Department Publications

Dry-contact ear-electroencephalography (Ear-EEG) enables wearable neural monitoring. However, motion induced electrode-skin impedance (ESI) mismatches between electrodes can severely degrade signal quality. To the best of our knowledge, this paper presents the first proof-of-concept dry-contact EarEEG system that uses a driven-right-leg (DRL) stimulus for continuous ESI mismatch monitoring, enabling online adaptive motion artifact cancellation. A 1 kHz sinusoidal stimulus is injected through the DRL electrode. The resulting response to the injected carrier is separated from the EEG using bandpass filtering and demodulation, and then used to extract the ESI mismatch information as the reference input for a normalized least-mean-square adaptive filter followed by a Hampel filtering stage. To evaluate artifact suppression and preservation of neural activity, alpha-band EEG activity was analyzed involving four healthy participants performing head nodding, electrode tapping, and jaw clenching. The system achieved artifact power reductions of 6.5, 12.6, and 9.0 dB (77.6%, 92.8%, and 86.4%, respectively) while alpha-band modulation remained clearly observable after processing. This demonstrates the feasibility of DRL-stimulusbased ESI mismatch monitoring for motion artifact cancellation in wearable dry-contact Ear-EEG.

Neurotransmitters, such as dopamine and serotonin, are endogenous chemicals that enable neurons to communicate with one another throughout the body. Alterations in the levels of specific neurotransmitters are associated with various neuropsychiatric disorders. Dopamine (DA) - often known as the feel-good hormone – is primarily responsible for reward and motivation and is a key biomarker of Parkinson’s disease. Medications such as Levodopa alter its level in biological fluids, monitoring of which is important to ensure the proper therapeutic range for sufficient medication to cross the blood-brain barrier. Serotonin (5-HT) regulates mood, stress response, sleep, and autonomic function, and its dysregulation is implicated in depression, anxiety, and other neuropsychiatric disorders. Continuous or longitudinal monitoring of serotonin—especially in accessible biological matrices—can provide critical insights into …