Browsing by Subject "EEG"

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.