In-hospital mortality risk stratification in children aged under 5 years with pneumonia with or without pulse oximetry: A secondary analysis of the Pneumonia REsearch Partnership to Assess WHO REcommendations (PREPARE) dataset.

OBJECTIVES: We determined the pulse oximetry benefit in pediatric pneumonia mortality risk stratification and chest-indrawing pneumonia in-hospital mortality risk factors. METHODS: We report the characteristics and in-hospital pneumonia-related mortality of children aged 2-59 months who were included in the Pneumonia Research Partnership to Assess WHO Recommendations dataset. We developed multivariable logistic regression models of chest-indrawing pneumonia to identify mortality risk factors. RESULTS: Among 285,839 children, 164,244 (57.5%) from hospital-based studies were included. Pneumonia case fatality risk (CFR) without pulse oximetry measurement was higher than with measurement (5.8%, 95% confidence interval [CI] 5.6-5.9% vs 2.1%, 95% CI 1.9-2.4%). One in five children with chest-indrawing pneumonia was hypoxemic (19.7%, 95% CI 19.0-20.4%), and the hypoxemic CFR was 10.3% (95% CI 9.1-11.5%). Other mortality risk factors were younger age (either 2-5 months [adjusted odds ratio (aOR) 9.94, 95% CI 6.67-14.84] or 6-11 months [aOR 2.67, 95% CI 1.71-4.16]), moderate malnutrition (aOR 2.41, 95% CI 1.87-3.09), and female sex (aOR 1.82, 95% CI 1.43-2.32). CONCLUSION: Children with a pulse oximetry measurement had a lower CFR. Many children hospitalized with chest-indrawing pneumonia were hypoxemic and one in 10 died. Young age and moderate malnutrition were risk factors for in-hospital chest-indrawing pneumonia-related mortality. Pulse oximetry should be integrated in pneumonia hospital care for children under 5 years.

Assembling a global database of child pneumonia studies to inform WHO pneumonia management algorithm: Methodology and applications.

Background: The existing World Health Organization (WHO) pneumonia case management guidelines rely on clinical symptoms and signs for identifying, classifying, and treating pneumonia in children up to 5 years old. We aimed to collate an individual patient-level data set from large, high-quality pre-existing studies on pneumonia in children to identify a set of signs and symptoms with greater validity in the diagnosis, prognosis, and possible treatment of childhood pneumonia for the improvement of current pneumonia case management guidelines. Methods: Using data from a published systematic review and expert knowledge, we identified studies meeting our eligibility criteria and invited investigators to share individual-level patient data. We collected data on demographic information, general medical history, and current illness episode, including history, clinical presentation, chest radiograph findings when available, treatment, and outcome. Data were gathered separately from hospital-based and community-based cases. We performed a narrative synthesis to describe the final data set. Results: Forty-one separate data sets were included in the Pneumonia Research Partnership to Assess WHO Recommendations (PREPARE) database, 26 of which were hospital-based and 15 were community-based. The PREPARE database includes 285 839 children with pneumonia (244 323 in the hospital and 41 516 in the community), with detailed descriptions of clinical presentation, clinical progression, and outcome. Of 9185 pneumonia-related deaths, 6836 (74%) occurred in children <1 year of age and 1317 (14%) in children aged 1-2 years. Of the 285 839 episodes, 280 998 occurred in children 0-59 months old, of which 129 584 (46%) were 2-11 months of age and 152 730 (54%) were males. Conclusions: This data set could identify an improved specific, sensitive set of criteria for diagnosing clinical pneumonia and help identify sick children in need of referral to a higher level of care or a change of therapy. Field studies could be designed based on insights from PREPARE analyses to validate a potential revised pneumonia algorithm. The PREPARE methodology can also act as a model for disease database assembly.

Derivation and validation of a novel risk assessment tool to identify children aged 2-59 months at risk of hospitalised pneumonia-related mortality in 20 countries.

INTRODUCTION: Existing risk assessment tools to identify children at risk of hospitalised pneumonia-related mortality have shown suboptimal discriminatory value during external validation. Our objective was to derive and validate a novel risk assessment tool to identify children aged 2-59 months at risk of hospitalised pneumonia-related mortality across various settings. METHODS: We used primary, baseline, patient-level data from 11 studies, including children evaluated for pneumonia in 20 low-income and middle-income countries. Patients with complete data were included in a logistic regression model to assess the association of candidate variables with the outcome hospitalised pneumonia-related mortality. Adjusted log coefficients were calculated for each candidate variable and assigned weighted points to derive the Pneumonia Research Partnership to Assess WHO Recommendations (PREPARE) risk assessment tool. We used bootstrapped selection with 200 repetitions to internally validate the PREPARE risk assessment tool. RESULTS: A total of 27 388 children were included in the analysis (mean age 14.0 months, pneumonia-related case fatality ratio 3.1%). The PREPARE risk assessment tool included patient age, sex, weight-for-age z-score, body temperature, respiratory rate, unconsciousness or decreased level of consciousness, convulsions, cyanosis and hypoxaemia at baseline. The PREPARE risk assessment tool had good discriminatory value when internally validated (area under the curve 0.83, 95% CI 0.81 to 0.84). CONCLUSIONS: The PREPARE risk assessment tool had good discriminatory ability for identifying children at risk of hospitalised pneumonia-related mortality in a large, geographically diverse dataset. After external validation, this tool may be implemented in various settings to identify children at risk of hospitalised pneumonia-related mortality.

Identification of α1,2-fucosylated signaling and adhesion molecules in head and neck squamous cell carcinoma.

Head and neck cancer is the seventh most common cancer in the world, and most cases manifest as head and neck squamous cell carcinoma. Despite the prominent role of fucosylated carbohydrate antigens in tumor cell adhesion and metastasis, little is known about the functional role of fucose-modified glycoproteins in head and neck cancer pathobiology. Inactivating polymorphisms of the fut2 gene, encoding for the α1,2-fucosyltransferase FUT2, are associated with an increased incidence of head and neck cancer among tobacco users. Moreover, the presence of the α1,2-fucosylated Lewis Y epitope, with both α1,2- and α1,3-linked fucose, has been observed in head and neck cancer tumors while invasive regions lose expression, suggesting a potential role for α1,2-fucosylation in the regulation of aggressive tumor cell characteristics. Here, we report an association between fut2 expression and head and neck cancer survival, document differential surface expression of α1,2-fucosylated epitopes in a panel of normal, dysplastic, and head and neck cancer cell lines, identify a set of potentially α1,2-fucosylated signaling and adhesion molecules including the epidermal growth factor receptor (EGFR), CD44 and integrins via tandem mass spectrometry, and finally, present evidence that EGFR is among the α1,2-fucosylated and LeY-displaying proteins in head and neck cancer. This knowledge will serve as the foundation for future studies to interrogate the role of LeY-modified and α1,2-fucosylated glycoproteins in head and neck cancer pathogenesis. Data are available via ProteomeXchange with identifier PXD029420.

Comparison of the Demographics and Visit Characteristics of Patients Who Left the Pediatric Emergency Department Without Being Seen With Those Who Were Evaluated in the Emergency Department.

BACKGROUND: We compared those patients who left without being seen (LWBS) with those who stay for evaluation and determined which subsets were more likely to depart prematurely in the largest pediatric population studied to date. METHODS: We retrospectively extracted data from the electronic medical records of all pediatric patients who visited the emergency department between January 1, 2013, and December 31, 2015. The demographics and visit characteristics were compared between patients who LWBS and those seen by a provider. Bivariate and multivariate analyses were used to determine the odds for premature departure of specific groups within the population. RESULTS: Of the 271,364 pediatric patients visiting the emergency department during the 3-year study period, 3835 (1.4%) LWBS by a provider. The mean age of those LWBS was younger, and the odds of leaving slightly decreased as the patient's age increased (odds ratio [OR], 0.98). Those triaged as having "nonurgent" medical conditions had a statistically significant increase in odds of premature departure when compared with those with "urgent" medical conditions (OR, 1.16). Patients arriving during the evening and overnight hours had a much greater odds of LWBS (OR, 6.7 and 7.3, respectively). CONCLUSIONS: Our findings demonstrated and confirmed that age, time of arrival, and acuity level upon presentation were predictors of patients leaving before evaluation. This can guide institutions with staffing and flow processes as they attempt to reduce LWBS rates but also raises further questions as to whether these subsets go forward to have worse clinical outcomes after leaving prematurely.

Ondansetron Prescription Is Associated With Reduced Return Visits to the Pediatric Emergency Department for Children With Gastroenteritis.

STUDY OBJECTIVE: We determine whether an ondansetron prescription for pediatric patients with vomiting or gastroenteritis is associated with decreased return visits to the emergency department (ED), and whether alternate diagnoses are more frequent on return visits in patients prescribed ondansetron. METHODS: This is a retrospective cohort study of patients 6 months to 18 years of age, presenting to a pediatric ED or its affiliated urgent care centers between 2012 and 2017 with an International Classification of Diseases, Ninth Revision or International Statistical Classification of Diseases and Related Health Problems, 10th Revision diagnosis of gastroenteritis, gastritis, vomiting, or vomiting with diarrhea. Multivariate logistic regression analysis was used to measure the association between an ondansetron prescription and the odds of 72-hour return visits. Rates of alternate diagnoses on return visits (appendicitis, intussusception, intracranial mass, meningitis, and diabetic ketoacidosis) were compared between patients who were prescribed ondansetron for home use and those who were not. RESULTS: A total of 82,139 patients were studied, with a median age of 4 years. An ondansetron prescription was given to 13.4% of patients on discharge. The 72-hour return visit rate was 4.7%. Patients receiving an ondansetron prescription had decreased odds of 72-hour return visits (adjusted odds ratio 0.84; 95% confidence interval 0.75 to 0.93). The subgroup of patients specifically receiving a diagnosis of gastroenteritis had decreased odds of 72-hour return visits (adjusted odds ratio 0.82; 95% confidence interval 0.72 to 0.95). There was no significant difference between groups in the diagnosis of appendicitis on return visit (odds ratio 0.97; 95% confidence interval 0.37 to 2.18). CONCLUSION: An ondansetron prescription is associated with reduced 72-hour ED return visit rates for children with vomiting or acute gastroenteritis and is not associated with masking alternate diagnoses.

Strategies discussed at the XIIth international conference on Kangaroo mother care for implementation on a countrywide scale.

AIM: Building strategies for the country-level dissemination of Kangaroo mother care (KMC) to reduce the mortality rate in preterm and low birth weight babies and improve quality of life. KMC is an evidence-based healthcare method for these infants. However, KMC implementation at the global level remains low. METHODS: The international network in Kangaroo mother brought 172 KMC professionals from 33 countries together for a 2-day workshop held in conjunction with the XIIth International KMC Conference in Bogota, Colombia, in November 2018. Participants worked in clusters to formulate strategies for country-level dissemination and scale-up according to seven pre-established objectives. RESULTS: The minimum set of indicators for KMC scale-up proposed by the internationally diverse groups is presented. The strategies for KMC integration and implementation at the country level, as well as the approaches for convincing healthcare providers of the safety of KMC transportation, are also described. Finally, the main aspects concerning KMC follow-up and KMC for term infants are presented. CONCLUSION: In this collaborative meeting, participants from low-, middle- and high-income countries combined their knowledge and experience to identify the best strategies to implement KMC at a countrywide scale.

Emotion Regulation Ability and Resilience in a Sample of Adolescents from a Suburban Area.

Earlier research has identified a remarkable number of related factors to resilience during adolescence. Historically, theoretical treatments of resilience have been focused almost exclusively on psychosocial levels of analysis to derive explanatory models. However, there is insufficient understanding of the role of emotion regulation explaining competent functioning despite the experience of adversity (resilience), especially during adolescence. This study explores the relationship between both, emotional regulation abilities and strategies, and resilience in a sample of adolescents from suburbs high-schools (Jerez de la Frontera, Spain). The study also examines how using different emotional regulation strategies may help the development of resilience levels at this stage. Participants of the study were 164 adolescents ranging from 13 to 16 years old (M = 13.98; SD = 0.66). Emotion regulation was measured using the Cognitive Emotional Regulation Questionnaire (CERQ, Garnefski et al., 2001), and sections D and H of Mayer-Salovey-Caruso Emotional Intelligence Test, a performance test (Emotion Regulation Ability sections, MSCEIT, Spanish version, Mayer et al., 2003). Resilience was evaluated with ERE (Educative Resilience Scale for children and adolescents, Saavedra and Castro, 2009). Verbal Intelligence (Yuste, 1997) and personality traits (Cattell and Cattell, 1986) were assessed as two independent variables. Results supported the idea that emotion regulation ability (MSCEIT, D and H sections, Extremera et al., 2006) is a significant predictor of adolescents' resilience. Moreover, cognitive regulation strategies, such as positive reappraisal, predicted perceived resilience among students. Sociability (A factor of HSPQ, sociability) also correlated with resilience levels. Hence, these results are promising, implying that emotion regulation ability may act as a helpful tool preventing adolescents from irrational risky behaviors, commonly assumed at this developmental stage.

Enhanced Drought Stress Tolerance by the Arbuscular Mycorrhizal Symbiosis in a Drought-Sensitive Maize Cultivar Is Related to a Broader and Differential Regulation of Host Plant Aquaporins than in a Drought-Tolerant Cultivar.

The arbuscular mycorrhizal (AM) symbiosis has been shown to improve maize tolerance to different drought stress scenarios by regulating a wide range of host plants aquaporins. The objective of this study was to highlight the differences in aquaporin regulation by comparing the effects of the AM symbiosis on root aquaporin gene expression and plant physiology in two maize cultivars with contrasting drought sensitivity. This information would help to identify key aquaporin genes involved in the enhanced drought tolerance by the AM symbiosis. Results showed that when plants were subjected to drought stress the AM symbiosis induced a higher improvement of physiological parameters in drought-sensitive plants than in drought-tolerant plants. These include efficiency of photosystem II, membrane stability, accumulation of soluble sugars and plant biomass production. Thus, drought-sensitive plants obtained higher physiological benefit from the AM symbiosis. In addition, the genes ZmPIP1;1, ZmPIP1;3, ZmPIP1;4, ZmPIP1;6, ZmPIP2;2, ZmPIP2;4, ZmTIP1;1, and ZmTIP2;3 were down-regulated by the AM symbiosis in the drought-sensitive cultivar and only ZmTIP4;1 was up-regulated. In contrast, in the drought-tolerant cultivar only three of the studied aquaporin genes (ZmPIP1;6, ZmPIP2;2, and ZmTIP4;1) were regulated by the AM symbiosis, resulting induced. Results in the drought-sensitive cultivar are in line with the hypothesis that down-regulation of aquaporins under water deprivation could be a way to minimize water loss, and the AM symbiosis could be helping the plant in this regulation. Indeed, during drought stress episodes, water conservation is critical for plant survival and productivity, and is achieved by an efficient uptake and stringently regulated water loss, in which aquaporins participate. Moreover, the broader and contrasting regulation of these aquaporins by the AM symbiosis in the drought-sensitive than the drought-tolerant cultivar suggests a role of these aquaporins in water homeostasis or in the transport of other solutes of physiological importance in both cultivars under drought stress conditions, which may be important for the AM-induced tolerance to drought stress.

Hormonal and Nutritional Features in Contrasting Rootstock-mediated Tomato Growth under Low-phosphorus Nutrition.

Grafting provides a tool aimed to increase low-P stress tolerance of crops, however, little is known about the mechanism (s) by which rootstocks can confer resistance to P deprivation. In this study, 4 contrasting groups of rootstocks from different genetic backgrounds (Solanum lycopersicum var. cerasiforme and introgression and recombinant inbred lines derived from the wild relatives S. pennellii and S. pimpinellifolium) were grafted to a commercial F1 hybrid scion and cultivated under control (1 mM, c) and P deficient (0.1 mM, p) conditions for 30 days, to analyze rootstocks-mediated traits that impart low (L, low shoot dry weight, SDW) or high (H, high SDW) vigor. Xylem sap ionic and hormonal anlyses leaf nutritional status suggested that some physiological traits can explain rootstocks impacts on shoot growth. Although xylem P concentration increased with root biomass under both growing conditions, shoot biomass under low-P was explained by neither changes in root growth nor P transport and assimilation. Indeed, decreased root P export only explained the sensitivity of the HcLp rootstocks, while leaf P status was similarly affected in all graft combinations. Interestingly, most of the nutrients analyzed in the xylem sap correlated with root biomass under standard fertilization but only Ca was consistently related to shoot biomass under both control and low-P, suggesting an important role for this nutrient in rootstock-mediated vigor. Moreover, foliar Ca, S, and Mn concentrations were (i) specifically correlated with shoot growth under low-P and (ii) positively and negatively associated to the root-to-shoot transport of the cytokinin trans-zeatin (t-Z) and the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC), respectively. Indeed, those hormones seem to play an antagonistic positive (t-Z) and negative (ACC) role in the rootstock-mediated regulation of shoot growth in response to P nutrition. The use of Hp-type rootstocks seems to enhance P use efficiency of a commercial scion variety, therefore could potentially be used for increasing yield and agronomic stability under low P availability.

Pediatric psychiatric emergency department visits during a full moon.

OBJECTIVE: This study aimed to verify the hypothesis that the lunar cycle influences the number of pediatric psychiatric emergency department (ED) visits. METHODS: Pediatric psychiatric ED visits between 2009 and 2011 were obtained retrospectively. Patients aged between 4 and 21 years presenting to Miami Children's Hospital ED with a primary psychiatric complaint were included in the study. Patients with a concomitant psychiatric problem and a secondary medical condition were excluded. The number of psychiatric visits was retrieved for the full moon dates, control dates as well as the day before and after the full moon when the moon appears full to the naked eye (full moon effect). A comparison was made using the 2-sample independent t test. RESULTS: Between 2009 and 2011, 36 dates were considered as the true full moon dates and 108 dates as the "full moon effect." A total of 559 patients were included in the study. The 2-sample independent t tests were performed between the actual full moon date and control dates, as well as between the "full moon effect" dates and control dates. Our results failed to show a statistical significance when comparing the number of pediatric psychiatric patients presenting to a children's hospital ED during a full moon and a non-full moon date. CONCLUSIONS: Our study's results are in agreement with those involving adult patients. The full moon does not affect psychiatric visits in a children's hospital.

Metallic stents for tracheobronchial pathology treatment.

PURPOSE: To present the 7-year experience of the treatment of benign and malignant tracheobronchial stenoses using metallic stents. PATIENTS AND METHODS: One hundred twenty-three stents were inserted in 86 patients (74 benign and 12 malignant stenoses). Ninety-seven stents were placed in the trachea and 26 in the bronchi. The procedures were performed under fluoroscopic and flexible bronchoscopic guidance with the patient under light sedation. In cases of severe stenotic lesions or obstructions, laser resection was performed before stent placement. Clinical and functional pulmonary data were recorded before and 3 months after the procedure. Follow-up involved clinical data and radiographic techniques at 48 h and at 1-, 3-, 6-, and 12-month intervals. RESULTS: The technical success was 100 %. Dyspnea disappearance, forced expiratory volume in the first second, and pulmonary functional data improvement was observed in all patients (p < 0.001). Complications were detected in 23 patients (26.7 %). Mean follow-up time was 6.3 ± 1.2 months in patients with malignant lesions and 76.2 ± 2.3 months patients with in benign lesions. By the end of the study, 100 % of patients with malignant pathology and 6.7 % of patients with benign lesions had died. CONCLUSION: Endoluminal treatment of tracheobronchial stenosis with metallic stents is a therapeutic alternative in patients who are poor candidates for surgery. In unresectable malignant lesions, the benefit of metallic stenting is unquestionable. In benign lesions, the results are satisfactory, but sometimes other interventions are required to treat complications. New stent technology may improve these results.

Prophylactic probiotics to prevent death and nosocomial infection in preterm infants.

BACKGROUND AND OBJECTIVE: It has been suggested that probiotics may decrease infant mortality and nosocomial infections because of their ability to suppress colonization and translocation of bacterial pathogens in the gastrointestinal tract. We designed a large double-blinded placebo-controlled trial using Lactobacillus reuteri to test this hypothesis in preterm infants. METHODS: Eligible infants were randomly assigned during the first 48 hours of life to either daily probiotic administration or placebo. Infants in the intervention group were administered enterally 5 drops of a probiotic preparation containing 10(8) colony-forming units of L reuteri DSM 17938 until death or discharge from the NICU. RESULTS: A total of 750 infants ≤ 2000 g were enrolled. The frequency of the primary outcome, death, or nosocomial infection, was similar in the probiotic and placebo groups (relative risk 0.87; 95% confidence interval: 0.63-1.19; P = .376). There was a trend toward a lower rate of nosocomial pneumonia in the probiotic group (2.4% vs 5.0%; P = .06) and a nonsignificant 40% decrease in necrotizing enterocolitis (2.4% vs 4.0%; P = .23). Episodes of feeding intolerance and duration of hospitalization were lower in infants ≤ 1500 g (9.6% vs 16.8% [P = .04]; 32.5 days vs 37 days [P = .03]). CONCLUSIONS: Although L reuteri did not appear to decrease the rate of the composite outcome, the trends suggest a protective role consistent with what has been observed in the literature. Feeding intolerance and duration of hospitalization were decreased in premature infants ≤ 1500 g.

Funding agencies in low- and middle-income countries: support for knowledge translation.

OBJECTIVE: The aim was to describe how selected health research funding agencies active in low- and middle-income countries promote the translation of their funded research into policy and practice. METHODS: We conducted inductive analysis of semi-structured interviews with key informants from a purposive sample of 23 national and international funding agencies that fund health research in Brazil, Colombia, India, the Philippines, South Africa and Thailand. We also surveyed web sites. FINDINGS: We found a commitment to knowledge translation in the mandate of 18 of 23 agencies. However, there was a lack of common terminology. Most of the activities were traditional efforts to disseminate to a broad audience, for example using web sites and publications. In addition, more than half (13 of 23) of the agencies encouraged linkage/exchange between researchers and potential users, and 6 of 23 agencies described "pull" activities to generate interest in research from decision-makers. One-third (9 of 23) of funding agencies described a mandate to enhance health equity through improving knowledge translation. Only 3 of 23 agencies were able to describe evaluation of knowledge translation activities. Furthermore, we found national funding agencies made greater knowledge translation efforts when compared to international agencies. CONCLUSION: Funding agencies are engaged in a wide range of creative knowledge translation activities. They might consider their role as knowledge brokers, with an ability to promote research syntheses and a focus on health equity. There is an urgent need to evaluate the knowledge translation activities of funding agencies.

Diseño de un protocolo de registro del potencial evocado somatosensorial del nervio tibial posterior / A protocol desigh for the record of the somatosensory-evoked potential of the posterior tibial nerve

La respuesta cortical del Potencial Somatosensorial del nervio tibial posterior se registra en la mayor parte de los laboratorios utilizando una sola derivación precisándose cada vez más el diseño de nuevos protocolos que abarquen el registro de mayor número de áreas corticales. Esta investigación se propuso diseñar e implementar el registro del Potencial Evocado Somatosensorial con 19 derivaciones del Sistema Internacional 10/20 en el equipo MEDICID-4 lo que permite el mapeo de la respuesta cortical de la P40 del nervio tibial posterior. Inicialmente se buscó el valor del corte a las altas más bajo, que permitiera obtener el registro sin modificar sus características. Para ello se registró el potencial en 10 sujetos sanos con el electromiógrafo NEURONICA-4 utilizando diferentes filtros a las altas frecuencias. Posteriormente se diseñó un protocolo con 19 derivaciones en el electroencefalógrafo MEDICID-4, utilizando un ancho de banda entre 0,5 y 300 Hz. Fue necesario modificar el software TrackWalker para que permitiera una frecuencia de muestreo de 1 kHz y para lograr que las marcas de sincronismo del estimulador externo fueran reconocidas por el software EP Workstation. Los resultados arrojaron que los cortes a las altas inferiores a 300 Hz modificaron marcadamente la latencia del componente P40. Con este corte se logró obtener respuestas sin diferencias significativas (p> 0,05) en latencia, amplitud y frecuencia a la obtenida con el corte a las altas frecuencias más recomendado en la literatura. Se concluyó que con este protocolo diseñado, es posible registrar la respuesta cortical del Potencial Evocado Somatosensorial del nervio tibial posterior en más de una derivación lo que permitirá contribuir a la caracterización del patrón de anormalidad en ciertos estados patológicos...(AU)

The cortical response of the somatosensory potential of the posterior tibial nerve is recordedin the most of laboratories using only one derivation and requiring even more the design ofthe new protocols involving the record with the most cortical areas; the present research triesto design and implement the Somatosensory Evoked Potential with 19 derivations from theInternational System 10/20 in the 4-MEDICID-equipment, allowing a mapping of the corticalresponse in P40 of the posterior tibial nerve. Initially, we look for the lower cutting value inthe high frequencies which allowed the record with any change in the characteristics. For thispurpose the potential in 10 healthy subjects is recorded using the 4- NEURONICA-electromyography, with the application of different filters in high frequencies. Later, aprotocol with 19 derivations is designed in the 4-MEDICI electromyography using a bandweigh between 0,5 and 300 Hz. It was necessary to modify the Trackwalker software forallowing a 1 kHz sample frequency and for obtaining that the synchronization traces of theexternal stimulator were recognized by EP Workstation software. Findings yielded that cutsat high frequencies less than 300 Hz modified significatively the latency of componentP40.With this cut ,responses with no significant differences were obtained ( p>0,05)according to latency, weigh and frequency in comparison to those obtained with the cut athigh frequencies which is more recommended in literature. It is concluded that with thisprotocol is possible to record the cortical response of the somatosensory evoked potential ofthe posterior tibial nerve in more than a derivation, contributing to the characterization ofabnormal pattern in some pathologic conditions...(AU)

Diseño de un protocolo de registro del potencial evocado somatosensorial del nervio tibial posterior / A Protocol Design for the Record of the Somatosensory Evoked Potential of the Posterior Tibial Nerve

La respuesta cortical del Potencial Somatosensorial del nervio tibial posterior se registra en la mayor parte de los laboratorios utilizando una sola derivación precisándose cada vez más el diseño de nuevos protocolos que abarquen el registro de mayor número de áreas corticales. Esta investigación se propuso diseñar e implementar el registro del Potencial Evocado Somatosensorial con 19 derivaciones del Sistema Internacional 10/20 en el equipo MEDICID-4 lo que permite el mapeo de la respuesta cortical de la P40 del nervio tibial posterior. Inicialmente se buscó el valor del corte a las altas más bajo, que permitiera obtener el registro sin modificar sus características. Para ello se registró el potencial en 10 sujetos sanos con el electromiógrafo NEURONICA-4 utilizando diferentes filtros a las altas frecuencias. Posteriormente se diseñó un protocolo con 19 derivaciones en el electroencefalógrafo MEDICID-4, utilizando un ancho de banda entre 0.5 y 300 Hz. Fue necesario modificar el software TrackWalker para que permitiera una frecuencia de muestreo de 1 kHz y para lograr que las marcas de sincronismo del estimulador externo fueran reconocidas por el software EP Workstation. Los resultados arrojaron que los cortes a las altas inferiores a 300 Hz modificaron marcadamente la latencia del componente P40. Con este corte se logró obtener respuestas sin diferencias significativas (p> 0.05) en latencia, amplitud y frecuencia a la obtenida con el corte a las altas frecuencias más recomendado en la literatura. Se concluyó que con este protocolo diseñado, es posible registrar la respuesta cortical del Potencial Evocado Somatosensorial del nervio tibial posterior en más de una derivación lo que permitirá contribuir a la caracterización del patrón de anormalidad en ciertos estados patológicos.

ABSTRACT The cortical response of the somatosensory potential of the posterior tibial nerve is recorded in the most of laboratories using only one derivation and requiring even more the design of the new protocols involving the record with the most cortical areas; the present research tries to design and implement the Somatosensory Evoked Potential with 19 derivations from the International System 10/20 in the 4-MEDICID-equipment, allowing a mapping of the cortical response in P40 of the posterior tibial nerve. Initially, we look for the lower cutting value in the high frequencies which allowed the record with any change in the characteristics. For this purpose the potential in 10 healthy subjects is recorded using the 4- NEURONICA- electromyography, with the application of different filters in high frequencies. Later, a protocol with 19 derivations is designed in the 4-MEDICI electromyography using a band weigh between 0.5 and 300 Hz. It was necessary to modify the Trackwalker software for allowing a 1 kHz sample frequency and for obtaining that the synchronization traces of the external stimulator were recognized by EP Workstation software. Findings yielded that cuts at high frequencies less than 300 Hz modified significatively the latency of component P40.With this cut ,responses with no significant differences were obtained ( p>0.05) according to latency, weigh and frequency in comparison to those obtained with the cut at high frequencies which is more recommended in literature. It is concluded that with this protocol is possible to record the cortical response of the somatosensory evoked potential of the posterior tibial nerve in more than a derivation, contributing to the characterization of abnormal pattern in some pathologic conditions.

Distribución topográfica de la respuesta cortical del potencial evocado somatosensorial del nervio tibial posterior

La respuesta cortical del Potencial Evocado Somatosensorial del nervio tibial posterior ha mostrado en diferentes investigaciones una gran variabilidad en cuanto a los resultados obtenidos por diferentes autores. Los objetivos de este trabajo fueron evaluar en una muestra de sujetos adultos sanos la distribución topográfica de la respuesta cortical del potencial evocado somatosensorial del nervio tibial posterior empleando un protocolo de registro con 19 derivaciones del Sistema Internacional 10/20 en el equipo MEDICID-4. Se estudiaron 18 sujetos adultos sanos. En todos los sujetos se obtuvo la respuesta cortical P40, manteniéndose los 19 canales de registro, modificándose los filtros a valores entre 0,5 y 300 Hz, y la frecuencia de muestreo se modificó a 1000 Hz. Los resultados muestran una máxima amplitud de la P 40 en línea media. Además, simultáneamente se obtiene dicha respuesta en la propia región centro-parietal ipsilateral, sin existir gran variabilidad intra e interindividuos. De esto se concluye que la estimulación del nervio tibial el pico P40 mostró una distribución cortical centro-parietal tanto en línea media como ipsilateral, con máxima amplitud en esta última, es decir, la P40 se obtuvo paradójicamente con mayor amplitud hacia la misma región del lado estimulado...(AU)

Distribución topográfica de la respuesta cortical del potencial evocado somatosensorial del nervio tibial posterior / Topographical distribution of the cortical response of the somatosensorial evoked potencial of the posterior tibial nerve

La respuesta cortical del Potencial Evocado Somatosensorial del nervio tibial posterior ha mostrado en diferentes investigaciones una gran variabilidad en cuanto a los resultados obtenidos por diferentes autores. Los objetivos de este trabajo fueron evaluar en una muestra de sujetos adultos sanos la distribución topográfica de la respuesta cortical del potencial evocado somatosensorial del nervio tibial posterior empleando un protocolo de registro con 19 derivaciones del Sistema Internacional 10/20 en el equipo MEDICID-4. Se estudiaron 18 sujetos adultos sanos. En todos los sujetos se obtuvo la respuesta cortical P40, manteniéndose los 19 canales de registro, modificándose los filtros a valores entre 0.5 y 300 Hz, y la frecuencia de muestreo se modificó a 1000 Hz. Los resultados muestran una máxima amplitud de la P 40 en línea media. Además, simultáneamente se obtiene dicha respuesta en la propia región centro-parietal ipsilateral, sin existir gran variabilidad intra e interindividuos. De esto se concluye que la estimulación del nervio tibial el pico P40 mostró una distribución cortical centro-parietal tanto en línea media como ipsilateral, con máxima amplitud en esta última, es decir, la P40 se obtuvo paradójicamente con mayor amplitud hacia la misma región del lado estimulado.

The cortical response of the somatosensorial evoked potential of the posterior tibial nerve has shown, in different research works, a great variability in terms of the results obtained by different authors. The aims of this paper were to evaluate in a sample of healthy adult individuals the topographical distribution of the cortical response of the somatosensorial evoked potential of the posterior tibial nerve by using a protocol registration with 19 derivations from the International System 10/20 in the MEDICID-4 team. Eighteen adult individuals were studied. In each individual the cortical response was P40, remaining the 19 registration canals, modifying the filter between 0.5 and 300 Hz, and the sampling frequency was modified to 1000 Hz. Results show a maximum amplitude of the P40 in the middle line. In addition, simultaneously, such response is registered in the central parietal ipsilateral region, with no great intraindividual and interindividual variability. As a conclusion, the stimulation of the tibial nerve and peak P40 showed a cortical central parietal distribution in the middle line, as well as ipsilaterally, with maximum amplitude in the latter. P40 was obtained paradoxically with a greater amplitude towards the same region of the stimulated site.