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Biomedical subjects

H L Swanson

Publications and source records attributed to H L Swanson.

At least 19 recordsLinked to original sources
PubMed2001

Mathematical problem solving and working memory in children with learning disabilities: both executive and phonological processes are important.

The purpose of this investigation was to explore the relationship between working memory (WM) and mathematical problem solving in children with learning disabilities (LD). Children with LD (age 11.5 years) were compared to chronologically age-matched (CA-M) and younger comprehension/computation achievement-matched children (age 8.9 years) on measures of verbal and visual-spatial WM, phonological processing, components of problem solving, and word-problem solving accuracy. The results showed that (1) children with LD were inferior on measures of word solution accuracy, components of problem solving, phonological processing, domain-general WM, and verbal WM when compared to children who were CA-M, (2) children with LD were comparable to younger children on all processing measures, except measures of domain-general WM, visual-spatial WM, phonemic deletion, and identifying problem goals, (3) measures of verbal and visual-spatial WM contributed significant variance to solution accuracy independent of phonological processing, and (4) the influence of WM on solution accuracy was mediated by long-term memory (LTM) processes related to the knowledge of algorithms. The results support the notion that information activated from LTM, rather than phonological processing, mediates the relationship between executive processing and solution accuracy in children with LD.

Child↗
PubMed2001

A case of Peters' anomaly in a springer spaniel.

An 8-week-old springer spaniel presented with a large central corneal opacity of the left globe, which was accompanied by cords of tissue spanning from the iris collarette to the posterior cornea. A posterior cortical cataract was noted in the right eye. At the owner's request the puppy was humanely destroyed, and a necropsy was performed. Upon sectioning the left globe in the vertical plane, a circle of pigmented strands of tissue was observed spanning the anterior chamber from the iris to the posterior aspect of the cornea. The right globe appeared normal when inspected grossly. Histologically, a membrane of pigmented tissue covered the posterior aspect of the broad central corneal leukoma of the left globe. This membrane and the cords traversing the anterior chamber were composed of vascular uveal tissue. Descemet's membrane and the corneal endothelium were reduced or absent in the zone of corneal opacity. Other than the changes associated with cataract, the right globe was histologically normal. The clinical and histological findings in the left globe were identical with those described for Peters>> anomaly in human beings.

Animals↗
PubMed1999

Reading comprehension and working memory in learning-disabled readers: Is the phonological loop more important than the executive system?

This investigation explores the contribution of two working memory systems (the articulatory loop and the central executive) to the performance differences between learning-disabled (LD) and skilled readers. Performances of LD, chronological age (CA) matched, and reading level-matched children were compared on measures of phonological processing accuracy and speed (articulatory system), long-term memory (LTM) accuracy and speed, and executive processing. The results indicated that (a) LD readers were inferior on measures of articulatory, LTM, and executive processing; (b) LD readers were superior to RL readers on measures of executive processing, but were comparable to RL readers on measures of the articulatory and LTM system; (c) executive processing differences remained significant between LD and CA-matched children when measures of reading comprehension, articulatory processes, and LTM processes were partialed from the analysis; and (d) executive processing contributed significant variance to reading comprehension when measures of the articulatory and LTM systems were entered into a hierarchical regression model. In summary, LD readers experience constraints in the articulatory and LTM system, but constraints mediate only some of the influence of executive processing on reading comprehension. Further, LD readers suffer executive processing problems nonspecific to their reading comprehension problems.

Child↗
PubMed1999

What develops in working memory? A life span perspective.

This study investigated whether working-memory (WM) span differences across age are attributable to specific or general processing functions. The study compared 9 age groups (6, 8, 10, 13, 16, 24, 35, 45, 57 years) on verbal and visuospatial WM performance under initial (no probes or cues), gain (cues that bring performance to an asymptotic level), and maintenance conditions (asymptotic conditions without cues). (a) Age-related performance differences in WM were found across all conditions and were not isolated to specific processes, (b) significant performance differences remained among age groups on gain and maintenance conditions, and (c) the gain (accessing new information) and maintenance conditions (maintenance of old information) for verbal and visuospatial WM tasks contributed independent variance to age-related performance. The results support a general capacity explanation of age-related differences. These differences in capacity reflect demands placed on both the accessing of new information and the maintenance of old information.

Achievement↗
PubMed1996

Learning-disabled readers' working memory as a function of processing demands.

The purpose of this study was to investigate whether limitations in the enhancement of learning-disabled readers' working memory performance are attributable to process or storage functions. For Experiment 1, performance of reading-disabled, chronological age-matched, and reading level-matched children was compared on verbal and visual-spatial working memory measures under initial (no probes or cues), gain (cues that bring performance to an asymptotic level), and maintenance conditions (asymptotic conditions without cues). The results indicated that (a) learning-disabled readers' working memory performance was comparable on visual-spatial measures, but inferior to CA-matched children on verbal working memory measures; (b) learning-disabled readers' performance was superior to reading-matched counterparts across working memory conditions; and (c) performance differences remained between learning-disabled and CA-matched children or gain and maintenance conditions, even when initial and processing efficiency (probe) scores were partialed out in the analyses. Experiment 2 included the same conditions as Experiment 1, except that verbal short-term memory scores were also partialed out in the analysis. The results indicated that learning-disabled readers are inferior on both verbal and visual-spatial working memory measures when compared to CA-matched children on high demand conditions (maintenance). Two findings that emerged across experiments were (a) intercorrelations among diverse WM measures increased on demanding conditions and (b) verbal WM was not directly related to reading skill. In sum, the results support the notion that learning-disabled readers' poor working memory performance on demanding conditions reflect constraints in a central executive storage system.

Child↗
PubMed1996

Individual differences in children's working memory and writing skill.

The purpose of this research is to address (a) whether individual differences in working memory (WM) and writing are related to a general or process-specific system, (b) whether WM tasks operate independently of phonological short-term memory (STM) on measures of writing and reading, and (c) whether working memory predicts variance in writing beyond that predicted by reading alone. The present study correlated several WM and phonological STM measures with writing and reading measures. The study showed among the memory measures that a four-factor model reflecting phonological STM, verbal WM span, executive processing, and visual-spatial WM span best fit the multivariate data set. Working memory was correlated significantly with a number of writing measures, particularly those related to text generation. WM measures contributed unique variance to writing that was independent of reading skill, and STM measures best predicted transcription processes and reading recognition, whereas WM measures best predicted text generation and reading comprehension. Both verbal and visual-spatial working memory measures predicted reading comprehension, whereas only WM measures that reflect executive processing significantly predicted writing. In general, the results suggest that individual differences in children's writing reflect a specific capacity system, whereas reading comprehension draws upon a multiple capacity system.

Attention↗
PubMed1996

The role of the anesthesia care coordinator in preadmission testing.

Surgery delays and cancellations are costly to hospitals and emotionally distressful to patients. At Sarasota (Fla) Memorial Hospital, staff members developed a critical pathway-the preanesthesia collaborative care track, called "the Track," to address problems associated with preparing patients for surgery. The track is designed to facilitate preoperative patient assessments and nursing interventions that achieve desirable patient outcomes and to enhance the delivery of quality health care to surgical patients. The RN anesthesia care coordinator of the Track assists in early patient-problem identification and ensures that appropriate clinical data are available for perioperative nurses, anesthesiologists, and surgeons to avoid last-minute delays and cancellations of scheduled surgical procedures.

Aged↗
PubMed1996

Learning disabled and average readers' working memory and comprehension: does metacognition play a role?

The present study investigates (a) whether learning disabled readers' working memory deficits that underlie poor reading comprehension are related to a general system, and (b) whether metacognition contributes to comprehension beyond what is predicted by working memory and word knowledge. To this end, performance between learning and disabled (N = 60) and average readers (N = 60) was compared on the reading comprehension, reading rate, and vocabulary subtests of the Nelson Skills Reading Test, Sentence Span test composed of high and low imagery words, and a Metacognitive Questionnaire. As expected, differences between groups in working memory, vocabulary, and reading measures emerged, whereas ability groups were statistically comparable on the Metacognitive Questionnaire. A within-group analysis indicated that the correlation patterns between working memory, vocabulary, metacognition, and reading comprehension were not the same between ability groups. For predicting reading comprehension, the metacognitive questionnaire best predicted learning disabled readers' performance, whereas the working memory span measure that included low-imagery words best predicted average achieving readers' comprehension. Overall, the results suggest that the relationship between learning disabled readers' generalised working memory deficits and poor reading comprehension may be mediated by metacognition.

Child↗
PubMed1996

Individual and age-related differences in children's working memory.

The purpose of this study was to investigate the degree to which age-related and individual differences in children's working memory (WM) are due to a general or task-specific capacity system. Experiment 1 correlated children's (N = 146; age range 5-19 years) verbal and visual-spatial working memory performance with various intelligence and achievement measures. The results supporting a general system were that (1) visual-spatial and verbal WM measures were significantly intercorrelated with and without age partialed out and (2) both verbal and visual-spatial WM measures were significantly correlated with diverse achievement and intelligence measures. Experiment 2 compared three age groups (N = 192; 7-, 10-, and 13-year-olds) on working-memory performance tasks under initial, enhanced (cued), and maintenance conditions. The results supporting a general capacity system were that (1) age-related performance differences in WM were found on all conditions and not isolated to specific processes, (2) the maintenance measures (high-load condition) predicted the variance better in age-related performance than process measures, and (3) although individual differences in WM performance reflected two independent operations, these operations produced similar correlations to achievement within age groups. Overall, the results support a general capacity explanation of age-related and individual differences in children's WM performance.

Adolescent↗
PubMed1995

The relationship between intelligence and vigilance in children at risk.

The purpose of this study was to compare two competing models as an explanation of the relationship between intelligence and sustained attention in educationally at-risk kindergarten children. One model assumes that lower-IQ subjects allocate greater amounts of attentional resource of information-processing tasks than higher-IQ subjects, whereas the other model assumes that a "less-than" optimal level of arousal is associated with decrements in task performance across time. Twenty-nine teacher-nominated at-risk and 29 normal achieving kindergarten students were administered the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R) and vigilance taks. Signal detection measures of stimulus detectability (d'), decision criterion (beta), correct detections, and false alarms were used to assess children's sustained attention across three time periods (2, 4, and 6 min). The important results were (a) high-risk children were inferior on d' measures when compared to normal achieving children, (b) vigilance measures did not vary over time in either group, and (c) intelligence and vigilance shared a common factor in high-risk, but not low-risk, children. The results suggest that children educationally at risk suffer deficits related to attentional capacity for processing information.

Achievement↗
PubMed1994

Short-term memory and working memory: do both contribute to our understanding of academic achievement in children and adults with learning disabilities?

Seventy-five children and adults with learning disabilities (age range = 5.0 to 42.10 yrs.) and 86 normally achieving children and adults (age range = 5.11 to 58.0 yrs.) were compared on short-term memory (STM) and working memory (WM) tasks to assess the relationship between STM and WM, and to test whether these measures independently relate to achievement. For both ability groups, the factor analyses indicated that STM and WM loaded on different factors, and the regressions and partial correlations showed that these different factors accounted for separate variance in reading comprehension and mathematics. Both STM and WM are important in understanding reading comprehension and mathematics performance in children and adults with learning disabilities; however, WM is more important for children and adults without learning disabilities. In contrast to WM, STM contributed minimal variance to word recognition in both ability groups. Overall, it was concluded that STM and WM do reflect different processes, both of which seem to separate the two ability groups. However, models of memory that view STM and WM as interchangeable, or STM in isolation, do not provide an adequate framework for capturing academic performance in children and adults with learning disabilities.

Achievement↗
PubMed1993

Working memory in learning disability subgroups.

The purpose of this study was to investigate (a) the degree to which working memory differences between learning-disabled and nondisabled children reflect a specific or generalized deficit, and (b) whether limitations in the enhancement of learning-disabled student's working memory performance are attributable to process or storage functions. To this end, performances of reading-disabled, math-disabled, chronological age (CA)-matched, and achievement-matched children were compared on verbal and visual-spatial working memory measures under initial, gain, and maintenance conditions. The results indicated that: (a) learning-disabled subtypes were not differentiated by their performance on verbal and visual-spatial working memory measures; and (b) learning-disabled children's working memory performance was inferior to CA-matched and superior to achievement-matched counterparts across initial, gain, and maintenance conditions. The results suggest that learning-disabled children suffer generalized working memory deficits, possibly due to storage constraints in the executive system.

Attention↗
PubMed1993

Metacognitive aspects of moral reasoning and behavior.

This study explored the notion that the development of moral reasoning and moral behavior may be linked to metacognition. The awareness of moral processes involved in moral reasoning and behavior was examined in 139 adolescents in three age groups. A number of significant moral metacognition-reasoning-behavior correlations were found. Intercorrelations for all dependent measures increased by age. A factor analysis revealed several components of moral metacognition (person, task, and strategy variables), and these were significantly related to increases in moral reasoning and behavior scores. More important, a contingency analysis supported the notion that specific types of metamoral knowledge (e.g., understanding the purpose, scope, and requirements of moral action) are related to high and low moral reasoning and behavior.

Adolescent↗
PubMed1991

Naturalistic memory in learning-disabled and skilled readers.

Three experiments compared learning-disabled and skilled readers' performance on naturalistic memory measures, as well as investigated the relationship between memory performance on everyday and laboratory tasks. In Experiment 1, the laboratory task (sentence span task) and everyday memory measures were correlated moderately for both ability groups. Compared to skilled readers, disabled readers performed poorly on the sentence span task, and were less likely than skilled readers to remember information related to common objects and consequential events. Disabled readers were also less likely to rely on external prompts to help them recall everyday information. Experiment 2 extended the previous findings to older subjects and found that the majority of significant correlations between the laboratory (word span task) and everyday memory tasks were isolated to disabled readers. When compared to chronological-age-matched subjects, disabled readers were inferior in recency performance on the laboratory (word span) and natural serial recall (e.g., recall of U.S. presidents) tasks. Experiment 3 showed that under conditions that facilitate item accessibility, ability group differences in recall were comparable. Taken together, the findings indicate that disabled readers' memory deficits are pervasive across naturalistic and laboratory measures at the younger age, but these deficits diminish for older students. Further, the deficits that occur at the older age are due to problems in accessing knowledge.

Achievement↗
PubMed1991

Learning disabilities, distinctive encoding, and hemispheric resources.

The purpose of this study was to isolate possible sources of learning ability differences in distinctive encoding of item-specific and relational information. Two mechanisms postulated as underlying ability group differences were attentional capacity (as inferred from the magnitude and direction of correlations between primary and secondary recall) and resource monitoring strategies (as reflected in measures of selective attention and laterality). In Experiment 1, learning disabled and nondisabled childrens' word recall was compared on dichotic listening recall tasks that included nonorienting instructions, and orienting instructions that directed children's attention toward semantic, phonemic, or structural word features. Disabled children showed lower recall and more diffuse selective attention to word features than nondisabled children. Reciprocity (negative correlations) between targeted and background words within and between ability groups was comparable, except when targeted word features were phonemically organized. Experiment 2 indicated that disabled childrens' cued recall was inferior to that of nondisabled children, even though both ability groups produced comparable symmetrical recall patterns related to ear presentations. Taken together, the results suggest that the locus of disabled childrens' distinctive encoding deficiencies is related to resource monitoring strategies during interhemispheric processing.

Attention↗
PubMed1990

Executive processing differences between learning-disabled, mildly retarded, and normal achieving children.

This study examined possible executive processing differences between mildly retarded, learning-disabled, and normal achieving children. To this end, the groups were compared as to their ability to recall central and secondary words from base and elaborative sentences under conditions of high and low encoding effort. Executive processing was inferred from the children's ability to maintain optimal recall performance for central and secondary words. Groups were comparable in central recall, but differences in secondary recall occurred for the high-effort encoding condition. Qualitative differences related to the prioritizing of resources (as reflected in the correlation between central and secondary recall) and monitoring the transfer of information (as reflected from central and secondary recall insertions) were found between groups. The results were discussed in terms of an executive processing framework that views retarded children as suffering from inefficiencies related to the sharing of resources, whereas the learning-disabled children's inefficiencies were related to the discrimination of resources.

Achievement↗
PubMed1990

Can learning disabilities be determined from working memory performance?

This study assumes that children of various academic abilities may be characterized by different patterns of memory function. To test this assumption, subgroups of children were identified through a hierarchical cluster analysis based upon a test battery of sentence span, preload, and concurrent memory demand tasks. One subtype presented a profile of children with learning disabilities showing severe memory performance deficits, while another subgroup yielded high memory and high academic performance. Four additional subtypes had variations in memory performance, which in turn reflected variations in external criteria related to reading, mathematics, and spelling performance. For each subtype, performance strengths and weaknesses were characterized within Baddeley's (1986) working memory model. The study provides partial validation for the classification of children with learning disabilities on psychometric measures according to patterns of memory performance.

Achievement↗