Trocar vs. Seldinger small bore pleural drains: does the technique influence the outcomes? A prospective single-centre study.

OBJECTIVE: The aim of this study is to compare two positioning techniques of 12-French (Fr) thoracic drains in terms of efficacy, safety, and patient comfort. PATIENTS AND METHODS: This is a prospective, non-randomized, competitive, non-inferiority study comparing the Seldinger vs. Trocar technique. The primary endpoint was an analysis of the factors that led to unsuccessful drainage positioning. Between the two groups, clinical variables, procedure times, pain, and complications were compared. RESULTS: Seventy-two patients were enrolled in group 1 (Seldinger) and 45 in group 2 (Trocar). The mean procedural time was 7.93±3.02 min vs. 7.09±3.67 min, respectively (p: 0.33). The mean VAS for procedural pain was 2.22±1.47 vs. 2.80±1.88, p: 0.07, and the mean at day 2 was 3.6±1.2 in the SBWGD group vs. 2.7±1.1 in the Unico Group (p: 0.04). There was no difference in terms of complications, residual effusion, and pneumothorax at the first post-procedural chest X-ray. Four days after the procedure, the drain removal rate was 11.6% in group 1 vs. 25% in group 2 p: 0.063). The chest tube was removed after a mean period of 8.87±7.20 days after resolution of pleural effusion or tube dislodgement (7 cases in group 1 vs. 11 in group 2, p: 0.053). CONCLUSIONS: The two techniques resulted in comparable pain and complication rates. Both drains are well-tolerated and efficient at draining pleural effusion, with very low rates of complications and failure. We recommend inserting a longer tube for patients who require chest drainage for an extended period of time.

Validated French translation of the ESIT-SQ standardized tinnitus screening questionnaire.

OBJECTIVES: The heterogeneity of tinnitus in terms of etiology, presentation and sometimes severe impact on quality of life hinders treatment and clinical research. The European School for Interdisciplinary Tinnitus Research Screening Questionnaire (ESIT-SQ) collects standardized tinnitus characteristics for patient subtyping. A validated French translation of the ESIT-SQ is presented here. METHOD: On the initiative of the French Interdisciplinary Tinnitus Association (AFREPA), 3 translators (1 professional translator, 1 clinician and 1 researcher) were missioned to translate the English version of the ESIT-SQ into French, adhering to good practice guidelines. Nine patients were recruited with the help of the France-Acouphènes patient association, to test and validate the translation. Lastly, an exploratory survey of responses to the French questionnaire was conducted online via the Siopi mobile phone application. RESULTS: The French translation of the ESIT-SQ was successfully validated. 105 patients responded to the exploratory survey, and their characteristics are presented here. CONCLUSION: This new validated French translation of the ESIT-SQ will enable epidemiological and clinical data to be collected in French-speaking populations, and thus compiled and compared with data collected with other versions of this questionnaire already published in other languages.

Percutaneous radiofrequency ablation using internally cooled wet electrodes for the treatment of patients with lung tumors.

OBJECTIVE: To assess the safety and feasibility of computed tomography-guided radiofrequency ablation (CT-guided RFA) in unresectable lung neoplasms, using a new 15G monopolar internally cooled wet electrode. PATIENTS AND METHODS: 15 consecutive patients with lung neoplasms (< 4 cm), both primary and secondary, unsuitable for or refusing surgery, underwent percutaneous CT-guided RFA using a 15G electrode with a 3-cm exposed tip. The prevalence and grade of adverse events and technical success were evaluated, as well as the extension of the ablation zone, the complete response rates, and the time to progression, determined at CT examination performed 1, 6, and 12 months after the procedure. RESULTS: A total of 22 lung neoplasms were treated (mean diameter: 28 mm; range: 20-39 mm). Technical success was obtained in all patients, without major complications or intraprocedural deaths. Mild or moderate pneumothorax was registered in 46.7% of patients, while a perilesional hemorrhage was observed in 5/15 cases. During the follow-up period, a complete response was obtained in 19 out of 22 lesions (86.4%) with three partial response, two of them successfully retreated with the same technique. CONCLUSIONS: Percutaneous RFA using a 15G internally cooled wet electrode is a safe and feasible treatment for unresectable lung neoplasms, with high complete response rates.

Skin safety and health prevention: an overview of chemicals in cosmetic products.

INTRODUCTION: Cosmetic products contain a wide range of chemicals to which we are exposed every day. The aim of the study was to determine the presence of potential dangerous substances which can cause adverse health effects by examining product labels. MATERIALS AND METHODS: A total of 283 products were collected from various shops in Lecce (Italy) and divided into 3 categories: rinse-off, leave-on and make-up. The label of every product was examined and a list including fragrances, preservatives and other chemicals of concern was created. RESULTS: Fragrances were present in 52.3% of the examined products, mostly limonene (76.9%) and linalool (64.6%) but also citronellol (34.1%), geraniol (31.5%), coumarin (30%) and hexyl cinnamal (29.2%). Preservatives showed a rate of 60% and the most frequently identified were phenoxyethanol (48.7%), sodium benzoate (35.6%), potassium sorbate (22%), methylparaben (15.2%) and MI/MCI (9.9%). The other chemicals of concern were detected in 58% of products; included PEGs (62.3%), acrylate copolymer (34%), petrolatum (17.2%), polysorbates (14,8%), BHT (14.7%), ethylhextyl methoxycinnamate (13.6%), benzophenone-1 (3.7%), benzophenone-3 (4.9%), BHA (1.6%), cocamide DEA and toluene (1.2%). CONCLUSIONS: The use of many of these substances is allowed within certain limits, due to their toxicity at higher concentrations. Other important aspects should be considered as, for instance, the possibility of long-term effects. On the other hand, other substances may induce several acute adverse side-effects, i.e. contact dermatitis and allergic reactions. For these reasons, an enhancement of the criteria used for cosmetics formulation is required since many chemicals used singularly or combined are potentially unsafe.

A review of classification algorithms for EEG-based brain-computer interfaces: a 10 year update.

OBJECTIVE: Most current electroencephalography (EEG)-based brain-computer interfaces (BCIs) are based on machine learning algorithms. There is a large diversity of classifier types that are used in this field, as described in our 2007 review paper. Now, approximately ten years after this review publication, many new algorithms have been developed and tested to classify EEG signals in BCIs. The time is therefore ripe for an updated review of EEG classification algorithms for BCIs. APPROACH: We surveyed the BCI and machine learning literature from 2007 to 2017 to identify the new classification approaches that have been investigated to design BCIs. We synthesize these studies in order to present such algorithms, to report how they were used for BCIs, what were the outcomes, and to identify their pros and cons. MAIN RESULTS: We found that the recently designed classification algorithms for EEG-based BCIs can be divided into four main categories: adaptive classifiers, matrix and tensor classifiers, transfer learning and deep learning, plus a few other miscellaneous classifiers. Among these, adaptive classifiers were demonstrated to be generally superior to static ones, even with unsupervised adaptation. Transfer learning can also prove useful although the benefits of transfer learning remain unpredictable. Riemannian geometry-based methods have reached state-of-the-art performances on multiple BCI problems and deserve to be explored more thoroughly, along with tensor-based methods. Shrinkage linear discriminant analysis and random forests also appear particularly useful for small training samples settings. On the other hand, deep learning methods have not yet shown convincing improvement over state-of-the-art BCI methods. SIGNIFICANCE: This paper provides a comprehensive overview of the modern classification algorithms used in EEG-based BCIs, presents the principles of these methods and guidelines on when and how to use them. It also identifies a number of challenges to further advance EEG classification in BCI.

A closed-form unsupervised geometry-aware dimensionality reduction method in the Riemannian Manifold of SPD matrices.

Riemannian geometry has been found accurate and robust for classifying multidimensional data, for instance, in brain-computer interfaces based on electroencephalography. Given a number of data points on the manifold of symmetric positive-definite matrices, it is often of interest to embed these points in a manifold of smaller dimension. This is necessary for large dimensions in order to preserve accuracy and useful in general to speed up computations. Geometry-aware methods try to accomplish this task while respecting as much as possible the geometry of the original data points. We provide a closed-form solution for this problem in a fully unsupervised setting. Through the analysis of three brain-computer interface data bases we show that our method allows substantial dimensionality reduction without affecting the classification accuracy.

A new score predicting intraprocedural risk in patients undergoing CT-guided percutaneous needle pulmonary biopsy (CATH-score).

OBJECTIVE: To develop a new score (CATH-score) for predicting intra-procedural risk in patients undergoing CT-guided percutaneous needle pulmonary biopsy. PATIENTS AND METHODS: 100 CT-guided lung biopsies performed with a 18 Gauge (G) needle (Pilot Group) were reviewed to analyse patient-, lesion- and procedure-related variables to identify risk factors for procedural complications (pneumothorax and parenchymal bleeding) and diagnosis failure. A scoring system for predicting complications and choosing the right needle (16 G, 18 G, 21 G) was developed using risk factors weighting and prospectively applied to 153 consecutive biopsies (CATH-score Group); complications and diagnostic rates obtained were compared with a group of patients (Control Group) that underwent lung biopsy; in this group of patients the choice of the calliper of the needle was based on the operator experience. RESULTS: lesion diameter (p=0.03), central location of lesion (p=0.02), centrilobular emphysema (p=0.04) and trans-pulmonary needle route (p=0.002) were associated with a higher complications rate in Pilot Group and were selected as risk factors to include in the CATH-score definition. Risk factors "cut-off" values were identified (Receiver Operating Characteristics curves) and risk-stratification groups were classified as follows: low (16 G, score 1), intermediate (18 G, score 2), and high procedural risk score (21 G, score 3). CATH-score usage limited complications rate despite a higher number of 16 G needle employed, with a diagnostic performance rising respect to Control Group. CONCLUSIONS: CATH-score seems to be a valuable tool for predicting the risk of complications and choosing the right needle, in order to increase diagnostic performance in patients undergoing TTNA.

Clinical features, imaging findings, treatment aspects of elastofibroma dorsi and long-term outcomes after surgical resection.

OBJECTIVE: We aim to present clinical features, imaging findings, treatment aspects of the elastofibroma dorsi (ED), which is a benign tumor arising from connective tissue at the scapular region, and long-term outcomes after surgical resection. PATIENTS AND METHODS: We evaluated retrospectively 82 patients (55 females, 27 males; mean age, 60 years; age range, 23-78 years) with ED who underwent surgery between January 1994 and May 2014; subsequently all patients were invited for follow-up, which consisted of physical and US examinations. RESULTS: Subscapular location was almost constant (79/82 patients). Right, left and bilateral location was noted in 39, 28 and 15 cases, respectively. 52/82 patients were symptomatic. The diagnosis was made on physical examination and imaging studies: 49 ultrasound, 43 computed tomography and 54 magnetic resonance examinations were performed overall. Surgical treatment consisted in marginal excision; in all cases diagnosis was confirmed by histological examination. The mean hospitalization was 3 days, with minor complications. Out of the 82 patients, only 25 gave their consent to follow-up; mean time passed after surgery was 64.7 months; 1 case of local recurrence was suspected by ultrasound and, then, confirmed by magnetic resonance imaging. CONCLUSIONS: In our series, clinical features and imaging findings of ED are consistent with current evidence; however, results of our follow-up group marks a difference from the literature, according to which there is no evidence of local recurrence after complete resection. Diagnosis of ED is based on clinical and imaging features; treatment is surgical, especially in symptomatic cases. Prolonging the clinical and US follow-up period may be useful in identifying local recurrence.

Neurofeedback: One of today's techniques in psychiatry?

OBJECTIVES: Neurofeedback is a technique that aims to teach a subject to regulate a brain parameter measured by a technical interface to modulate his/her related brain and cognitive activities. However, the use of neurofeedback as a therapeutic tool for psychiatric disorders remains controversial. The aim of this review is to summarize and to comment the level of evidence of electroencephalogram (EEG) neurofeedback and real-time functional magnetic resonance imaging (fMRI) neurofeedback for therapeutic application in psychiatry. METHOD: Literature on neurofeedback and mental disorders but also on brain computer interfaces (BCI) used in the field of neurocognitive science has been considered by the group of expert of the Neurofeedback evaluation & training (NExT) section of the French Association of biological psychiatry and neuropsychopharmacology (AFPBN). RESULTS: Results show a potential efficacy of EEG-neurofeedback in the treatment of attentional-deficit/hyperactivity disorder (ADHD) in children, even if this is still debated. For other mental disorders, there is too limited research to warrant the use of EEG-neurofeedback in clinical practice. Regarding fMRI neurofeedback, the level of evidence remains too weak, for now, to justify clinical use. The literature review highlights various unclear points, such as indications (psychiatric disorders, pathophysiologic rationale), protocols (brain signals targeted, learning characteristics) and techniques (EEG, fMRI, signal processing). CONCLUSION: The field of neurofeedback involves psychiatrists, neurophysiologists and researchers in the field of brain computer interfaces. Future studies should determine the criteria for optimizing neurofeedback sessions. A better understanding of the learning processes underpinning neurofeedback could be a key element to develop the use of this technique in clinical practice.

Single-Trial Classification of Multi-User P300-Based Brain-Computer Interface Using Riemannian Geometry.

The classification of electroencephalographic (EEG) data recorded from multiple users simultaneously is an important challenge in the field of Brain-Computer Interface (BCI). In this paper we compare different approaches for classification of single-trials Event-Related Potential (ERP) on two subjects playing a collaborative BCI game. The minimum distance to mean (MDM) classifier in a Riemannian framework is extended to use the diversity of the inter-subjects spatio-temporal statistics (MDM-hyper) or to merge multiple classifiers (MDM-multi). We show that both these classifiers outperform significantly the mean performance of the two users and analogous classifiers based on the step-wise linear discriminant analysis. More importantly, the MDM-multi outperforms the performance of the best player within the pair.

The effects of individual upper alpha neurofeedback in ADHD: an open-label pilot study.

Standardized neurofeedback (NF) protocols have been extensively evaluated in attention-deficit/hyperactivity disorder (ADHD). However, such protocols do not account for the large EEG heterogeneity in ADHD. Thus, individualized approaches have been suggested to improve the clinical outcome. In this direction, an open-label pilot study was designed to evaluate a NF protocol of relative upper alpha power enhancement in fronto-central sites. Upper alpha band was individually determined using the alpha peak frequency as an anchor point. 20 ADHD children underwent 18 training sessions. Clinical and neurophysiological variables were measured pre- and post-training. EEG was recorded pre- and post-training, and pre- and post-training trials within each session, in both eyes closed resting state and eyes open task-related activity. A power EEG analysis assessed long-term and within-session effects, in the trained parameter and in all the sensors in the (1-30) Hz spectral range. Learning curves over sessions were assessed as well. Parents rated a clinical improvement in children regarding inattention and hyperactivity/impulsivity. Neurophysiological tests showed an improvement in working memory, concentration and impulsivity (decreased number of commission errors in a continuous performance test). Relative and absolute upper alpha power showed long-term enhancement in task-related activity, and a positive learning curve over sessions. The analysis of within-session effects showed a power decrease ("rebound" effect) in task-related activity, with no significant effects during training trials. We conclude that the enhancement of the individual upper alpha power is effective in improving several measures of clinical outcome and cognitive performance in ADHD. This is the first NF study evaluating such a protocol in ADHD. A controlled evaluation seems warranted due to the positive results obtained in the current study.

Mixed-norm regularization for brain decoding.

This work investigates the use of mixed-norm regularization for sensor selection in event-related potential (ERP) based brain-computer interfaces (BCI). The classification problem is cast as a discriminative optimization framework where sensor selection is induced through the use of mixed-norms. This framework is extended to the multitask learning situation where several similar classification tasks related to different subjects are learned simultaneously. In this case, multitask learning helps in leveraging data scarcity issue yielding to more robust classifiers. For this purpose, we have introduced a regularizer that induces both sensor selection and classifier similarities. The different regularization approaches are compared on three ERP datasets showing the interest of mixed-norm regularization in terms of sensor selection. The multitask approaches are evaluated when a small number of learning examples are available yielding to significant performance improvements especially for subjects performing poorly.

A comparison of recording modalities of P300 event-related potentials (ERP) for brain-computer interface (BCI) paradigm.

AIMS OF THE STUDY: A brain-computer interface aims at restoring communication and control in severely disabled people by identification and classification of EEG features such as event-related potentials (ERPs). The aim of this study is to compare different modalities of EEG recording for extraction of ERPs. The first comparison evaluates the performance of six disc electrodes with that of the EMOTIV headset, while the second evaluates three different electrode types (disc, needle, and large squared electrode). MATERIAL AND METHODS: Ten healthy volunteers gave informed consent and were randomized to try the traditional EEG system (six disc electrodes with gel and skin preparation) or the EMOTIV Headset first. Together with the six disc electrodes, a needle and a square electrode of larger surface were simultaneously recording near lead Cz. Each modality was evaluated over three sessions of auditory P300 separated by one hour. RESULTS: No statically significant effect was found for the electrode type, nor was the interaction between electrode type and session number. There was no statistically significant difference of performance between the EMOTIV and the six traditional EEG disc electrodes, although there was a trend showing worse performance of the EMOTIV headset. However, the modality-session interaction was highly significant (P<0.001) showing that, while the performance of the six disc electrodes stay constant over sessions, the performance of the EMOTIV headset drops dramatically between 2 and 3h of use. Finally, the evaluation of comfort by participants revealed an increasing discomfort with the EMOTIV headset starting with the second hour of use. CONCLUSION: Our study does not recommend the use of one modality over another based on performance but suggests the choice should be made on more practical considerations such as the expected length of use, the availability of skilled labor for system setup and above all, the patient comfort.

Pneumonectomy with and without induction chemo-radiotherapy for non-small cell lung cancer: short and long-term results from a single centre.

BACKGROUND AND OBJECTIVES:   Pneumonectomy for non small cell lung cancer (NSCLC) after induction radio-chemotherapy (IT) has been associated with high peri-operative risk and its safety and efficacy is still debated. The aim of this retrospective study was to compare short and long-term results of pneumonectomy in patients treated with and without IT (radiotherapy plus chemotherapy) for NSCLC. MATERIALS AND METHODS: From 1995 to 2008, 85 consecutive patients underwent pneumonectomy: 49 received pre-operative radiotherapy and chemotherapy (IT group), and 36 patients did not (non-IT group). Peri-operative and long-term outcomes were compared. RESULTS: Major complications rate was 14.3% for IT group and 16.7% for non-IT group (p = n.s.). Mortality rate was 2% in IT group and 5.5% in non-IT group (p = n.s.). Post-operative hospital stay was significantly longer in the IT group (p < 0.0001) as the need for blood transfusion (p = 0.002). Indeed, the mortality rate was similar in the left- and right-sided operations. 5 years survival was 45.3% for IT group and 38.4% for non-IT group (p = n.s.) and 5 year disease free survival rates were 42.3% vs. 37.8% for the two groups, respectively (p = n.s.). Among the clinical, surgical and pathological features no differences on long term outcomes were found with regards to IT. DISCUSSION: Pneumonectomy is a feasible and safe procedure even after pre-operative IT. Our results showed a prolonged hospitalization and the need for blood transfusion in the IT group.

Malignant solitary fibrous tumour of the chest wall: a challenging case.

Solitary fibrous tumors are very rare neoplasms that seldomly appear in extra-serosal soft tissues. In such cases, an accurate preoperative diagnosis is often difficult and challenging, especially in extrapleural ones. Traditionally, extrapleural solitary fibrous tumours have been regarded as indolent neoplasms similar to their intra-thoracic counterparts, although there has been some evidence that this subgroup could be a subset of more aggressive malignant tumours. For these reasons, surgical excision is mandatory and represents, to date, the best therapeutic option. In this article we report a case of a malignant solitary fibrous tumor of the chest wall in a 58-year-old man. Problems related to differential diagnosis and the possible pitfalls that can be encountered in the diagnostic process of such rare tumors are discussed.

[Clinical effect of bovine pericardial strips on air leak after stapled pulmonary resection in "frail" patients: early results]. / Impiego clinico di suturatrici rivestite con pericadio bovino nella prevenzione delle perdite aeree postoperatorie in pazienti "fragili" sottoposti a resezione polmonare.

AIM: Postoperative air leaks and in particular persistent air leaks (>5 days) after pulmonary resection still represent a common complication and the first cause of hospital stay delay. Aim of this experimental trial was to investigate the efficacy of the use of bovine pericardium strips (in terms of reduction of postoperative leakage and hospital stay) in "critical" patients (COPD, emphysema etc.) who underwent pulmonary resection. METHODS: From October 2010 to February 2011, eight patients (experimental group, Group A) were preoperative selected and underwent pulmonary resection with bovine pericardium strips (Peri-Strips Dry; Synovis ). The inclusion criteria of a "frail patient" were established by a dedicate pneumologist according with clinical and functional data (predicted postoperative FEV1 ranging from 35% and 80% of the theorical predicted value). For comparison, from January 2010 to September 2010, we retrospectively reviewed the data of 28 patients who satisfied the same inclusion criteria and underwent pulmonary resection with standard surgical procedures. This group of patients represents our control group (Group B). RESULTS: There were no significant differences between the two groups in age, gender, preoperative risk factors for developing a postoperative air leak, preop FEV1 and type of resection. No technical deficiencies in the use of bovine pericardium strips were observed in Group A. Postoperative leakage was significant different in the two groups being persistent air leak detected in 0% in Group A versus 17.8% of Group B (P=0.046). Consequently, chest tube duration (6.75±0.84 days [Group A] vs. 9.70±1.26 days (Group B), P=0.019) and hospital stay (10.13±0.83 days [Group A] vs. 12.95±1.37 days [Group B], P=0.013) were lower in the experimental group. CONCLUSION: Bovine pericardium strips are safe and easy-to-do technique to reduce postoperative air leaks after pulmonary resection in "critical" patients.

Insular lateralization in tinnitus distress.

Tinnitus affects 15% of the population. Of these 1-2% are severely disabled by it. The role of the autonomic system in tinnitus is hardly being investigated. The aim of this study is to investigate the relationship between tinnitus distress and lateralization of the anterior insula, known to be involved in interoceptive awareness and (para)sympathetic changes. For this, Tinnitus Questionnaire scores are correlated to Heart Rate Variability markers, and related to neural activity in left and right anterior insula. Our results show that tinnitus distress is related to sympathetic activation, in part mediated via the right anterior insula.

sw-SVM: sensor weighting support vector machines for EEG-based brain-computer interfaces.

In many machine learning applications, like brain-computer interfaces (BCI), high-dimensional sensor array data are available. Sensor measurements are often highly correlated and signal-to-noise ratio is not homogeneously spread across sensors. Thus, collected data are highly variable and discrimination tasks are challenging. In this work, we focus on sensor weighting as an efficient tool to improve the classification procedure. We present an approach integrating sensor weighting in the classification framework. Sensor weights are considered as hyper-parameters to be learned by a support vector machine (SVM). The resulting sensor weighting SVM (sw-SVM) is designed to satisfy a margin criterion, that is, the generalization error. Experimental studies on two data sets are presented, a P300 data set and an error-related potential (ErrP) data set. For the P300 data set (BCI competition III), for which a large number of trials is available, the sw-SVM proves to perform equivalently with respect to the ensemble SVM strategy that won the competition. For the ErrP data set, for which a small number of trials are available, the sw-SVM shows superior performances as compared to three state-of-the art approaches. Results suggest that the sw-SVM promises to be useful in event-related potentials classification, even with a small number of training trials.

Vascular phenotypes in primary non-small cell lung carcinomas and matched brain metastases.

BACKGROUND: Anti-angiogenic therapy with bevacizumab (an anti-vascular endothelial growth factor (VEGF) antibody) predominantly targets immature blood vessels. Bevacizumab has shown a survival benefit in non-small cell lung carcinoma (NSCLC) and has recently been demonstrated to be safe in patients with brain metastases. However, it is not known whether bevacizumab is effective against brain metastases or whether metastases are representative of their primary in terms of VEGF expression, hypoxia, proliferation and vascular phenotype. The aim of this study was to evaluate these factors in a series of matched primary NSCLCs and brain metastases. METHODS AND RESULTS: Immunohistochemistry showed strong correlation of carbonic anhydrase 9 expression (a marker of hypoxia) in primary and secondary cancers (P=0.0002). However, the proliferation index, VEGF expression, microvessel density and the proportion of mature vessels were discordant between primary and secondary cancers. The mean proportion of mature vessels was 63.2% higher in the brain metastases than the primary tumours (P=0.004). Moreover, the vascular pattern of the primary tumour was not representative of the metastasis. CONCLUSIONS: Brain metastases have a significantly higher proportion of mature vasculature, suggesting that they may be refractory to anti-VEGF therapy. These findings may have implications for clinical trials and biomarker studies evaluating anti-angiogenic agents in brain metastases.

A robust sensor-selection method for P300 brain-computer interfaces.

A brain-computer interface (BCI) is a specific type of human-computer interface that enables direct communication between human and computer through decoding of brain activity. As such, event-related potentials like the P300 can be obtained with an oddball paradigm whose targets are selected by the user. This paper deals with methods to reduce the needed set of EEG sensors in the P300 speller application. A reduced number of sensors yields more comfort for the user, decreases installation time duration, may substantially reduce the financial cost of the BCI setup and may reduce the power consumption for wireless EEG caps. Our new approach to select relevant sensors is based on backward elimination using a cost function based on the signal to signal-plus-noise ratio, after some spatial filtering. We show that this cost function selects sensors' subsets that provide a better accuracy in the speller recognition rate during the test sessions than selected subsets based on classification accuracy. We validate our selection strategy on data from 20 healthy subjects.