Subjective Cognitive Decline: Are there Reliable Biomarkers?

Magda Tsolaki^* and Ioulietta Lazarou

Aristotle University of Thessaloniki, Greece

Background: Subjective Cognitive Decline (SCD) is a common entity among elderly population and despite that it has been associated with an increased risk of future progression to Alzheimerʼs Diseases (AD) or other dementias, is still unexplored. The examination of this stage of AD spectrum is among the most important research subjects currently.

Methods: The literature review was performed across a number of electronic databases in October 2020, including Medline (via PubMed), EMBASE, PsycINFO (Psychological Abstracts), Cochrane Database and CINAHL Database. Among the several terms, the search included the following: “subjective cognitive decline”, “memory complaint”, “neuropsychological assessment”, “tests”, “Subjective memory/cognitive impairment” and “subjective memory loss”, “EEG”, “MRI”, “APOE4”, “neuroimaging”. The searches were not limited by date of publication or study design. Only English studies were included.

Results: 875 citations were identified, 432 papers were obtained, of which 80 were selected for containing neuropsychological examination, neuroimaging assessment and biomarker detection of SCD. Although they may not present detectable signs of disease, SCD score lower on several neuropsychological tests than the healthy controls (HC) and they also have a higher incidence of future cognitive decline. Regarding the APOE ε4, the results provide mixed evidence linking coincident APOE ε4-positive genotype and SCD. On the other hand, magnetic resonance imaging studies in SCD reveal a pattern of hippocampal atrophy similar to that of amnestic mild cognitive impairment, while brain connectivity as found after EEG examination shows aberrant connections and local dysfunction in several network metrics in the SCD compared to HC.

Conclusions: Narrative review provided mixed evidence linking worse neuropsychological performance, brain atrophy and brain network organization in SCD compared to HC. Though there was little evidence to suggest that a particular test predisposes individuals to developing SCD, several assessments found to be promising in order to discriminate this population.

Biography:
Magda Tsolaki received her PhD, specialty as a Neuropsychiatrist. She has been a Professor of Neurology since 2010 and currently she is the Head of the 1st University Department of Neurology (2017-2020) where she was committed to her clinical, educational and research work. Since November 2020 she is working also at Euromedica General Clinic. In 2004, she was invited as a visiting professor at the Boston University, Massachusetts, USA. She has founded the Greek Alzheimer Association in 1995 and the Greek Federation of Alzheimerʼs Disease (AD) in 2007, in which she is up to today the Chair, while also being the scientific director of two Public Dementia Units (founded by her in 2007 and 2009) for outpatients. The last five years she was invited to join as a member the Greek National Observatory for Dementia. She has given more than 516 lectures throughout Greece. She has participated in more than 60 funded research programmes and 31 funded clinical trials. In total, she has received 70 awards. Dr. Magda Tsolaki has been the main author of many Books (53), many abstracts in Greek (531) and International (489) Conferences, she is the first author or co-author in many Papers in Greek (285) and International Journals (477 - 396 in PubMed), (h-index=80 and more than 30.000 Citations in Google Scholar). She has participated as invited speaker in more than 105 meetings-conferences in English and 256 in Greek Language. Furthermore, she has been a reviewer for Conferences and Journals (430) and has organised 27 national and 5 international conferences on AD. Finally, she was one of the three or seven advisory members for 32 doctoral theses-completed.

Neurological Foundations of Knowledge Representation and the Memory Capacity of the Brain

Yingxu Wang

University of Calgary, Canada

It is recognized that the natural neural networks and neuro signals in the nerves systems embody the structural and functional representations of human abstraction power and consciousness. This keynote presents a Neural Circuit (NC) theory [1] and the Spick Frequency Modulation (SFM) theory [2] for explaining the cognitive mechanism of neurology. The former denotes the structural models of neurology and the space-divided semantics of neural pathways. The latter decodes the functional models of the time-divided neural signals for representing the quantification of neuroinformatics. Both NC and SFM theories provide a formal model for neuroinformation representation, transmission, processing, memorization, retrieval and reasoning [3].

The neurological foundation of knowledge science [4] not only explains the human abstraction and quantification mechanisms for knowledge representation via neurol structures, but also reveals the mechanisms of the sixth yet the most important form of human and machine learning for knowledge acquisition, which is fundamentally different from traditional aggressive learnings for pattern regression in AI. The myth about the potential capacity of human memory is quantitively revealed based on the properties of neural networks in the brain. It leads to the clarification of how the four-level cognitive entities in the brain, i.e., data, information, knowledge and intelligence are inductively aggregated from the bottom up. It becomes a common neurological foundation for enabling highly autonomous systems [5] for cognitive robots, cognitive computers and human intelligence augmentation systems in the era from information revolution to intelligent revolution.

[1] Y. Wangand G. Fariello (2012), On Neuroinformatics: Mathematical Models of Neuroscience and Neurocomputing, Journal of Advanced Mathematics and Applications, 1(2), 206-217.

[2] Y. Wang, Keynote: Latest Advances on Theory of Spike Frequency Modulation (SFM) in Neuroinformatics, 22nd International Conference on Neurology & Neurophysiology (ENʼ18), Rome, Italy, April 23-25, pp. 38.

[3] Y. Wang(2011), Towards the Synergy of Cognitive Informatics, Neural Informatics, Brain Informatics and Cognitive Computing, International Journal of Cognitive Informatics and Natural Intelligence, 5(1), 75-93.

[4] Y. Wang (2017), Keynote: Cognitive Foundations of Knowledge Science and Deep Knowledge Learning by Cognitive Robots, IEEE 16th Intʼl Conf. on Cognitive Informatics & Cognitive Computing (ICCI*CCʼ17), Univ. of Oxford, UK, July, p.4.

[5] Y. Wang, M. Hou, K.N. Plataniotis, S. Kwong, H. Leung, E. Tunstel, I.J. Rudas and L. Trajkovic (2021), Towards a Theoretical Framework of Autonomous Systems Underpinned by Intelligence and Systems Sciences, IEEE Journal of Automatic aSinica, 8(1):52-63.

Biography:
Yingxu Wang is a professor of cognitive systems, brain science, software science and intelligent mathematics. He is the Founding President of International Institute of Cognitive Informatics and Cognitive Computing (ICICC). He is FIEEE, FBCS, FICICC and FWIF. He has held visiting professor positions at Univ. of Oxford (1995, 2018-22), Stanford Univ. (2008, 16), UC Berkeley (2008) and MIT (2012). He received a PhD in Computer Science from the Nottingham Trent University, UK in 1998 and has been a full professor since 1994. He is the founder and steering committee chair of IEEE Intʼl Conference Series on Cognitive Informatics and Cognitive Computing (ICCI*CC) since 2002. He is founding Editor-in-Chiefs of Intʼl Journal of Cognitive Informatics & Natural Intelligence (IJCINI), of Software Science & Computational Intelligence (IJSSCI), of Advanced Mathematics and Applications (JAMA) and of Mathematical & Computational Methods (IJMCM). He is an Associate Editor of IEEE Trans. on Systems, Man and Cybernetics-Systems (TSMC-Systems), Cognitive and Development Systems (TCDS) and SMCM and the IEEE Computer Society Representative to the steering committee of TCDS. He is Chair of IEEE SMCS TC-BCS on Brain-inspired Cognitive Systems and Co-Chair of IEEE CS TC-CLS on Computational Life Science. He is an IEEE FDC Steering Board Member on Symbiotic Autonomous Systems Initiative and members of the IEEE Brain and SPS Autonomous Systems Initiatives. He has published 530+ peer reviewed papers and 36 books. He has presented 58 invited keynote speeches in international conferences. He has served as honorary, general and program chairs for 38 international conferences. He has led 10+ international, European and Canadian research projects as PI. His h-index is 53 with 15,238+ citations. He is recognized by Research Gate as among the top 2.5% scholars worldwide with a 46.9 RG score and 328,000+ reading-index.