The identification of specific biomarkers for neurodegenerative diseases such as dementia is one of the main objectives of current clinical research, mainly because these are crucial in the early, differential diagnosis and monitoring of the disease. This study aims to evaluate and identify the relationship between blood biomarkers (e.g., IL-1B, TNF-α, AB1-40, AB 1-42) and the neuropsychological profile (e.g., memory, attention, language, executive) in dementias. A better understanding of this relationship may contribute to an early diagnosis and monitoring of the progression of dementia. In the present study, a systematic literature review was performed using PubMED, LILACS, EmBASE, BMC, CINAHL, World Wide Science e Google Scholar databases. For data collection, the PRISMA guidelines were followed. The keywords used for the research and selection of articles were: “blood-based biomarkers” OR “plasma biomarkers” OR “dementia” OR “alzheimer” OR “neuropsychological” OR “neuropsychological evaluation” OR “peripherical biomarkers” OR “TNF- α” OR “IL-1B” OR “Aβ 1-40” OR “Aβ 1-42”. Search terms were applied in different combinations. Before reading and qualitatively evaluating the articles, a selection method based on inclusion/exclusion criteria was applied. The inclusion criteria included research works and clinical cases in English. On the other hand, incomplete articles, dissertations, theses and articles that were not compatible with the topic addressed were excluded. In this sense, 10 eligible articles were found, essentially experimental, which had the collection and analysis of data related to one or more peripheral biomarkers and neuropsychological measures. In the selected articles, 80% of them showed some type of association or relationship between the cognitive variables and the analyzed biomarkers. β- amyloid (Aβ) proteins were associated with General Cognitive Decline (GCD) (30%), memory (20%), cognition and executive function (10%). Neurofilament lumen (NfL) was associated with GCD (10%), memory and language mastery (10%). P-tau was associated with memory (20%), global cognition, attention, ability; and to the domain of language and DCG (10%). The PTX3 biomarker was associated with change in cognition, decline in psychomotor speed and executive function (10%). IL-2 and IL-8 were associated with memory and language (10%). ET-1 was associated with language decline and psychomotor speed (10%). Furthermore, the assessment method “Cognitive Preclinical Alzheimer's Compound (CCPA)” was found to be better over the MMSE to verify associations with DCG and Aβ42/Aβ40. Finally, it is concluded that plasma amyloid biomarkers, tau pathology, NfL, PTX3, IL-2 and IL-8 associated with the assessment of GCD, memory and language may be indicative for early identification of dementia diseases. This research presented limitations mainly in the interpretation of the relationship between neuropsychological biomarkers and biomarkers. In the analysis of the different studies, it was observed that the sample size, age, race can interfere in the results, not allowing to generalize to the entire population the results that were obtained by the authors in their studies. On the other hand, and as highlighted by several authors, the heterogeneity of the sample and lack of data such as: cognitive background, lifestyle and premorbid characteristics of the participants constitutes one of the main problems for the possibility of generalizing the results.
| Date of Award | 4 Nov 2022 |
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| Original language | Portuguese |
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| Awarding Institution | - Universidade Católica Portuguesa
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| Supervisor | Carla Pais-Vieira (Supervisor) |
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