Background: Brain injury is the primary cause of mortality and morbidity in resuscitated cardiac arrest. This abstract describes a planned study designed to provide detailed and longitudinal information on cognition after out-of-hospital cardiac arrest (OHCA) and its relationship to associated factors as emotional function, fatigue, and sleep. There is a lack of longitudinal studies examining several cognitive domains post-cardiac arrest. A secondary aim is to utilize this information to validate a neurocognitive screening battery used 6 months after OHCA in the large pragmatic Target Temperature Management 2 Trial (TTM2-trial), assessing effectiveness of controlled hypothermia after OHCA. This screening battery could be practical to include in routine follow-up.

Methods/design: This longitudinal multi-center clinical study is a sub-study of the TTM2-trial. Approximately 7 and 24 months after OHCA, survivors (n≈100) at selected study sites will perform a standardized neuropsychological assessment including performance-based tests of cognition and questionnaires of behavioral and emotional function, fatigue, and insomnia. At 1:1 ratio, a control group of myocardial infarction (MI) patients but no occurrence of cardiac arrest will be recruited and perform the same test battery. Group differences at 7 and 24 months will be analyzed per cognitive domain (verbal, visual/constructive, short-term working memory, episodic memory, processing speed, executive functions). Results of the OHCA survivors on the TTM2 neurocognitive screening battery will be compared with neuropsychological test results at 7 months time. This study starts in summer 2018. OHCA and MI patients are adjacently included.

Conclusion: This sub-study of the TTM2-trial will provide detailed knowledge on cognitive impairment from a holistic perspective after OHCA. This, along with validating the shorter neurocognitive screening used in the main TTM2-trial, will make unique and important information available that may be used to guide clinical trials, inform patients and families, and design rehabilitation programs.

2 - Neuropsychological outcome after cardiac arrest: Rationale and description of a sub-study of The Target Temperature Management 2 Trial