New Intracranial Pressure Probe Overcomes Technical Problems

Researchers have developed a cable-free intracranial sensor that monitors cerebral pressure without attaching the patient to the reader apparatus, enables long-term implantation, and much reduces the need for inpatient hospitalization.

The causes underlying sudden increases of cerebral pressure in susceptible people are still unknown; however, the consequences are better understood: blood circulation is disrupted and parts of the brain may eventually die off, in some cases leading to dementia or even death. An estimated 10% of all dementia cases are considered attributable to rising blood pressure in the brain, but making the diagnosis is currently very difficult. Intracranial pressure is currently monitored using a probe inserted through the skullcap into the brain, but remains connected to a cable that keeps the patient connected to the measuring apparatus. Since cerebral pressure fluctuates, extensive measurements are required to arrive at a definitive diagnosis so patients must remain in hospital typically for several days, sometimes even weeks.


Medical device research engineers at the Fraunhofer Institute for Biomedical Engineering (IBMT; St. Ingbert, Germany have now developed a small sensor that overcomes the main technical problems that have long prevented predecessor prototypes from being developed into useful products. In addition to the cable connection problem, other models are quickly corroded by moisture penetration due to use of biologically accepted synthetics for encasement. Instead, the Fraunhofer team produced a waterproof casing made of high-grade metal. Externally, the probe resembles a thick button cell battery, about 1 cm high, 2 cm wide. Resting on its inside is a pressure sensor made of silicon, similar to sensors currently used in automobiles to handle demanding measurement tasks.

“The cover of the tiny metal container is made from a pliable metal membrane that reacts to pressure changes in the brain,” said project manager Dr. Thomas Velten, manager of the department of biomedical microsystems at IBMT, in describing the unique aspects of the system. This pressure is transmitted to the silicon chip on the inside. The measurement value is transmitted to the measuring device outside the body through a radio impulse. “The benefits are immense,” said Dr. Velten. “The patient no longer has to be checked in on an inpatient basis but comes to the clinic for a brief measurement appointment instead.” The sensor is read from the outside within seconds. Furthermore, it operates without batteries since it is activated by the reading device. Thus, the patient can wear the sensor for several months, or even a number of years, without requiring additional surgery.

During the Medica 2012 trade fair (Düsseldorf, Germany), November 14-17, 2012, researchers from IBMT plan to demonstrate the sensor using a glass model head at the Fraunhofer joint exhibition stand in Hall 10, stand F05.

Related Links:
Fraunhofer Institute for Biomedical Engineering
Medica 2012