on or off (order counterbalanced across medication conditions). Test performance differences between the stimulation conditions were attenuated "off" as compared to "on" medication. Vim stimulation consistently, albeit subtly, improved semantic verbal fluency but interfered with immediate recall of word lists. Parallels to findings from acute, intraoperative thalamic stimulation studies are explored. The hypothesis is offered that left Vim stimulation might facilitate access to semantic memory, but interfere with episodic memory processes.

Adult↗

PubMed1996

On the nature of naming errors in aging and dementia: a study of semantic relatedness.

This study investigated the nature of naming errors produced on the Boston Naming Test by patients with mild and moderate Alzheimer's disease (AD) and elderly and young controls, using a newly devised scoring system. This new approach involved ratings of error responses on a scale of semantic relatedness to the target name. Error responses of both mild and moderate AD subjects were no less semantically related to target names than were responses of age- and education-matched controls. We conclude that some available evidence of semantic loss in AD may be an artifact of the methodology chosen for evaluating naming errors.

Adult↗

PubMed1997

Double dissociation of semantic categories in Alzheimer's disease.

Data that demonstrate distinct patterns of semantic impairment in Alzheimer's disease (AD) are presented. Findings suggest that while groups of mild-moderate patients may not display category specific impairments, some individual patients do show selective impairment of either natural kinds or artifacts. We present a model of semantic organization in which category specific impairments arise from damage to distributed features underlying different types of categories. We incorporate the crucial notions of intercorrelations and distinguishing features, allowing us to demonstrate (1) how category specific impairments can result from widespread damage and (2) how selective deficits in AD reflect different points in the progression of impairment. The different patterns of impairment arise from an interaction between the nature of the semantic categories and the progression of damage.

Aged↗

PubMed1997

Semantic memory impairment does not impact on phonological and orthographic processing in a case of developmental hyperlexia.

Recent evidence from patients with progressive language disorders and dementia has been used to suggest that phonological and orthographic processing depend on intact semantic memory. These claims challenge the traditional view that there are functionally separate modules in the language system. The effect of a severe, but nonprogressive, semantic impairment on phonological and orthographic processing was evaluated in LA, a mentally retarded child with hyperlexia. Knowledge of a word's meaning did not affect LA's word repetition, a measure of phonological processing, or his acquisition and retention of orthographic patterns for writing to dictation low-frequency words with exceptional spellings. These findings support the assertion that both orthographic and phonological whole-word representations can be acquired, stored, and retrieved in the absence of a functional link to semantic memory.

Child↗

PubMed1997

The gradual deterioration of syntax and semantics in a patient with progressive aphasia.

FM is a progressive aphasic patient whose language comprehension we studied over a 4-year period. We developed a variety of implicit and explicit tasks to chart progressive changes in the representation of linguistic knowledge (in particular, syntax and semantics) and the automatic and controlled processes which operate on that knowledge. The representation of FM's semantic knowledge remained essentially intact over the years, but she became increasingly impaired at combining the meanings of words. She also showed progressive impairments in the processes of syntactic combination. Thus, FM's disease resulted in a progressive inability to engage in those combinatorial processes necessary for the normal comprehension of a spoken utterance. This is not a selective deficit in the traditional sense of the term, since aspects of both syntax and semantics are implicated; but it is selective in the sense that other aspects of language comprehension remain intact.

Aphasia↗