Examination and comparison of methods to increase communication speed of paralysed patients by brain-computer interfaces [Elektronische Ressource] / vorgelegt von Michael Bensch

Michael Bensch

Sujets

• Informatik

Informations

• Publié par: eberhard_karls_universitat_tubingen
• Publié le: 01 janvier 2010
• Nombre de lectures: 25
• Langue: English
• Poids de l'ouvrage: 9 Mo

Extrait

Examination and Comparison of Methods to
Increase Communication Speed
of Paralysed Patients by Brain-Computer Interfaces
Dissertation
der Fakultät für Informations- und Kognitionswissenschaften
der Eberhard-Karls-Universität Tübingen
zur Erlangung des Grades eines
Doktors der Naturwissenschaften
(Dr. rer. nat.)
vorgelegt von
Dipl.-Inform. Michael Bensch
aus Nürtingen
Tübingen
2010Tag der mündlichen Qualifikation: 3. November 2010
Dekan: Prof. Dr.-Ing. Oliver Kohlbacher
1. Berichterstatter: Prof. Dr. Wolfgang Rosenstiel
2. Prof. Dr. Martin Bogdan
(Universität Leipzig)Acknowledgements
First and foremost I would like to thank Prof. Dr. Wolfgang Rosenstiel and Prof. Dr. Martin Bogdan for placing
their trust in me and guiding me throughout my work. Prof. Dr. Rosenstiel has given me the opportunity to
participate in his research group, which I greatly appreciate. I am truly indebted to Prof. Dr. Bogdan for his
patience and time spent in discussions with me. He has been extremely responsive to any queries I had, no
matter what day of the week or time of day.
I would also like to express my appreciation towards my close colleagues in the NeuroTeam group, Michael
Tangermann, Lothar Ludwig, Elena Sapojnikova, Thomas Hermle and Dominik Brugger for their valuable
advice and company during my time at the Computer Engineering Department. Many colleagues have
become friends, and I thank Prakash Mohan Peranandam, Pradeep Kumar Nalla, Djones Lettnin and Julio
Oliveira Filho for their continued fellowship throughout these years.
I wish to convey my sincere gratitude to Prof. Dr. Niels Birbaumer and Prof. Dr. Andrea Kübler for their
expert opinion, guidance and support concerning the work with patients. I am equally indebted to Dr. Hubert
Preißl for giving me the opportunity to use the MEG facilities for my studies. Without the assistance of
Dr. med. Michael Schulze, Sonja Kleih, and Martin Spüler, some particular studies would not have been
possible — their effort is greatly appreciated.
Many of the illustrations in this work were created with a software framework developed in a fervent
display of brilliance by Jeremy Hill. Amongst further colleagues of the Tübingen BCI research group,
Barbara Wilhelm, Femke Nijboer, Suzanne Martens, Jürgen Mellinger, Sebastian Halder and Ander Ramos
Murguialday have contributed to the quality of this work and have supported me in persevering.
The cooperation of all the ALS patients participating in various studies was a prerequisite for this
dissertation. Thank you for your interest and patience.
I affectionately thank my wife Jessica Kay Bensch for her loving moral support and never ending faith in
me. Even in the most difficult moments, her belief and comforting words gave me new strength.
Lastly, I wish to thank my parents for their love and for instilling in me the courage and faith to go forward
on this path.Contents
1. Introduction 1
1.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2. Main Contributions for Patients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3. Structure of the Dissertation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Fundamentals of Brain-Computer Interfaces 5
2.1. BCI Paradigms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1.1. Cortical Origin of Electrical Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.2. Spontaneous Brain Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.3. Evoked Response Potentials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2. Recording Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2.1. Electroencephalogram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2.2. Electrocorticogram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2.3. Magnetoencephalogram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3. User Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.1. Healthy Subjects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.2. Locked-in Patients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3.3. Stroke and Epilepsy Patients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4. Signal Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4.1. Feature Extraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.4.2. Connectivity Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.4.3. Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.5. Evaluation Criteria and Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.5.1. Bit Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.5.2. Receiver Operating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.5.3. Statistical Test For Two Distributions . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.5.4. Binary Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.5.5. Multiclass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.6. Error-Related Potentials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3. State of the Art 23
3.1. Connectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.2. Multiclass BCI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.3. Cognition Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.4. Error-Related Potentials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4. Connectivity Methods 29
4.1. Patients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.2. Multiclass Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.2.1. Prerecorded Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4.2.2. Experimental Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
iContents
4.2.3. Artefact Rejection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
4.2.4. Feature Extraction and Classification . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.2.5. Patient Recording Sessions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.3. Cognition Detection Study With Two Patients . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.3.1. Prerecorded Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4.3.2. Experimental Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5. Error Correction Methods 45
5.1. Prerecorded Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
5.2. Experimental Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
5.3. Participating Subjects and Patients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
5.4. Treatment of Artefacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.5. Feature Extraction and Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.6. Online Classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
6. Results 53
6.1. Multiclass Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
6.1.1. Connectivity Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
6.1.2. Binary, Ternary and Quaternary Classification . . . . . . . . . . . . . . . . . . . . . 55
6.1.3. Patient Sessions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
6.2. Cognition Detection Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
6.2.1. Significance of Evoked Response Potentials . . . . . . . . . . . . . . . . . . . . . . 63
6.2.2. Latency of Evoked Response Potentials . . . . . . . . . . . . . . . . . . . . . . . . 67
6.2.3. Spectral Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.3. Error-Related Potentials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
6.3.1. Offline Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
6.3.2. Online . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
7. Summary 83
7.1. Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
7.1.1. Multiclass Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
7.1.2. Cognition Detection in CLIS Patients . . . . . . . . . . . . . . . . . . . . . . . . . 84
7.1.3. Error-Related Potentials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
7.2. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
7.3. Outlook . . . . . . .