Donders Institute for Brain, Cognition and Behaviour
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Thesis defense Rutger Vlek (Donders Series 164)

9 December 2014

Promotor: Prof.dr. P. Desain, copromotors: Dr. J. Farquhar, dr. P. Haselager

From Beat to BCI: A musical paradigm for, and the ethical aspects of Brain-Computer Interfacing

Most people are familiar with the experience of 'having a song in one's head’; they 'hear' the song (or parts of it) internally and are fully aware that the song is not audible in the outside world. This form of musical activity is known as auditory imagery. For this thesis, research was done on 'subjective accenting'. This is a slightly different form of auditory imagery, where there are sounds in the outside world presented to a person, but the person subjectively changes the way the sounds are perceived by imagining emphasis (accents) on some of them. While subjects were listening to a series of identical and regular pulse sounds, they were asked to imagine a stronger emphasis (or accent) on some of these pulses, such that they subjectively turn the series of pulses into a 2-, 3-, or 4-beat meter. During this task, their brain activity was measured with electro-encephalography (EEG).

The aim of the work in this thesis was to gain fundamental insights in 'subjective accenting', as well as to investigate the potential for practical application of this knowledge in a brain-computer interface (BCI). This thesis also addresses the ethical aspects of brain-computer interfacing, considering present and future use of BCI, how BCIs could impact society, and what ethical issues may arise, attempting to make the ethical debate surrounding BCI accessible to a wider audience.

Results from this work show that subjective accenting is detectable for individual beats in EEG measurement of brain-activity. 2-, 3- and 4-beat sequences of subjectively accented and non-accented beats can be automatically decoded in a way that makes brain-computer interfacing possible, although further research is required to achieve real-life applications with this novel paradigm. Furthermore, evidence was found for the presence of shared mechanisms in the brain for auditory perception and imagery. The unique nature of BCI brings forward a range of ethical issues, related to working with sensitive user groups, dealing with technological complexity and handling multidisciplinary teams. Ethical issues also arise where there is a conflict of treatment and research interests, and managing the personal and public expectations of BCI is very important.