Researchers develop sensor to measure blood pressure in the brain
ST INGBERT, Germany: A slow increase in cerebral pressure can cause dementia and destroy the brain. Companies have long sought monitoring sensors that can be implanted into the brain and read from outside the body. Now German researchers have developed a tiny sensor that may provide the solution.
Scientists still cannot explain sudden increases in cerebral pressure in certain people. The consequences, however, are better understood: blood circulation is disrupted and after a while parts of the brain may necrotise, similar to what occurs in a stroke. This can lead to dementia.
Experts estimate that up to ten per cent of dementia cases in Europe can be attributed to rising blood pressure in the brain. However, diagnosis is complicated. People with a high risk of intracranial pressure require intensive care. They are implemented a sensor that passes through the skull into the brain and is linked to the monitoring apparatus via a cable. Since cerebral pressure fluctuates, a definitive diagnosis requires extensive measurements. Thus, patients typically stay in hospital for several days, sometimes even weeks.
Developers of medical devices have been working on an intracranial pressure sensor that operates without a cable and that can be read using radio-wave transmission. However, no established product exists for long-term implantation because the sensor casing, which is usually made of a biocompatible material, allows moisture to penetrate, which rapidly destroys the sensor.
Researchers at the Fraunhofer Institute for Biomedical Engineering in St Ingbert have now developed a waterproof sensor encased in a high-quality metal instead of synthetic material. The device resembles a thick watch battery and is about 1 cm high and 2 cm wide, but it will become smaller as it is refined. Inside the casing is a pressure sensor made of silicon, similar to sensors used in cars for measurement.
“The cover of the tiny metal container is made from a flexible metal membrane that reacts to pressure changes in the brain,” explained project leader Dr Thomas Velten, head of the Department of Biomedical Microsystems at the institute. This pressure is transmitted to the silicon chip on the inside, and then to the measuring device outside the body through a radio signal. “The benefits are immense,” said Velten. “The patient no longer has to be checked into hospital but only comes to the clinic for a brief measurement appointment.”
The sensor is read from the outside of the body within seconds. It operates without batteries, since it is activated by the reading device. Thus, the patient can wear the device for several months, or even a number of years, without requiring additional surgery.