Memory Profiles of Down, Williams, and Fragile X Syndromes: Implications for Reading Development

Conners, Frances A.; Moore, Matthew D.; Loveall, Susan J.; Merrill, Edward C.

doi:10.1097/dbp.0b013e3182168f95

Cited by 41 publications

(40 citation statements)

References 184 publications

(206 reference statements)

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“…The average IQ for individuals with WS is approximately 50 to 60, indicating mild to moderate intellectual disability [10,11]. The WS cognitive profile is characterized by deficits in visuospatial and implicit memory as well as strengths in language, verbal short-term memory, face and object recognition, and music processing skills [12-16]. In addition, individuals with WS often demonstrate increased non-social anxiety and phobias, paired with hypersociability and heightened empathy [17-19].…”

Section: Introductionmentioning

confidence: 99%

Differences in age-related effects on brain volume in Down syndrome as compared to Williams syndrome and typical development

Koran

Hohman

Edwards

et al. 2014

J Neurodevelop Disord

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BackgroundIndividuals with Down Syndrome (DS) are reported to experience early onset of brain aging. However, it is not well understood how pre-existing neurodevelopmental effects versus neurodegenerative processes might be contributing to the observed pattern of brain atrophy in younger adults with DS. The aims of the current study were to: (1) to confirm previous findings of age-related changes in DS compared to adults with typical development (TD), (2) to test for an effect of these age-related changes in a second neurodevelopmental disorder, Williams syndrome (WS), and (3) to identify a pattern of regional age-related effects that are unique to DS.MethodsHigh-resolution T1-weighted MRI of the brains of subjects with DS, WS, and TD controls were segmented, and estimates of regional brain volume were derived using FreeSurfer. A general linear model was employed to test for age-related effects on volume between groups. Secondary analyses in the DS group explored the relationship between brain volume and neuropsychological tests and APOE.ResultsConsistent with previous findings, the DS group showed significantly greater age-related effects relative to TD controls in total gray matter and in regions of the orbitofrontal cortex and the parietal cortex. Individuals with DS also showed significantly greater age-related effects on volume of the left and right inferior lateral ventricles (LILV and RILV, respectively). There were no significant differences in age-related effects on volume when comparing the WS and TD groups. In the DS group, cognitive tests scores measuring signs of dementia and APOE ϵ4 carrier status were associated with LILV and RILV volume.ConclusionsIndividuals with DS demonstrated a unique pattern of age-related effects on gray matter and ventricular volume, the latter of which was associated with dementia rating scores in the DS group. Results may indicate that early onset of brain aging in DS is primarily due to DS-specific neurodegenerative processes, as opposed to general atypical neurodevelopment.

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Section: Introductionmentioning

confidence: 99%

Differences in age-related effects on brain volume in Down syndrome as compared to Williams syndrome and typical development

Koran

Hohman

Edwards

et al. 2014

J Neurodevelop Disord

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“…As with DS, WS is also associated with cognitive impairment, with average full-scale IQ for individuals ranging from 50 to 60, indicating mild to moderate intellectual disability (Martens et al, 2008). The WS cognitive profile is characterized by deficits in visuospatial and implicit memory and strengths in language, verbal short-term memory, face and object recognition, and music processing skills (Conners et al, 2011;Dykens et al, 2005;Hocking et al, 2011;Tsai et al, 2008). In addition, individuals with WS often demonstrate increased nonsocial anxiety and phobias, paired with hypersociability and heightened empathy (Dykens, 2003;Mervis and John, 2010;Morris, 2010).…”

mentioning

confidence: 99%

Resting-State Functional Connectivity in Individuals with Down Syndrome and Williams Syndrome Compared with Typically Developing Controls

et al. 2015

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The emergence of resting-state functional connectivity (rsFC) analysis, which examines temporal correlations of low-frequency ( < 0.1 Hz) blood oxygen level-dependent signal fluctuations between brain regions, has dramatically improved our understanding of the functional architecture of the typically developing (TD) human brain. This study examined rsFC in Down syndrome (DS) compared with another neurodevelopmental disorder, Williams syndrome (WS), and TD. Ten subjects with DS, 18 subjects with WS, and 40 subjects with TD each participated in a 3-Tesla MRI scan. We tested for group differences (DS vs. TD, DS vs. WS, and WS vs. TD) in between-and within-network rsFC connectivity for seven functional networks. For the DS group, we also examined associations between rsFC and other cognitive and genetic risk factors. In DS compared with TD, we observed higher levels of between-network connectivity in 6 out 21 network pairs but no differences in within-network connectivity. Participants with WS showed lower levels of within-network connectivity and no significant differences in between-network connectivity relative to DS. Finally, our comparison between WS and TD controls revealed lower within-network connectivity in multiple networks and higher betweennetwork connectivity in one network pair relative to TD controls. While preliminary due to modest sample sizes, our findings suggest a global difference in between-network connectivity in individuals with neurodevelopmental disorders compared with controls and that such a difference is exacerbated across many brain regions in DS. However, this alteration in DS does not appear to extend to within-network connections, and therefore, the altered between-network connectivity must be interpreted within the framework of an intact intra-network pattern of activity. In contrast, WS shows markedly lower levels of within-network connectivity in the default mode network and somatomotor network relative to controls. These findings warrant further investigation using a taskbased procedure that may help disentangle the relationship between brain function and cognitive performance across the spectrum of neurodevelopmental disorders.

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“…The DS cognitive profile is associated with poor verbal abilities, but relatively stronger visuospatial abilities (Conners et al, 2011b). Previous research on reading in Down syndrome has illustrated word identification abilities that are higher than what might be expected based on mental age (i.e.…”

Section: Discussionmentioning

confidence: 87%

“…Individuals with DS may struggle with production tasks due to poor language abilities (Abbeduto et al, 2003) and poor working memory (Jarrold & Baddeley, 2001). With strengths in visual processing (Buckley, 1985;Conners et al, 2011b), individuals with DS may show stronger evidence of orthographic knowledge using recognition tasks, such as orthographic awareness and orthographic choice. It is possible that their performance on these measures could surpass what would be expected based on their IQ, reading ability and mental age, as they are recognition and not production tasks.…”

Section: Phonological Processing Research On Phonological Recoding Imentioning

confidence: 99%

“…The present study will include Exception Word Reading (a production task), as well as two additional measures of orthographic knowledge, both recognition tasks. Based on previous research indicating poor language and poor working memory (Abbeduto et al, 2003;Cain et al, 2004), but stronger visual skills (Buckley, 1985;Conners et al, 2011b), I predict that individuals with DS will perform better on orthographic knowledge tasks overall when recognition measures are included in the protocol.…”

Section: Primary Hypothesesmentioning

confidence: 99%

See 1 more Smart Citation

Reading Skills in Down Syndrome: An Examination of Orthographic Knowledge

Loveall

Conners

2016

American Journal on Intellectual and Developmental Disabilities

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The primary purpose of the present study was to examine orthographic knowledge in a sample of individuals with Down syndrome (DS) in comparison to typically developing (TD) children matched on word identification ability. Phonological recoding was also compared across groups. A secondary purpose of the study was to estimate literacy rates in DS using parent reports. Results of the parent study revealed that most individuals with DS over the age of 5 years can read words. Results of the child study revealed that individuals with DS performed worse than TD controls on a measure of phonological recoding, but similarly on two measures of orthographic knowledge. Interestingly, the group with DS performed worse on a third measure of orthographic knowledge. The first two orthographic tasks both included real words as stimuli; the third orthographic task used letter patterns, but did not include real words. These results suggest that individuals with DS may have a relative strength in word-specific orthographic knowledge but not in general orthographic knowledge.iii DEDICATION This dissertation is dedicated to mothers. To the mothers of my participants, who never stop believing in or fighting for their children, I am continually amazed and touched by your dedication and love. To my own mother, who is my rock and inspiration, thank you for telling me I could do anything I set my mind to, for believing it, and for helping me believe it. My success is your success. Love you.iv

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Memory Profiles of Down, Williams, and Fragile X Syndromes: Implications for Reading Development

Cited by 41 publications

References 184 publications

Differences in age-related effects on brain volume in Down syndrome as compared to Williams syndrome and typical development

Differences in age-related effects on brain volume in Down syndrome as compared to Williams syndrome and typical development

Resting-State Functional Connectivity in Individuals with Down Syndrome and Williams Syndrome Compared with Typically Developing Controls

Reading Skills in Down Syndrome: An Examination of Orthographic Knowledge

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