| Epilepsy is a neurological disorder which affects nearly one percent of the world's population and is characterized by the spontaneous occurrence of debilitating seizures. One third of epilepsy patients do not respond to pharmaceutical treatments which leaves surgical removal of the seizure generation focus as the primary treatment option. This is still not viable for some individuals as it is impossible to localize the seizure focus. Furthermore, the removal of neural tissue is an irreversible process and the surgery is a high-risk procedure.;Some form of epileptic seizure control with applied electrical stimulation have been demonstrated over the past decades. Specifically, proportional feedback control of polarizing low-frequency electric field (PLEF) stimulation has been shown to effectively suppress seizures in slice preparations. Research carried out in intact rodents and humans indicates that feedback control may be effective for electric control of seizures. This treatment option would be advantageous to patients whose epilepsy is drug-resistant, as the implantable electrodes are relatively small, can be removed, and the stimulation protocol can be tuned to maximize efficacy. One impediment to implementing feedback control is the existence of the stimulus artifact: a spurious, additive electric potential at the recording sites caused by the stimulus current.;In this thesis, we propose a prototype set of electronics for concurrent neural recording and stimulation. These consist of a head-mounted preamplifier, a PC-controlled amplifier bank, and an optically-isolated stimulator. The performance of these electronics permit the recording of the underlying neural activity and the complete stimulus artifact. Furthermore, we present the necessary signal processing techniques for the prediction of stimulus artifacts caused by an arbitrary stimulus waveform. Finally, we show verification of the artifact subtraction system and some associated measurements of in vivo tissue properties. |
PDF Full Text Request