Automated Pain Spots Recognition Algorithm Provided by a Web Service-Based Platform: Instrument Validation Study.

Background: Understanding the causes and mechanisms underlying musculoskeletal pain is crucial for developing effective treatments and improving patient outcomes. Self-report measures, such as the Pain Drawing Scale, involve individuals rating their level of pain on a scale. In this technique, individuals color the area where they experience pain, and the resulting picture is rated based on the depicted pain intensity. Analyzing pain drawings (PDs) typically involves measuring the size of the pain region. There are several studies focusing on assessing the clinical use of PDs, and now, with the introduction of digital PDs, the usability and reliability of these platforms need validation. Comparative studies between traditional and digital PDs have shown good agreement and reliability. The evolution of PD acquisition over the last 2 decades mirrors the commercialization of digital technologies. However, the pen-on-paper approach seems to be more accepted by patients, but there is currently no standardized method for scanning PDs. Objective: The objective of this study was to evaluate the accuracy of PD analysis performed by a web platform using various digital scanners. The primary goal was to demonstrate that simple and affordable mobile devices can be used to acquire PDs without losing important information. Methods: Two sets of PDs were generated: one with the addition of 216 colored circles and another composed of various red shapes distributed randomly on a frontal view body chart of an adult male. These drawings were then printed in color on A4 sheets, including QR codes at the corners in order to allow automatic alignment, and subsequently scanned using different devices and apps. The scanners used were flatbed scanners of different sizes and prices (professional, portable flatbed, and home printer or scanner), smartphones with varying price ranges, and 6 virtual scanner apps. The acquisitions were made under normal light conditions by the same operator. Results: High-saturation colors, such as red, cyan, magenta, and yellow, were accurately identified by all devices. The percentage error for small, medium, and large pain spots was consistently below 20% for all devices, with smaller values associated with larger areas. In addition, a significant negative correlation was observed between the percentage of error and spot size (R=-0.237; P=.04). The proposed platform proved to be robust and reliable for acquiring paper PDs via a wide range of scanning devices. Conclusions: This study demonstrates that a web platform can accurately analyze PDs acquired through various digital scanners. The findings support the use of simple and cost-effective mobile devices for PD acquisition without compromising the quality of data. Standardizing the scanning process using the proposed platform can contribute to more efficient and consistent PD analysis in clinical and research settings.

Identifying Weekly Trajectories of Pain Severity Using Daily Data From an mHealth Study: Cluster Analysis.

BACKGROUND: People with chronic pain experience variability in their trajectories of pain severity. Previous studies have explored pain trajectories by clustering sparse data; however, to understand daily pain variability, there is a need to identify clusters of weekly trajectories using daily pain data. Between-week variability can be explored by quantifying the week-to-week movement between these clusters. We propose that future work can use clusters of pain severity in a forecasting model for short-term (eg, daily fluctuations) and longer-term (eg, weekly patterns) variability. Specifically, future work can use clusters of weekly trajectories to predict between-cluster movement and within-cluster variability in pain severity. OBJECTIVE: This study aims to understand clusters of common weekly patterns as a first stage in developing a pain-forecasting model. METHODS: Data from a population-based mobile health study were used to compile weekly pain trajectories (n=21,919) that were then clustered using a k-medoids algorithm. Sensitivity analyses tested the impact of assumptions related to the ordinal and longitudinal structure of the data. The characteristics of people within clusters were examined, and a transition analysis was conducted to understand the movement of people between consecutive weekly clusters. RESULTS: Four clusters were identified representing trajectories of no or low pain (1714/21,919, 7.82%), mild pain (8246/21,919, 37.62%), moderate pain (8376/21,919, 38.21%), and severe pain (3583/21,919, 16.35%). Sensitivity analyses confirmed the 4-cluster solution, and the resulting clusters were similar to those in the main analysis, with at least 85% of the trajectories belonging to the same cluster as in the main analysis. Male participants spent longer (participant mean 7.9, 95% bootstrap CI 6%-9.9%) in the no or low pain cluster than female participants (participant mean 6.5, 95% bootstrap CI 5.7%-7.3%). Younger people (aged 17-24 y) spent longer (participant mean 28.3, 95% bootstrap CI 19.3%-38.5%) in the severe pain cluster than older people (aged 65-86 y; participant mean 9.8, 95% bootstrap CI 7.7%-12.3%). People with fibromyalgia (participant mean 31.5, 95% bootstrap CI 28.5%-34.4%) and neuropathic pain (participant mean 31.1, 95% bootstrap CI 27.3%-34.9%) spent longer in the severe pain cluster than those with other conditions, and people with rheumatoid arthritis spent longer (participant mean 7.8, 95% bootstrap CI 6.1%-9.6%) in the no or low pain cluster than those with other conditions. There were 12,267 pairs of consecutive weeks that contributed to the transition analysis. The empirical percentage remaining in the same cluster across consecutive weeks was 65.96% (8091/12,267). When movement between clusters occurred, the highest percentage of movement was to an adjacent cluster. CONCLUSIONS: The clusters of pain severity identified in this study provide a parsimonious description of the weekly experiences of people with chronic pain. These clusters could be used for future study of between-cluster movement and within-cluster variability to develop accurate and stakeholder-informed pain-forecasting tools.

Pain assessment tools in adults with communication disorders: systematic review and meta-analysis.

BACKGROUND: Verbal communication is the "gold standard" for assessing pain. Consequently, individuals with communication disorders are particularly vulnerable to incomplete pain management. This review aims at identifying the current pain assessment instruments for adult patients with communication disorders. METHODS: A systematic review with meta-analysis was conducted on PubMed, PEDRO, EBSCOhost, VHL and Cochrane databases from 2011 to 2023 using MeSH terms "pain assessment, "nonverbal communication" and "communication disorders" in conjunction with additional inclusion criteria: studies limited to humans, interventions involving adult patients, and empirical investigations. RESULTS: Fifty articles were included in the review. Seven studies report sufficient data to perform the meta-analysis. Observational scales are the most common instruments to evaluate pain in individuals with communication disorders followed by physiological measures and facial recognition systems. While most pain assessments rely on observational scales, current evidence does not strongly endorse one scale over others for clinical practice. However, specific observational scales appear to be particularly suitable for identifying pain during certain potentially painful procedures, such as suctioning and mobilization, in these populations. Additionally, specific observational scales appear to be well-suited for certain conditions, such as mechanically ventilated patients. CONCLUSIONS: While observational scales dominate pain assessment, no universal tool exists for adults with communication disorders. Specific scales exhibit promise for distinct populations, yet the diverse landscape of tools hampers a one-size-fits-all solution. Crucially, further high-quality research, offering quantitative data like reliability findings, is needed to identify optimal tools for various contexts. Clinicians should be informed to select tools judiciously, recognizing the nuanced appropriateness of each in diverse clinical situations. TRIAL REGISTRATION: This systematic review is registered in PROSPERO (International prospective register of systematic reviews) with the ID: CRD42022323655 .

Medición del dolor durante el trabajo de parto: evaluación de la usabilidad de un nuevo dispositivo / Pain measurement during labor: usability evaluation of a new device

Objetivo: Evaluar la usabilidad de un dispositivo para medir el dolor durante el trabajo de parto a través de siete ítems: tamaño, textura, facilidad de uso, peso, resistencia, comodidad y seguridad. Método: Estudio descriptivo. Se solicitó a 60 pacientes usar el sensor manual durante el transcurso de seis contracciones uterinas (aproximadamente 10-20 minutos) y al día siguiente se aplicó una encuesta en la que las pacientes evaluaron la usabilidad del dispositivo en cuanto a textura, peso, resistencia, comodidad, facilidad de uso, tamaño del sensor, seguridad de uso, peso del sensor, resistencia y comodidad, mediante una escala de Likert de 1 a 7. La seguridad fue evaluada con una escala de 1 a 5. Resultados: Se realizaron gráficos de caja. Con respecto a la seguridad, un 86% de las usuarias marcaron 5 puntos en la escala, percibiendo el dispositivo como seguro. Conclusiones: El dispositivo fue percibido como seguro, liviano, fácil de usar y cómodo.

Objective: To evaluate the usability of a device to measure pain during labor through seven items: size, texture, ease of use, weight, resistance, comfort, and safety. Method: Longitudinal observational study. 60 patients were asked to use the manual sensor during the course of six uterine contractions (approximately 10-20 minutes) and the following day a survey was applied where the patients evaluated the usability of the device in terms of texture, weight, resistance, comfort, easiness of use, sensor size, safety of use, sensor weight, resistance and comfort through a Likert scale from 1 to 7. Safety was evaluated with a scale from 1 to 5. Results: They were schematized with a box plot. Regarding safety, 86% of the users scored 5 points on the scale, perceiving the device as safe. Conclusions: It can be seen that the device was perceived as safe, light, easy to use and comfortable.

Reference intervals and sources of variation of pressure pain threshold for quantitative sensory testing in a Japanese population.

Quantitative sensory testing (QST) is useful when analysing musculoskeletal pain disorders. A handheld algometer is most commonly used for pressure pain threshold (PPT) tests. However, reference intervals for PPTs are not elucidated. We assessed reference intervals of PPTs for QST in 158 healthy adult Japanese with no history of musculoskeletal or neurological problems. A handheld algometer was used to record PPT at five different assessment sites on the body: lumbar paravertebral muscle, musculus gluteus maximus, quadriceps, tibialis anterior muscle, and anterior talofibular ligament. Multiple regression analysis was performed to explore sources of variation of PPT according to sex, age, body mass index, UCLA Activity Level Rating, and Tegner Activity Score. Reference intervals were determined parametrically by Gaussian transformation of PPT values using the two-parameter Box-Cox formula. Results of multiple regression analysis revealed that age was significantly associated with PPT of lumbar paravertebral muscle and musculus gluteus maximus. In females, body mass index showed significant positive correlation with PPT of anterior talofibular ligament, and UCLA Activity Level Rating also showed significant positive association with tibialis anterior muscle and anterior talofibular ligament. Site-specific reference intervals of PPTs for Japanese are of practical relevance in fields of pain research using a handheld algometer.

The usability of an AAC pain description system for patients with acquired expressive communication disorders.

Augmentative and alternative communication (AAC) has been used by patients with acquired expressive communication disorders as an alternative to natural speech. The use of symbols to express pain, which is intangible, is challenging because designing a series of comprehensible symbols to represent personal experiences such as pain is not straightforward. This study describes (a) the development of symbols to express pain that were derived from Chinese pain-related similes and metaphors for an AAC mobile application developed specifically for this study known as PainDiary and (b) an assessment of the appropriateness of the app compared to conventional methods of collecting pain information. The symbols depicted headache pain and discomfort, which is prevalent among neurosurgical patients. The participants were 31 patients diagnosed with acquired expressive communication disorders who were receiving treatment in a neurosurgery general ward of Chang Gung Memorial Hospital in Taiwan and 14 nurses who worked on the ward. Pain information was collected by nurses using conventional methods and the PainDiary app. Assessment data, including the accuracy and efficiency of and user satisfaction with PainDiary, are compared. The results show that use of the app was effective in reporting pain and that patients required less time to report a pain event. The results further indicate that the PainDiary app was better received by younger individuals than by their older counterparts.

Efficacy of Buccal Infiltration with or without Palatal Injection for Posterior Maxillary Teeth Extraction - A Split-Mouth Randomized Trial

ABSTRACT Objective: To evaluate the feasibility of posterior maxillary teeth extraction buccal infiltration with or without the use of palatal injection. Material and Methods: A total of 70 patients underwent extraction of bilateral maxillary posterior teeth under 2% lignocaine hydrochloride with 1:2,00000 adrenaline infiltration in this single-centric split-mouth randomized trial. The test side was administered with a buccal infiltration of 2 mL of anesthetic alone. An extended waiting period of 10 minutes was given before the commencement of the procedure. A standard protocol was followed for the control side. A single operator performed all extractions. Results: A total of 140 posterior maxillary teeth were extracted. Patients marked pain perception on a visual analogue scale in three different instances. During the administration of injections for the test side, the pain score was less than that of the control side and was statistically significant. The overall pain during the extraction procedure was comparable and statistically insignificant. The overall success of the method was 90%. Conclusion: Extraction of posterior maxillary teeth was feasible with a single buccal infiltration without palatal injection in most cases using an extended waiting period. Dentists can attempt extraction without palatal injections with optimal success. However, the alternate technique could be used when there is a necessity for rescue palatal anesthesia.

Subgrouping of Peripheral Neuropathic Pain Patients According to Sensory Symptom Profile Using the Korean Version of the PainDETECT Questionnaire.

BACKGROUND: A culturally validated Korean version of the PainDETECT Questionnaire (PD-Q) was used to identify neuropathic pain components (NeP) in patients suffering from chronic pain. The purpose of this study was to determine if the Korean PD-Q can be used to subgroup patients with peripheral NeP according to sensory symptom profiles. METHODS: This study included 400 Korean patients with peripheral neuropathic pain diagnosed as probable or definite NeP. The total scores and subscores for each item in PD-Q were transformed into a Z-score for standardization. Hierarchical cluster analysis was performed to identify clusters of subjects by PD-Q scores. RESULTS: The mean total PD-Q score of the study participants was 14.57 ± 6.46. A hierarchical cluster analysis identified 5 clusters with distinct pain characteristic profiles. Cluster 1 had relatively severe burning and tingling sensations. The mean total PD-Q score for cluster 2 was the lowest of the 5 clusters. Cluster 3 tended to be vulnerable to pain in response to cold/heat stimulation. Cluster 4 showed relatively severe pain induced by physical stimuli, such as light touch or slight pressure. Cluster 5 had high scores for all NeP symptoms. CONCLUSION: This study demonstrates the ability of patients to cluster by symptoms using the Korean PD-Q. Subgrouping of peripheral neuropathic pain by sensory symptom profile may be useful in making effective drug treatment decisions.

Pain Perception Associated with Mini-Implants and Interventions for Pain Management: A Cross-Sectional Questionnaire-Based Survey.

BACKGROUND: Orthodontists use mini-implants temporarily as an effective mode of skeletal anchorage devices. The placement of mini-implants can cause pain and discomfort to the patients. Patients often develop swelling, and the pain could interfere with their daily activities. Practitioners tend to prescribe antibiotics and pain medication for management. OBJECTIVES: The main objectives of this study are to evaluate the pain perception and discomfort due to mini-implant placement experienced by the patient and evaluate the interventions for pain management commonly practiced among orthodontists. MATERIALS AND METHODS: The study was designed as a questionnaire-based cross-sectional study. A total of 271 patients were assessed, for whom 625 mini-implants (ranging from 1.2 to 2 mm diameter and length 8-14 mm) were placed. Pain scores were assessed using the VAS and the "Faces" pain rating scale to collect data about discomfort in daily activity and function. Data was collected from 244 patients. A total of 155 orthodontists were questioned regarding the prescription of medications and the interventions for managing pain and adverse effects. RESULTS: Average pain score among female subjects was 16.71 and among men was 13.5. The highest pain scores were recorded for palatal mini-implants with an average score of 36.29 and the least for interradicular mini-implants with an average score of 9.02. Among the subjects, 47.9% of them took analgesics, and the most commonly prescribed analgesics were paracetamol (39%). Swelling at the site is where the mini-implants were placed, and ulceration due to implants were commonly dealt with the excision of the surrounding soft tissue, composite placement, and palliative care with oral analgesic gels. CONCLUSION: Female subjects had more mini-implants placed, and female subjects had also given more pain scores than their male counterparts. Palatal mini-implants caused the highest pain, followed by mini-implants placed at the infrazygomatic crest and the buccal shelf region. Palatal mini-implants caused maximum discomfort during speech and eating, followed by the mini-implant in the buccal shelf and the infrazygomatic crest region that also caused difficulty in yawning and laughing. Infiltration anesthesia was commonly given for the placement of interradicular implants and extra-alveolar mini-implants. Paracetamol was the most prescribed by the orthodontists, and more than half the doctors did not regularly prescribe antibiotics.

An Artificial Mechano-Nociceptor with Mott Transition.

Intelligent touch sensing is now becoming an essential part of various human-machine interactions and communication, including in touchpads, autonomous vehicles, and smart robotics. Usually, sensing of physical objects is enabled by applied force/pressure sensors; however, reported conventional tactile devices are not able to differentiate sharp and blunt objects, although sharp objects can cause unavoidable damage. Therefore, it is central issue to implement electronic devices that can classify sense of touch and simultaneously generate pain signals to avoid further potential damage from sharp objects. Here, concept of force-enabled nociceptive behavior is proposed and demonstrated using vanadium oxide-based artificial receptors. Specifically, versatile criteria of bio-nociceptor like threshold, relaxation, no adaptation, allodynia, and hyperalgesia behaviors are triggered by pointed force, but the device does not mimic any of these by the force applied by blunt objects; thus, the proposed device classifies the intent of touch. Further, supported by finite element simulation, the nanoscale dynamic is unambiguously revealed by conductive atomic force microscopy and results are attributed to the point force-triggered Mott transition, as also confirmed by temperature-dependent measurements. The reported features open a new avenue for developing mechano-nociceptors, which enable a high-level of artificial intelligence within the device to classify physical touch.

Available Instruments to Assess Pain in Infants.

Pain assessment in newborns and infants is challenging for clinicians. Although behavioral and behavioral-physiological scales are validated pain assessment instruments, their use in this age group has significant limitations. In this review, we summarize the methods currently available for assessing pain in neonates and infants. It is possible that these pain detection methods are also useful for assessing the quality of anesthesia and analgosedation in these populations. Further research should be aimed at confirming the usefulness of these tools in infants and identifying additional pain assessment options for clinical practice.

TailTimer: A device for automating data collection in the rodent tail immersion assay.

The tail immersion assay is a widely used method for measuring acute thermal pain in a way which is quantifiable and reproducible. It is non-invasive and measures response to a stimulus that may be encountered by an animal in its natural environment. However, quantification of tail withdrawal latency relies on manual timing of tail flick using a stopwatch, and precise temperatures of the water at the time of measurement are most often not recorded. These two factors greatly reduce the reproducibility of tail immersion assay data and likely contribute to some of the discrepancies present among relevant literature. We designed a device, TailTimer, which uses a Raspberry Pi single-board computer, a digital temperature sensor, and two electrical wires, to automatically record tail withdrawal latency and water temperature. We programmed TailTimer to continuously display and record water temperature and to only permit the assay to be conducted when the water is within ± 0.25°C of the target temperature. Our software also records the identification of the animals using a radio frequency identification (RFID) system. We further adapted the RFID system to recognize several specific keys as user interface commands, allowing TailTimer to be operated via RFID fobs for increased usability. Data recorded using the TailTimer device showed a negative linear relationship between tail withdrawal latency and water temperature when tested between 47-50°C. We also observed a previously unreported, yet profound, effect of water mixing speed on latency. In one experiment using TailTimer, we observed significantly longer latencies following administration of oral oxycodone versus a distilled water control when measured after 15 mins or 1 h, but not after 4 h. TailTimer also detected significant strain differences in baseline latency. These findings valorize TailTimer in its sensitivity and reliability for measuring thermal pain thresholds.

Effectiveness of Mobilization with Movement on the Management of Knee Osteoarthritis: A Systematic Review of Randomized Controlled Trials.

Background: Osteoarthritis is becoming a global major cause of pain and functional disability worldwide, especially in the elderly population. Nowadays, evidence shows that mobilization with movement (MWM) has a beneficial effect on knee osteoarthritis subjects. However, its adequacy remains unclear. Objective: To review the best available evidence for the effectiveness of MWMs on pain reduction and functional improvement in patients with knee osteoarthritis. Methods: A comprehensive search of literature was conducted using the following electronic databases: Google Scholar, PubMed, Physiotherapy Evidence Database (PEDro), Science Direct, Cochrane Library, and Scopus. Only randomized controlled trials (RCTs) were included, and the methodological quality of the studies was appraised using the PEDro scale. It was reported according to the guideline of the PRISMA statement. Results: A total of 15 RCTs having 704 participants were included. The present systematic review suggests that there were significant differences between MWM groups and control groups in terms of visual analogue scale (VAS), Western Ontario and MacMaster Universities Osteoarthritis Index (WOMAC) scale, and flexion range of motion. Conclusions: This systematic review demonstrated that MWM was effective to improve pain, range of motion, and functional activities in subjects with knee osteoarthritis.

Measurement properties of pain scoring instruments in farm animals: A systematic review protocol using the COSMIN checklist.

Society has been increasingly concerned about the impact of pain on farm animal welfare. This systematic review aims to provide evidence relating to the measurement properties (i.e. reliability, validity, and sensitivity) of pain scoring instruments used for pain assessment in farm animals. A literature search will be performed using five databases (MEDLINE, EMBASE, Web of Science, CAB abstracts and Biological Abstracts) and search terms related to pain, pain scales and different species of farm animals. Eligibility criteria will include full-text studies on the development and/or validation of acute and chronic pain scoring instruments for farm animals including bovine (beef and dairy), ovine, caprine, camel, swine and poultry. Exclusion criteria will include studies that report the use of pain scales for the validation of another instrument, or those reporting ethograms/list of behaviors potentially indicating pain without a scoring system. Study titles and their abstracts will be screened for eligibility by one investigator. Full-text articles will be independently reviewed for eligibility and evaluated by two investigators. Relevant information will be recorded and evaluated systematically according to the Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) checklist using an adapted data collection sheet. The following measurement properties and characteristics of the instruments will be assessed: content validity (internal consistency, structural and cross-cultural validity), reliability, measurement error, criterion and construct validity, responsiveness, interpretability and feasibility. Following the assessment of methodological quality and quality of the findings, evidence for each measurement property will be summarized into high, moderate, low or very low. This systematic review will provide further insights into the evidence-based measurement properties of pain scoring instruments in farm animals. It may identify possible gaps of knowledge with these tools as a potential target for future studies in farm animals with a positive impact on animal welfare.

Cross Cultural Adaptation and Validation of Italian Version of the Leeds Assessment of Neuropathic Symptoms and Signs Scale and Pain DETECT Questionnaire for the Distinction between Nociceptive and Neuropathic Pain.

Objective: This study aimed to validate Italian versions of Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) scale and Pain DETECT questionnaire (PD-Q) and evaluate the ability of these questionnaires to discriminate between nociceptive and neuropathic pain. Design: Multicenter prospective validation cohort study. Subjects and Setting. One hundred patients were included with a diagnosis formulated by a specialist in outpatient settings (50 affected by knee osteoarthritis as nociceptive pain and 50 affected by trigeminal or postherpetic neuralgia as neuropathic pain). Methods: The Italian versions of both questionnaires according to Italian cultural characteristics were performed according to the following steps: (1) translation of the questionnaires from English into Italian; (2) review by a bilingual individual for consistency; (3) proposed version after a mail round between experts; (4) backward translation; (5) comparison with the original English version by the experts; (6) approved version of the questionnaires. One hundred patients were enrolled and completed the two questionnaires administered by a specialist or blinded nursing staff, at the baseline and after 24/48 hours. Internal consistency, stability, validity, and discriminative power were analyzed. Results: Statistically significant differences were reported about the ability of both questionnaires to discriminate between patients affected by neuropathic or nociceptive pain. Internal consistency for the Italian version of the LANSS was 0.76, and for PD-Q, it was 0.80, assessed by Cronbach's α; LANSS showed a good test-retest reliability with an ICC of 0.76, and PD-Q showed a high test-retest reliability with an ICC of 0.96. For interrater reliability, there was a concordance rate of 83.3% between reference diagnosis and LANSS (Cohen's kappa = 0.67, CI 95% 0.52-0.75). Conclusions: This study validated the Italian versions of LANSS and PD-Q as reliable instruments with good psychometric characteristics, for pain evaluation, discriminating between nociceptive and neuropathic pain. Our findings were similar to those observed in the original study. Furthermore, we have reported the test-retest reliability for both questionnaires, not addressed in original validation studies.

Validation of the Critical-Care Pain Observation Tool-Neuro in brain-injured adults in the intensive care unit: a prospective cohort study.

BACKGROUND: Pain assessment in brain-injured patients in the intensive care unit (ICU) is challenging and existing scales may not be representative of behavioral reactions expressed by this specific group. This study aimed to validate the French-Canadian and English revised versions of the Critical-Care Pain Observation Tool (CPOT-Neuro) for brain-injured ICU patients. METHODS: A prospective cohort study was conducted in three Canadian and one American sites. Patients with a traumatic or a non-traumatic brain injury were assessed with the CPOT-Neuro by trained raters (i.e., research staff and ICU nurses) before, during, and after nociceptive procedures (i.e., turning and other) and non-nociceptive procedures (i.e., non-invasive blood pressure, soft touch). Patients who were conscious and delirium-free were asked to provide their self-report of pain intensity (0-10). A first data set was completed for all participants (n = 226), and a second data set (n = 87) was obtained when a change in the level of consciousness (LOC) was observed after study enrollment. Three LOC groups were included: (a) unconscious (Glasgow Coma Scale or GCS 4-8); (b) altered LOC (GCS 9-12); and (c) conscious (GCS 13-15). RESULTS: Higher CPOT-Neuro scores were found during nociceptive procedures compared to rest and non-nociceptive procedures in both data sets (p < 0.001). CPOT-Neuro scores were not different across LOC groups. Moderate correlations between CPOT-Neuro and self-reported pain intensity scores were found at rest and during nociceptive procedures (Spearman rho > 0.40 and > 0.60, respectively). CPOT-Neuro cut-off scores ≥ 2 and ≥ 3 were found to adequately classify mild to severe self-reported pain ≥ 1 and moderate to severe self-reported pain ≥ 5, respectively. Interrater reliability of raters' CPOT-Neuro scores was supported with intraclass correlation coefficients > 0.69. CONCLUSIONS: The CPOT-Neuro was found to be valid in this multi-site sample of brain-injured ICU patients at various LOC. Implementation studies are necessary to evaluate the tool's performance in clinical practice.

Objective characterization of hip pain levels during walking by combining quantitative electroencephalography with machine learning.

Pain is an undesirable sensory experience that can induce depression and limit individuals' activities of daily living, in turn negatively impacting the labor force. Affected people frequently feel pain during activity; however, pain is subjective and difficult to judge objectively, particularly during activity. Here, we developed a system to objectively judge pain levels in walking subjects by recording their quantitative electroencephalography (qEEG) and analyzing data by machine learning. To do so, we enrolled 23 patients who had undergone total hip replacement for pain, and recorded their qEEG during a five-minute walk via a wearable device with a single electrode placed over the Fp1 region, based on the 10-20 Electrode Placement System, before and three months after surgery. We also assessed subject hip pain using a numerical rating scale. Brain wave amplitude differed significantly among subjects with different levels of hip pain at frequencies ranging from 1 to 35 Hz. qEEG data were also analyzed by a support vector machine using the Radial Basis Functional Kernel, a function used in machine learning. That approach showed that an individual's hip pain during walking can be recognized and subdivided into pain quartiles with 79.6% recognition Accuracy. Overall, we have devised an objective and non-invasive tool to monitor an individual's pain during walking.

The Tourniquet Ischemia Test in the Diagnosis of Complex Regional Pain Syndrome.

BACKGROUND: The tourniquet ischemia test (IT) is a hitherto rarely used tool for the diagnostic work-up of patients with suspected complex regional pain syndrome (CRPS). This analysis aims to determine the sensitivity and specificity of this test, and elucidate factors that can influence the test result. METHODS: Consecutive data on clinical presentation, results of the IT and other diagnostic tests, and clinical characteristics were analyzed from patients presenting at our autonomic laboratory between 2000 and 2011. IT results were compared with the final clinical diagnosis at discharge, and statistical analysis was performed to determine specificity, sensitivity, and positive and negative predictive values of the IT. RESULTS: A total of 78 patients were assessed. IT results were positive (≥50% reduction in pain during ischemia) in 26 cases and negative in 52 cases. CRPS was the final diagnosis in 45 cases, and in 33 cases, a different diagnosis was made. This results in a test sensitivity of 49% and a specificity of 88%, with a positive predictive value of 85% and a negative predictive value of 56%. Age, sex, the type and stage of CRPS, and the affected extremity did not influence the test result in a statistically significant manner. Specificity worsened to 76% if any pain reduction was rated as a positive test result. CONCLUSIONS: A positive tourniquet IT has a high positive predictive value for the diagnosis of CRPS. It is thus useful as a confirmatory assay in patients with suspected CRPS. Low sensitivity rules out its use as a screening test. SIGNIFICANCE: This study retrospectively analyzed the clinical significance of the tourniquet IT that was routinely used in patients with suspected CRPS. It showed that a positive IT result is useful as a confirmatory assay in patients fulfilling the clinical criteria.

Analgesia nociception index as a tool to predict hypotension after spinal anaesthesia for elective caesarean section.

Arterial hypotension is the main disadvantage of spinal anaesthesia (SA) for caesarean delivery with deleterious effects on maternal-foetal outcomes. Recently, a non-invasive device 'analgesia nociception index' (ANI) has been developed to evaluate the parasympathetic component of the nervous autonomous system. The aim of this study was to evaluate the ability of ANI to predict the risk of hypotension after SA for elective caesarean section. One hundred patients scheduled for elective caesarean delivery under SA were recruited in this observational prospective study. Hemodynamic and ANI parameters were recorded in supine position (TB), in sitting position (T0), after induction of SA (T1) and then every three minutes (T2, T3, Tn) until the end of surgery or having resort to ephedrine. After SA, women were classified into two groups according to occurrence of hypotension (group H, n = 80) or not (group C, n = 20). The variations of ANI between T2 and T0 were significantly higher in the group H as compared to the control group. A threshold of 4.5 points decrease in instantaneous ANI value could predict maternal hypotension. ANI is a simple and effective tool in predicting the risk of SA-related hypotension.Impact statementWhat is already known on this subject? Arterial hypotension is the main disadvantage of spinal anaesthesia for caesarean delivery with deleterious effects on maternal-foetal outcomes. The balance between the sympathic and parasympathic systems could be used to predict the onset of hypotension following spinal anaesthesia. Analgesia nociception index (ANI) is an index calculated based on heart rate variability HRV analysis, designed originally to evaluate the antinociception/Nociception balance.What do the results of this study add? We have shown that the analysis of HRV with ANI was a predictor of maternal hypotension after spinal anaesthesia.What are the implications of these findings for clinical practice and/or further research? ANI is an effective tool in predicting the risk of spinal anaesthesia-related hypotension. These findings are of potential clinical importance in the obstetrical anaesthesia setting. Further studies are required in order to implement this simple tool and optimise prophylactic measures especially vasopressors.

Mechanical Nociception in Mice and Rats: Measurement with Automated von Frey Equipment.

von Frey hairs are important tools for the study of mechanisms of cutaneous stimulation-induced sensory input. Mechanical force is exerted via application of a particular hair to the cutaneous receptive field until buckling of the hair occurs. The most commonly used von Frey filaments are productive in evaluating behavioral responses of neuropathic pain in preclinical and clinical research. To reduce the potential experimenter bias, automated instruments are being developed for behavioral assessment.