DISCUSSION
cognitive impairment, fatigue, stroke, POCD, dementia, cognitive failures
STROKE
Our key findings were beneficial effects 3 months after discharge from rehabilitation in several health‐related quality‐of‐life domains. These have been found in role limitations due to emotional problems, energy and fatigue, social functioning, the average of all SF‐36 factors, health change from the past year to the present time, and the mental component summary. The treatment success of cardiac surgery is potentially based on the objective clinical or physiological status. The subjective patient‐centered changes (physical and psychological) seem to be important as well and may especially contribute to the treated patient's quality of life (Koch et al, A computerized approach has shown enhancements for health‐related quality of life after postoperative cognitive training, which is in line with our results (Ajtahed et al., Cognitive abilities were evaluated as an additional outcome in this study because they contribute substantially to independence, personality, and self‐image for elderly patients, and also represent another important factor of health‐related quality of life. In the present investigation, the subjective assessment of cognitive failures in everyday living has not shown a difference between the groups. Therefore, we assumed that the CFQ‐questionnaire might not be sensitive enough to reveal alterations from the cognitive training. There is evidence that subjective assessments of cognitive ratings are unrelated to objective testing of cognitive performance (Brück et al., Nevertheless, we have shown that cognitive training is associated with psychometrically confirmed improvements in postoperative cognition (Butz et al., A few limitations should be mentioned. First, a comparison with patients without the use of an ECC or a healthy control cohort does not seem possible, as we only examined patients who had been operated with ECC. Related to the results reported here and a previously published article concerning the objectively determined frequency of POCD (Butz et al., Since our training concept was able to decrease POCD or maintain and improve health‐related quality of life after cardiac surgery, it could also be useful for noncardiac surgery patients potentially affected by POCD. In general, it may also be beneficial for patients suffering cognitive impairment after stroke or in the context of dementia. In addition, our concept is designed to be continued in an ambulatory setting after clinical implementation (e.g., in a home‐based environment) or performed in a home‐based setting prior to surgery that has the potential to impair cognition. Preoperative cognitive training might build up a so‐called cognitive reserve, which could provide prophylactic protection of the brain (Saleh et al., 