Complexity modulation in heart rate variability during pathological mental states of bipolar disorders

This study reports on a Multiscale Entropy (MSE) analysis on Heart Rate Variability (HRV) series gathered from eight patients with pathological mental states. Specifically, we found that an HRV complexity modulation exists in bipolar patients who exhibit mood states among depression, hypoma-nia, and euthymia, i.e., good affective balance. Two different methodologies for the choice of the sample entropy radius value were also compared. MSE analysis was performed on long-term night recordings acquired using a comfortable sensing t-shirt with integrated fabric electrodes and sensors developed in the frame of the European project PSYCHE. As the current clinical practice in diagnosing patients affected by psychiatric disorders such as bipolar disorder is only based on verbal interviews and scores from specific questionnaires, these findings increase the reliability of using heartbeat complexity as a more objective clinical biomarkers for bipolar disorders.