A Real-Time fMRI-Based Spelling Device Immediately Enabling Robust Motor-Independent Communication

Abstract

Human communication entirely depends on the functional integrity of the neuromuscular system. This is devastatingly illustrated in clinical conditions such as the so-called locked-in syndrome (LIS), in which severely motor-disabled patients become incapable to communicate naturally--while being fully conscious and awake. For the last 20 years, research on motor-independent communication has focused on developing brain-computer interfaces (BCIs) implementing neuroelectric signals for communication (e.g., [2-7]), and BCIs based on electroencephalography (EEG) have already been applied successfully to concerned patients. However, not all patients achieve proficiency in EEG-based BCI control. Thus, more recently, hemodynamic brain signals have also been explored for BCI purposes. Here, we introduce the first spelling device based on fMRI. By exploiting spatiotemporal characteristics of hemodynamic responses, evoked by performing differently timed mental imagery tasks, our novel letter encoding technique allows translating any freely chosen answer (letter-by-letter) into reliable and differentiable single-trial fMRI signals. Most importantly, automated letter decoding in real time enables back-and-forth communication within a single scanning session. Because the suggested spelling device requires only little effort and pretraining, it is immediately operational and possesses high potential for clinical applications, both in terms of diagnostics and establishing short-term communication with nonresponsive and severely motor-impaired patients.

Real-time fMRI-based self-regulation of brain activation across different visual feedback presentations

“…Six healthy participants were asked to self-regulate fMRI activation within a pre-defined brain region in the posterior parietal cortex (PPC) by means of a mental calculation task (cf. [28][29][30]), with the help of three different visual feedback representations: (1) a commonly used vertical Thermometer display, (2) a Circle display which decreases or increases in physical size, and (3) a Numbers display showing Arabic digits. These rather basic representations were chosen over more advanced ones (e.g.…”

Assessing Decision-Making Capacity in the Behaviorally Nonresponsive Patient With Residual Covert Awareness

“…Neuroimaging research in this patient group has advanced rapidly in the past 10 years. With reduced costs of imaging equipment, a larger patient population, and several recent innovations in BCI neuroimaging Bardin, Schiff, and Voss 2012;Cruse et al 2011;Goldfine et al 2011;Hampshire et al 2013;Naci et al 2012;Sorger et al 2012), it is likely these technical limitations will be resolved in the future.…”

Civil Law and Neuroscience

“…11 An example can be found in an experimental method to help patients suffering from 'locked-in syndrome' (whereby patients are unable to communicate as a result of complete paralysis) to communicate by means of converting their brain activity into words on a screen. 12 Secondly, neuroscience can contribute by offering insight into behaviour that is relevant for legal practice and the aims that the law strives to achieve. Neuroscientific knowledge can, for example, be relevant in cases in which concepts such as legal capacity, accountability and culpability play a central role.…”