Clustering of indicators of the cognitive status in cardiac surgery patients to assess the risk of postoperative decline

Abstract

The aim of the study. To determine the informational value of psychometric indicators used for the integral assessment of cognitive status in cardiac patients, and to find those that would help differentiate the individual sensibility to postoperative cognitive dysfunction (POCD).Materials and methods. The clustering methods were analyzed the extended psychometric testing data in 256 cardiac surgery patients. The psychometric testing carried out 3–5 days before and on days 7–10 after surgery using the psychophysiological complex program “Status PF”.Results. The cluster analysis revealed that the most informative tests for a screening risk assessment of POCD are the testing the speed of response to visual stimuli with feedback of changes in the stimuli exposition according to the individual reaction time and the testing short-term memory (memorized words). While the analysis of postoperative psychometric indicators, the patients in a modified clustering group were characterized by a deterioration of verbal memory and a decrease of the time reaction to visual stimuli whereas that its observed acceleration in the general “stable” group.Conclusion. The clustering methods enabled the identification of cardiac surgery patients in the preoperative stage who had less cognitive reserve for recovery after surgery. The changes in the relationship of complex visual and motor response, attention, and memory indicators, which depended on the belonging to the identified clusters, suggest that the preoperative period is characterized by the dedifferentiation of cognitive functions indicating a cognitive deficit.