A brain-computer interface (BCI) speller provides non-muscular communication via detection of EEG features. In a non-disabled population, a Checkerboard (CB) stimulus presentation has been shown to improve BCI performance over the standard Row/Column (RC) paradigm. Another improvement is a gray-to-color (CL) paradigm that presents perceptually-salient targets defined by nine unique colors. The current study examines the RC, CB, and CL paradigms in an amyotrophic lateral sclerosis (ALS) population (N = 7). Pilot data suggest improved performance of CB and CL over RC. The results suggest matrices including CB and CL provide more efficient communication and higher user satisfaction in an ALS population.

Brain-Computer Interface is an alternative method of communication. The present BCI operates via eventrelated potentials (ERPs) extracted from the electroencephalograph (EEG). Items (i.e., alphanumeric characters and keyboard commands) attended to by the subject should produce a P300 ERP; unattended items should not. Participants are assigned to either a Motivation condition or a Non-motivation condition. We hypothesized that performance on a copy spelling task will be affected by an individual’s motivation, or drive, to perform well. Before the BCI task is introduced to the subjects in the motivation condition, they are read a paragraph describing the importance of the task. Subjects in the non-motivation condition are introduced to the BCI task and begin the experiment. Mean accuracy in the motivation group was 93%, significantly higher than accuracy in the nonmotivation group, 84% (t < .001). These results show that motivation can be an important factor to successful BCI use. Motivation should be considered as a factor that will influence BCI performance in disabled populatio

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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.

Individuals affected by severe physical limitations, such as those caused by amyotrophic lateral sclerosis (ALS) or brainstem stroke, may not have the physical ability required to use clinically available augmentative and assistive communication systems. The P300 speller relies on the detection of responses elicited in EEG signals and has been used as a method of technology access for individuals with significant disability 1, 2. Our research focuses on improving P300 spellers in two areas: improved pattern recognition techniques and channel selection techniques for detecting P300 event-related potentials (ERPs) in the measured multi-channel EEG data, and optimal stimulus selection for improved efficiency and performance.

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.

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.

Depression in transitional aged youth (TAY; aged ~16-24yr) has become a major issue of concern, with 14-25% of those aged 12-21yr experiencing at least one episode of depression. As such, the burden of disease of depression in this population is substantial. Depression in TAY is characterized as a chronic, relapsing disorder, with 50-70% of remitted patients developing a subsequent depressive episode within five years. Further, in younger adulthood (~21-38yr) individuals who experience depression do not always show complete functional recovery between episodes and report residual cognitive impairments. However, research examining the neural correlates of putative cognitive impairments in depressed individuals has traditionally focused on adult populations, with more limited research in depressed TAY. One means of characterizing neural profiles during cognitive processing is via electroencephalography (EEG), and event-related potentials (ERPs) extracted from EEG. To date, it is unclear if ERP profiles during tasks tapping into certain cognitive processes known to be altered in depressed adults are comparable in depressed TAY. Greater insight into the neural features of cognitive processes in the context of depression can, ultimately, help in refining intervention and perhaps prevention strategies in depressed youth. The primary aim of this work was to assess ERP-indexed neural profiles of attention, including novelty orienting, and inhibition via the auditory oddball and visual flanker tasks in depressed, unmedicated TAY (DEP) vs. non-depressed TAY (HC). Specifically, the N2 and P3 ERPs elicited by incongruent and congruent stimuli in a visual flanker task were assessed, as were the P3a and P3b ERPs extracted from an auditory novelty oddball task. Further, behavioural scores on three tasks, measured by the National Institutes of Health (NIH) Toolbox, that tap into similar cognitive processes as the ERP tasks (i.e., executive function, stimulus evaluation, inhibition, and working memory) were compared between groups using well-validated cognitive tests. Finally, correlations were carried out on the entire sample’s cognition scores and ERP measures, as well as the DEP group’s clinical scores and ERP measures to explore the relation between behavioural and neural features. A significant difference was found between groups for the early P3a (eP3a) latency elicited by unexpected novel sounds in the oddball task; the DEP group had a significantly shorter latency than the HC group. For the flanker task, group differences were found for N2 amplitude to incongruent flanker stimuli, wherein the DEP group showed significantly higher amplitudes than the HC group. No group differences were found between composite scores of three NIH Toolbox tasks assessed. Correlations revealed a positive relation between the Dimensional Change Card Sort test (NIH Card Sort task), generally regarded as a test of executive function, and P3 amplitude to both congruent and incongruent stimuli on the ERP Flanker task. Second, a positive relation existed between the Flanker Inhibitory Control and Attention task (NIH Flanker) and P3 latency on the ERP Flanker task. This study failed to replicate previous reports of reduced ERP amplitudes and increased latencies of the oddball and flanker tasks in a depressed adult populations population. However, they contribute to our limited knowledge on the effects of depression in youth on cognitive processes and associated neuronal profiles. Indeed, the data suggest that non-severely depressed and unmedicated young people exhibited more efficient cortical processing to novelty orienting than matched controls, perhaps reflecting a hyper-vigilant state. Further, depressed TAY appeared to exhibit more pronounced cortical resource allocation to processes implicated in inhibition. Across all participants, we were also able to demonstrate a relation between better executive function and increased cortical resource allocation to attentive processes, and greater behavioural inhibition being associated with longer cortical processes of attention. Collectively, these data inform our understanding of the neural processes in young people with depression; such insight may aid in more refined intervention and prevention strategies in the future.