Date of Award

Winter 2005

Project Type


Program or Major

Electrical and Computer Engineering

Degree Name

Doctor of Philosophy

First Advisor

John R LaCourse


The electroencephalogram is the recording of bioelectrical potentials on the scalp due to neural current sources in the brain and are typically recorded using wet surface electrodes that make ohmic contact with the scalp surface using an electrolyte gel. Unfortunately, wet electrodes are intrusive to the user, problematic for EEG studies requiring high spatial resolution, and are unsuitable for long-duration EEG recordings. Wet electrodes ultimately limit spatial resolution since the gel can short neighboring electrodes. They also do not meet long-duration recording demands since the gel can dry out over time.

This dissertation explores the feasibility of measuring the EEG at room temperature, through hair, without scalp contact using two capacitive probe techniques. This is achieved by focusing on measurement of the alpha rhythm, an oscillatory EEG signal that is common among the population and is easily elicited with eye closure. Research results suggest that it is possible to sense the alpha rhythm within 4.0mm of scalp-probe spacing and that the ultra-high impedance fieldmeter probe technique is the most promising. Non-contact recordings are compared to wet electrode recordings and issues related to hair and motion artifact are discussed. Areas critical to the development of this technology are suggested.