PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Semantics”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,423 records · Page 79Linked to original sources
PubMed1978

Auditory semantic, syntactic, and retention errors made by aphasic subjects on the Token Test.

The Token Test was administered to 25 mild aphasic and 25 matched normal subjects for the purpose of determining the linguistic nature of the auditory verbal comprehension error responses. As was expected, the aphasic subjects obtained significantly poorer scores on the Token Test than did the normal subjects, with minimal overlap between the two groups. In Parts I-IV, the errors were exclusively semantic, and reflected only the amount of required verbal memory. In Part V, the syntactic structures vary, and the aphasic subjects showed a similar pattern of difficulty as did the normal subjects. Syntactic errors were more prevalent than semantic errors in Part V, suggesting that syntactic complexity was the most important factor in verbal comprehension on this part. In comparison to previous research utilizing the Token Test with normal children, the aphasic subjects in the present study generally had high error rates on the same items as did the children.

Adult↗
PubMed1987

The effects of self-instruction training on a deaf child's semantic and pragmatic production.

Effects of self-instruction training on the communication skills of a profoundly hearing-impaired child were studied. Self-instruction training included modeling a series of problem-solving steps in order to direct communication production. Communication production was operationalized as signed semantic and pragmatic functions. A multiple baseline was used to assess treatment and generalization (treatment variations of person and setting) effects. There was evidence to suggest that self-instruction was immediately effective on pragmatic behaviors but such behaviors were reduced when another person administered treatment. In contrast, self-instruction training had a gradual influence on semantic behaviors and those effects were maintained when treatment included a different person and setting. Implications of the clinical study were discussed.

Behavior Therapy↗
PubMed1986

Intraverbal acquisition of semantic concepts by preschoolers.

Intraverbal learning is a process through which semantic knowledge is acquired from purely linguistic information. The concern of this study is to investigate the role of intraverbal learning in the preschool-aged child's acquisition of semantic concepts. Three- and 4-year-old children were either shown pictures illustrating novel concepts or they were told verbal definitions of novel concepts, the definitions containing information about key physical and functional properties. An additional manipulation consisted of including or omitting information about the superordinate category membership of the concept. Concept acquisition was assessed via a battery of comprehension tasks; these tasks assessed both referential and formal knowledge of the concepts. Results indicate a correspondence between the type of information received and the type of knowledge acquired, with intraverbal information resulting in broader knowledge than pictorial information. Purely pictorial information was associated with referential knowledge only, while intraverbal information enhanced both referential and formal knowledge.

Child, Preschool↗
PubMed1983

Visual field differences in semantic comparative judgments with digits and Kanji stimulus materials.

Hemisphere specialization for two types of semantic comparative judgments were examined. In the first experiment a pair of Arabic numerals of different physical size were displayed and subjects were asked to judge if the physical size of the stimulus and the numerical magnitude were congruent or not by pressing the appropriate button. Reaction times were faster in the right visual field than in the left visual field. In the second experiment a pair of different physical sized Kanji representing concrete objects were displayed and subjects were required to judge if the physical size of the Kanji was congruent or not with the relative real life object size by pressing the appropriate button. Reaction times were faster in the left visual field. In the third experiment a pair of different physical sized Kanji representing numerical magnitude were displayed and subjects judged if the physical size of the Kanji and the numerical magnitude were congruent or not. Results showed a right visual field advantage and eliminated the possibility that Kanji complexity was the cause of the left visual field advantage in the second experiment. These results were interpreted as providing support for the proposal that there are two types of semantic comparative judgments, one relying on the verbal code and the other relying on the use of imagery, and suggesting that the former calls for stronger engagement of the left hemisphere while the latter calls for a stronger contribution from the right hemisphere.

Adult↗
PubMed1989

Dichotic listening indices of right hemisphere semantic processing.

A new dichotic listening technique, based on a psychophysical threshold procedure and providing ordinal scale measurement of lateral asymmetry, was used to investigate variation in the size of right-ear advantage for verbal vs manual response modalities across three semantic categories of stimuli in 60 right-handed males. For manual responders, abstract words elicited a significantly greater right-ear advantage than did concrete words, while emotional words elicited a non-significant left-ear advantage. Verbal responders showed no significant difference in the size of right-ear advantage across stimuli. The results suggest that both response modality and stimulus type are important variables for dichotic listening paradigms seeking evidence of right hemisphere contributions to semantic processing.

Adult↗
PubMed1992

Semantically-bounded anomia: implications for the neural implementation of naming.

We describe a patient whose anomia is disproportionately severe for fruits and vegetables when familiarity and name frequency are taken into account. His fruit and vegetable naming impairment was evident in a variety of different tasks. In contrast, he retained good general knowledge of fruits and vegetables, and he could access their names when given a phonemic cue. We discuss the phenomenon of semantically-bounded anomia in relation to the issues of local vs distributed representation, the existence of semantic "maps" in the brain, and the implementation of arbitrary associations in neural networks.

Anomia↗
PubMed1992

Semantic memory impairment in Alzheimer's disease: failure of access or degraded knowledge?

A battery of neuropsychological tests designed to assess semantic knowledge about the same items both within and across different modalities was administered to a group of 22 patients with dementia of the Alzheimer type (DAT) and 26 matched controls. The DAT patients were impaired on tests of category fluency, picture naming, spoken word-picture matching, picture sorting and generation of verbal definitions. A relative preservation of superordinate knowledge on the sorting and definition tests, as well as a disproportionate reduction in the generation of exemplars from lower order categories was noted. Analysis of the errors made by each patient across the different tests, revealed a significant correspondence between the individual items. These findings offer compelling evidence that the semantic breakdown in DAT is caused by storage degradation.

Aged↗
PubMed1984

Semantic errors reconsidered in the procedural light of stack concepts.

The purpose of this paper is to demonstrate the relevance of the stack concept in neuropsycholinguistics, a stack being a file with serially ordered elements. Number names (one, two, three, . . .) and the names of the days in the week may be viewed in this way. In a stack structure, any element is identified by two pieces of information: the particular stack to which it belongs and its position within that stack. Two experiments are reported that demonstrate a double dissociation. A deep dyslexic patient with agrammatism was found to sort stack elements on the basis of identity of position-within-stacks, while a fluent aphasic with semantic verbal paraphasias used another criterion, grouping together the items of the same stack. First revealed when handling number names, the two psycholinguistic procedures are also shown to be differentially operative with other linguistic material. Introducing the stack concept thus permits a procedural reinterpretation of some "semantic confusions," particularly but not exclusively those dealing with quantities.

Adult↗
PubMed1984

The effect of semantic plausibility on sentence comprehension in aphasia.

Tested were 50 aphasic patients (16 Broca's, 15 Wernicke's, 10 global, and 9 amnesic), 13 nonaphasic brain damaged patients, and 13 normal adults to evaluate the effect of semantic plausibility on sentence comprehension in active affirmative declarative sentences with a sentence-picture matching task. A plate of two pictures was provided for each stimulus sentence, and the subject was required to choose the picture corresponding to the sentence presented auditorily. Two types of sentences in terms of plausibility were prepared, i.e., probable sentences (P) describing common events in our daily life and improbable sentences (I) describing rare events. There were four kinds of combinations of a picture with the other to make a correct/(distractor) set, i.e., P/(P), P/(I), I/(P), and I/(I) constructions. The results indicated that probable sentences were more comprehensible than improbable sentences, and that the effect of semantic plausibility did not differ among aphasic types.

Adult↗
PubMed1985

Impaired ranking of semantic attributes in dementia.

The present work explored the loss of semantic attributes that is said to occur in dementia. In the first two experiments, subjects had to select attributes that went with concepts like airplane and church. The finding that demented subjects maintained high levels of accuracy when selecting attributes suggested that the semantic content of their concepts was relatively well preserved. The organization of the content was explored in a third experiment by having subjects order attributes according to their relative importance in defining concepts. While demented subjects performed better than chance, they did not rank attributes as well as healthy aged subjects, suggesting a disruption in organization whereby the importance of central attributes is reduced. The hypothesized disruption in organization is viewed in relation to the learning and memory deficit that is the hallmark of the dementias.

Aged↗
PubMed1987

Aphasics' appreciation of hierarchical semantic categories.

The mental representative structure of hierarchically ordered semantic categories was explored with 66 aphasic patients and 60 normal adults by a word-verification task. Four words concerning living things and 10 line drawings depicting an object were prepared as stimuli. All possible pairings of each of the four words with each of the 10 line drawings were made to be verified. The results indicated that subjective category domains were more diffusive in aphasic patients than in normal adults, and that this alteration was exclusively due to increase of peripheral members, but not of central members. It was also revealed that normative category boundaries may be preserved vestigially or incompletely in aphasic patients except the severe fluent subgroup, in whom there may be profound disintegration of boundaries. On the other hand, some common features concerning intracategorical structure and preference among levels of abstraction across normal adults and aphasic patients permit the hypothesis that aphasic patients may retain partially normal semantic knowledge.

Aphasia↗
PubMed1987

Semantic priming with abstract and concrete words: differential asymmetry may be postlexical.

We investigated whether abstract and concrete words would be differentially effective in priming lexical decisions to words presented to the right and left visual fields. Under low probability prime conditions, where priming is presumed to reflect a spreading activation process within the lexicon, equivalent priming was obtained in each VF for both abstract and concrete primes. However, when the same words were used in a high probability prime paradigm, abstract primes were much less effective in the LVF than in the RVF, while priming with concrete words did not differ across the visual fields. Since such priming may reflect a postlexical semantic integration stage, the results imply that hemisphere differences for processing abstract and concrete words may arise only after lexical access has occurred, when semantic information retrieved from the lexicon becomes available for subsequent processing.

Adult↗
PubMed1988

Automatic and attentional processing: an event-related brain potential analysis of semantic priming.

Event-related brain potentials (ERPs) and behavioral measures (reaction time and percentage errors) were measured in a semantic priming lexical decision task. In one block of trials, instructions and the proportion of related word pairs were designed to influence subjects to process the first member of each pair (prime) automatically. In another block, subjects were induced to attend to the meaning of each prime. ERPs to the primes were more positive between 200 and 600 msec and more negative between 750 and 1150 msec when subjects attended to the primes as opposed to when only automatic processing was required. Target word ERP activity between 200 and 525 msec (N400) was more negative in the neutral than in the semantically related condition in both blocks of trials, but more so in the attentional block, while a late ERP positively between 525 and 1100 msec (Slow Wave) was more positive in the unrelated than the neutral condition, but only in the attentional block. The results are discussed in terms of the two-process model proposed by Posner and Snyder (1975a, 1975b).

Adolescent↗
PubMed1989

Semantic processing in patients with Alzheimer's disease.

Ten patients with dementia of the Alzheimer type and 10 normal controls performed a lexical decision, semantic facilitation task. The performance of the patients differed from that seen in normals. A post hoc subdivision of the data suggested that the diviation from normality was not uniform throughout the patient population. Six of the 10 Alzheimer patients showed an advantage of related primes over unrelated primes, while 4 of the 10 were actually faster in the unrelated condition than in the related condition. Nevertheless, both group of Alzheimer patients showed lexical decision latency differences between unrelated and related prime words, suggesting that patients with Alzheimer's disease are sensitive to the semantic relationships between words.

Aged↗
PubMed1990

Response consistency on a semantic memory task in persons with dementia of the Alzheimer type.

The purpose of this investigation was to determine the test-retest response consistency rate on a semantic memory task in persons with dementia of the Alzheimer type (DAT). Ten mildly and 13 moderately impaired DAT subjects and 14 normal controls matched for age, years of education, and estimated IQ participated in this study. The Peabody Picture Vocabulary Test (PPVT) was administered twice to each subject with a 7-day intertest interval. The mild and moderate DAT subjects responded inconsistently to significantly more PPVT items than normal controls. When the effects of guessing were considered, moderate DAT subjects gave significantly more inconsistent PPVT responses than normal controls and mild DAT subjects showed a trend toward giving more inconsistent responses. These results substantiate the conclusion that the impairment of specific conceptual knowledge in DAT subjects cannot be reliably measured with a single administration of a semantic memory task such as the PPVT.

Aged↗
PubMed1991

Mechanisms for accessing lexical representations for output: evidence from a category-specific semantic deficit.

We report the performance of a neurologically impaired patient, JJ, whose oral reading of words exceeded his naming and comprehension performance for the same words--a pattern of performance that has been previously presented as evidence for "direct, nonsemantic, lexical" routes to output in reading. However, detailed analyses of JJ's reading and comprehension revealed two results that do not follow directly from the "direct route" hypothesis: (1) He accurately read aloud all orthophonologically regular words and just those irregular words for which he demonstrated some comprehension (as indicated by correct responses or within-category semantic errors in naming and comprehension tasks); and (2) his reading errors on words that were not comprehended at all (but were recognized as words) were phonologically plausible (e.g., soot read as "suit"). We account for these results by proposing that preserved sublexical mechanisms for converting print to sound, together with partially preserved semantic information, serve to mediate the activation of representations in the phonological output lexicon in the task of reading aloud. We present similar arguments for postulating an interaction between sublexical mechanisms and lexical output components of the spelling process.

Aged↗
PubMed1991

Semantic priming effects, lexical repetition effects, and contextual disambiguation effects in healthy aged individuals and individuals with senile dementia of the Alzheimer type.

An experiment is reported that addresses semantic priming effects, lexical repetition effects, and the influence of context on meaning selection for ambiguous words in 32 healthy aged individuals and 32 individuals with Senile Dementia of the Alzheimer Type (SDAT). On each of 232 trials, subjects pronounced each of three words. The four major conditions were concordant (music-organ-piano), discordant (kidney-organ-piano), neutral (ceiling-organ-piano), and unrelated (kidney-ceiling-piano). In order to address lexical repetition effects, target words were repeated across Blocks 1 and 2 but not in Block 3. Analyses of naming latencies indicated that semantic priming effects and lexical repetition effects were slightly larger in SDAT individuals than in healthy aged individuals. More importantly, healthy aged individuals produced normal selective access of the contextually biased meaning whereas SDAT individuals produced evidence consistent with nonselective meaning access. These results are discussed within both an attentional and a connectionist account of homograph disambiguation.

Aged↗