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mindBEAGLE is a brain–computer interface (BCI) system that is specialized for consciousness assessment and communication. The mindBEAGLE system consists of hardware and software that are designed to work with persons diagnosed as comatose, vegetative, or minimally conscious. mindBEAGLE was developed by Guger Technologies OG, or g.tec, an Austrian company that manufactures BCI systems and components. mindBEAGLE was introduced in 2013 and is currently used in scientific and clinical research with different university and hospital partners.

Motivation and need
Every year, thousands of persons are diagnosed as comatose, Minimally Conscious (MC), or in a Vegetative State (VS). These diagnoses may result from a stroke, severe brain injury, or degenerative disease like Lou Gehrig’s disease (also called Amyotrophic Lateral Sclerosis or ALS). These people are generally considered totally unaware of their environments, with very little or no ability to hear, feel, think, or understand. Family and friends often stop trying to communicate with them, and may make end-of-life decisions based on the belief that communication may never be possible.

However, recent work has shown that some of these diagnoses may be in error. Monti and colleagues asked 24 patients in a Vegetative State yes or no questions, such as “Is your father’s name Thomas?” Four of the patients (17%) showed brain activity in an fMRI scanner that differed for yes versus no questions, suggesting that they were in fact able to hear and understand some questions. Related work suggested that 43% of these patients are misdiagnosed.

Patients may be misdiagnosed for different reasons. Some patients may only be alert for a few hours per day, at different times. Some patients’ conditions may improve after the initial diagnosis. For various reasons, some patients who seem unresponsive might never be thoroughly evaluated by medical staff with the necessary time, expertise, or equipment.

Later research showed that EEG methods could also assess whether patients are conscious and provide communication. EEG systems are much more portable, comfortable, affordable, and practical than fMRI systems. Many studies have validated EEG-based BCIs with severely disabled patients, but these studies usually relied on visual stimuli. Since patients diagnosed as comatose, MC, or VS do not typically have intact vision, researchers had to rely on other sensory modalities. Although most P300 BCIs rely on visual stimuli, such as flashing letters on a monitor, prior research had validated P300 BCIs based on touch or hearing. In one study, patients wore three vibrotactile stimulators – one on each wrist, and one on the back. These painless devices would briefly vibrate while the patient was asked to focus attention on one stimulator while ignoring the two other stimulators. Some patients could produce distinct brain activity to the target stimulator, demonstrating they could understand instructions and potentially answer questions. With three stimulators, people could answer “yes”, “no”, and a third option such as “skip” or “rephrase.” A different research group validated a BCI based on 6 different tactile stimulators, suggesting that more response options might be possible. Other research showed that locked-in patients can produce distinct brain responses to auditory questions. These recent scientific studies have shown that some people who are diagnosed as comatose, VS, or MC can not only understand questions but can produce distinct brain activity patterns that could (at least) enable them to answer yes or no questions. These results indicate that there is an urgent need for a system that can improve consciousness assessment (to determine whether patients can understand questions) and real-time communication through a BCI. This need motivated the development of mindBEAGLE.

MindBEAGLE components and features
mindBEAGLE is a BCI system that consists of a portable medical grade amplifier, an electrode cap with active electrodes, earphones that can be placed in the patient’s ear for auditory stimuli, vibrotactile stimulators that can be placed on the body, and a laptop with the mindBEAGLE software. The amplifier relies on oversampling at 2.4 GHz, noise-resistant electronics, and other methods to improve performance in regions with electrical noise, such as hospital environments. The electrode cap uses 16 channels, mostly over central electrode sites, including a reference at site FPz and a ground on the right earlobe. The mindBEAGLE can present stimuli to the user through the earphones, vibrotactile stimulators, or other methods. The software also presents feedback to the system operator, records data for future analysis, and includes adaptive real-time software tools so patients can communicate through a BCI. mindBEAGLE is a standalone product for Windows that does not require Matlab, Simulink, or a strong technical background. mindBEAGLE can help the operator ask the patient yes or no questions through three different paradigms:


 * 1) Auditory P300: The operator must ask the subject a question through the earphones. Next, the mindBEAGLE system presents high and low beeps through the earphones several times. The subject is asked to silently count one of these beeps (called the target beep) while ignoring the other beep. This generates a P300 to the target beep only, which the BCI can detect to determine whether the user means “yes” or “no”. For example, the operator might ask the user is s/he is tired, and the user would count the high beep to convey “yes”.
 * 2) Tactile P300: The operator must place two vibro-tactile stimulators on the patient’s body, such as on each wrist. Next, the operator must ask the patient to silently count each time that one stimulator vibrates (such as the left wrist) to say “yes”, and to count the other stimulator’s vibrations to say “no”. The operator then asks a question, and the patient must then convey “yes” or “no” by counting each time the corresponding stimulator vibrates. Like other P300 BCIs, the mental activity involved in counting each vibration produces a P300 (and other brainwaves) that do not occur when a stimulus is ignored. The BCI detects this P300 activity to enable communication.
 * 3) Motor imagery: In this mindBEAGLE paradigm, a patient can communicate by thinking about movement. This mental activity produces changes that include Event-Related Desynchronization (ERD) over brain areas involved with movement . As with other paradigms, the operator must ask a question that can be answered with a “yes” or “no”. The user can then convey “yes” by imagining moving the left wrist, and “no” by thinking about moving the right wrist. The system can be customized to map different answers to these body areas. Some users may need some training to use this approach effectively, and might find it more effective if they imagine moving other areas (such as the fingers or feet).

In all of these paradigms, the mindBEAGLE software can present data to the operator in real-time, such as the subject’s P300 or motor imagery activity over different sites. mindBEAGLE can also present feedback to the user in real-time, such as “yes” or “no”, based on the user’s brain activity. mindBEAGLE has adaptive software tools that can learn the user’s distinct brain activity patterns to improve accuracy. When working with patients who may be unable to communicate, the selection and presentation of questions is very important. Operators must be careful to ask clear, simple questions that can be answered with “yes” or “no”. The operators must ask one question at a time, wait patiently for a response, and periodically ask if the patient wants to rest or change previous answers. Any patients should be given maximum privacy and told if other people are in the room. Operators should make several efforts to communicate in case the patient was not in a period of wakefulness. Other hardware and software platforms are available, such as OpenVibe, BCILab, intendiX, and BCI2000. A recent book chapter summarized many of the different software platforms. mindBEAGLE is unique because it is the only system that is developed for consciousness assessment and communication. It is also the only system that has been validated with such patients. In addition to relying on stimuli and paradigms that are specialized for consciousness assessment and communication, the mindBEAGLE system uses medical-grade equipment and software to optimize performance in noisy environments. The 16-channel electrode montage relies primarily on central electrode sites, and includes frontal and parietal sites, which is designed to record activity from brain regions used in motor imagery and P300 BCIs. In summary, recent research has shown that some users who are diagnosed as unable to communicate may be misdiagnosed. mindBEAGLE is a BCI system designed to help assess whether users are conscious and then provide communication for them. Although it would work with most people, it is specialized for helping users who are diagnosed as comatose, VS, or MC.