1. Department of Electrical and Computer Engineering, Sultan Qaboos University, Al-Khoud, 123 Muscat, Oman
2. Department of Neurology, University of Kiel, D-24105 Kiel, Germany
3. Department of Neurology, Movement Disorders and Neurostimulation, Biomedical Statistics and Multimodal Signal Processing, University Medical Center of Johannes Gutenberg-University Mainz, 55131-Mainz, Germany
4. Institute for Circuit and System Theory, Faculty of Engineering, University of Kiel, D-24143 Kiel, Germany