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Victorino DB, Faber J, Pinheiro DJLL, Scorza FA, Almeida ACG, Costa ACS, Scorza CA. Toward the Identification of Neurophysiological Biomarkers for Alzheimer's Disease in Down Syndrome: A Potential Role for Cross-Frequency Phase-Amplitude Coupling Analysis. Aging Dis 2023; 14:428-449. [PMID: 37008053 PMCID: PMC10017148 DOI: 10.14336/ad.2022.0906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/06/2022] [Indexed: 11/18/2022] Open
Abstract
Cross-frequency coupling (CFC) mechanisms play a central role in brain activity. Pathophysiological mechanisms leading to many brain disorders, such as Alzheimer's disease (AD), may produce unique patterns of brain activity detectable by electroencephalography (EEG). Identifying biomarkers for AD diagnosis is also an ambition among research teams working in Down syndrome (DS), given the increased susceptibility of people with DS to develop early-onset AD (DS-AD). Here, we review accumulating evidence that altered theta-gamma phase-amplitude coupling (PAC) may be one of the earliest EEG signatures of AD, and therefore may serve as an adjuvant tool for detecting cognitive decline in DS-AD. We suggest that this field of research could potentially provide clues to the biophysical mechanisms underlying cognitive dysfunction in DS-AD and generate opportunities for identifying EEG-based biomarkers with diagnostic and prognostic utility in DS-AD.
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Affiliation(s)
- Daniella B Victorino
- Discipline of Neuroscience, Department of Neurology and Neurosurgery, Federal University of São Paulo / Paulista Medical School, São Paulo, SP, Brazil.
| | - Jean Faber
- Discipline of Neuroscience, Department of Neurology and Neurosurgery, Federal University of São Paulo / Paulista Medical School, São Paulo, SP, Brazil.
| | - Daniel J. L. L Pinheiro
- Discipline of Neuroscience, Department of Neurology and Neurosurgery, Federal University of São Paulo / Paulista Medical School, São Paulo, SP, Brazil.
| | - Fulvio A Scorza
- Discipline of Neuroscience, Department of Neurology and Neurosurgery, Federal University of São Paulo / Paulista Medical School, São Paulo, SP, Brazil.
| | - Antônio C. G Almeida
- Department of Biosystems Engineering, Federal University of São João Del Rei, Minas Gerais, MG, Brazil.
| | - Alberto C. S Costa
- Division of Psychiatry, Case Western Reserve University, Cleveland, OH, United States.
- Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH, United States.
| | - Carla A Scorza
- Discipline of Neuroscience, Department of Neurology and Neurosurgery, Federal University of São Paulo / Paulista Medical School, São Paulo, SP, Brazil.
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2
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Bartesaghi R. Brain circuit pathology in Down syndrome: from neurons to neural networks. Rev Neurosci 2022; 34:365-423. [PMID: 36170842 DOI: 10.1515/revneuro-2022-0067] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 08/28/2022] [Indexed: 11/15/2022]
Abstract
Down syndrome (DS), a genetic pathology caused by triplication of chromosome 21, is characterized by brain hypotrophy and impairment of cognition starting from infancy. While studies in mouse models of DS have elucidated the major neuroanatomical and neurochemical defects of DS, comparatively fewer investigations have focused on the electrophysiology of the DS brain. Electrical activity is at the basis of brain functioning. Therefore, knowledge of the way in which brain circuits operate in DS is fundamental to understand the causes of behavioral impairment and devise targeted interventions. This review summarizes the state of the art regarding the electrical properties of the DS brain, starting from individual neurons and culminating in signal processing in whole neuronal networks. The reported evidence derives from mouse models of DS and from brain tissues and neurons derived from individuals with DS. EEG data recorded in individuals with DS are also provided as a key tool to understand the impact of brain circuit alterations on global brain activity.
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Affiliation(s)
- Renata Bartesaghi
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40126 Bologna, Italy
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3
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Abiyev A, Yakaryılmaz FD, Öztürk ZA. A new diagnostic approach in Alzheimer's disease: The critical flicker fusion threshold. Dement Neuropsychol 2022; 16:89-96. [PMID: 35719254 PMCID: PMC9170257 DOI: 10.1590/1980-5764-dn-2021-0054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 08/30/2021] [Accepted: 09/20/2021] [Indexed: 11/22/2022] Open
Abstract
Alzheimer's disease (AD) is the most common cause of dementia in the elderly. Although AD treatment is still insufficient despite all the recent developments, detection and treatment in the early stage of disease have provided more clinical benefits.
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Affiliation(s)
- Azar Abiyev
- Gazi University, Faculty of Medicine, Department of Gastroenterology, Ankara, Turkey
| | | | - Zeynel Abidin Öztürk
- Gaziantep University, Faculty of Medicine, Department of Geriatrics, Gaziantep, Turkey
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4
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Musaeus CS, Salem LC, Kjaer TW, Waldemar G. Electroencephalographic functional connectivity is altered in persons with Down syndrome and Alzheimer's disease. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2021; 65:236-245. [PMID: 33336867 DOI: 10.1111/jir.12803] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 10/06/2020] [Accepted: 11/21/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND Persons with Down syndrome (DS) are at increased risk of developing Alzheimer's dementia (DS-AD). Due to heterogeneity in the functioning in persons with DS, it is difficult to use cognitive testing to assess whether a person with DS has developed dementia due to AD. Electroencephalography (EEG) functional connectivity has shown promising results as a diagnostic tool for AD in persons without DS. In the current exploratory study, we investigated whether EEG functional connectivity could be used as a diagnostic marker of AD in persons with DS and the association with symptoms. METHODS Electroencephalography from 12 persons with DS and 16 persons with DS-AD were analysed, and both coherence and weighted phase lag index were calculated. In addition, we calculated the average coherence for fronto-parietal and temporo-parietal connections. Lastly, we investigated the correlation between the informant-based Dementia Screening Questionnaire in Intellectual Disability (DSQIID) and total alpha coherence. RESULTS Decreased alpha and increased delta coherence and weighted phase lag index were observed in DS-AD as compared with DS. The decrease in alpha coherence was more marked in the fronto-parietal connections as compared with the temporo-parietal connections. No significant correlation was found between DSQIID and total alpha coherence (P value = 0.095, rho = -0.335). CONCLUSION The decreased alpha coherence and weighted phase lag index have previously been found in AD. The increased delta coherence and weighted phase lag index may indicate a different initial neurophysiological presentation as compared with patients with AD or may be a sign of more advanced disease. Larger studies are needed to confirm the current findings.
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Affiliation(s)
- C S Musaeus
- Department of Neurology, Danish Dementia Research Centre (DDRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - L C Salem
- Department of Neurology, Danish Dementia Research Centre (DDRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - T W Kjaer
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Neurophysiology Center, Zealand University Hospital, Roskilde, Denmark
| | - G Waldemar
- Department of Neurology, Danish Dementia Research Centre (DDRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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5
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Hamburg S, Rosch R, Startin CM, Friston KJ, Strydom A. Dynamic Causal Modeling of the Relationship between Cognition and Theta-alpha Oscillations in Adults with Down Syndrome. Cereb Cortex 2020; 29:2279-2290. [PMID: 30877793 PMCID: PMC6458903 DOI: 10.1093/cercor/bhz043] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 02/09/2019] [Indexed: 01/17/2023] Open
Abstract
Individuals with Down syndrome (DS) show high inter-subject variability in cognitive ability and have an ultra-high risk of developing dementia (90% lifetime prevalence). Elucidating factors underlying variability in cognitive function can inform us about intellectual disability (ID) and may improve our understanding of factors associated with later cognitive decline. Increased neuronal inhibition has been posited to contribute to ID in DS. Combining electroencephalography (EEG) with dynamic causal modeling (DCM) provides a non-invasive method for investigating excitatory/inhibitory mechanisms. Resting-state EEG recordings were obtained from 36 adults with DS with no evidence of cognitive decline. Theta–alpha activity (4–13 Hz) was characterized in relation to general cognitive ability (raw Kaufmann’s Brief Intelligence Test second Edition (KBIT-2) score). Higher KBIT-2 was associated with higher frontal alpha peak amplitude and higher theta–alpha band power across distributed regions. Modeling this association with DCM revealed intrinsic self-inhibition was the key network parameter underlying observed differences in 4–13 Hz power in relation to KBIT-2 and age. In particular, intrinsic self-inhibition in right V1 was negatively correlated with KBIT-2. Results suggest intrinsic self-inhibition within the alpha network is associated with individual differences in cognitive ability in adults with DS, and may provide a potential therapeutic target for cognitive enhancement.
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Affiliation(s)
- Sarah Hamburg
- Division of Psychiatry, Faculty of Brain Sciences, University College London, 149 Tottenham Court Road, London, UK.,Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK.,The London Down Syndrome Consortium (LonDownS), London, UK
| | - Richard Rosch
- MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, London, UK
| | - Carla Marie Startin
- Division of Psychiatry, Faculty of Brain Sciences, University College London, 149 Tottenham Court Road, London, UK.,Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK.,The London Down Syndrome Consortium (LonDownS), London, UK
| | - Karl John Friston
- Wellcome Centre for Human Neuroimaging, Institute of Neurology, University College London, 12 Queen Square, London, UK
| | - André Strydom
- Division of Psychiatry, Faculty of Brain Sciences, University College London, 149 Tottenham Court Road, London, UK.,Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, London, UK.,The London Down Syndrome Consortium (LonDownS), London, UK
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Musaeus CS, Salem LC, Sabers A, Kjaer TW, Waldemar G. Associations between electroencephalography power and Alzheimer's disease in persons with Down syndrome. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2019; 63:1151-1157. [PMID: 31025465 DOI: 10.1111/jir.12627] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/14/2019] [Accepted: 03/20/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND It is complicated to diagnose dementia in persons with Down syndrome (DS). Older studies have, however, demonstrated low-frequency activity in electroencephalography (EEG) in persons with concurrent DS and Alzheimer's disease (DS-AD). The aim of this study was to examine whether it was possible to identify AD-associated changes (increased high-frequency power and decreased low-frequency power) in persons with DS-AD compared with DS. METHODS We included 21 persons with DS-AD and 16 with DS without cognitive deterioration assessed by the informant-based Dementia Screening Questionnaire in Intellectual Disability. EEG was recorded for all participants. Absolute power for each electrode and global power were calculated for all frequency bands for both eyes open and eyes closed. RESULTS For global power in the eyes closed condition, we found an increased global slow-frequency activity and a decreased global high-frequency activity in DS-AD compared with DS. In addition, we found a significant difference in the global alpha/delta ratio with the largest difference found for global alpha power in DS-AD compared with DS. CONCLUSIONS In the current study, we found that changes known to be associated with AD could also be identified when comparing DS-AD with DS using quantitative EEG. In general, these findings suggest that EEG might be a useful tool in diagnosing AD in persons with DS, but larger studies are needed.
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Affiliation(s)
- C S Musaeus
- Department of Neurology, Danish Dementia Research Centre (DDRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - L C Salem
- Department of Neurology, Danish Dementia Research Centre (DDRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - A Sabers
- The Epilepsy Clinic, Department of Neurology, Rigshospitalet-Blegdamsvej, University Hospital, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - T W Kjaer
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Neurophysiology Center, Zealand University Hospital, Roskilde, Denmark
| | - G Waldemar
- Department of Neurology, Danish Dementia Research Centre (DDRC), Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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7
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García-Alba J, Ramírez-Toraño F, Esteba-Castillo S, Bruña R, Moldenhauer F, Novell R, Romero-Medina V, Maestú F, Fernández A. Neuropsychological and neurophysiological characterization of mild cognitive impairment and Alzheimer's disease in Down syndrome. Neurobiol Aging 2019; 84:70-79. [PMID: 31518951 DOI: 10.1016/j.neurobiolaging.2019.07.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/03/2019] [Accepted: 07/30/2019] [Indexed: 10/26/2022]
Abstract
Down syndrome (DS) has been considered a unique model for the investigation of Alzheimer's disease (AD) but intermediate stages in the continuum are poorly defined. Considering this, we investigated the neurophysiological (i.e., magnetoencephalography [MEG]) and neuropsychological patterns of mild cognitive impairment (MCI) and AD in middle-aged adults with DS. The sample was composed of four groups: Control-DS (n = 14, mean age 44.64 ± 3.30 years), MCI-DS (n = 14, 51.64 ± 3.95 years), AD-DS (n = 13, 53.54 ± 6.58 years), and Control-no-DS (healthy controls, n = 14, 45.21 ± 4.39 years). DS individuals were studied with neuropsychological tests and MEG, whereas the Control-no-DS group completed only the MEG session. Our results showed that the AD-DS group exhibited a significantly poorer performance as compared with the Control-DS group in all tests. Furthermore, this effect was crucially evident in AD-DS individuals when compared with the MCI-DS group in verbal and working memory abilities. In the neurophysiological domain, the Control-DS group showed a widespread increase of theta activity when compared with the Control-no-DS group. With disease progression, this increased theta was substituted by an augmented delta, accompanied with a reduction of alpha activity. Such spectral pattern-specifically observed in occipital, posterior temporal, cuneus, and precuneus regions-correlated with the performance in cognitive tests. This is the first MEG study in the field incorporating both neuropsychological and neurophysiological information, and demonstrating that this combination of markers is sensitive enough to characterize different stages along the AD continuum in DS.
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Affiliation(s)
- Javier García-Alba
- Research and Psychology in Education Department, Complutense University of Madrid, Madrid, Spain; Center for Biomedical Technology, Laboratory of Cognitive and Computational Neuroscience, Technical University of Madrid, Campus Montegancedo, Madrid, Spain.
| | - Federico Ramírez-Toraño
- Center for Biomedical Technology, Laboratory of Cognitive and Computational Neuroscience, Technical University of Madrid, Campus Montegancedo, Madrid, Spain; Department of Experimental Psychology, Complutense University of Madrid, Campus de Somosaguas, Pozuelo de Alarcón, Madrid, Spain
| | - Susanna Esteba-Castillo
- Specialized Department in Mental Health and Intellectual Disability, Parc Hospitalari Martí i Julià - Institut d'Assistència Sanitària, Institut d'Assistència Sanitària (IAS), Girona, Spain; Neurodevelopment group [Girona Biomedical Research Institute]-IDIBGI, Institute of Health Assistance (IAS), Parc Hospitalari Martí i Julià, Girona, Spain
| | - Ricardo Bruña
- Center for Biomedical Technology, Laboratory of Cognitive and Computational Neuroscience, Technical University of Madrid, Campus Montegancedo, Madrid, Spain; Department of Experimental Psychology, Complutense University of Madrid, Campus de Somosaguas, Pozuelo de Alarcón, Madrid, Spain; Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
| | - Fernando Moldenhauer
- Internal Medicine Department, Adult Down Syndrome Unit, La Princesa University Hospital, Health Research Institute, Madrid, Spain
| | - Ramón Novell
- Specialized Department in Mental Health and Intellectual Disability, Parc Hospitalari Martí i Julià - Institut d'Assistència Sanitària, Institut d'Assistència Sanitària (IAS), Girona, Spain; Neurodevelopment group [Girona Biomedical Research Institute]-IDIBGI, Institute of Health Assistance (IAS), Parc Hospitalari Martí i Julià, Girona, Spain
| | - Verónica Romero-Medina
- Center for Biomedical Technology, Laboratory of Cognitive and Computational Neuroscience, Technical University of Madrid, Campus Montegancedo, Madrid, Spain
| | - Fernando Maestú
- Center for Biomedical Technology, Laboratory of Cognitive and Computational Neuroscience, Technical University of Madrid, Campus Montegancedo, Madrid, Spain; Department of Experimental Psychology, Complutense University of Madrid, Campus de Somosaguas, Pozuelo de Alarcón, Madrid, Spain; Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
| | - Alberto Fernández
- Center for Biomedical Technology, Laboratory of Cognitive and Computational Neuroscience, Technical University of Madrid, Campus Montegancedo, Madrid, Spain; Department of Legal Medicine, Psychiatry and Pathology, Complutense University of Madrid, Spain, Madrid, Spain
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8
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Ruiz-Mejias M. Outer Brain Oscillations in Down Syndrome. Front Syst Neurosci 2019; 13:17. [PMID: 31139056 PMCID: PMC6519307 DOI: 10.3389/fnsys.2019.00017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/12/2019] [Indexed: 11/13/2022] Open
Abstract
The present article reviews the relationship between sleep and oscillatory activity in Down Syndrome (DS), as well as the featuring emergent rhythmic activity across different brain states. A comprehensive discussion of the data from electroencephalographic studies in DS humans and transgenic/trisomic mouse models is provided, as well as data from signals collected from local field potentials (LFP) and intracellular recordings in DS mouse models. The first sections focus specially on the alpha phenotype consistently observed in DS subjects, as well as its description in DS childhood and aging. Subsequently, a review of the data reported in DS mouse models is presented with the aim to deepen on the mechanisms underlying altered rhythmic patterns. Further sections situate the state-of-the-art of the field, with a discussion on the possible circuit alterations that may underlie impaired alpha and gamma oscillatory activity. A further aim is to highlight the importance of studying network oscillatory activity in mouse models to infer alterations in the underlying circuits related to cognition, such as in intellectual disability. In this direction, a view of alpha and gamma rhythms generated by the cerebral cortex as a tool for evaluating an unbalance between excitation and inhibition in DS is claimed, which points out toward an over-inhibited network. A final aim is to situate oscillatory activity as a key phenomenon that may be used as a biomarker for monitoring as well the effect of novel therapeutic strategies.
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Affiliation(s)
- Marcel Ruiz-Mejias
- Systems Neuroscience, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain
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9
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Prasher VP, Sachdeva N, Tarrant N. Diagnosing dementia in adults with Down's syndrome. Neurodegener Dis Manag 2016; 5:249-56. [PMID: 26107323 DOI: 10.2217/nmt.15.8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Individuals with Down's syndrome (DS) are living longer and many will survive into their fifth or sixth decade of life. Among the DS population, the prevalence of dementia in Alzheimer's disease increases from 9.4% in age group 30-39 years to 54.5% age group 60-69 years. The psychopathology of dementia in Alzheimer's disease is similar to that seen in the general population although differences are apparent due to the underlying intellectual disability in DS and on the reliance on collateral information from informants. The diagnostic workup follows accepted practice although neuropsychological tests and neuroimaging will only be adjuncts to the clinical assessment; such investigations have limited diagnostic value. Presently, research is focused on identifying genetic and biological measures of Alzheimer's disease in DS.
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Affiliation(s)
- Vee P Prasher
- Birmingham Community Healthcare NHS Trust, Birmingham Learning Disability Service, The Greenfields, 30 Brookfield Road, Birmingham, B30 3QY, UK
| | - Niyati Sachdeva
- Birmingham Community Healthcare NHS Trust, Birmingham Learning Disability Service, The Greenfields, 30 Brookfield Road, Birmingham, B30 3QY, UK
| | - Nick Tarrant
- Birmingham Community Healthcare NHS Trust, Birmingham Learning Disability Service, The Greenfields, 30 Brookfield Road, Birmingham, B30 3QY, UK
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10
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Salem LC, Sabers A, Kjaer TW, Musaeus C, Nielsen MN, Nielsen AG, Waldemar G. Quantitative Electroencephalography as a Diagnostic Tool for Alzheimer's Dementia in Adults with Down Syndrome. Dement Geriatr Cogn Dis Extra 2015; 5:404-13. [PMID: 26628899 PMCID: PMC4662295 DOI: 10.1159/000438857] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 07/20/2015] [Indexed: 12/29/2022] Open
Abstract
Background Assessment of dementia in individuals with intellectual disability is complex due to great inter-individual variability in cognitive function prior to dementia and a lack of standardized instruments. Studies have indicated that quantitative electroencephalography (qEEG) results may be used as a diagnostic marker for dementia. The aim of this study was to examine the value of qEEG in the diagnostic evaluation of dementia in patients with Down syndrome (DS). Method The study included 21 patients with DS and mild-to-moderate dementia due to Alzheimer's disease (DS-AD) and 16 age-matched adults with DS without cognitive deterioration assessed by the informant-based Dementia Screening Questionnaire in Intellectual Disability (DSQIID). Conventional EEG was performed and analysed quantitatively using fast Fourier transformation. Outcomes were centroid frequency, peak frequency, absolute power, and relative power. Results In several regions of the brain, a significant decrease in the theta-1 band (4-7 Hz) was identified for the centroid frequency. A significant negative correlation was demonstrated between the mean of the centroid frequency of the theta-1 band and the total DSQIID score. Conclusion We found that qEEG can detect a significant decrease in centroid frequency in a sample of patients with DS-AD as compared to a sample of adults with DS and no cognitive deterioration.
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Affiliation(s)
- Lise Cronberg Salem
- Danish Dementia Research Centre, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Anne Sabers
- Epilepsy Clinic, Department of Neurology, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Troels W Kjaer
- Neurophysiology Center, Roskilde University Hospital, Roskilde, Denmark
| | - Christian Musaeus
- Danish Dementia Research Centre, Copenhagen University Hospital, Rigshospitalet, Denmark
| | - Martin N Nielsen
- Department of Clinical Neurophysiology, Copenhagen University Hospital, Rigshospitalet, Denmark
| | | | - Gunhild Waldemar
- Danish Dementia Research Centre, Copenhagen University Hospital, Rigshospitalet, Denmark
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11
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Cognitive deficits and associated neurological complications in individuals with Down's syndrome. Lancet Neurol 2010; 9:623-33. [PMID: 20494326 DOI: 10.1016/s1474-4422(10)70112-5] [Citation(s) in RCA: 289] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Improvements in medical interventions for people with Down's syndrome have led to a substantial increase in their longevity. Diagnosis and treatment of neurological complications are important in maintaining optimal cognitive functioning. The cognitive phenotype in Down's syndrome is characterised by impairments in morphosyntax, verbal short-term memory, and explicit long-term memory. However, visuospatial short-term memory, associative learning, and implicit long-term memory functions are preserved. Seizures are associated with cognitive decline and seem to cause additional decline in cognitive functioning, particularly in people with Down's syndrome and comorbid disorders such as autism. Vision and hearing disorders as well as hypothyroidism can negatively impact cognitive functioning in people with Down's syndrome. Dementia that resembles Alzheimer's disease is common in adults with Down's syndrome. Early-onset dementia in adults with Down's syndrome does not seem to be associated with atherosclerotic complications.
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12
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Cortical sources of EEG rhythms are abnormal in down syndrome. Clin Neurophysiol 2010; 121:1205-12. [PMID: 20362500 DOI: 10.1016/j.clinph.2010.02.155] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Revised: 02/05/2010] [Accepted: 02/24/2010] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Previous studies have been inconclusive whether dominant resting state alpha rhythms are greater or lower in amplitude in subjects with Down syndrome (DS) when compared to control subjects, ample resting alpha rhythms being considered as a reflection of good mechanisms of cortical neural synchronization. Here we tested the hypothesis that when the effects of head volume conduction are taken into account by the normalization of the cortical sources of resting alpha rhythms, these sources are lower in amplitude in DS subjects than in controls in line with typical findings in Alzheimer's disease patients. METHODS Eyes-closed resting electroencephalographic (EEG) data were recorded in 45 DS subjects (25 males; mean age of 22.8years+/-0.7 standard error of mean (SEM)) and in 45 age-matched cognitively normal subjects (25 males; mean age of 22.4years+/-0.5 SEM). EEG rhythms of interest were delta (2-4Hz), theta (4-8Hz), alpha 1 (8-10.5Hz), alpha 2 (10.5-13Hz), beta 1 (13-20Hz), beta 2 (20-30Hz), and gamma (30-40Hz). Cortical EEG sources were estimated by low resolution electromagnetic tomography (LORETA) and normalized across all voxels and frequencies. RESULTS Central, parietal, occipital, and temporal cortical sources of resting alpha and beta rhythms were lower in amplitude in the DS than control subjects, whereas the opposite was true for occipital delta cortical sources. A control analysis on absolute source values showed that they were globally larger in amplitude across several frequency bands in DS than control subjects. CONCLUSIONS These results suggest that normalized cortical sources of alpha rhythms are lower in amplitude in DS than control subjects, as it is typically found in Alzheimer's disease. SIGNIFICANCE DS is accompanied by a functional impairment of cortical neuronal synchronization mechanisms in the resting state condition.
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13
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Inter-hemispheric functional coupling of eyes-closed resting EEG rhythms in adolescents with Down syndrome. Clin Neurophysiol 2009; 120:1619-27. [PMID: 19643663 DOI: 10.1016/j.clinph.2009.06.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 05/13/2009] [Accepted: 06/18/2009] [Indexed: 11/20/2022]
Abstract
OBJECTIVE We tested the hypothesis that inter-hemispheric directional functional coupling of eyes-closed resting EEG rhythms is abnormal in adolescents with Down syndrome (DS). METHODS Eyes-closed resting EEG data were recorded in 38 DS adolescents (18.7 years +/-0.67 SE, IQ=49+/-1.9 SE) and in 17 matched normal control subjects (NYoung=19.1 years +/-0.39 SE). The EEG data were recorded from 8 electrodes (Fp1, Fp2, C3, C4, T3, T4, O1, O2) referenced to vertex. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). Power of EEG rhythms was evaluated by FFT for control purposes, whereas inter-hemispheric directional EEG functional coupling was computed by directed transfer function (DTF). RESULTS As expected, alpha, beta, and gamma power was widely higher in NYoung than DS subjects, whereas the opposite was true for delta power. As a novelty, DTF (directionality) values globally prevailed from right to left occipital areas in NYoung subjects and in the opposite direction in DS patients. A control experiment showed that this DTF difference could not be observed in the comparison between DS adults with mild cognitive impairment and normal age-matched adults. CONCLUSIONS These results indicate a peculiar abnormal directional inter-hemispheric interplay in visual occipital areas of DS adolescents. SIGNIFICANCE Direction of inter-hemispheric EEG functional coupling unveils a new abnormal brain network feature in DS adolescents.
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Menéndez M. Down syndrome, Alzheimer's disease and seizures. Brain Dev 2005; 27:246-52. [PMID: 15862185 DOI: 10.1016/j.braindev.2004.07.008] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2004] [Revised: 07/20/2004] [Accepted: 07/21/2004] [Indexed: 11/26/2022]
Abstract
Neuropathologically, Alzheimer-type abnormalities are demonstrated in patients with Down syndrome (DS), both demented and nondemented and more than a half of patients with DS above 50 years develop Alzheimer's disease (AD). The apolipoprotein E epsilon4 allele, oestrogen deficiency, high levels of Abeta1-42 peptide, elevated expression of BACE2, and valine polymorphism of prion protein gene are associated with earlier onset of dementia in DS individuals. Advanced AD alone may be an important risk factor for new-onset seizures in older adults and age above 60 years is a recognized risk factor for poor outcome from convulsive and nonconvulsive status epilepticus. DS patients aged over 45 years are significantly more likely to develop Alzheimer's disease than those less than 45 years and up to 84% demented individuals with DS develop seizures. Late-onset epilepsy in DS is associated with AD, while early-onset epilepsy is associated with an absence of dementia. In AD patients with a younger age of dementia onset are particularly susceptible to seizures. DS adults with epilepsy score significantly higher overall on the adaptive behaviour profile. Language function declined significantly more rapidly in AD patients with seizures and there is a good correlation between the severity of EEG abnormalities and cognitive impairment whereas in DS slowing of the dominant occipital rhythm is related to AD and the frequency of the dominant occipital activity decreases at the onset of cognitive deterioration.
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Affiliation(s)
- Manuel Menéndez
- Secretaría de Neurología I, Hospital Universitario Central de Asturias, C/Julián Clavería s/n C.P. 33006 Oviedo, Spain.
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da Nóbrega AM, Nunesmaia HG, Viana NDO, Filgueiras MA. [Electroencephalographic modification in Down syndrome]. ARQUIVOS DE NEURO-PSIQUIATRIA 1999; 57:580-6. [PMID: 10667280 DOI: 10.1590/s0004-282x1999000400007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The frequency of epilepsy in Down syndrome (DS) has been reported in literature varying from 6 to 17%. A typical electroencephalographic (EEG) pattern has not been established for this condition. There is a great variation on EEG abnormalities and most of them are not associated to behavior alterations or neurological signs. The aim of this study was to establish epidemiological and electroencephalographic parameters in institutionalized patients with clinical diagnosis of DS. We studied 77 individuals of both sexes, age ranging from 0-38 years old. The EEG was performed on all the patients; 20.7% had EEG abnormalities and 31.3% of these were epileptic. The non-epileptic patients presented inespecific EEG abnormalities. Therefore, our data did not allow us to propose a typical EEG pattern for DS.
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Claus JJ, Strijers RL, Jonkman EJ, Ongerboer de Visser BW, Jonker C, Walstra GJ, Scheltens P, van Gool WA. The diagnostic value of electroencephalography in mild senile Alzheimer's disease. Clin Neurophysiol 1999; 110:825-32. [PMID: 10400195 DOI: 10.1016/s1388-2457(98)00076-5] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
OBJECTIVE We investigated the diagnostic value of the visually assessed electroencephalogram (EEG) in patients with mild Alzheimer's disease (AD), using the grand total of EEG (GTE) score. METHODS Forty-nine non-demented control subjects with and without minimal cognitive impairment from the general population and 86 probable AD patients (NINCDS-ADRDA criteria), consecutively referred to a memory clinic, participated in this study. RESULTS Frequency of rhythmic background activity (P<0.05), diffuse slow activity (P<0.001), and reactivity of the rhythmic background activity (P<0.001) were statistically significant related to the diagnosis control subject or AD patient, using logistic regression analysis with adjustment for age and sex. When these subscores were used to confirm the diagnosis of AD, thus at high specificity of 89.1% (GTE cut-off point of 3), the sensitivity was 44.6% and positive predictive value was 88.1%. Incremental ruling-in and ruling-out curves showed a maximum diagnostic gain of 38% for a positive test result at a prior probability ranging from 30 to 40%. At high pretest probability levels of 80-90%, the diagnostic gain for a positive test result was low, varying from 7 to 14%. CONCLUSION In conclusion, the visually assessed EEG may give a clinically meaningful contribution to the diagnostic evaluation of AD when there is diagnostic doubt.
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Affiliation(s)
- J J Claus
- Department of Neurology, Academic Medical Centre, Amsterdam, The Netherlands.
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