Cortical control of a tablet computer by people with paralysis.
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ABSTRACT:
SUBMITTER: Nuyujukian P
PROVIDER: S-EPMC6248919 | biostudies-literature | 2018
REPOSITORIES: biostudies-literature
Publications
Cortical control of a tablet computer by people with paralysis.
Nuyujukian Paul P Albites Sanabria Jose J Saab Jad J Pandarinath Chethan C Jarosiewicz Beata B Blabe Christine H CH Franco Brian B Mernoff Stephen T ST Eskandar Emad N EN Simeral John D JD Hochberg Leigh R LR Shenoy Krishna V KV Henderson Jaimie M JM
PloS one 20181121 11
General-purpose computers have become ubiquitous and important for everyday life, but they are difficult for people with paralysis to use. Specialized software and personalized input devices can improve access, but often provide only limited functionality. In this study, three research participants with tetraplegia who had multielectrode arrays implanted in motor cortex as part of the BrainGate2 clinical trial used an intracortical brain-computer interface (iBCI) to control an unmodified commerc ...[more]
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Project description:Brain-computer interfaces (BCIs) have the potential to restore communication for people with tetraplegia and anarthria by translating neural activity into control signals for assistive communication devices. While previous pre-clinical and clinical studies have demonstrated promising proofs-of-concept (Serruya et al., 2002; Simeral et al., 2011; Bacher et al., 2015; Nuyujukian et al., 2015; Aflalo et al., 2015; Gilja et al., 2015; Jarosiewicz et al., 2015; Wolpaw et al., 1998; Hwang et al., 2012; Spüler et al., 2012; Leuthardt et al., 2004; Taylor et al., 2002; Schalk et al., 2008; Moran, 2010; Brunner et al., 2011; Wang et al., 2013; Townsend and Platsko, 2016; Vansteensel et al., 2016; Nuyujukian et al., 2016; Carmena et al., 2003; Musallam et al., 2004; Santhanam et al., 2006; Hochberg et al., 2006; Ganguly et al., 2011; O'Doherty et al., 2011; Gilja et al., 2012), the performance of human clinical BCI systems is not yet high enough to support widespread adoption by people with physical limitations of speech. Here we report a high-performance intracortical BCI (iBCI) for communication, which was tested by three clinical trial participants with paralysis. The system leveraged advances in decoder design developed in prior pre-clinical and clinical studies (Gilja et al., 2015; Kao et al., 2016; Gilja et al., 2012). For all three participants, performance exceeded previous iBCIs (Bacher et al., 2015; Jarosiewicz et al., 2015) as measured by typing rate (by a factor of 1.4-4.2) and information throughput (by a factor of 2.2-4.0). This high level of performance demonstrates the potential utility of iBCIs as powerful assistive communication devices for people with limited motor function.Clinical Trial No: NCT00912041.
| S-EPMC5319839 | biostudies-literature
Project description:OBJECTIVE:Brain-computer interface (BCI) technology aims to provide individuals with paralysis a means to restore function. Electrocorticography (ECoG) uses disc electrodes placed on either the surface of the dura or the cortex to record field potential activity. ECoG has been proposed as a viable neural recording modality for BCI systems, potentially providing stable, long-term recordings of cortical activity with high spatial and temporal resolution. Previously we have demonstrated that a subject with spinal cord injury (SCI) could control an ECoG-based BCI system with up to three degrees of freedom (Wang et al 2013 PLoS One). Here, we expand upon these findings by including brain-control results from two additional subjects with upper-limb paralysis due to amyotrophic lateral sclerosis and brachial plexus injury, and investigate the potential of motor and somatosensory cortical areas to enable BCI control. APPROACH:Individuals were implanted with high-density ECoG electrode grids over sensorimotor cortical areas for less than 30 d. Subjects were trained to control a BCI by employing a somatotopic control strategy where high-gamma activity from attempted arm and hand movements drove the velocity of a cursor. MAIN RESULTS:Participants were capable of generating robust cortical modulation that was differentiable across attempted arm and hand movements of their paralyzed limb. Furthermore, all subjects were capable of voluntarily modulating this activity to control movement of a computer cursor with up to three degrees of freedom using the somatotopic control strategy. Additionally, for those subjects with electrode coverage of somatosensory cortex, we found that somatosensory cortex was capable of supporting ECoG-based BCI control. SIGNIFICANCE:These results demonstrate the feasibility of ECoG-based BCI systems for individuals with paralysis as well as highlight some of the key challenges that must be overcome before such systems are translated to the clinical realm. ClinicalTrials.gov Identifier: NCT01393444.
| S-EPMC5841472 | biostudies-literature
Project description:Intracortical brain-computer interfaces (BCIs) can enable individuals to control effectors, such as a computer cursor, by directly decoding the user's movement intentions from action potentials and local field potentials (LFPs) recorded within the motor cortex. However, the accuracy and complexity of effector control achieved with such "biomimetic" BCIs will depend on the degree to which the intended movements used to elicit control modulate the neural activity. In particular, channels that do not record distinguishable action potentials and only record LFP modulations may be of limited use for BCI control. In contrast, a biofeedback approach may surpass these limitations by letting the participants generate new control signals and learn strategies that improve the volitional control of signals used for effector control. Here, we show that, by using a biofeedback paradigm, three individuals with tetraplegia achieved volitional control of gamma LFPs (40-400 Hz) recorded by a single microelectrode implanted in the precentral gyrus. Control was improved over a pair of consecutive sessions up to 3 days apart. In all but one session, the channel used to achieve control lacked distinguishable action potentials. Our results indicate that biofeedback LFP-based BCIs may potentially contribute to the neural modulation necessary to obtain reliable and useful control of effectors. NEW & NOTEWORTHY Our study demonstrates that people with tetraplegia can volitionally control individual high-gamma local-field potential (LFP) channels recorded from the motor cortex, and that this control can be improved using biofeedback. Motor cortical LFP signals are thought to be both informative and stable intracortical signals and, thus, of importance for future brain-computer interfaces.
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Project description:OBJECTIVE:When using an intracortical BCI (iBCI), users modulate their neural population activity to move an effector towards a target, stop accurately, and correct for movement errors. We call the rules that govern this modulation a 'feedback control policy'. A better understanding of these policies may inform the design of higher-performing neural decoders. APPROACH:We studied how three participants in the BrainGate2 pilot clinical trial used an iBCI to control a cursor in a 2D target acquisition task. Participants used a velocity decoder with exponential smoothing dynamics. Through offline analyses, we characterized the users' feedback control policies by modeling their neural activity as a function of cursor state and target position. We also tested whether users could adapt their policy to different decoder dynamics by varying the gain (speed scaling) and temporal smoothing parameters of the iBCI. MAIN RESULTS:We demonstrate that control policy assumptions made in previous studies do not fully describe the policies of our participants. To account for these discrepancies, we propose a new model that captures (1) how the user's neural population activity gradually declines as the cursor approaches the target from afar, then decreases more sharply as the cursor comes into contact with the target, (2) how the user makes constant feedback corrections even when the cursor is on top of the target, and (3) how the user actively accounts for the cursor's current velocity to avoid overshooting the target. Further, we show that users can adapt their control policy to decoder dynamics by attenuating neural modulation when the cursor gain is high and by damping the cursor velocity more strongly when the smoothing dynamics are high. SIGNIFICANCE:Our control policy model may help to build better decoders, understand how neural activity varies during active iBCI control, and produce better simulations of closed-loop iBCI movements.
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Project description:Introduction Tobacco smoking is related with a substantial morbidity and mortality as well as with tremendous socioeconomic burden. Therefore, an early successful smoking cessation bears an enormous medical and socioeconomic importance. The gold standard of smoking cessation, a combination of behavioral und pharmacologic therapy reaches only few smokers every year and so, guideline-based, low-threshold and broadly available digital cessation support could considerably increase the annual cessation rate. With the digital cessation program "Nichtraucherhelden" such a guideline-based program is available in Germany since December 2016.Methods The program consists of 2 preparation days and 10 program days und contains the major features of common smoking cessation courses. The present study examined the participants from December 2016 to November 2019 (n = 2491) regarding acceptance, adherence and effectivity. 69 % were female and the average age was 46 years.Results On average cessation was attained after 19 days. One year after the program a cessation rate of 15 % was achieved. Surprisingly, the cessation rate was higher in more addictive compared to less addictive participants.Conclusion The study shows that a digital guideline-based cessation program is feasible and effectual. For confirmation a control and randomized study is required.
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Project description:ObjectiveTo test the efficacy of a tablet computer training intervention to improve cognitive abilities of older adults.DesignProspective randomized controlled trial.SettingCommunity-based aging intervention study, Edinburgh, UK.ParticipantsForty-eight healthy older adults aged 65 to 76 years were recruited at baseline with no or minimal tablet experience; 43 completed follow-up testing.InterventionTwenty-two participants attended a weekly 2-hour class for 10 weeks during which they learned how to use a tablet and various applications on it.MeasurementsA battery of cognitive tests from the WAIS-IV measuring the domains of Verbal Comprehension, Perceptual Processing, Working Memory, and Processing Speed, as well as health, psychological, and well-being measures.ResultsA 2 × 2 mixed model ANOVA suggested that the tablet intervention group (N = 22) showed greater improvements in Processing Speed (η2 = 0.10) compared with controls (N = 21), but did not differ in Verbal Comprehension, Perceptual Processing, or Working Memory (η2 ranged from -0.03 to 0.04).ConclusionsEngagement in a new mentally challenging activity (tablet training) was associated with improved processing speed. Acquiring skills in later life, including those related to adopting new technologies, may therefore have the potential to reduce or delay cognitive changes associated with ageing. It is important to understand how the development of these skills might further facilitate everyday activities, and also improve older adults' quality of life.
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