The current clinical study demonstrates the viability of EEG as a biomarker and with results consistent with previous experimental results. The combined method of machine learning and electroencephalography offers promising results for future developments of personalized pain treatment.

BackgroundExperimental models have been used extensively to evaluate pain using e.g., visual analogue scales or electroencephalography (EEG). Stimulation using tonic pain has been shown to better mimic the unpleasantness of chronic pain, but has mainly been evoked by non-clinical stimuli. This study aims to, evaluate the EEG during clinical pain in patients scheduled for total hip replacement with control and resting conditions.MethodsThe hip scheduled for replacement was moved by the examiner to evoke pain for 30 seconds while recording EEG. The control condition entailed movement of the opposite hip in a similar fashion and holding it for 30 seconds. In addition, EEG was recorded during the resting condition with open eyes. The relative spectral content was calculated from the EEG as well as functional connectivity using phase-lag index for frequency bands delta (1–4Hz), theta (4–8Hz), alpha (8–12Hz) and beta (12–32Hz). A mixed model was used for statistical comparison between the three recording conditions.ResultsSpectral content differed between conditions in all bands. Functional connectivity differed in delta and theta frequency bands. Post-hoc analysis revealed differences between the painful and control condition in delta, theta and beta for spectral content. Pain during the hip rotation was correlated to the theta (r = -0.24 P = 0.03) and beta (r = 0.25 P = 0.02) content in the EEG.ConclusionEEG differences during hip movements in the affected and unaffected hip appeared in the spectral beta and theta content. This was correlated to the reported pain perceived, pointing towards pain specific brain activity related to clinical pain.

Current practice of pediatric pain management varied widely and the recommendations of guidelines, like regular pain management, were frequently not met. However, improvements could be observed since 1999, for example, an increase in regular pain measurements (4% vs 67%). Furthermore, pain management in hospitals running a pediatric department had a higher degree of organization, and more sophisticated analgesic techniques.

Content, structure and type of the evaluated treatment standards showed a considerable heterogeneity with respect to the availability of rescue and baseline medication. Safety aspects were not addressed in many cases. These findings show that despite the requirements of the German guidelines for treatment of perioperative and posttraumatic pain for treatment standards, there are still no practical recommendations with respect to contents and structure of such standards.

This is the first analysis of a large sample of standardized protocols for acute pain management focusing on the degree of organization and the possible influence on courses of action. The analysis shows how different the structures and presumably the practical objectives of the various concepts are. The analyzed protocols with a lower degree of organization can manage only the assignment of a particular medication to the corresponding patient group, with a presumably high requirement for considerable implicit knowledge of the responsible employees. Accordingly, a requirement for such protocols should be that they not only describe the preferred standard therapy, but also define the interactions between the staff members involved. It remains questionable whether a protocol with a low level of organization and a comparably high requirement for implicit knowledge and individual action--also from nonmedical personnel--is able to ensure efficient pain therapy, particularly in view changing staff and dynamic responses to changing pain situations.