Presenter: Gautham Krishnamurthy
Advisor(s): Maysam Ghovanloo
Author(s): Gautham Krishnamurthy
Graduate Program: Electrical Engineering

Title: A Switched-Capacitor based Low-Power Head-Mounted Neurostimulating System for Deep Brain Stimulation

Abstract: Deep Brain Stimulation (DBS) is an important treatment that has proved to be particularly effective in the management of neurological movement disorders such as Parkinsonís disease, essential tremor and dystonia. It involves electrical stimulation of targeted deep brain structures via electrodes implanted in a patientís brain. DBS, being a new method, has not yet been optimized in its implementation at the level of either stimulation parameters or hardware used. Existing stimulators are bulky and require leads running up to the top of the head from the pacemaker-sized device placed in the chest. The primary objective of this study is to develop smaller, more energy-efficient stimulating circuits than the ones currently used by relying on a conceptually different form of electrical stimulation of the brain. Our integrated microstimulator in its final form would be fitted in the skull, outside the brain, close to the targeted deep-brain region, significantly reducing risk of mechanical lead failure. In order to achieve the noted objectives we are investigating switched-capacitor stimulation (SCS) circuits. Based on the concept of controlled capacitive discharge these would allow precise control of charge injection to the tissue. The new technology is expected to combine the power efficiency, safety and stimulation parameter controllability previously not possible together. We have designed programmable SCS circuits and prototype systems that allow us to compare the power efficiency and stimulation pulse parameter control of these circuits to existing DBS circuits. Animal experiments are underway to evaluate the efficacy of various stimulation waveforms by measuring the DBS circuit output power versus neural response of the brain tissues. Computer modeling of electrode and waveform influence on the surrounding tissue is being used alongside experimental data to fine tune the system and confirm its advantages. Preliminary results show promise from the energy efficiency as well as stimulation efficacy perspectives.