Brain-computer interfaces (BCIs) provide communication that does not depend on neuromuscular activity. Several studies have demonstrated that those with advanced ALS can use noninvasive BCIs (e.g.,1,2,3). In able-bodied users, Townsend et al2 showed that a pseudorandom -or checkerboard paradigm (CBP) significantly improves P300-BCI performance compared to the standard or row/column paradigm (RCP). The CBP flashes stimuli in quasi-random groups that do not contain adjacent items, and it ensures at least six flashes between flashes of a given item. The combination of these two factors improves accuracy and bitrate. Townsend et al [2] also reported anecdotal improvements with the CBP in people with ALS who had extensive experience with the RCP. The present study seeks to verify these results in a larger group of people with ALS.

Most healthy young people can use a visual P300-based speller in a controlled laboratory setting1. Previous studies in people with severe disabilities have been limited to relatively small populations [2,3,4] or have been in populations with a variety of different disorders [5,6]. Here, we evaluate the performance of a larger population of people severely disabled by ALS. We sought to identify factors that affect performance and methods for improving performance. The study is part of a program that is providing the P300 speller for long-term independent home use.

Severe motor disabilities such as amyotrophic lateral sclerosis (ALS) reduce or eliminate neuromuscular control and deprive affected patients of vital communication and control. Recent advances in noninvasive EEG-based BCIs have given patients new hope for communication and environmental control not provided by other assistive devices[1]. General lapses of attention, mind wandering, and lack of focus may all undermine BCI performance[2]. In a P300-BCI, non-target flashes are exogenous cues that could attract attention away from the endogenous task of attending to target item flashes. Thus, inducing a heightened state of attentional awareness and reducing distractibility may improve BCI performance. Mindfulness meditation and induction (MMI) offers such a possibility[3,4]. We expect MMI to have several important consequences for P300-based BCI use: one, it will focus attention to the target item; two, it will reduce distraction from non-target flashes; three, it will reduce P300 target latencies; four it will produce higher amplitude ERPs

Since the introduction of the P300 BCI speller by Farwell and Donchin1 speed and accuracy of the system has been significantly improved. Larger electrode montages and various signal processing techniques are responsible for most of the improvement in performance. The present study takes advantage of a new presentation paradigm to improve performance, the “checkerboard?(CB) paradigm2. The CB presents quasi-random groups of six items instead of using the typical row/column presentation. To determine if reducing distraction from neighbouring items could improve subsequent performance on a copy-spelling task, the CB paradigm was used and compared to a condition that suppressed (i.e., did not flash) items during the calibration phase of the experiment.

Since its inception, the P300-based BCI has typically flashed in rows and columns [1]. Recently, the “checkerboard?(CB) paradigm was introduced in which targets are grouped in rows and columns on two “virtual matrices?taken from the white and black squares of a checkerboard overlaid on the physical matrix [2]. Disassociating the physical rows and columns of the matrix from how they are grouped to flash brings advantages by: 1) avoiding the problematic effects of double target flashes [3], and 2) not allowing adjacent targets to flash together. In this study, this disassociation of the “flash groups?from the physical matrix is taken further. The flash groups become purely “abstract?bearing no relationship to rows or columns either physical or virtual. This study compares performance of this new paradigm named ?-Flash?(5F) to the CB.

To date, only one study has situationally bolstered attentional resources in an effort to improve P300-BCI performance. The current study implements a 4-week Mindfulness Meditation Training Program (MMTP) as a nonmedicinal means to increase concentrative attention and to reduce lapses of attention; MMTP is expected to improve P300-BCI performance by enhancing attentional resources and reducing distractibility. A second aim is to test the efficacy of the checkerboard paradigm (CBP) against the standard row-column paradigm (RCP). Online results show that MMTP had greater accuracies than CTRL and that CBP outperformed the RCP. MMTP participants provided greater amplitude positive target responses, but these differences were not statistically significant. CBP had greater positive amplitude peaks and negative peaks than RCP. The discussion focuses on potential benefits of MMTP for P300-based BCIs, provides further support for the construct validity of mindfulness, and addresses future directions of the translational applicability of MMTP to in-home settings.

BACKGROUND: Food-related visual cues may affect eating behavior and energy intake. The purpose of this study was to determine the neural response to pictures of food and whether or not the neural responses were associated with energy intake. METHODS: Using a cross-sectional design, 60 adults participated in this study. Each participant reported to the laboratory in a fasted state, were fitted with a 128-electrode electroencephalogram (EEG) net, and were shown pictures grouped into three categories: high-calorie foods, low-calorie foods, and distractor pictures. These pictures were shown in random order. Furthermore, participants were shown these pictures in one passive condition and two active conditions (also in random order). The passive condition required participants to view pictures in a relaxed state while neural responses were recorded. The active conditions required participants to be actively engaged with the picture by pressing or withholding a specified button on a keyboard (go/no go task). The active conditions included only high- and low-calorie foods. Event Related Potentials (ERP) of interest were the N2, P300, and late positive potential (LPP). The National Cancer Institute's Automated Self-administered 24-hour Dietary Recall (ASA24) was used to assess energy and macronutrient intake. RESULTS: The N2 amplitude, when amplitude for high-calorie pictures is subtracted from the amplitude of low-calorie pictures, was significantly different for each active condition (F = 41.23; p < 0.0001). However, neural responses to picture-type for the N2, P300 and LPP were not different (p > 0.05). The difference in N2 amplitude, for the high-calorie no go condition that results from the amplitude for low and high-calorie pictures being subtracted from each other, was significantly associated with carbohydrate intake (r = -0.263) and significantly predicted carbohydrate intake (regression coefficient = -56.821; p = 0.043) but not energy, fat, or protein intake (p > 0.05). Neither the P300 nor the LPP was correlated with or predicted energy and macronutrient intake (p > 0.05). CONCLUSION: The N2 differentiates depending on the no go stimulus. The difference in N2 amplitude, for the high-calorie no go condition, may be an index of carbohydrate intake. The P300 and LPP do not appear to differentiate between pictures of high- and low-calorie foods, nor do they correlate with energy or macronutrient intake.

Many questions remain unanswered regarding the intricacies of the human brain, especially with regard to the complexities of language processing. One essential component of human sentence processing is the ability to detect, decipher, and recover from errors in the interpretation of both verbal and written language. This process of repair of ungrammatical sentences and revision or reinterpretation of ambiguous sentences has been studied extensively in recent years. A variety of tools have been developed, including the use of event-related potentials (ERPs) in order to assess how language is processed and developed, and to help better identify the nature of these processes. The purpose of this study was to compare event-related potential effects of speech processing of spoken and written sentences containing both incorrect and correct semantic and syntactic information. Specifically, sentences containing correct and incorrect gapping structures, each with a "missing" verb, were presented along with other grammatical and ungrammatical sentences in order to elicit and measure the P300, N400, and P600 amplitudes and latencies. The aim was to determine some of the commonalities and differences in these electrophysiological responses via the auditory and visual modalities. Two experiments were conducted with each participant, one in the auditory modality, and one within the visual using two sets of stimuli. Amplitude and topography differences were noted within and between modalities for each of the components (P300, N400, and P600), as well as between stimulus types. Significant findings suggest that in the adolescent population, incorrect gapping structures are generally processed as semantic errors, as evidenced by the N400 response, followed by the P600 response in both the auditory and visual modalities. The exact nature of the P600 component within gapping structures remains unclear. Of particular interest was the involvement of the occipital area of the brain for the processing of gapping structures. Minimal differences were noted overall between adolescents and the adult populations.

This project examined the effects menstruation may have on visual attention in women. A recent study examined electroencephalographic (EEG) gender differences using a visual object recognition task. Results indicated certain EEG amplitudes (specifically, P300 and N400) are greater in women than men. This study extended the previous findings to determine if these increased EEG amplitudes vary across menstrual phases. Eighteen female participants participated in a series of 3 EEG recording sessions using the same visual object recognition task from the previous study; 18 male participants completed this task once. Analyses from 15 of the 18 female and 16 of the 18 male participants support the previous finding of larger P300 amplitudes in response to relevant stimuli for women compared with men. While there was no distinctive N400 component in this study, there was a late negative (LN) component which was found to vary significantly between men and women. In addition, multiple visual evoked potential (VEP) components varied significantly across the menstrual cycle. In particular, the N200 component appeared to provide greater differences between menstrual phases than either the P300 or LN components; however, the results varied greatly by head location. The differentiation found with VEP components in response to the pop-out task used in this study provide support for basic visual processing variation across the menstrual cycle and between genders.

Objective: An electroencephalographic brain-computer interface (BCI) can provide a non-muscular means of communication for people with amyotrophic lateral sclerosis (ALS) or other neuromuscular disorders. We present a novel P300-based BCI stimulus presentation - the checkerboard paradigm (CBP). CBP performance is compared to that of the standard row/column paradigm (RCP) introduced by Farwell and Donchin (1988). Methods: Using an 8 × 9 matrix of alphanumeric characters and keyboard commands, 18 participants used the CBP and RCP in counter-balanced fashion. With approximately 9-12 min of calibration data, we used a stepwise linear discriminant analysis for online classification of subsequent data. Results: Mean online accuracy was significantly higher for the CBP, 92%, than for the RCP, 77%. Correcting for extra selections due to errors, mean bit rate was also significantly higher for the CBP, 23 bits/min, than for the RCP, 17 bits/min. Moreover, the two paradigms produced significantly different waveforms. Initial tests with three advanced ALS participants produced similar results. Furthermore, these individuals preferred the CBP to the RCP. Conclusions: These results suggest that the CBP is markedly superior to the RCP in performance and user acceptability. Significance: The CBP has the potential to provide a substantially more effective BCI than the RCP. This is especially important for people with severe neuromuscular disabilities.