Brain Function After Cardiac Arrest (Measured With FMRI and Cognitive Tests)
Condition: Cardiac Arrest; Cognitive Function
MeSH terms: Heart Arrest
Study type: Observational

Summary: 
      The aim of this longitudinal study is to determine whether brain function is affected after a
      cardiac arrest.

      The primary question is whether cognitive function is affected after cardiac arrest and
      whether it changes over time (during the first year after the event), compared with a healthy
      control group. Brain function during cognitive tasks and emotion processing will also be
      studied using functional MRI (fMRI). Another aim is to study whether clinical outcomes such
      as PTSD, anxiety and depression can be correlated with cognitive function and whether health-
      related quality of life is affected after a cardiac arrest.

      The results from the cardiac arrest patient group will be compared with a healthy control
      group.
    

Detailed description: 
      The study is a prospective cohort study and aims to enroll 30 cardiac arrest patients and 30
      matched (regarding age, gender and level of education), healthy controls.

      Patients who are enrolled in the study will on three different occasions (in the acute phase,
      after six and after twelve months) answer questions regarding their health state and perform
      a computerized cognitive test and a behavioral test.

      Patient/ control health status will be assessed through the following tests:

        -  Cognitive function will be assessed using the Montreal Cognitive Assessment (MoCa)
           screening tool which measures attention/concentration, executive functions, memory,
           verbal skills, visual construction skills, abstract thinking, computation and
           orientation.

        -  Presence of delirium will be assessed using the Confusion Assessment Method for the
           Intensive Care Unit (CAM- ICU) and will be complemented with information from the
           patients' medical records.

        -  The Richmond Agitation - Sedation Scale (RASS) will be used to assess sedation.

        -  Health- related quality of life will be measured using the three level version of EQ-5D
           (EQ-5D-3L; Euro-Qol 5-Dimensions).

        -  A Mini International Neuropsychiatric Interview (MINI) will be performed to detect
           psychiatric syndromes (such as PTSD, anxiety and depression). Symptoms of anxiety and
           depression will also be measured using The Montgomery-Åsberg Depression Rating Scale-
           Self report (MADRS-S) and Impact of Event Scale-Revised -22. Alcohol use will be
           assessed using AUDIT (Alcohol Use Disorders Identification Test).

      Information will also be collected from the patients' medical records.

      Cognitive/ neuropsychological testing will be performed using the Cambridge
      Neuropsychological Test Automated Battery (CANTAB), which measures amongst others memory,
      planning, executive functions and attention. For this study, the following CANTAB modules
      will be used:

        -  Delayed matching to sample (DMS)

        -  Paired associate learning test (PAL)

        -  Stockings of Cambridge (SOC)/ One Touch Stockings of Cambridge (OTS)

        -  Motor Screening Task (MOT), which provides a general assessment of whether sensorimotor
           deficits or lack of comprehension will limit the collection of valid data from the
           participant.

      The tests are performed on a tablet. All task stimuli are non- verbal.

      An approach- avoidance test that measures avoidance behavior will also be performed. Patients
      will be presented with auditory and visual (pictures) stimuli and will choose whether the
      stimuli presented to them will be of a neutral or aversive character. Patients will be
      informed that choosing the aversive stimuli will reward them with a small amount of money.

      Functional magnetic resonance imaging (fMRI) will be performed six and twelve months after
      the cardiac arrest. The MRI scan will also include morphological images. The fMRI sequence
      will include tests regarding emotional activation, emotional memory and cognitive
      interference. A DMS task with emotionally loaded stimuli will be performed. Blood oxygenation
      level dependent (BOLD)- imaging will be used to produce the fMRI images, where differences in
      blood flow in different parts of the brain will be registered through echo planar imaging
      (EPI). The images will be analyzed with the Statistical Parametric Mapping (SPM)-12 program
      using MATLAB computing language.

      The healthy control group will on two occasions (with the second occasion taking place six
      months after the first) answer questions regarding their health state, perform cognitive
      testing and fMRI. The same will be assessed for the control as for the patient group, with
      the exception of CAM-ICU, RASS and information from medical records, which will not be
      included in the control group.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        The study population will consist of 30 cardiac arrest patients and 30 matched (regarding
        age, gender and educational level), healthy controls.
      
Keywords: Cardiac arrest; Cognitive impairment; Depression; Anxiety; PTSD; Health- related quality of life; functional MRI