Cognitive impairments and subjective cognitive complaints after survival of cardiac arrest: a prospective longitudinal cohort study

BACKGROUND: Cardiac arrest can lead to hypoxic brain injury, which can affect cognitive functioning.

OBJECTIVE: To investigate the course of objective and subjective cognitive functioning and their association during the first year after cardiac arrest.

METHODS: A multi-centre prospective longitudinal cohort study with one year follow-up (measurements at two weeks, three months and one year). Cognitive functioning was measured with a neuropsychological test battery and subjective cognitive functioning with the Cognitive Failures Questionnaire.

RESULTS: 141 cardiac arrest survivors participated. Two weeks post cardiac arrest 16% to 29% of survivors were cognitively impaired varying on the different tests, at three months between 9% and 23% and at one year 10% to 22% remained impaired with executive functioning being affected most. Significant reduction of cognitive impairments was seen for all tests, with most recovery during the first three months after cardiac arrest. Subjective cognitive complaints were present at two weeks after cardiac arrest in 11%, 12% at three months and 14% at one year. There were no significant associations between cognitive impairments and cognitive complaints at any time point.

CONCLUSIONS: Cognitive impairments are common in cardiac arrest survivors with executive functioning being mostly affected. Most recovery is seen in the first three months after cardiac arrest. After one year, a substantial number of patients remain impaired, especially in executive functioning. Because of absence of associations between impairments and complaints, cognitive testing using a sensitive test battery is important and should be part of routine follow-up after a cardiac arrest.