Miniature Devices to Predict Epilepsy and Treat Glaucoma Developed

by VR Sreeraman on Aug 8 2007 4:26 PM

Researchers at Purdue University have developed miniature implanted devices to predict and prevent epileptic seizures and treat glaucoma.

The new miniature devices are to be implanted in the brain in case of epileptic seizures and a nanotech sensor is to be implanted in the eye for glaucoma.

As part of the study Pedro Irazoqui, Jenna Rickus and colleagues focussed on a tiny transmitter three times the width of a human hair to be implanted below the scalp to detect the signs of an epileptic seizure before it occurs. The system will record neural signals relayed by electrodes in various points in the brain and an external receiver will pick up data from the implanted transmitter.

"When epileptics have a seizure, a particular part of the brain starts firing in a way that is abnormal. Being able to record signals from several parts of the brain at the same time enables you to predict when a seizure is about to start, and then you can take steps to prevent it,” Irazoqui said.

The most critical aspect of the research was creating a transmitting device that could transfer a large amount of data at low power. The transmitter consumes 8.8 milliwatts, or about one-third as much power as other implantable transmitters while transmitting 10 times more data. Another key advantage is that the transmitter has the capacity to collect data specifically related to epileptic seizures from 1,000 channels, or locations in the brain.

While the transmitter and its battery are to be implanted below the scalp, the electrodes that pick up data will be inserted directly in the brain through holes in the skull and then connected to the transmitter by wires.

The new technology that is still to be tested on humans, aims to control seizures by predicting its onset and immediately dispensing a neurotransmitter called GABA directly to calms the brain area where the seizure is starting.

Researchers have developed a ‘living electrode’ coated with specially engineered neurons that, when stimulated, releases the neurotransmitter to inhibit the seizure. The engineered neurons are living tissue stimulated with a microchip.

Another biomedical engineering project involved the development of a sensor to be implanted in the eye to monitor glaucoma by measuring pressure in the eye's interior.

"The problem is that your interocular pressure spikes over hours, sometimes minutes. So you can be fine today and fine in six months and spend three months in the middle where it's very high, killing your optic nerve. What you really need to do is check it often, every couple of minutes, but you can't go to the doctor every couple of minutes for the rest or your life. So what you need is a device that measures your eye pressure continuously,” Irazoqui said.

The findings of the study will be presented at the Engineering in Medicine and Biology Society's Sciences and Technologies for Health conference in Lyon, France.