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Megari K, Sofologi M, Kougioumtzis G, Thomaidou E, Thomaidis G, Katsarou D, Yotsidi V, Theodoratou M. Neurocognitive and psycho-emotional profile of children with disabilities. APPLIED NEUROPSYCHOLOGY. CHILD 2024:1-6. [PMID: 38574392 DOI: 10.1080/21622965.2024.2304781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
OBJECTIVE Neurocognitive deficits in attention, short-term memory, and sequential information processing are present in children with a variety of disabilities, whereas language and visuospatial abilities vary. METHOD We compared the performance of 59 children (mean age, 15 years) with learning disabilities (n = 18), Down syndrome (n = 21), and intellectual disabilities (n = 20). A series of neuropsychological tests were used to evaluate the neurocognitive processes of memory, attention, visuospatial perception, and executive function. To better understand what emotions they experience, we assessed emotions like anxiety, depression, and positive and negative mood. RESULTS The performance of children with Down syndrome was statistically significantly different from that of other groups, indicating lower performance (p = 0.001). In comparison to other groups, children with Down syndrome performed significantly worse across all cognitive domains. Additionally, there were no statistically significant differences between groups and low emotional functioning scores across the board for all children. People with DS frequently have distinctive neurocognitive and neurobehavioral profiles that appear during particular developmental phases and have many distinct strengths and weaknesses that should be respected as they mature over the course of their lives. The current findings have substantial consequences for interventions that are focused on achieving the best results.
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Affiliation(s)
- Kalliopi Megari
- Department of Psychology, CITY College, University of York Europe Campus, Thessaloniki, Greece
- School of Psychology, University of Western Macedonia, Florina, Greece
| | - Maria Sofologi
- Department of Psychology, University of Ioannina, Ioannina, Greece
| | - George Kougioumtzis
- Department of Turkish Studies and Modern Asian Studies, Faculty of Economic and Political Sciences, National and Kapodistrian University of Athens, Greece
| | | | | | - Dimitra Katsarou
- Department of Preschool Education Sciences and Educational Design, Faculty of Humanities, University of the Aegean, Mytilene, Greece
| | - Vasiliki Yotsidi
- Department of Psychology, Panteion University of Social and Political Sciences, Athens, Greece
| | - Maria Theodoratou
- Department of Psychology, School of Health Sciences, Neapolis University Pafos, Paphos, Cyprus
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Schworer EK, Soltani A, Altaye M, Fidler DJ, Esbensen AJ. Cognitive flexibility assessment in youth with Down syndrome: Reliability, practice effects, and validity. RESEARCH IN DEVELOPMENTAL DISABILITIES 2023; 133:104416. [PMID: 36603310 PMCID: PMC9852016 DOI: 10.1016/j.ridd.2022.104416] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 12/14/2022] [Accepted: 12/30/2022] [Indexed: 05/31/2023]
Abstract
BACKGROUND Cognitive flexibility refers to the ability to switch between different mental sets, tasks, or strategies and is challenging for some individuals with Down syndrome (DS). The lack of reliable and valid cognitive flexibility measures for individuals with DS is a major barrier to clinical trials and intervention studies designed to address cognitive challenges specific to DS. To avoid measurement limitations that could confound interpretations of performance in clinical trials in children with DS, it is critical to use phenotype-sensitive and psychometrically sound measures of cognitive flexibility. AIM This study aimed to evaluate the psychometric properties of three measures of cognitive flexibility including Rule-Shift, Weigl Sorting, and KiTAP Flexibility in a sample of 97 youth with DS aged 6-17 years old. METHOD Data were collected at two time points with a two-week interval. Parents also completed adaptive behavior and cognitive flexibility questionnaires. Child cognitive and language abilities were also assessed. RESULTS The Weigl Sorting met the most psychometric criteria, with adequate feasibility (≥ 80 %) and significant correlations with most of the broader developmental domains; however, the levels of test-retest reliability, practice effects, and convergent validity did not meet a priori criteria. Rule-Shift and KiTAP Flexibility measures did not have acceptable feasibility; although sensitivity and specificity analyses revealed that Rule-Shift may be appropriate for a subgroup of the participants. CONCLUSION No evaluated measures met all psychometric study criteria and, therefore, additional evaluation of cognitive flexibility measures is needed for use among individuals with DS.
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Affiliation(s)
- Emily K Schworer
- Division of Developmental and Behavioral Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; University of Wisconsin-Madison, Waisman Center, Madison, WI, USA.
| | - Amanallah Soltani
- Department of Educational Psychology, Kerman Branch, Islamic Azad University, Kerman, Iran
| | - Mekibib Altaye
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA; Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital, Cincinnati, OH, USA
| | - Deborah J Fidler
- Human Development and Family Studies, Colorado State University, Fort Collins, CO, USA
| | - Anna J Esbensen
- Division of Developmental and Behavioral Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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Shields N, Mizzi N, Buhlert‐Smith K, Strydom A, Prendergast L, Hocking DR. A 12-week exercise programme has a positive effect on everyday executive function in young people with Down syndrome: a pilot non-randomised controlled trial. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2022; 66:924-938. [PMID: 36101998 PMCID: PMC9825892 DOI: 10.1111/jir.12979] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 07/24/2022] [Accepted: 08/17/2022] [Indexed: 05/15/2023]
Abstract
BACKGROUND Exercise has the potential to reduce cognitive decline in people with Down syndrome by maximising their cognitive function. The aim of the study was to determine the effect of regular exercise on cognitive functioning in young people with Down syndrome. METHOD People with Down syndrome were eligible if aged between 13 and 35 years and enrolled to participate in an exercise programme (called FitSkills). The intervention was a 12-week community-based exercise programme completed with a student mentor. Outcomes were assessed before (week 0) and immediately after (week 13) the intervention. Executive functioning (planning, response inhibition, attention shifting) was assessed using Tower of London, Sustained Attention to Response Task, CANTAB Intra-extra Dimensional Set Shift Test, Cognitive Scale for Down Syndrome, and Behaviour Rating Inventory of Executive Function (BRIEF). Working memory was assessed using the CANTAB Paired Associates Learning task, and information processing speed was assessed using the Motor Screening Task. Outcomes were analysed using ANCOVA with the baseline measure as the covariate. RESULTS Twenty participants (9 women; mean age 23.6 ± 6.6 years) enrolled. Between-group differences, in favour of the experimental group, were found for the global executive composite score of the BRIEF (mean difference -4.77 units, 95% CI -9.30 to -0.25). There were no between group differences for any other outcome measured. CONCLUSION Participation in a 12-week exercise programme was effective in improving everyday executive functions in young people with Down syndrome. These preliminary findings need to be confirmed in future randomised controlled trials of community-based exercise with larger sample sizes.
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Affiliation(s)
- N. Shields
- Department of Physiotherapy, Podiatry and Prosthetics and Orthotics, School of Allied Health, Human Services and SportLa Trobe UniversityMelbourneAustralia
| | - N. Mizzi
- Developmental Neuromotor & Cognition Lab, School of Psychology and Public HealthLa Trobe UniversityMelbourneAustralia
| | - K. Buhlert‐Smith
- Department of Physiotherapy, Podiatry and Prosthetics and Orthotics, School of Allied Health, Human Services and SportLa Trobe UniversityMelbourneAustralia
| | - A. Strydom
- Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology & NeuroscienceKings College LondonLondonUK
| | - L. Prendergast
- Department of Mathematics and StatisticsLa Trobe UniversityMelbourneAustralia
| | - D. R. Hocking
- Developmental Neuromotor & Cognition Lab, School of Psychology and Public HealthLa Trobe UniversityMelbourneAustralia
- Centre for Mental HealthSwinburne University of TechnologyMelbourneAustralia
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Evidence of Energy Metabolism Alterations in Cultured Neonatal Astrocytes Derived from the Ts65Dn Mouse Model of Down Syndrome. Brain Sci 2022; 12:brainsci12010083. [PMID: 35053826 PMCID: PMC8773919 DOI: 10.3390/brainsci12010083] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/01/2022] [Accepted: 01/04/2022] [Indexed: 12/10/2022] Open
Abstract
For many decades, neurons have been the central focus of studies on the mechanisms underlying the neurodevelopmental and neurodegenerative aspects of Down syndrome (DS). Astrocytes, which were once thought to have only a passive role, are now recognized as active participants of a variety of essential physiological processes in the brain. Alterations in their physiological function have, thus, been increasingly acknowledged as likely initiators of or contributors to the pathogenesis of many nervous system disorders and diseases. In this study, we carried out a series of real-time measurements of oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) in hippocampal astrocytes derived from neonatal Ts65Dn and euploid control mice using a Seahorse XFp Flux Analyzer. Our results revealed a significant basal OCR increase in neonatal Ts65Dn astrocytes compared with those from control mice, indicating increased oxidative phosphorylation. ECAR did not differ between the groups. Given the importance of astrocytes in brain metabolic function and the linkage between astrocytic and neuronal energy metabolism, these data provide evidence against a pure “neurocentric” vision of DS pathophysiology and support further investigations on the potential contribution of disturbances in astrocytic energy metabolism to cognitive deficits and neurodegeneration associated with DS.
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Schworer EK, Esbensen AJ, Fidler DJ, Beebe DW, Carle A, Wiley S. Evaluating working memory outcome measures for children with Down syndrome. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2022; 66:195-211. [PMID: 33763953 PMCID: PMC8463631 DOI: 10.1111/jir.12833] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 01/13/2021] [Accepted: 03/02/2021] [Indexed: 05/13/2023]
Abstract
BACKGROUND There is a critical need for the psychometric evaluation of outcome measures to be used in clinical trials targeting cognition in Down syndrome (DS). This study examines a specific cognitive skill that is of particular importance in DS, working memory, and the psychometric properties of a set of standardised measurements to assess working memory in individuals with DS. METHODS Ninety children and adolescents ages 6 to 18 years old with DS were assessed on a selection of verbal and visuospatial working memory subtests of standardised clinical assessments at two time points to examine feasibility, distributional qualities, test-retest reliability and convergent validity against a priori criteria. Caregivers also completed an adaptive behaviour questionnaire to address working memory subtests' associations with broader developmental functioning. RESULTS The Stanford Binet-5 Verbal Working Memory, Differential Ability Scales-2 Recognition of Pictures, Stanford Binet-5 Nonverbal Working Memory and Wechsler Intelligence Scale for Children-5 Picture Span measures met the most psychometric criteria overall across the full age and IQ range of the study. Although Differential Ability Scales-2 Recall of Sequential Order and Differential Ability Scales-2 Recall of Digits Backward met the fewest a priori criteria, follow-up analyses suggested greater feasibility in specific age and IQ ranges. CONCLUSIONS Several working memory measures appear to be psychometrically sound and appropriate for use in clinical trials for children with DS, especially when focusing on raw scores. However, floor effects on standard scores and feasibility of some measures were problematic. Guidelines for use of the working memory subtests with this population are provided.
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Affiliation(s)
- Emily K. Schworer
- Division of Developmental and Behavioral Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Anna J. Esbensen
- Division of Developmental and Behavioral Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Deborah J. Fidler
- Human Development and Family Studies, Colorado State University, Fort Collins, CO, USA
| | - Dean W. Beebe
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- Division of Behavioral Medicine and Clinical Psychology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Adam Carle
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
- James M Anderson Center for Health Systems Excellence, Cincinnati, OH, USA
- Department of Psychology, University of Cincinnati, Cincinnati, OH, USA
| | - Susan Wiley
- Division of Developmental and Behavioral Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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Costa ACS, Brandão AC, Boada R, Barrionuevo VL, Taylor HG, Roth E, Stasko MR, Johnson MW, Assir FF, Roberto MP, Salmona P, Abreu-Silveira G, Bederman I, Prendergast E, Hüls A, Abrishamcar S, Mustacchi Z, Scheidemantel T, Roizen NJ, Ruedrich S. Safety, efficacy, and tolerability of memantine for cognitive and adaptive outcome measures in adolescents and young adults with Down syndrome: a randomised, double-blind, placebo-controlled phase 2 trial. Lancet Neurol 2021; 21:31-41. [PMID: 34942135 DOI: 10.1016/s1474-4422(21)00369-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 10/02/2021] [Accepted: 10/11/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND Down syndrome is a chromosomal disorder with considerable neurodevelopmental impact and neurodegenerative morbidity. In a pilot trial in young adults with Down syndrome, memantine (a drug approved for Alzheimer's disease) showed a significant effect on a secondary measure of episodic memory. We aimed to test whether memantine would improve episodic memory in adolescents and young adults with Down syndrome. METHODS We did a randomised, double-blind, placebo-controlled phase 2 trial with a parallel design, stratified by age and sex. Participants (aged 15-32 years) with either trisomy 21 or complete unbalanced translocation of chromosome 21 and in general good health were recruited from the community at one site in Brazil and another in the USA. Participants were randomly assigned (1:1) to receive either memantine (20 mg/day orally) or placebo for 16 weeks. Computer-generated randomisation tables for both sites (allocating a placebo or drug label to each member of a unique pair of participants) were centrally produced by an independent statistician and were shared only with investigational pharmacists at participating sites until unblinding of the study. Participants and investigators were masked to treatment assignments. Neuropsychological assessments were done at baseline (T1) and week 16 (T2). The primary outcome measure was change from baseline to week 16 in the California Verbal Learning Test-second edition short-form (CVLT-II-sf) total free recall score, assessed in the per-protocol population (ie, participants who completed 16 weeks of treatment and had neuropsychological assessments at T1 and T2). Linear mixed effect models were fit to data from the per-protocol population. Safety and tolerability were monitored and analysed in all participants who started treatment. Steady-state concentrations in plasma of memantine were measured at the end of the trial. This study is registered at ClinicalTrials.gov, number NCT02304302. FINDINGS From May 13, 2015, to July 22, 2020, 185 participants with Down syndrome were assessed for eligibility and 160 (86%) were randomly assigned either memantine (n=81) or placebo (n=79). All participants received their allocated treatment. Linear mixed effect models were fit to data from 149 (81%) participants, 73 in the memantine group and 76 in the placebo group, after 11 people (eight in the memantine group and three in the placebo group) discontinued due to COVID-19 restrictions, illness of their caregiver, adverse events, or low compliance. The primary outcome measure did not differ between groups (CVLT-II-sf total free recall score, change from baseline 0·34 points [95% CI -0·98 to 1·67], p=0·61). Memantine was well tolerated, with infrequent mild-to-moderate adverse events, the most common being viral upper respiratory infection (nine [11%] participants in the memantine group and 12 [15%] in the placebo group) and transient dizziness (eight [10%] in the memantine group and six [8%] in the placebo group). No serious adverse events were observed. Amounts of memantine in plasma were substantially lower than those considered therapeutic for Alzheimer's disease. INTERPRETATION Memantine was well tolerated, but cognition-enhancing effects were not recorded with a 20 mg/day dose in adolescents and young adults with Down syndrome. Exploratory analyses point to a need for future work. FUNDING Alana Foundation. TRANSLATION For the Portuguese translation of the abstract see Supplementary Materials section.
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Affiliation(s)
- Alberto C S Costa
- Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA; Department of Psychiatry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
| | - Ana C Brandão
- Hospital Israelita Albert Einstein, São Paulo, Brazil
| | - Richard Boada
- Department of Pediatrics, School of Medicine, University of Colorado Aurora, CO, USA
| | | | - Hudson G Taylor
- Center for Biobehavioral Health, Nationwide Children's Hospital Research Institute, Ohio State University, Columbus, OH, USA
| | - Elizabeth Roth
- Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Melissa R Stasko
- Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Mark W Johnson
- Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | | | | | - Patrícia Salmona
- São Paulo Center for Clinical Studies and Research-CEPEC-SP, São Paulo, Brazil
| | | | - Ilya Bederman
- Department of Genetics and Genome Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Erin Prendergast
- Department of Genetics and Genome Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Anke Hüls
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, USA; Gangarosa Department of Environmental Health, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Sarina Abrishamcar
- Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, USA
| | - Zan Mustacchi
- São Paulo Center for Clinical Studies and Research-CEPEC-SP, São Paulo, Brazil
| | - Thomas Scheidemantel
- Department of Psychiatry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Nancy J Roizen
- Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Stephen Ruedrich
- Department of Psychiatry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
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Cognitive Function during the Prodromal Stage of Alzheimer's Disease in Down Syndrome: Comparing Models. Brain Sci 2021; 11:brainsci11091220. [PMID: 34573242 PMCID: PMC8471085 DOI: 10.3390/brainsci11091220] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 12/01/2022] Open
Abstract
Accurate identification of the prodromal stage of Alzheimer’s disease (AD), known as mild cognitive impairment (MCI), in adults with Down syndrome (MCI-DS) has been challenging because there are no established diagnostic criteria that can be applied for people with lifelong intellectual disabilities (ID). As such, the sequence of cognitive decline in adults with DS has been difficult to ascertain, and it is possible that domain constructs characterizing cognitive function in neurotypical adults do not generalize to this high-risk population. The present study examined associations among multiple measures of cognitive function in adults with DS, either prior to or during the prodromal stage of AD to determine, through multiple statistical techniques, the measures that reflected the same underlying domains of processing. Participants included 144 adults with DS 40–82 years of age, all enrolled in a larger, multidisciplinary study examining biomarkers of AD in adults with DS. All participants had mild or moderate lifelong intellectual disabilities. Overall AD-related clinical status was rated for each individual during a personalized consensus conference that considered performance as well as health status, with 103 participants considered cognitively stable (CS) and 41 to have MCI-DS. Analyses of 17 variables derived from 10 tests of cognition indicated that performance reflected three underlying factors: language/executive function, memory, and visuomotor. All three domain composite scores significantly predicted MCI-DS status. Based upon path modeling, the language/executive function composite score was the most affected by prodromal AD. However, based upon structural equation modeling, tests assessing the latent construct of memory were the most impacted, followed by those assessing visuomotor, and then those assessing language/executive function. Our study provides clear evidence that cognitive functioning in older adults with DS can be characterized at the cognitive domain level, but the statistical methods selected and the inclusion or exclusion of certain covariates may lead to different conclusions. Best practice requires investigators to understand the internal structure of their variables and to provide evidence that their variables assess their intended constructs.
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Grieco JA, Hartnick CJ, Skotko BG, Yu PK, Pulsifer MB. Preliminary Neurocognitive Results Post Hypoglossal Nerve Stimulation in Patients With Down Syndrome. Laryngoscope 2021; 131:2830-2833. [PMID: 34363400 DOI: 10.1002/lary.29808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/28/2021] [Accepted: 07/27/2021] [Indexed: 11/11/2022]
Affiliation(s)
- Julie A Grieco
- Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts, U.S.A.,Harvard Medical School, Boston, Massachusetts, U.S.A
| | - Christopher J Hartnick
- Harvard Medical School, Boston, Massachusetts, U.S.A.,Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, U.S.A
| | - Brian G Skotko
- Harvard Medical School, Boston, Massachusetts, U.S.A.,Down Syndrome Program, Division of Medical Genetics and Metabolism, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, U.S.A
| | - Phoebe K Yu
- Harvard Medical School, Boston, Massachusetts, U.S.A.,Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, U.S.A
| | - Margaret B Pulsifer
- Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts, U.S.A.,Harvard Medical School, Boston, Massachusetts, U.S.A.,Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, U.S.A
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Atypical electrophysiological and behavioral responses to diazepam in a leading mouse model of Down syndrome. Sci Rep 2021; 11:9521. [PMID: 33947925 PMCID: PMC8096846 DOI: 10.1038/s41598-021-89011-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/15/2021] [Indexed: 02/02/2023] Open
Abstract
Mounting evidence implicates dysfunctional GABAAR-mediated neurotransmission as one of the underlying causes of learning and memory deficits observed in the Ts65Dn mouse model of Down syndrome (DS). The specific origin and nature of such dysfunction is still under investigation, which is an issue with practical consequences to preclinical and clinical research, as well as to the care of individuals with DS and anxiety disorder or those experiencing seizures in emergency room settings. Here, we investigated the effects of GABAAR positive allosteric modulation (PAM) by diazepam on brain activity, synaptic plasticity, and behavior in Ts65Dn mice. We found Ts65Dn mice to be less sensitive to diazepam, as assessed by electroencephalography, long-term potentiation, and elevated plus-maze. Still, diazepam pre-treatment displayed typical effectiveness in reducing susceptibility and severity to picrotoxin-induced seizures in Ts65Dn mice. These findings fill an important gap in the understanding of GABAergic function in a key model of DS.
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10
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Koenig KA, Oh SH, Stasko MR, Roth EC, Taylor HG, Ruedrich S, Wang ZI, Leverenz JB, Costa ACS. High resolution structural and functional MRI of the hippocampus in young adults with Down syndrome. Brain Commun 2021; 3:fcab088. [PMID: 33977271 PMCID: PMC8100000 DOI: 10.1093/braincomms/fcab088] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 02/19/2021] [Accepted: 03/22/2021] [Indexed: 11/29/2022] Open
Abstract
Down syndrome is the phenotypic consequence of trisomy 21, with clinical presentation including both neurodevelopmental and neurodegenerative components. Although the intellectual disability typically displayed by individuals with Down syndrome is generally global, it also involves disproportionate deficits in hippocampally-mediated cognitive processes. Hippocampal dysfunction may also relate to Alzheimer’s disease-type pathology, which can appear in as early as the first decade of life and becomes universal by age 40. Using 7-tesla MRI of the brain, we present an assessment of the structure and function of the hippocampus in 34 individuals with Down syndrome (mean age 24.5 years ± 6.5) and 27 age- and sex-matched typically developing healthy controls. In addition to increased whole-brain mean cortical thickness and lateral ventricle volumes (P < 1.0 × 10−4), individuals with Down syndrome showed selective volume reductions in bilateral hippocampal subfields cornu Ammonis field 1, dentate gyrus, and tail (P < 0.005). In the group with Down syndrome, bilateral hippocampi showed widespread reductions in the strength of functional connectivity, predominately to frontal regions (P < 0.02). Age was not related to hippocampal volumes or functional connectivity measures in either group, but both groups showed similar relationships of age to whole-brain volume measures (P < 0.05). Finally, we performed an exploratory analysis of a subgroup of individuals with Down syndrome with both imaging and neuropsychological assessments. This analysis indicated that measures of spatial memory were related to mean cortical thickness, total grey matter volume and right hemisphere hippocampal subfield volumes (P < 0.02). This work provides a first demonstration of the usefulness of high-field MRI to detect subtle differences in structure and function of the hippocampus in individuals with Down syndrome, and suggests the potential for development of MRI-derived measures as surrogate markers of drug efficacy in pharmacological studies designed to investigate enhancement of cognitive function.
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Affiliation(s)
- Katherine A Koenig
- Imaging Sciences, Imaging Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Se-Hong Oh
- Imaging Sciences, Imaging Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Department of Biomedical Engineering, Hankuk University of Foreign Studies, Yongin 449-791, Republic of Korea
| | - Melissa R Stasko
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Elizabeth C Roth
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106, USA
| | - H Gerry Taylor
- Abigail Wexner Research Institute at Nationwide Children's Hospital, and Department of Pediatrics, The Ohio State University, Columbus, OH 43215, USA
| | - Stephen Ruedrich
- Department of Psychiatry, University Hospitals, Cleveland, OH 44106, USA
| | - Z Irene Wang
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - James B Leverenz
- Lou Ruvo Center for Brain Health, Neurological Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Alberto C S Costa
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106, USA.,Department of Psychiatry, University Hospitals, Cleveland, OH 44106, USA
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Abstract
PURPOSE OF REVIEW People with Down syndrome represent the world's largest population with a genetic risk for Alzheimer's disease. This review will provide a short summary of what is known and will include recent findings from the field. RECENT FINDINGS There has been an increasing focus on biomarker research in this population, with a number of studies presenting findings on promising new markers - Neurofilament Light (NfL) appears to be one such promising marker that has emerged. Imaging studies have increased our knowledge on the progression of Alzheimer's disease in this population. SUMMARY The inclusion of people with Down syndrome in dementia research is vital from a scientific and an equity perspective. Recent advances in the field can have further impact with multisite, cross country collaborative efforts. For this to happen, instruments need to be validated across language and cultures.
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12
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Martínez de Lagrán M. Mapping behavioral landscapes in Down syndrome animal models. PROGRESS IN BRAIN RESEARCH 2020; 251:145-179. [DOI: 10.1016/bs.pbr.2020.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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