%0 Journal Article %J J Neural Eng %D 2011 %T Closing the sensorimotor loop: haptic feedback facilitates decoding of motor imagery. %A Gomez-Rodriguez, M %A Peters, J %A Jeremy Jeremy Hill %A Schölkopf, B %A Gharabaghi, A %A Grosse-Wentrup, Moritz %K Brain %K Evoked Potentials, Motor %K Evoked Potentials, Somatosensory %K Feedback, Physiological %K Female %K Humans %K Imagination %K Male %K Movement %K Robotics %K Touch %K User-Computer Interface %X

The combination of brain-computer interfaces (BCIs) with robot-assisted physical therapy constitutes a promising approach to neurorehabilitation of patients with severe hemiparetic syndromes caused by cerebrovascular brain damage (e.g. stroke) and other neurological conditions. In such a scenario, a key aspect is how to reestablish the disrupted sensorimotor feedback loop. However, to date it is an open question how artificially closing the sensorimotor feedback loop influences the decoding performance of a BCI. In this paper, we answer this issue by studying six healthy subjects and two stroke patients. We present empirical evidence that haptic feedback, provided by a seven degrees of freedom robotic arm, facilitates online decoding of arm movement intention. The results support the feasibility of future rehabilitative treatments based on the combination of robot-assisted physical therapy with BCIs.

%B J Neural Eng %V 8 %P 036005 %8 06/2011 %G eng %U http://www.ncbi.nlm.nih.gov/pubmed/21474878 %N 3 %R 10.1088/1741-2560/8/3/036005 %0 Journal Article %J Clin Neurophysiol %D 2011 %T Transition from the locked in to the completely locked-in state: a physiological analysis. %A Murguialday, A Ramos %A Jeremy Jeremy Hill %A Bensch, M %A Martens, S M M %A S Halder %A Nijboer, F %A Schoelkopf, Bernhard %A Niels Birbaumer %A Gharabaghi, A %K Adult %K Amyotrophic Lateral Sclerosis %K Area Under Curve %K Brain %K Communication Aids for Disabled %K Disease Progression %K Electroencephalography %K Electromyography %K Humans %K Male %K Signal Processing, Computer-Assisted %K User-Computer Interface %X

OBJECTIVE: 

To clarify the physiological and behavioral boundaries between locked-in (LIS) and the completely locked-in state (CLIS) (no voluntary eye movements, no communication possible) through electrophysiological data and to secure brain-computer-interface (BCI) communication.

METHODS: 

Electromyography from facial muscles, external anal sphincter (EAS), electrooculography and electrocorticographic data during different psychophysiological tests were acquired to define electrophysiological differences in an amyotrophic lateral sclerosis (ALS) patient with an intracranially implanted grid of 112 electrodes for nine months while the patient passed from the LIS to the CLIS.

RESULTS: 

At the very end of the LIS there was no facial muscle activity, nor external anal sphincter but eye control. Eye movements were slow and lasted for short periods only. During CLIS event related brainpotentials (ERP) to passive limb movements and auditory stimuli were recorded, vibrotactile stimulation of different body parts resulted in no ERP response.

CONCLUSIONS: 

The results presented contradict the commonly accepted assumption that the EAS is the last remaining muscle under voluntary control and demonstrate complete loss of eye movements in CLIS. The eye muscle was shown to be the last muscle group under voluntary control. The findings suggest ALS as a multisystem disorder, even affecting afferent sensory pathways.

SIGNIFICANCE: 

Auditory and proprioceptive brain-computer-interface (BCI) systems are the only remaining communication channels in CLIS.

%B Clin Neurophysiol %V 122 %P 925-33 %8 06/2011 %G eng %U http://www.ncbi.nlm.nih.gov/pubmed/20888292 %N 5 %R 10.1016/j.clinph.2010.08.019