Abstract
BackgroundThe number of patients with cognitive impairment after sepsis or septic shock is high. However, the underlying neurophysiological basis of sepsis induced cognitive impairment is not fully understood.Methods/DesignThis is a prospective, controlled observational study. We are in the process of recruiting 25 survivors of severe sepsis or septic shock who will be investigated with functional MRI (fMRI), T1-weighted MRI und Diffusion Tensor Imaging (DTI) as well as Magnetoencephalography (MEG). Furthermore, patients will undergo neuropsychological evaluation using the DemTect and the clock drawing tests. In addition, verbal and declarative memory is assessed by the Verbal Learning and Memory Test. The primary aim is to determine the volumetry of the amygdala and the hippocampus. The secondary aim is to analyze the relationship between cognitive tests and MEG, and the (f)MRI results. Moreover, a between-group comparison will be evaluated to an age-matched group of healthy controls.DiscussionIn a previous MEG study, we observed a significant slowing of the prominent background activity in sepsis survivors and hepatic encephalopathy patients in particular shortly after discharge from the ICU. Intriguingly, the rhythmic brain activity after visual flickering stimulation was altered in sepsis survivors in comparison to age-matched healthy volunteers. We propose that this desynchronization is based on affected underlying neuronal responses between various interconnected brain regions. The current project will analyze whether the modifications are related to a damage of the fibers connecting different brain regions or to a disturbance of the functional interaction between different brain regions or even due to an atrophy of certain brain regions.Trial registration“Langzeitfolgen nach schwerer Sepsis: Kognitive Beeinträchtigungen und strukturelle Veränderungen am Gehirn, eine MRT Studie”; German Clinical Trials Register (DRKS00005484).
Highlights
The number of patients with cognitive impairment after sepsis or septic shock is high
In a previous MEG study, we observed a significant slowing of the prominent background activity in sepsis survivors and hepatic encephalopathy patients in particular shortly after discharge from the Intensive care unit (ICU)
The rhythmic brain activity after visual flickering stimulation was altered in sepsis survivors in comparison to age-matched healthy volunteers
Summary
In a group of 25 sepsis survivors with long-lasting cognitive deficits after sepsis, we investigate patients’ functional status using MEG and fMRI. We showed impairments in rhythmic brain activity after visual flickering stimulation in patients with liver cirrhosis and sepsis survivors. This ability was severely impaired in patients with liver cirrhosis They showed a broader frequency band with no dynamical adaptation to the flickering stimulation (entrainment at the signal when flickering, no signal during pause) and a weaker coupling to the flickering stimulation. We suggest that the temporal coordination of neuronal responses is affected and causes a desynchronization between various interconnected brain regions This could be linked to a reduction in cerebral blood flow. In sepsis survivors, our score positively correlated to the performance in the DemTect and to the time after ICU discharge These results imply that cognitive impairments in patients after sepsis are related to a disturbed functional interaction between regions.
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