A review on brain computer interfaces: contemporary achievements and future goals towards movement restoration (original) (raw)

Severe motor impairment and disability can be caused by many clinical situations and constitutes a challenge yet unmet by contemporary medicine 1 . Ranging from appendix movement loss to high spinal cord damage and from upstarting Amyotrophic Lateral Sclerosis (ALS) to complete locked-in syndrome, these situations mostly remain effectively uncured. Patients in those cases share one common characteristic: a severed link between thought and action, meaning a block between the transmission of the patient's will to move, speak or otherwise communicate with her surroundings (thought) and the actual movement, speech and communication (action). Bridging those two elements has been a focal point of many research fields, including pharmacology, biology and genetics and, lately, neuroinformatics. The concept of Man-Machine Interfaces (MMI) has been under research essentially since the 80s 2 (and perceived soon after by science fiction), but only in the 90s and onwards has solidified itself into the formed, separate scientific field of Human-Computer Interaction (HCI) and, more specifically and importantly, the field of Brain-Computer Interfaces (BCI) 3 . Those interfaces aim to somehow "restore" the loss of brain-environment communication and bypass the cause of that loss, thereby posing as a promising solution/treatment to the aforementioned medical conditions. Brain Computer Interfaces are systems that use brain activity to interpret voluntary movement thought to control of external devices such as, computer cursors and computers, wheelchairs and neuroprosthetics and robotic arms 4 . Brain activity is identified by electric, magnetic or metabolic brain signals as extracted by depictive methods already used in medicine and is classified, analysed and translated by computer software to be appended to device control functions. Among those methods, electroencephalography (EEG) ABStrAct: Restoration of motor functions of patients with loss of mobility constitutes a yet unsolved medical problem, but also one of the most prominent research areas of neurosciences. Among suggested solutions, Brain Computer Interfaces have received much attention. BCI systems use electric, magnetic or metabolic brain signals to allow for control of external devices, such as wheelchairs, computers or neuroprosthetics, by disabled patients. Clinical applications includespinal cord injury, cerebrovascular accident rehabilitation, Amyotrophic Lateral Sclerosis patients. Various BCI systems are under research, facilitated by numerous measurement techniques including EEG, fMRI, MEG, nIRS and ECoG, each with its own advantages and disadvantages. Current research effort focuses on brain signal identification and extraction. Virtual Reality environments are also deployed for patient training. Wheelchair or robotic arm control has showed up as the first step towards actual mobility restoration. The next era of BCI research is envisaged to lie along the transmission of brain signals to systems that will control and restore movement of disabled patients via mechanical appendixes or directly to the muscle system by neurosurgical means.