Browsing by Subject "EEG"
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(2022)Objectives. Some patients with impaired consciousness exhibit no behavioural signs of subjective consciousness, but are able to communicate covert consciousness as observed by brain imaging methods. Behavioural assessment, such as GCS, doesn’t take covert consciousness into account, so it might not fully represent a patient’s state. Paradigms concerning covert consciousness have been researched with chronic disorders of consciousness (DOC) but there is less information about them in intensive care unit. Accurate assessment of consciousness is important at an early phase of DOC because the diagnosis impacts rehabilitation and care. Urgent clinical decisions concerning continued life support are also mostly made during intensive care. The aim of this review is to evaluate paradigms assessing covert consciousness in ICU, the correlation between early covert consciousness and examine ethical considerations brouht up by these methods. Methods. Because of their availability, reviewed brain imaging techniques were limited to EEG and fMRI. Articles included in this review were found from scientific databases (Scopus, Pubmed) using terms ”disorder of consciousness”, ”covert consciousness” or ”covert awareness”, ”EEG” or ”fMRI” or ”brain imaging” or ”neuroimaging” and ”icu” or ”intensive care unit”. In addition to studies, reviews concerning ethical challenges and clinical usage were included. Results and conclusions. Paradigms used to assess covert consciousness were suitable to use with ICU patients, and discovered signs of it in patients without behavioural evidence of consciousness. Both EEG- and fMRI-based techniques were successful in assessing cognitive motor dissonance (CMD) and higher-order cortex motor dissociation (HMD). CMD provides most sound evidence of covert consciousness, but HMD indicates intact higher cognitive fuctions. Results concerning correlation between CMD and prognosis a year after injury were inconsistent. Notable ethical considerations with covert consciousness in ICU include uncertainty interpreting results, communication with patients’ loved ones and assessments weight in clinical decision making. For these, it is important to use brain imaging in assistance of behavioural assessment and develop an ethical framework for clinicians. In the future research it is important to utilize bigger sample sizes and consider possibilities for communication using covert consciousness.
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(2016)Models of moral judgment and decision-making are traditionally divided into rationalist and intuitionist models depending on whether moral judgments are thought to be the result of a rational reasoning process or moral intuitions. The social intuitionist model represents intuitionist models of moral judgment and suggests that moral judgments are the result of affectively based moral intuitions and that moral reasoning mainly occurs as a post-hoc rationalization. The objective of this thesis is to review recent neuroimaging studies on moral decision-making and to evaluate the validity of the social intuitionist model in that moral judgments are caused by moral intuitions and not by moral reasoning. Functional magnetic resonance imaging (fMRI) studies examining the neural correlates of moral decision-making indicate that affective processing and abstract reasoning can both result in moral judgments. Brain areas associated with emotion become more activated in moral personal dilemmas than in impersonal dilemmas, whereas impersonal dilemmas engage brain regions associated with working memory. In addition, utilitarian judgments made in difficult personal dilemmas depend more on brain areas associated with cognitive conflict monitoring and cognitive control compared with deontological judgments. Electroencephalographic (EEG) studies support the idea that moral intuitions arise early in the decision-making process. However, affective processing may begin even in the later stages of moral decision-making after moral intuitions have been initiated, thus questioning the role of emotion in moral intuitions. The social intuitionist model has both gained support and been criticized. In the light of neuroimaging studies, it appears that moral reasoning has a more significant role in moral judgments than assumed in the model. In addition, moral intuitions may not be affectively based as assumed in the social intuitionist model. It might be necessary to update the model regarding the role of reasoning in moral judgments and the relationship between emotion and moral intuition. In the future, more comparable experimental designs should be employed to make the comparison of the variety of neuroimaging studies more sensible.
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(2024)Tiivistelmä: Tavoitteet: Vaikka unien näkemistä on tutkittu laajalti, luotettavia unien näkemistä ennustavia elektrofysiologisia tekijöitä ei toistaiseksi ole tunnistettu. Myös unien näkemiseen ja niiden muistamiseen liittyvien prosessien mahdolliset eroavaisuudet ovat pitkälti tuntemattomia. Tämän kirjallisuuskatsauksen tarkoituksena oli selvittää, minkälaiset tekijät aivojen sähköfysiologiassa vaikuttavat unien raportoimiseen sekä kartoittaa, onko aivojen unenaikaisesta aktiivisuudesta mahdollista tunnistaa nimenomaan unien muistamisen kannalta keskeisiä prosesseja. Menetelmät: Tähän integratiiviseen kirjallisuuskatsaukseen sisällytettiin tutkimuksia, jotka käsittelevät unien näkemiseen ja raportoimiseen liittyviä aivojen elektrofysiologisia tapahtumia sekä REM- että NREM-unen aikana. Katsaukseen valittiin ainoastaan terveillä koehenkilöillä tehtyjä tutkimuksia. Tutkimuksia etsittiin sekä PubMed- ja Google Scholar -tietokannoista että aiheeseen liittyvien artikkeleiden lähdeluetteloista. Tulokset ja johtopäätökset: Tutkimuskirjallisuudessa unien raportoimisen on havaittu olevan yhdenmukaisimmin yhteydessä matalataajuisen aktiivisuuden vähenemiseen, korkeataajuisen aktiivisuuden lisääntymiseen sekä EEG-synkronian vähenemiseen. Tutkimusnäyttö aiheesta on kuitenkin osin ristiriitaista, eivätkä kaikki tutkimukset ole onnistuneet tunnistamaan unien näkemisen elektrofysiologisia korrelaatteja. Vaikka tutkimuskirjallisuudessa ei ole juurikaan eroteltu unien näkemiseen liittyviä prosesseja niiden muistamiseen liittyvistä prosesseista, vaikuttaa siltä, että temporaali- ja frontaalialueiden aktiivisuus on keskeistä nimenomaan unimuistojen muodostumisen ja tallentamisen kannalta. Unien tutkimiseen liittyy laajoja metodologisia eroavaisuuksia ja rajoitteita, joiden huomioiminen on keskeistä tulevaisuuden tutkimuksissa.
Now showing items 1-3 of 3