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Following a previous review about the different components of memory (Eustache et al., Revue Neurologique, 1998), this paper is devoted to the evaluation of both autobiographical and semantic memory. An original method to analyse autobiographical memory is proposed. The different tasks used for the analysis of semantic memory are detailed with a particular emphasis given to the category -specific semantic impairments.
The semantic interpretation of natural language utterances is usually based on a large number of transformation rules which map syntactic structures (parse trees) onto some kind of meaning representation. However, those interpretation rules exhibit an insufficient degree of abstraction so that the scalability and portability of such natural language processing systems is hard to maintain. In this paper, we introduce an approach that is able to cope with a wide variety of semantic interpretation patterns in medical free texts by applying a small inventory of abstract semantic interpretation schemata. These schemata address generalized graph configurations within syntactic dependency parse trees, which abstract away from specific syntactic constructions.
OBJECTIVE: To evaluate the utility of SNOMED RT in support of a natural language interface for encoding of clinical assessments. METHOD: Using a random sample of clinical terms from the UNMC Lexicon, I mapped the terminology into canonical data entries using SNOMED RT. Working from the source term language, I evaluated lexical mapping to the SNOMED term set, and the function of the SNOMED RT semantic network in support of a language-based clinical coding interface. RESULTS: Ambiguity in the source terms was low at 0.3%. Lexical (language-based) mapping could account for only 48.8% of meaning from the source terms. The RT semantic network accounted for 39.5% of meaning, and supplementing the lexical map this led to 80.2% capture of source content. Error rates in the segment of RT which I reviewed were low at 0.6%. 97.6% of source content could be accurately captured in SNOMED RT. CONCLUSION: SNOMED RT supported an accurate and reliable representation of clinical assessment data in this sample. The semantic network of RT substantially enhanced the encoding of concepts relative to lexical mapping. However these data suggest that natural language encoding with SNOMED RT in an enterprise environment is unlikely at this time.
Sociolinguists have contended that children, and especially black children, from families of poverty commonly fail in school not because they have either a cognitive or language deficit but because they have a dialect problem. Being unfamiliar with standard English, they are forced to undertake a double task while learning to read. In order to test the validity of this contention, 54 Head Start and 33 nursery-school children of four years were examined with a test of shape identification. The children of Head Start identified six shapes perceptually by matching them about as well as did the nursery-school children. On the other hand, a much smaller percentage of Head Start than of nursery school named correctly all the shapes as they were indicated by the examiners or indicated correctly all the shapes when they were named by the examiners. Sex differences in semantic mastery of shapes are absent; and among the children of Head Start, race differences in semantic mastery of shapes are also absent. The deficit in semantic mastery for shapes is clearly evident, and demonstrating the existence of such deficits can be useful in guiding compensatory education.
This study was done to test the validity of two hypotheses of why children, and especially black children, of families of the poverty sector commonly fail in school. Sociologists deny for them either a cognitive or a linguistic deficit, and blame their failures on having to master the unfamiliar dialect of standard English while learning to read. The authors, on the other hand, blame the failures on inadequacies of early preschool experience that result in such deficits as one in semantic mastery of various elementary abstractions. In 1970-1971, 87 four-year-old students (58 black and 29 white) of Head Start and 33 of nursery school were examined with a five part test of number identification. In 1971-1972, the study was repeated with 69 four-year-olds of Head Start and 46 of the nursery school. A much smaller percentage of Head Start than of nursery school identify the numbers of blocks from 2 through 4 by either the heard or spoken mode of number identification. For numbers 5 and 6, most children of both classes fail. The evidence for a semantic deficit for number is very strong. The evidence indicates also a deficit in the span of apprehension and suggests the existence of class differences in the power of examiner demands for heard and for spoken identification to elicit the counting strategy. Evidence of sex differences in semantic mastery of number is absent, and among Head Start children, race differences lack statistical significance. These findings are highly dissonant with the contention of the sociolinguists that no cognitive or linguistic deficits exist and uncovering them can be helpful in guiding compensatory education.
Recent investigations have tested the applicability of various terminology models for the representing nursing concepts including those related to nursing diagnoses, nursing interventions, and standardized nursing assessments as a prerequisite for building a reference terminology that supports the nursing domain. We used the semantic structure of Clinical LOINC (Logical Observations, Identifiers, Names, and Codes) as a reference terminology model to support the integration of standardized assessment terms from two nursing terminologies into the Medical Entities Dictionary (MED), the concept-oriented, metadata dictionary at New York Presbyterian Hospital. Although the LOINC semantic structure was used previously to represent laboratory terms in the MED, selected hierarchies and semantic slots required revisions in order to incorporate the nursing assessment concepts. This project was an initial step in integrating nursing assessment concepts into the MED in a manner consistent with evolving standards for reference terminology models. Moreover, the revisions provide the foundation for adding other types of standardized assessments to the MED.
The generation effect is moderated by experimental design, affecting recall in within-subjects designs but typically not in between-subjects designs. However, N. W. Mulligan (2001) found that the generation effect emerged over repeated recall tests in a between-subjects design, calling into question the generality of this limiting condition. In addition, the generate condition but not the read condition produced hypermnesia (increased recall over tests). The present experiments demonstrate that semantic-based (semantic-associate and category-associate) generation tasks produce this pattern of results whereas nonsemantic (letter transposition, rhyme, word fragment) generation tasks do not. Thus, the emergent generation effect appears to be a byproduct of semantic elaboration rather than a direct product of generation. In addition, high- and low-imagery words produced equivalent hypermnesia and emergent generation effects, arguing against a mediating role for imagistic encoding. Finally, there is no evidence of an emergent generation effect for nonwords, another traditional limiting condition of the generation effect.
Identification deficits were investigated in ELM, a temporal lobe stroke patient with category-specific deficits. We replicated previous work done on FS, a patient with category specific deficits as a result of herpes viral encephalitis. ELM was tested using novel, computer generated shapes that were paired with artifact labels. We paired semantically close or disparate labels to shapes and ELM attempted to learn these pairings. Overall, ELM's shape-label confusions were most detrimentally affected when we used labels that referred to objects that were visually and semantically close. However, as with FS, ELM had as many errors when shapes were paired with the labels "donut," "tire," and "washer" as he did when they were paired with visually and semantically close artifact labels. Two explanations are put forth to account for the anomalous performance by both patients on the triad of donut-tire-washer.
BACKGROUND: Apraxia, broadly understood as the acquired inability to perform learned, skilled movements not caused by paresis or incomprehension, occurs with greater frequency among patients recovering from prolonged post-traumatic coma than has previously been reported. The present article prevents an evaluation of the effectiveness of a rehabilitation program called Semantic Priming, aimed at rebuilding praxis in these patients. MATERIAL/METHODS: Out of a consecutive series of 51 patients with post-traumatic coma lasting longer than 4 weeks treated at the centers represented by the authors, 24 were found to have pathological scores on the Boston Test of Praxis. These patients were divided into two matched groups, of whom the experimental group received the Semantic Priming program (involving the systematic use of verbal cues to prime movement activation patterns), and the control group did not. Progress was measured by the Boston Test of Praxis and a test developed by the authors on the basis of Luria's procedure for testing praxis. RESULTS: After 5 weeks of therapy the patients in the experimental group showed significantly greater improvement in all measured parameters (p<0.001). CONCLUSIONS: Apraxia in the broader sense is a more common problem among post-coma patients than heretofore recognized, and causes concrete problems in rehabilitation and adjustment to daily living. Our program based on the use of semantic priming of activation proved to be highly successful in remediating apraxia in these patients.
We examined a patient (NM) with probable Alzheimer's disease who showed phonologically plausible errors in kanji (logogram) writing. In semantic tasks, she showed no deficits in pointing or naming but had difficulty in more complex tasks such as proverb comprehension. In reading aloud of kanji words, she could read most kanji words correctly and showed little phonologically plausible reading errors. She performed poorly in lexical decision and on-reading of one-letter kanji (Sino-Japanese pronunciation derived from the Chinese language at the time of borrowing). Writing to dictation demonstrated no mistakes in kana letters and words, but many errors in kanji, which were phonologically equivalent but semantically inappropriate. To explore the relationship between the writing errors in kanji words and comprehension of the word meanings, we selected 33 words that she made phonologically plausible writing errors. We gave her the following five tasks using these words; 1) to ask meanings of the words, 2) to dictate the words, 3) to dictate sentences including these words, 4) to discriminate appropriate target words from distracters including her own erroneous responses, and 5) to write these words again. She showed no consistent errors in these tasks. In some occasions, she could write correct kanji words without understanding word meanings. She also showed phonologically plausible writing errors in spite of describing correct word meanings. In Japanese, word meaning deficits like Gogi aphasia were thought to cause phonologically plausible writing errors. As the impairments of word meanings in NM are comparatively mild, the underpinning of her kanji agraphias might be different from that of phonologically plausible errors in Gogi aphasia. It would be suggested that she frequently wrote phonologically equivalent errors because of her lexical deficits in spite that her phonological processing was preserved. Furthermore, she would not necessarily use the semantics (word meanings) of kanji words during dictation.
In replicating 1 of the within-language conditions of E. Fox's (1996) Experiment 1, the authors confirmed that unattended words presented 2.4 degrees above and below fixation are mostly unavailable to awareness. However, no negative semantic priming was observed in a lexical decision on a probe letter string appearing about 1 s later, which does not replicate Fox's finding. These results are compatible with the hypothesis underlying the present study, according to which positive semantic priming, if any, rather than negative semantic priming is expected in Fox's situation. The reason is that unavailability to awareness of the parafoveal words is not achieved by means of an act of selective inhibition combined with attentional diversion through masking but is achieved simply by means of perceptual degradation.
A semantic normal form (SNF) for a clinical drug, designed to represent the meaning of an expression typically seen in a practitioner's medication order, has been developed and is being created in the UMLS Metathesaurus. The long term goal is to establish a relationship for every concept in the Metathesaurus with semantic type "clinical drug" with one or more of these semantic normal forms. First steps have been taken using the Veterans Administration National Drug File (VANDF). 70% of the entries in the VANDF could be parsed algorithmically into the SNF. Next steps include parsing other drug vocabularies included in the UMLS Metathesaurus and performing human review of the parsed vocabularies. After machine parsed forms have been merged in the Metathesaurus Information Database (MID), editors will be able to edit matched SNFs for accuracy and establish relationships and relationship attributes with other clinical drug concepts.
De-identification of a patient's personal data from medical records is a protective legal requirement imposed before medical documents can be used for research purposes or transferred to other healthcare providers (e.g., teachers, students, tele-consultations). This de-identification process is tedious if performed manually, and is known to be quite faulty in direct search and replace strategies [9]. In this paper, we report on the identification step of this process. The proposed algorithm is based on estimating the fitness of candidate patient name references to a set of semantic selectional restrictions. The semantic restrictions place tight contextual requirements upon candidate words in the report text and are determined automatically from a manually tagged corpus of training reports. Maximum entropy classifiers are used to provide a probabilistic measure of the belief of a given candidate token to a given semantic restriction. We report on the design and preliminary evaluation of the system within the do-main of pediatric urology.
Cognitive aging research documents reduced access to contextually specific episodic details inolder adults, whereas access to semantic or other nonepisodic information is preserved or facilitated. The present study extended this finding to autobiographical memory by using a new measure; the Autobiographical Interview. Younger and older adults recalled events from 5 life periods. Protocols were scored according to a reliable system for categorizing episodic and nonepisodic information. Whereas younger adults were biased toward episodic details reflecting happenings, locations, perceptions, and thoughts, older adults favored semantic details not connected to a particular time and place. This pattern persisted after additional structured probing for contextual details. The Autobiographical Interview is a useful instrument for quantifying episodic and semantic contributions to personal remote memory.
The authors investigated the impact of semantic knowledge on visual object analysis by assessing the performance of patients with semantic dementia on a different-views object matching test and on 2 object decision tests differing, for example, in whether the nonreal items were nonsense objects or chimeras of 2 real objects. On average, the patients scored normally on both the object matching and the object decision test including nonsense objects but were impaired on the object decision test including chimeras; this latter was also the only visual object test that correlated significantly with degree of semantic impairment. These findings demonstrate that object decision is not a single task or ability and that it is not necessarily independent of conceptual knowledge.
OBJECTIVE: The authors evaluated the usefulness and psychometric properties of the Semantic Interference Test (SIT) in patients with mild Alzheimer disease (AD). METHODS: Subjects were first presented with 10 common objects to be learned over three trials. Proactive interference was assessed by having subjects recall 10 new objects that were semantically related to the previous ones. Retroactive interference was assessed by having subjects recall the original 10 objects. RESULTS: Controlling for overall memory impairment, very mildly impaired AD patients demonstrated significantly greater proactive and retroactive interference effects than the normal, community-dwelling comparison group. The proactive score alone and the combined proactive-plus-retroactive score index were more effective than traditional neuropsychological measures of delayed recall in distinguishing between the very mildly impaired AD group and the normal-comparison group. CONCLUSION: The authors discuss the potential usefulness of the SIT in identifying vulnerability to semantic interference in early AD.
OBJECTIVE: To investigate of changes in N400 event-related potentials (ERPs) in recognition of semantically matching ending words of Chinese sentences for analysis of the characteristics of Chinese sentence N400 in healthy subjects. METHODS: Fifteen healthy right-handed volunteers aging from 21 to 36 years old were tested for N400 when they were asked to read Chinese sentences with semantically matching or mismatching ending words. RESULTS: Significant differences were found in N400 latencies and amplitudes when the subjects were reading the carefully designed Chinese sentences (P<0.05). The latencies of N400 were delayed and the amplitudes increased when the subjects were confronted with mismatching ending words, in the event of which N400 amplitudes were higher in the left than in the right hemisphere of the brain. CONCLUSIONS: N400 in Chinese sentence-ending word matching test is close by related to the semantic context of the word recognition, and possesses clinically valuable recognition potential for assessing language disorders.
This study of a dyslexic patient supports the view that the level of impairment of the phonological route plays a role in the production of semantic paralexias. The patient's reading was based on a defective phoneme-to-grapheme transcoding, in spite of evidence that semantic information was available through non phonological routes. The hypothesis that the residual ability to carry out phonological recoding could block the production of semantic paralexias was confirmed by tachistoscopic reading, assumed to interfere with phonological recoding in this patient, that provoked a definite rise of this type of error. The relationship between the degree of damage of phonological route and the clinical expression of the syndromes of phonological dyslexia and deep dyslexia is also discussed.