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Brain Wave Monitor Could Replace Lumbar Puncture

December 16, 2004

Scientists in Southampton have developed non-invasive technology to measure the fluid pressure in the brain safely and painlessly which they hope will eventually reduce the need for a lumbar puncture. Collaborators in London now believe it could be a major advance in the diagnosis and treatment of conditions such as meningitis, head injury and sleeping disorders. It could even be used by astronauts in space.

At the Physiological Society meeting in London today (18 December), Dr Jean-Pierre Lin, a paediatric neurologist at Guy's and St Thomas's Hospitals in London, described the technology, known as the cerebral and cochlear fluid pressure - CCFP - analyser. The patient wears headphones with an earplug that is linked to a computer and monitors the fluid pressure in the brain. "It's usually very difficult to know what is going on in the head without disturbing the brain, but the CCFP analyser seems to be quick, safe and reliable. The patient does not need to be sedated or anaesthetised, and that is a giant leap forward in the painless care of children and babies," he said.

The CCFP analyser monitors brain pressure activity in the cochlear aqueduct, a small channel that connects the inner ear with the brain. Pressure waves from the brain are transferred through the minute structures within the ear and can be measured at the ear drum. There are a host of reasons why the pressure within the brain may rise, disrupting the delicate pressure wave balance. A brain tumour, for example, may affect this balance, as can diseases of other systems and organs in the body. The only way to find out what is going on in the brain has been to surgically implant a pressure sensor in the head or carry out a lumbar puncture. Both procedures are painful, hazardous and distressing for the patient.

Based on their experiences of monitoring pressure in the brain using the CCFP analyser or lumbar puncture, Dr Lin is collaborating with bioengineer and physicist, Dr Robert Marchbanks at the University of Southampton. The CCFP technique is has been in use since the Millennium but it was only in the summer this year that the team discovered that individual arterial and respiratory brain pressure waves emerge from the ear and precise measurement can be made via this route. "It came as a complete surprise that a pulse in the ear matches exactly the pulse linked to breathing or heart rate seen when directly monitoring brain pressure," said Dr Marchbanks.

Therefore, the CCFP analyser could be useful for diagnosing and managing complications due to raised pressure inside the brain arising from a wide range of conditions. Examples include high blood pressure and its potentially damaging effects on the brain; monitoring someone having coronary bypass heart surgery; or direct assessment of the state of the comatose patient. "We usually have no idea what is going on in the brains of unconscious patients. Fluid administration is essential for brain function and survival, which in the first few hours after an injury, can make the difference between life and death, and life with or without disability. The analyser will help us make accurate decisions at a critical stage," said Dr Lin.

Studies are about to commence looking at the wider application of the technology. Research will also begin shortly in Kenya to look at the benefits of the analyser in patients with cerebral malaria where death from the disease is common.

Dr Marchbanks is also carrying out research for NASA. In space, the pressure redistributes itself and increases in the head causing space sickness and altered cognition. Astronauts are being trained to use the specially adapted equipment during space missions to try and overcome these problems. It is important for NASA to understand and alleviate these problems if their vision of human exploration of space is to be achieved, hence the important role played by the CCFP analyser. Similarly, the analyser could be used for altitude sickness and deep sea divers where fluid pressure changes.

The research into the potential uses of the CCFP analyser for investigating brain pressure waves is still at an early stage, but is very promising. "We routinely carry out ECGs to monitor the health of the heart," said Dr Marchbanks. "We should be able to do the same for brain pressure."

Snell Communications Ltd