Memory Processes in Cardiac Arrest Patients

Resuscitated patients sometimes report impressions that occurred to them during cardiac arrest. Since the electrical activity of the brain stops within seconds after interruption of blood supply, the question arises how such impressions were possible. In rare cases, patients even claim to have witnessed their resuscitation from a position outside their bodies. Scientific investigations into such phenomena are rare and incomplete. We are planning to participate in an international study at 10 different hospitals. For best documentation of appropriate cases, the participating emergency units will be equipped with sensors for the registration of blood supply and electric activity in the frontal cortex, and with computer screens presenting random images out of sight of persons present in the room. This project will recruit a medical technical employee in charge for the sensors and the image presentation, while the emergency team will stay focused on the immediate life-saving procedures. If resuscitated patients later claim visual impressions, these claims can be verified by evaluating the history of images presented by the computer. Our project not only has the potential to contribute scientific data to the discussion of a controversial issue, but also to improve technical procedures accompanying cardiopulmonary resuscitation.

The KLIF453 project was designed to apply and extend locally developed techniques for the AWARE project on memories during cardiac arrest within an AWARE II follow up study. Goal was to extend the number of highly standardized patient interviews and - for the first time - try to acquire physiological data on the patients spontaneous and evoked brain function. Such data allow a first correlation of memory reports related to cardiac arrest with documentation of the brains functional state. During the project more than 100 complex data sets from cardiac arrest patients were acquired and an extended local data analysis is currently running. Further, a major novel brain stimulation technique based on ultrasound has been developed during this project to allow better investigation of evoked brain function. This technique (Transcranial Pulse Stimulation TPS) has been published in leading scientific journals and may also be used as a novel non-invasive brain therapy. Benefits have already been observed for patients with memory deficits (dementia) and motor problems (Parkinsons's).