Public defence in Biomedical Engineering, M.Sc. (Tech) Aino Nieminen

Automation enables more effective magnetic brain stimulation

Transcranial magnetic stimulation (TMS) is used to study brain functions and to treat neurological and psychiatric disorders. The stimulation coil placed over the scalp is typically steered by manual movements, and the TMS operator decides on how to administer the stimuli based on a brain image or, for example, upon evoked muscle movements. Therefore, the outcome of a research study or therapy depends on the operator, making it challenging to interpret and compare the results. In addition, it is not known how the stimuli should be targeted to achieve the most effective TMS therapy. The main goal of this Thesis was to improve TMS targeting by developing automated methods to guide the stimulation.

This work presents methods to determine optimal stimulation location and orientation. The developed methods automatically searched for the stimulus location and orientation that produced maximal responses measured with electromyography or electroencephalography. This Thesis also provides new information about how the stimulus orientation affects brain responses. The developed automation methods speed up the operation of TMS and makes it user-independent. Instead of a manually operated stimulation coil, this work employed a multi-locus TMS system, which allows steering the cortical stimulation site electronically with several overlapping coils. In addition, a multi-locus TMS system comprising five coils was validated by measurements. This system enables automated guiding of TMS on a larger brain area. This work also includes an analysis of errors related to the TMS navigation systems based on brain images. The automation methods developed in this Thesis, together with accurate navigation, ease the application of TMS in brain research and are expected to increase the efficacy of TMS therapy.

Opponent: Professor Fabio Babiloni, Sapienza University of Rome, Italy

Custos: Professor Risto Ilmoniemi, Aalto University School of Science, Department of Neuroscience and Biomedical Engineering

Contact details of the doctoral student: [email protected], +358504530082

The defence will be organized on campus (Otakaari 3, lecture hall F239a)

The doctoral thesis will be publicly displayed 10 days before the defence in the publication archive of Aalto University.

Electronic doctoral thesis