ArticlesBrain-computer communication: Self-regulation of slow cortical potentials for verbal communication☆,☆☆,★,★★,♢
Section snippets
Patients
Patient 1 (male; age, 45yr) was diagnosed with ALS in 1994. He had severe tetraparesis in legs and arms and lost the ability to speak by the end of 1999. He lives at home and is cared for by his family. Eye muscles are still under voluntary control. Training was conducted at the patient's home, 2 to 3 days weekly.
Patient 2 (male; age, 31yr) was diagnosed with ALS in 1998. He is almost completely paralyzed and dependent on invasive artificial ventilation via tracheostoma. He lives at home and is
Results
Figure 5 depicts representative curves for the slow cortical potentials of both patients.About 200 trials were averaged according to the task requirement. The top panel in each graph shows the course of the amplitude at the vertex referenced to A1
Discussion
The present training procedure enabled severely paralyzed patients to communicate verbally. Brain-computer communication was achieved by self-control of slow cortical potentials. The question was whether the patients could use the self-regulation skill for letter or word selection in the Language Support Program. To learn self-regulation, 2 elements are crucial: feedback of the slow cortical potential amplitude and positive reinforcement of correct behavior. It has long been shown that healthy
Conclusion
Although many varieties of brain-computer interfaces have been proposed that could be used for communication in severely paralyzed patients, no data were available on how to enable these patients to use the system. A reason for this deficit may be the enormous difficulty and additional effort required to train severely paralyzed patients in a field environment compared with the development of a system in a laboratory. The training procedure described in the present article may be a suitable way
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Supported by the Deutsche Forschungsgemeinschaft and the Institut für Grenzgebiete in der Psychologie und Psychohygiene (Freiburg, Germany).
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No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the author(s) or upon any organization with which the author(s) is/are associated.
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Reprint requests to Andrea Kübler, PhD, Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Gartenstr 29, 72074 Tübingen, Germany, e-mail: [email protected].
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Supplier
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a. EEG 8; Contact Precision Instruments Inc, PO Box 605, Kendall Square, Cambridge, MA 02142.