Simple and choice reaction times are prolonged following extracorporeal circulation: a potential method for the assessment of acute neurocognitive deficit
Zeno Ajtay, Lorand Kellenyi, Laszlo Hejjel, Andor Solymos, Adam Nemeth, Imre Bartfai, Norbert Kovacs, Attila Cziraki, Lajos Papp
Med Sci Monit 2009; 15(9): CR470-476
Available online: 2009-08-31
Cognitive deficit related to open heart surgery came into the focus of interest according to professional and social expectations. The negative effects on quality of life and the large number of involved patients emphasize the need its investigation.
Material and Method: The bedside measurement of simple and choice reaction times (sRT and cRT) has the objectivity of cortical evoked potential analysis without the need for EEG instrumentation and laboratory. This is a functional assessment similar to neuropsychological tests, but requires a significantly shorter time and is less demanding for the patient.
Results: Fifty patients who had undergone open heart surgery were investigated. Statistically significant positive correlation of sRT and cRT prolongation and perfusion time was found. At the same time there were no statistically significant changes in mean sRT and cRT values before (sRT: 208+/-54 s, cRT: 369+/-59 s) and after (sRT: 229+/-67 s, cRT: 392+/-105 s) the surgery, probably due to the inhomogeneous patient population. The weak correlation (coefficients: 0.1418-0.8484) for sRT and cRT changes as a function of perfusion time confirms the presence of other factors of postoperative brain damage.
Conclusions: The investigated bedside test is clinically feasible, simple, and can be completed within 30 minutes. Further studies are encouraged to compare this method with other tests in a larger, stratified cardiac surgery population.
Keywords: Reaction Time - physiology, Psychomotor Performance - physiology, Point-of-Care Systems, Neuropsychological Tests, Extracorporeal Circulation - adverse effects, Cognition Disorders - physiopathology, Adult, Regression Analysis, Thoracic Surgery - methods