Possibilities and prospects for assessing pain nociception in patients with chronic disorders of consciousness

The objective was to study the possibilities of assessing pain nociception in patients with chronic disorders of consciousness (CDC) using the ANI index and to identify differences depending on the level of CDC, to create systems for objectification of pain sensations of patients with CDC. Materials and methods. The study included 29 patients with CDC. Group 1 (9 patients) – vegetative state / unresponsive wakefulness syndrome (VS/UWS), group 2 (20 patients) – minimally conscious state (MCS) – “plus”. The pain stimulus (PS) consisted in pressing on the nail phalanx of the hand with a reflex hammer. The ANI index was recorded three times: at rest (ANI 1), during the application of PS (ANI 2), 30 minutes after the application of PS (ANI 3). The assessment on the pain scale (NCS-R) was performed once during the application of PS. Statistical processing was carried out using the R programming language, a package of applied statistical programs SPSS STATISTICS.Results. The average values of the index difference ANI 2 and ANI 1 in group 1 differed, ANI 2 – ANI 3 had no differences. The average values of the ANI 3 index in groups 1 and 2 differed statistically significantly. A rank correlation between the ANI index and the NCS-R score existed in group 1 in the period after the application of BS. A statistically significant negative correlation was found in group 1 during the application of BS. When comparing the ANI index and the difference between the CRS-R index at discharge and admission, it was found that in group 2, the greater the difference between the CRS-R index at discharge and admission, the lower the value of the ANI index at all stages of the study, and in group 1 the opposite relationship was obtained. In group 1, there was a statistical relationship between the Kerdo index (IR) and the difference between the indices ANI 2 and ANI 1, ANI 2 and ANI 1 and IR, for group 2, the relationship could not be established.Conclusion. The data obtained during the study indicate that there are certain differences in the response to PS in patients in the VS / UWS and MCS ≪plus≫. Сreation of systems for objectification of pain sensations of patients in the VS / UWS will contribute to improving their quality of life.