Motivation and Aims
Each year, a large number of people are diagnosed with a disorder of consciousness or a disorder leading to motor impairment. Such people are then confronted with two severe gaps of knowledge:
- Firstly, there is a likelihood of up to 40% that they will be misdiagnosed
- Secondly, if motor impairment becomes permanent a single-switch device independent of motor output is not readily available
We may classify non-responsive patients according to their aetiology in two large groups:
- Patients who fail to respond due to low arousal, lack of intention or short attention span; the motor system may maintain a certain repertoire of function in those patients.
Examples for such diseases are:
- Persistent vegetative state, e.g. after traumatic brain injury, stroke, or anoxia
- Minimally conscious state, e.g. traumatic brain injury, stroke or anoxia
- Akinetic mutism, e.g., after lesions in the anterior cingulate cortex
- Parkinson’s disease
- Patients who do not respond due to failure of the motor system, in presence of a preserved awareness. Examples of such disease are:
- High-level spinal cord injury
- Amyotrophic lateral sclerosis
- Multiple sclerosis
- Muscular dystrophy
- Stroke (brainstem and cerebellar)
Brain disorders (psychiatric, neurological diseases together) are amongst the leading causes of disease and disability. Data from WHO suggest that brain disorders cause 35% of the burden of all diseases in Europe. Among brain disorders, those of interest in DECODER can represent the cause of the most severe levels of disability.
It is important to mention that it is not only the patients themselves who are affected by these diseases. The uncertainty of diagnosis strongly affects partners and relatives of patients and the inability to communicate poses a tremendous burden for those who are caring for the patients. Thus, the diagnostic battery and the ssBCI with its applications developed by DECODER will bring a significant improvement of the quality of life of patients and their families.
Most of the listed diseases may lead to a non-responsive state in which no communication is possible between the patient and other people or the environment. For patients with disorders of consciousness (DOC) like persistent vegetative state (PVS) and minimally conscious state (MCS) non-responsiveness is even a criterion for diagnosis of the disease. Patients with DOC present a great challenge to diagnostics, prognostics and therapeutics.
The non-responsiveness of such patients implies that they can only be diagnosed by means of exclusion criteria like “no goal-directed eye movement” or “no execution of commands”.
Those behavioural signs may be very discrete, short-termed and the performance may be fluctuating. The signs may therefore pass without being noticed. Thus, there is an urgent NEED for a hierarchical approach to diagnosis of consciousness. DECODER would greatly improve diagnosis, because it included active components.
There are two equivalent primary aims of DECODER:
- Overcome the diagnostic gap by promoting and establishing diagnostic tools for non-responsive patients which will be easy to handle, to apply and the results of which will be unequivocal. A hierarchical approach to cortical processing and consciousness will be developed and established mainly on the basis of the EEG as it provides a brilliant resolution in time of brain activity. As spatial resolution of the EEG is less fine graded as possible by imaging technology, this gap will be bridged with optical imaging. Current diagnostic tools on the basis of functional magnetic resonance imaging will be transferred to optical imaging (near infrared spectroscopy) which can be applied at the patients’ bedside.
- Overcome the output gap by further developing and adapting existing BCI systems and applications to single-switch BCI control. As currently funded projects (TOBI and BRAIN) will provide practical assistive BCI, we will focus on adapting this technology to single-switch control. This is important as it can be envisaged that non-responsive patients even after rehabilitation will not be able to recover motor or cortical functioning to such an extent that they will be able to control multi-switch devices or hybrid BCI. Thus, DECODER is aiming at promoting single-switch BCI for inclusion by developing new software tools for the recognition of intention in brain activity and for translating this intention into commands for single-switch BCI.
What we propose with DECODER will merge the so far independent streams of research: detection of consciousness and BCI-based communication and control for the benefit of the patients.
At least, DECODER’s results have to be then disseminated as guidelines, manuals and tools among other non-benefit research and commercial research groups to boost further development.
Possible inaccuracies of information are under the responsability of the project team. The text reflects solely the authors´views. The European Commission is not liable for any use that may be made of the information contained therein.
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