Analgesia Nociception Index: Heart Rate Variability Analysis of Emotional Status.

Background Analgesia nociception index (ANI) has been developed for real-time pain measurement during a surgical procedure under general anesthesia. The index is based on heart rate variability and constitutes a measure of parasympathetic tone. In this paper, we hypothesized that this index could be used as a tool to investigate the process of emotional regulation of a human subject. Materials and methods Twenty adult volunteers were recruited for the study, wherein ANI response to the emotional stimulus was evaluated. An emotional stimulus was obtained through a 60-second music sound record from the song "Ala Gözlerini Sevdiğim Dilber," performed by the Turkish rock band Badem. ANI measurements were obtained before the song presentation (Tpre), at the end of the record presentation (T0), and each minute thereafter until the end of the five-minute observation (T1-T5). Results Twenty participants were investigated; 10 males and 10 females. The mean age of the participants was 17.0 ± 0.9 (min: 16, max: 20). ANI measurements were significantly lower in T0 and T3 compared with Tpre (P = 0.009). The differences between other values were not statistically significant. Conclusion ANI can be used for assessment of parasympathetic changes related to the emotional state of conscious patients.