Research on Epilepsy

1. Research on Epilepsy BY Tracy Waweru Working under Dr. Walter Besio

2. Background • Epilepsy affects approximately one percent of the world population. A huge chunk of the people who have epilepsy live in 3rd world countries so they are not able to access the medicine and treatments available now. • Nowadays antiepileptic drugs are available but many times they are found to be ineffective in approximately 30% of patients and have side effects. • All the techniques used for testing epileptic seizures, such as deep brain stimulation and responsiveness neurostimulation, all require invasive surgery to implant devices.

3. Objective: • The objective for this project was to develop non-invasive ways for testing epileptic seizures. My research on this project involved building the material and equipment that would be used for testing on patients using brain-computer interface and electrical stimulation.

4. Project: • The project required building two tripolar board consisting of 20 channels. These boards were used to test out brainwaves and were connected to computers and peoples head in order for us to read signals. • From each channel we gathered an output on the 1/16, Outer ring, Middle Disk, and Central Disk. For each channel on the board, there were 14 resistors placed and each resistor ranged from 2.61KΩ to 100kΩ. • On the ends of the tripolar boards we attached the wires that would be attached to the oscilloscope and computer in order to give us signals.

5. Testing • After each soldering session done on each individual channels, the connecting wires placed on each end of the board were plugged into an oscilloscope to test out whether each channel had been administered properly. • A voltmeter was used to determine the voltage that was coming from battery that was attached to board, and also how much power was running across each channel. Too much power could potentially burn out the channels gates and counters, also could cause a shock to occur on the test subject’s head. Too little power would have the opposite effect and not give off a strong reading. • After testing whether each channel worked, electrodes were inserted into each channel of the tripolar board. The electrodes were attached to various parts on the head of the person being tested. By doing so, the brain–computer interface of the project came into play and we were able to see how didn’t thoughts and actions affected our project. • The board was then plugged into other devices that would be plugged into the computer. From there, we were able to • get signals from electrodes to the computer • on what the brain was doing at certain times.

6. partial seizure onset HFOs generalized seizure onset Fig. 4. Panel B shows 12 minutes of bipolar EEG from Fp2-F4. Panel A is the corresponding spectrogram. Panel E shows 30 seconds of EEG from Panel B at the onset of the generalized seizure (dashed line). Panels C, D, and F are the corresponding tEEG signals from Fp2’. Notice the black ellipse in Panel C highlighting high frequency oscillations (HFOs) just prior to the partial seizure. The tEEG in Panel F during the tonic seizure activity was less contaminated with muscle and movement artifacts than the EEG in Panel E. Also note the high power in EEG (Panel A) from approx. 400 to 650 s when the patient is still anxious/disoriented and moving much while recovering from the seizure. During that same period the artifact power is much lower in tEEG in Panel C.

7. Conclusion: • The data and results that were attained from the brain computer interface varied a lot. There were many times when the equipment would fail based on the connection between the tripolar board and the computer, the electrodes not giving a good signal to read based on their placing, or certain parts of the board being shot. All of these results were expected due to the fact that the research is in it’s introductory phase and very experimental. • A lot of tedious work was put into building each of the components of the project. The circuit design for each channel of the board, which were done by an associate PhD student Zhenghan, required a lot of work and knowledge of how all of the parts would be connected while at the same time giving us the correct signal. • The testing phase of the equipment also required a lot of work on both the researcher and the person being tested on. The person had to direct a specific amount of focus to the task at hand, whether it be imagining to move the right hand or left hand, while the researcher would be busy looking at all the data and results. All in all, the project was successful.