Problems and challenges in patient information retrieval: a descriptive study.
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Many patients now turn to the Web for health care information. However, a lack of domain knowledge and unfamiliarity with medical vocabulary and concepts restrict their ability to successfully obtain information they seek. The purpose of this descriptive study was to identify and classify the problems a patient encounters while performing information retrieval tasks on the Web, and the challenges it poses to informatics research. In this study, we observed patients performing various retrieval tasks, and measured the effectiveness of, satisfaction with, and usefulness of the results. Our study showed that patient information retrieval often failed to produce successful results due to a variety of problems. We propose a classification of patient IR problems based on our observations. (+info)
Comparing frequency of word occurrences in abstracts and texts using two stop word lists.
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Retrieval tests have assumed that the abstract is a true surrogate of the entire text. However, the frequency of terms in abstracts has never been compared to that of the articles they represent. Even though many sources are now available in full-text, many still rely on the abstract for retrieval. 1,138 articles with their abstracts were downloaded from Journal of the American Medical Association, New England Journal of Medicine, the British Medical Journal, and the Lancet. Based on two stop word lists, one long and one short, content bearing words were extracted from the articles and their abstracts and the frequency of each word was counted in both sources. Each article and its abstract were tested using a chi-squared test to determine if the words in the abstract occurred as frequently as would be expected. 96% to 98% of the abstracts tested were not significantly different than random samples of the articles they represented. In these four journals, the abstracts are lexical, as well as intellectual, surrogates for the articles they represent. (+info)
Exposure to Reach Out and Read and vocabulary outcomes in inner city preschoolers.
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To examine the association between exposure to Reach Out and Read and vocabulary outcomes in children, a consecutive sample of 200 parent/child pairs was studied at two inner-city health centers. Children at clinic A were exposed to Reach Out and Read, a clinic-based literacy intervention, for 3 years at the time of the study; children at clinic B were unexposed. Main outcome measures were the "Expressive and Receptive One Word Picture Vocabulary Tests" to measure vocabulary in the children and the "Home Literacy Orientation" scale and "READ" subscale of the STIMQ, to measure book-sharing activities. A total of 200 subjects participated, and the mean age of children was 3.8 years. Demographic characteristics were comparable for both clinics at baseline. Exposed children scored higher on receptive vocabulary (81.5 vs. 74.3; p = 0.005). They also scored higher on both the Home Literacy Orientation scale (4.3 vs. 3.3; p = 0.002) and the STIMQ-READ (12.6 vs. 11.0; p = 0.056). There were no differences in expressive vocabulary scores between the two sites (79.5 vs. 77.5; p = 0.26). In conclusion, we found a positive association between exposure to Reach Out and Read and better receptive vocabulary scores. We also found higher scores for Reach Out and Read-exposed children on measures of home reading activities. (+info)
Perceptual match effects in direct tests of memory: the role of contextual fan.
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The aim of the present study was to determine whether physical attributes of a memory representation would affect explicit memory performance and, if so, what type of factors would affect the size of a perceptual match effect. Subjects studied words in different, uncommon fonts and were later asked whether the word had been studied earlier. Words could be re-presented in the original font, a font studied with another word, or a font not seen earlier. In two additional experiments, we varied the numbers of words studied in the same unusual font (1 vs. 12 words per font). Recognition memory for the words was better if the test and study fonts matched, and this effect was larger for fonts not shared with other words. Moreover, old judgments were most likely to be classified as remember responses when words were re-presented in the same font when it had not been studied with other words. Although we found a significant effect of levels of processing, this factor did not interact with whether the font matched between study and test. These results are consistent with the predictions of the source of activation confusion model of memory and suggest that perceptual information operates according to the same memory principles as conceptual information. (+info)
Speech segmentation by native and non-native speakers: the use of lexical, syntactic, and stress-pattern cues.
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Varying degrees of plasticity in different subsystems of language have been demonstrated by studies showing that some aspects of language are processed similarly by native speakers and late-learners whereas other aspects are processed differently by the two groups. The study of speech segmentation provides a means by which the ability to process different types of linguistic information can be measured within the same task, because lexical, syntactic, and stress-pattern information can all indicate where one word ends and the next begins in continuous speech. In this study, native Japanese and native Spanish late-learners of English (as well as near-monolingual Japanese and Spanish speakers) were asked to determine whether specific sounds fell at the beginning or in the middle of words in English sentences. Similar to native English speakers, late-learners employed lexical information to perform the segmentation task. However, nonnative speakers did not use syntactic information to the same extent as native English speakers. Although both groups of late-learners of English used stress pattern as a segmentation cue, the extent to which this cue was relied upon depended on the stress-pattern characteristics of their native language. These findings support the hypothesis that learning a second language later in life has differential effects on subsystems within language. (+info)
Graded aspects of morphological processing: task and processing time.
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Effects on targets of orthographically (O) and semantically (S) related primes were compared with morphologically related (M) primes in the lexical decision, naming, and go/no go naming tasks. The overall pattern typified the graded nature of morphological processing. Morphological relatedness produced facilitation whose magnitude varied across a range of stimulus onset asynchronies (SOAs of 66-300 ms) and tasks. The effect of semantic and orthographic similarity also depended on SOA and on task. Importantly, the effects of morphological relatedness and orthographic similarity diverged along a time course that reflected semantic processing but could only be approximated by the effect of semantic relatedness between prime and target. (+info)
Adult age differences in visual word identification: functional neuroanatomy by positron emission tomography.
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Adult age differences in the neural systems mediating semantic (context-independent) memory were investigated using positron emission tomography (PET). Younger (20-29 years) and older (62-70 years) participants performed lexical decision (word/nonword discrimination) and nonsemantic (simple visual search) baseline tasks during PET scanning. Within the lexical decision task, display duration and presentation rate were varied across scans. The behavioral data suggested that although an age-related slowing was evident in visual feature and response processing, the retrieval of semantic/lexical information was similar for younger and older adults. For both age groups, lexical-related activation occurred in inferior prefrontal and occipitotemporal regions of the left hemisphere. Differential activation, as a function of age group, was observed in the left occipitotemporal pathway as a result of older adults' maintaining higher levels of neural activity in striate cortex (during visual search) and in inferior temporal cortex (during lexical decision). The prefrontal activation was similar for the two age groups. Thus, although this form of semantic memory retrieval does not undergo significant age-related decline, an age-related change in the associated pattern of neural activation is evident. These findings differ from previous neuroimaging studies of episodic (context-dependent) memory retrieval, which have suggested that age-related compensatory mechanisms are expressed primarily by greater activation of prefrontal regions for older adults than for younger adults. (+info)
Non-word reading, lexical retrieval and stuttering: comments on Packman, Onslow, Coombes and Goodwin (2001).
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A recent study by Packman, Onslow, Coombes and Goodwin (2001) employed a non-word-reading paradigm to test the contribution of the lexical retrieval process to stuttering. They consider that, with this material, the lexical retrieval process could not contribute to stuttering and that either anxiety and/or the motor demand of reading are the governing factors. This paper will discuss possible processes underlying non-word reading and it argues that the conclusion arrived at by Packman et al. does not stand up to close scrutiny. In their introduction, the authors acknowledge that the lexicalization process involves retrieval and encoding of words. In a non-word-reading task, the word retrieval component is eliminated. The possibility that the encoding component of the lexicalization process leads to stuttering is, however, completely ignored by the authors when they attribute stuttering to motor demands. As theories put forward by Postma and Kolk (the Covert Repair Hypothesis, 1993) and Howell and Au-Yeung (the EXPLAN theory, 2002) argue heavily for the role of the phonological encoding processes in stuttering, Packman et al.'s work does not evaluate such theories. Theoretical issues aside, Packman et al.'s arguments about reading rate and stuttering rate based on reading time is also questionable. (+info)