Online Detection of P300 and Error Potentials in a BCI Speller

Error potentials (ErrPs), that is, alterations of the EEG traces related to the subject perception of erroneous responses, have been suggested to be an elegant way to recognize misinterpreted commands in brain-computer interface (BCI) systems. We implemented a P300-based BCI speller that uses a genetic algorithm (GA) to detect P300s, and added an automatic error-correction system (ECS) based on the single-sweep detection of ErrPs. The developed system was tested on-line on three subjects and here we report preliminary results. In two out of three subjects, the GA provided a good performance in detecting P300 (90% and 60% accuracy with 5 repetitions), and it was possible to detect ErrP with an accuracy (roughly 60%) well above the chance level. In our knowledge, this is the first time that ErrP detection is performed on-line in a P300-based BCI. Preliminary results are encouraging, but further refinements are needed to improve performances

The utility metric: A novel method to assess the overall performance of discrete braincomputer interfaces

Abstract-A relevant issue in a brain-computer interface (BCI) is the capability to efficiently convert user intentions into correct actions, and how to properly measure this efficiency. Usually, the evaluation of a BCI system is approached through the quantification of the classifier performance, which is often measured by means of the information transfer rate (ITR). A shortcoming of this approach is that the control interface design is neglected, and hence a poor description of the overall performance is obtained for real systems. To overcome this limitation, we propose a novel metric based on the computation of BCI Utility. The new metric can accurately predict the overall performance of a BCI system, as it takes into account both the classifier and the control interface characteristics. It is therefore suitable for design purposes, where we have to select the best options among different components and different parameters setup. In the paper, we compute Utility in two scenarios, a P300 speller and a P300 speller with an Error Correction System (ECS), for different values of accuracy of the classifier and recall of the ECS. Montecarlo simulations confirm that Utility predicts the performance of a BCI better than ITR. Index Terms-brain-computer interface (BCI), BCI performance, P300 speller, error potentia

Workshops of the Sixth International Brain–Computer Interface Meeting: brain–computer interfaces past, present, and future

Brain–computer interfaces (BCI) (also referred to as brain–machine interfaces; BMI) are, by definition, an interface between the human brain and a technological application. Brain activity for interpretation by the BCI can be acquired with either invasive or non-invasive methods. The key point is that the signals that are interpreted come directly from the brain, bypassing sensorimotor output channels that may or may not have impaired function. This paper provides a concise glimpse of the breadth of BCI research and development topics covered by the workshops of the 6th International Brain–Computer Interface Meeting

The Celebrity System: a National and International Phenomenon.

none2Celebrity worship has been studied for many years and yet it still is an elusive phenomenon, one that is hardly predictable and at times inexplicable. The three elements of communication - celebrities, product (movie, fiction and show) and public – are part of this specific type of communication too. The main psychological mechanism used by fans is projection, because, through fanatism, they can experience certain emotions “by proxy”. Methods – The aim of this research is to analyze the features that make a character become a celebrity. We identified four fields in society that can produce divism: show business, sport, jet set, politics. A specific questionnaire was created and submitted to 120 subjects (average: 23,8 years old). This questionnaire was about the evaluation of 47 well known national and international personalities, belonging to one of the four identified fields and whose presence in tabloid “Chi” was particularly rich in 2007, 2008 and 2009. Results and conclusions – Cinema creates an international type of celebrity worship and television a “widespread” one or, in other words, a celebrity worship that is short, local and less charismatic. Stars’ most peculiar aspect is fame and their most frequently acknowledge qualities are beauty, luckiness, stubbornness and richness. To conclude, international celebrities keep alive the classical meaning of celebrity worship but there’s also a local acceptation of the term that makes this less showy celebrity worship an element that’s almost part of our everyday lifes.noneMariselda Tessarolo; Marta Dal SenoTessarolo, Mariselda; Marta Dal, Sen

The Utility Metric: A Novel Method to Assess the Overall Performance of Discrete Brain-Computer Interfaces

A relevant issue in a brain–computer interface (BCI) is the capability to efficiently convert user intentions into correct actions, and how to properly measure this efficiency. Usually, the evaluation of a BCI system is approached through the quantification of the classifier performance, which is often measured by means of the information transfer rate (ITR). A shortcoming of this approach is that the control interface design is neglected, and hence a poor description of the overall performance is obtained for real systems. To overcome this limitation, we propose a novel metric based on the computation of BCI Utility. The new metric can accurately predict the overall performance of a BCI system, as it takes into account both the classifier and the control interface characteristics. It is therefore suitable for design purposes, where we have to select the best options among different components and different parameters setup. In the paper, we compute Utility in two scenarios, a P300 speller and a P300 speller with an error correction system (ECS), for different values of accuracy of the classifier and recall of the ECS. Monte Carlo simulations confirm that Utility predicts the performance of a BCI better than ITR