首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
Phenylketonuria (PKU) is a genetic disorder characterized by hyperphenylalaninemia. Treatment involves dietary phenylalanine restriction to prevent mental retardation. Because phenylalanine is involved in tyrosine synthesis and tyrosine is a catecholamine precursor, low tyrosine may lead to brain dopamine deficiencies. Because dopamine is involved in the modulation of prefrontally orchestrated executive functions, deficiencies may lead to executive impairments. Despite treatment, impairments in executive cognitive functions have been reported in young children with PKU. Outcome beyond middle childhood has not been extensively investigated. In this study, PKU-affected adolescents (N = 18) with normal-range IQ scores completed neuropsychological tests, and their performance was compared with unaffected peers (N = 16) and chronically ill controls (N = 17). Results demonstrated that the overall performance of the PKU group did not differ from that of the other two groups, but that performance of the PKU proband was associated with phenylalanine and tyrosine levels, and most strongly with phenylalanine-to-tyrosine ratios at several points in development. These findings provide a preliminary test of the dopamine hypothesis of PKU as it applies to adolescents and young adults.  相似文献   

2.
The purpose of this study was to determine the components of working memory (WM) that underlie less skilled readers' comprehension and word recognition difficulties. Performance of 3 less skilled reading subgroups---children with reading disabilities (RD) in both word recognition and comprehension; children with comprehension deficits only; and children with low verbal IQ, word recognition, and comprehension (poor readers)--was compared to that of skilled readers on WM, short-term memory (STM), processing speed, executive, and phonological processing measures. Ability group comparisons showed that (a) skilled readers outperformed all less skilled readers on measures of WM, updating, and processing speed; (b) children with comprehension deficits only outperformed children with RD on measures of WM, STM, phonological processing, and processing speed; and (c) children with RD outperformed poor readers on WM and phonological processing measures. A hierarchical regression analysis showed that (a) subgroup differences on WM tasks among less skilled readers were moderated by a storage system not specific to phonological skills, and (b) STM and updating contributed significant variance to WM beyond what was contributed by reading group classification. The latter finding suggested that some differences in storage and executive processing emerged between skilled and less skilled readers that were not specific to reading.  相似文献   

3.
Recent theoretical advances in working memory guided analyses of cognitive measures in 122 children with dyslexia and their 200 affected biological parents in families with a multigenerational history of dyslexia. Both children and adults were most severely impaired, on average, in three working memory components— phonological word-form storage, time-sensitive phonological loop, and executive functions involving phonology. Structural equation modeling showed that, for children, first-order factors from the phonological, orthographic, and/or morphological word forms uniquely predicted 11 reading and writing outcomes but, for adults, a second-order factor (reflecting interrelationships among the three first-order word-form factors) was more likely to be significant in predicting the same reading and writing outcomes. Structural equation modeling of the three working memory component factors showed that the most consistent predictor of text-level reading and writing for both children and adults was the second-order word-form factor. Phonological loop and executive support could be modeled as separate factors in children but only as combined factors in adults. Executive support in children and combined phonological loop and executive support in adults contributed uniquely to oral reading but did not contribute uniquely to reading comprehension or written expression. For both children and adults, individual differences occurred as to which of the three working memory components or three word forms fell outside the normal range.  相似文献   

4.
The purpose of this study was to explore the profiles of classroom behaviour relating to attention and executive functions in children with very poor working memory, and to test the hypothesis that inattentive behaviour and working memory problems co-occur. Teachers rated problem behaviours of 52 children with low working memory scores aged 5/6 and 9/10 years on teacher rating measures of attention and executive function behaviours. The majority of children with low working memory scores obtained atypically high ratings of cognitive problems/ inattentive symptoms, and were judged to have short attention spans, high levels of distractibility, problems in monitoring the quality of their work, and difficulties in generating new solutions to problems. These results extend previous findings that working memory problems and inattentive behaviour co-occur to a non-clinical sample. It is suggested that reduced working memory capacity may play a causal role in the problem behaviours of these children.  相似文献   

5.
RESEARCH FINDINGS: This study examined whether children's executive functions before kindergarten would predict variance in executive functions after kindergarten. We obtained behavioral (working memory task performance), parental-reported (temperament-based inhibitory control), and psychophysiological (working memory-related changes in heart rate and brain electrical activity) measures of executive functions from a group of preschool-aged children. After children finished kindergarten, approximately 2 years later, parents were asked to complete an assessment of children's executive function skills. A regression analysis revealed that pre-kindergarten behavioral, parental-reported, and psychophysiological measures accounted for variance in post-kindergarten executive functions. Specifically, working memory task performance, temperament-based inhibitory control, and working memory-related changes in brain electrical activity accounted for unique variance in post-kindergarten executive functions. These data provide a unique contribution to the executive function literature: No other study has examined whether behavioral, psychophysiological, and parental-reported executive function measures can account for unique variance in future executive function. PRACTICE OR POLICY: These findings are discussed in relation to children's transition to school and executive function training programs.  相似文献   

6.
Intact and Impaired Memory Functions in Autism   总被引：21，自引：0，他引：21  
This study examined memory functions in individuals with autism. Based on previous evidence of executive function (EF) deficits, we hypothesized that subjects with autism would demonstrate a pattern of intact and imparred memory functions similar to that found in other groups with EF deficits, such as patients with frontal lobe pathology. We compared the performance of high-functioning children and adolescents with autism (n = 19) and clinical comparison subjects (n = 19) matched on sex, CA, and VIQ on measures of memory and EF. The group with autism performed significantly worse than comparison subjects on measures of temporal order memory, source memory, supraspan free recall, working memory, and EF, but not on short- and long-term recognition, cued recall, or new learning ability, consistent with the predictions of the EF theory. The cognitive measures were significantly more intercorrelated in the autism group than the comparison group, consistent with a limit in central cognition.  相似文献   

7.
The focus of the present study is on the developmental antecedents of domain-general experimentation skills. We hypothesized that false-belief understanding would predict the ability to distinguish a conclusive from an inconclusive experiment. We conducted a longitudinal study with two assessment points (t1 and t2) to investigate this hypothesis. As language, executive functioning, working memory, and intelligence have been discussed as potential influencing factors in theory of mind and scientific reasoning development, we included measures of these abilities as control variables. We recruited 161 preschool children (73 girls and 88 boys); we administered a false-belief task, an experimentation task, and the control variables at t1 when the children were 4 years old. We repeated the false-belief and experimentation tasks at t2 when the children were 5 years old. Our results show that children who solved the false-belief task correctly at age 4 were more likely to solve the experimentation task correctly at age 5, but not vice versa, even after controlling for the influence of language, executive functioning, working memory, and intelligence. The implications of these results on theories about the development of scientific reasoning and for science education concepts for young children are briefly discussed.  相似文献   

8.
Children with developmental reading disabilities (RD) frequently display impaired working memory functioning. However, research has been divergent regarding the characteristics of the deficit. Our investigation addressed this controversy by assessing Baddeley's working memory model as a whole rather than focusing on particular aspects of it, as has been done by much of the research to date. Participants included 20 children with RD and 20 typical readers between the ages of 9 and 13. The phonological loop, visual-spatial sketchpad, and central executive were assessed according to Baddeley's model. The results demonstrated that children with RD have an impaired phonological loop but intact visual-spatial sketchpad and central executive functioning as compared to controls. In terms of the phonological loop, the deficit appears to be specific to the phonological store. Furthermore, our research supports a relationship between phonological processing and phonological loop functioning.  相似文献   

9.
In the past years, an increasing number of studies have investigated executive functions as predictors of individual differences in mathematical abilities. The present longitudinal study was designed to investigate whether the executive functions shifting, inhibition, and working memory differ between low achieving and typically achieving children and whether these executive functions can be seen as precursors to math learning disabilities in children. Furthermore, the predictive value of working memory ability compared to preparatory mathematical abilities was examined. Two classifications were made based on (persistent) mathematical ability in first and second grade. Repeated measures analyses and discriminant analyses were used to investigate which functions predicted group membership best. Group differences in performance were found on one inhibition and three working memory tasks. The working memory tasks predicted math learning disabilities, even over and above the predictive value of preparatory mathematical abilities.  相似文献   

10.
The working memory skills of children with four categories of special educational needs (SEN) were investigated: general learning difficulties, language problems, literacy problems, and attentional and behavioural problems. Children with general learning difficulties performed poorly on measures of all three components of the working memory model: the phonological loop, central executive, and the visuo‐spatial sketchpad. Children with problems specific to language had impairments of the phonological loop and the central executive only. The working memory abilities of the groups with literacy and behavioural problems fell within the normal range. These findings are explained in terms of specific roles played by components of working memory in supporting learning activities.  相似文献   

11.
Oh S  Lewis C 《Child development》2008,79(1):80-99
This study assessed executive function and mental state understanding in Korean preschoolers. In Experiment 1, forty 3.5- and 4-year-old Koreans showed ceiling performance on inhibition and switching measures, although their performance on working memory and false belief was comparable to that of Western children. Experiment 2 revealed a similar advantage in a sample of seventy-six 3- and 4-year-old Koreans compared with sixty-four age-matched British children. Korean children younger than 3.5 years of age showed ceiling effects on some inhibition measures despite more stringent protocols and the link between executive function and mental state understanding was not as strong as in the British sample. The results raise key questions about the nature and development of the executive system and its relation to social understanding.  相似文献   

12.
The purpose of this study was to examine how executive function skills in verbal and nonverbal auditory tasks are related to early reading skills in beginning readers. Kindergarteners (N = 41, aged 5 years) completed verbal (phonemes) and nonverbal (environmental sounds) Continuous Performance tasks yielding measures of executive function (misses, false alarms, and shift) as well as reaction time and D-Prime (sensitivity). Year-end measures of early reading skill included tests of phoneme awareness, letter knowledge, as well as reading (words and nonwords). The children made more errors on the verbal than the nonverbal tasks, suggesting that executive function abilities may differ by task. Adding to the literature on the role of inhibitory skills in reading, verbal inhibitory executive function skills were tied more closely to early reading than other verbal or nonverbal skills when age, short-term memory, and vocabulary were controlled.  相似文献   

13.
The purpose of this study was to investigate whether changes in working memory (WM) of children with reading disabilities (RD) were related to a domain-specific or a domain-general system. Based on Daneman and Carpenter's (1980) Sentence Listening Span task, children were subgrouped into a group of high executive processing (high listening span) children without RD, a group of low executive processing (low listening span) children with RD, and a group of children with and without RD matched on executive processing (moderate listening span). Subgroups were compared on phonological, visual-spatial, and semantic WM tasks across initial (no probes or cues), gain (cues that bring performance to an asymptotic level), and maintenance conditions (asymptotic conditions without cues). The results showed that (a) children without RD high in executive processing ability outperformed all other subgroups, (b) the RD subgroup low in executive processing performed poorly relative to all other subgroups across task and memory conditions, (c) children with and without RD matched on executive processing were comparable in WM span and changes in WM for all tasks, and (d) WM performance of children with RD was a strong linear function of the high executive processing group, suggesting that the nature or the specific componential makeup of the tasks are not the main contributors to WM performance. Taken together, the results suggest that a domain-general system may partially contribute to poor WM in children with RD, and that this system may operate independently of their reading deficits.  相似文献   

14.
Studies have shown that young children with autism are not impaired on prefrontal tasks relative to what would be expected for their mental age, raising questions about the executive dysfunction hypothesis of autism. These studies did not include ventromedial prefrontal tasks, however. The present study examined whether young children with autism spectrum disorder (ASD) are impaired on ventromedial prefrontal tasks, and whether performance on such tasks is correlated with a core autism symptom, joint attention ability. Seventy-two 3- to 4-year-old children with ASD, 34 3- to 4-year-old developmentally delayed children, and 39 12- to 46-month-old typically developing children, matched on mental age, were administered ventromedial and dorsolateral prefrontal tasks and joint attention tasks. Children with ASD performed similarly to comparison groups on all executive function tasks, indicating that at this early age, there is no autism-specific pattern of executive dysfunction. Ventromedial, but not dorsolateral, prefrontal task performance was strongly correlated with joint attention ability, however. The ventromedial prefrontal cortex is hypothesized to play a role in the development of joint attention and possibly some aspects of the autistic syndrome.  相似文献   

15.
This study examined whether the characteristic reading speed impairment of German dyslexic children results from a general skill-automatization deficit sensu Nicolson and Fawcett (1990) or from more specific deficits in visual naming speed and phonological skills. The hypothesized skill-automatization deficit was assessed by balancing, peg moving, and visual search. Rapid "automatized" naming tasks served as measures of impaired visual naming speed, and the phonological deficit was assessed by speech perception, phonological sensitivity, and phonological memory tasks. Dyslexic German children and age-matched control children (all boys) were tested at the end of Grade 2 and as participants of a longitudinal study also at the beginning of Grade 1. No evidence for a skill-automatization deficit was found, as the dyslexic children did not differ at all on the balancing tasks and little on the other nonverbal skill tasks. However, the dyslexic children showed impaired visual naming speed and impaired phonological memory performance that were observed not only in Grade 2 but also before learning to read. Overall, the findings support the conclusion that, even in regular orthographies, difficulties in learning to read are due to a phonological deficit and not to a general skill-automatization deficit.  相似文献   

16.
A study was designed to test 2 alternative hypotheses—a symbolic hypothesis and an executive function hypothesis—for the imitation and pantomime deficits found in previous studies of autism. The subjects were 17 adolescent high-functioning subjects with autism spectrum disorders and 15 clinical comparison subjects who were matched on chronological age and verbal IQ. Meaning and sequence were manipulated in facial and manual imitation tasks. Sequence was manipulated in the pantomime and control tasks. Recognition memory and motor control tasks were matched to the experimental tasks. The results provided no support for the symbolic deficit hypothesis; meaning aided rather than hindered the performance of the group with autism. Partial support for the executive deficit hypothesis was found. There were no group differences on motor control tasks, and few on the memory control tasks, arguing against deficits in motor initiation, basic motor coordination, or visual recognition memory.  相似文献   

17.
Abstract. In this study, we investigated the relationships between rapid naming of letters, digits and colours, and reading ability and executive function. We gave fifty-six grade three and four children rapid automatised naming tasks using letters and digits as stimuli, executive function measures including the Stroop task, a working memory task and the Trailmaking B task. The latter three tasks were used as measures of executive function. We also administered tests of verbal ability, reading and a behaviour checklist. The rapid naming of letters and digits was significantly correlated with reading, but not with executive function or behaviour ratings. The rapid naming of colours (from the Stroop task) was significantly correlated with the executive function tasks and the behaviour ratings but not with reading. We discuss the implications of this double dissociation for further studies of RAN.  相似文献   

18.
Executive Functions in Young Children with Autism   总被引：17，自引：0，他引：17  
The executive dysfunction hypothesis of autism has received support from most studies of older people with autism; however, studies of young children have produced mixed results. Two studies are presented that compare the performance of preschoolers with autism (mean = 51 months/4.3 years of age) to a control group matched on age, and verbal and nonverbal ability. The first study (n = 18 autism and 17 control) found no group differences in performance on 8 executive function tasks (A not B, Object Retrieval, A not B with Invisible Displacement, 3-Boxes Stationary and Scrambled, 6-Boxes Stationary and Scrambled, and Spatial Reversal), but did find that children with autism initiated fewer joint attention and social interaction behaviors. The second (longitudinal) study of a subset of the children (n = 13 autism and 11 control) from the first study found that neither groups' performance on Spatial Reversal changed significantly over the course of a year. The results of these studies pose a serious challenge to the executive dysfunction hypothesis of autism.  相似文献   

19.
We examined visual recognition memory and executive functioning (spatial working memory [SWM], spatial planning, rule learning, and attention shifting) in 12‐year‐olds (n = 150) who participated in the Bucharest Early Intervention Project, a randomized controlled trial of foster care for institutionally reared children. Similar to prior reports at 8 years of age, institutionally reared children showed significant deficits in visual recognition memory and SWM. Deficits in attention shifting and rule learning were also apparent at this time point. These data suggest that early experiences continue to shape the development of memory, learning, and executive functioning processes in preadolescence, which may explain broader cognitive and learning difficulties commonly associated with severe early life neglect.  相似文献   

20.
The authors compared 6- to 11-year-olds with developmental coordination disorder (DCD) and those with specific language impairment (SLI) on measures of memory (verbal and visuospatial short-term and working memory) and learning (reading and mathematics). Children with DCD with typical language skills were impaired in all four areas of memory function for their age level, and this pattern was also found to be characteristic of a larger DCD group with varied language abilities. SLI-group deficits in standard scores were observed for the verbal versions of the short-term and working memory tasks only. There were also differential links between memory and attainment between the two groups, with visuospatial working memory strongly related to numeracy in the SLI group and all of the memory measures correlated with at least one attainment measure in the DCD group. Reasons for why working memory contributes to learning in these two developmental groups are discussed.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号