Download Manchester 2004 poster version3

An Update on Tympanic Membrane Displacement:New Measurements & New Applications
Robert J. Marchbanks1, Tony Birch1 & Colin P. Please2
1 Department
of Medical Physics and Bioengineering, Southampton General Hospital.
2 School
of Mathematics, University of Southampton.
The use of Tympanic Membrane Displacement (TMD) measurements for assessing inner ear pressure has been the subject of
research over the past 15 or more years. In most people, the inner ear fluids are connected through to the intracranial fluids, so that
a change in intracranial pressure (ICP) is reflected in terms of a corresponding change in inner ear pressure. Applications of the
TMD technique (i.e. the MMS-11 CCFP Analyser) include screening of patients with audiovestibular disorders to investigate whether
an abnormal ICP is the underlying cause. Also accurate ICP measurements are vital for the successful treatment and monitoring of
many seriously ill patients with neurological problems. The development of the ‘MMS-11 Cerebral and Cochlear Fluid Pressure (CCFP)
Analyser’ by Marchbanks Measurement Systems has provided the opportunity for non-invasive measurements by studying the
movement of the tympanic membrane as induced by intracranial pressure waves and in response to various stimuli. 1, 2.
The Signal Processing Challenge
We know that these intracranial pressure waves contain significant
information concerning the status of the brain, for example, in the
brain-injured patient. The challenge is to find the best method of
analysing the pressure signals so as to extract underlying baseline
pressure shifts and interactions between different types of pressure
waves, and to take account of distortions. The main interaction of
interest is between cerebral cardiovascular and respiratory pressure
waves and how this interaction changes with posture - finding a
means of analysis and visualisation will provide major clinical
benefits.3
From the NASA Photograph Archive
Cerebral Malaria:
Each year many thousands of children
suffer cerebral malaria and many of
these children will die.
A concerted
effort is underway throughout the
African Continent to more fully
understand and clinically manage
patients with this condition. Important
objectives are the rapid differential
diagnosis of cerebral malaria on patient
admission and the identification of
sudden increases in the intracranial
pressure that inhibit blood flow to the
brain and result in death.
The TMD
technique is to be used in a cerebral
malaria project based in Kilifi, Kenya,
and will be used to measure intra-aural
pressure waves in terms of TMD. It is
expected that these pressure waves will
change in a predictable manner if the
mean ICP is raised, with changes in
intracranial compliance and when
sudden pressure increases occur.
Ultimately it is intended that continuous
ICP monitoring will be undertaken and
this will be facilitated using the new
equipment designed for the NASA
project.
Space Adaptation Syndrome (SAS)
We are directly involved in a joint US project commissioned by the
NASA Johnson Space Center.
Project E148 is to use the TMD
technique aboard the NASA Space Shuttles to investigate changes in
crew-members’ intracranial pressure and any relationships with Space
Adaptation Syndrome (SAS) as the astronauts adapt to zero gravity
conditions and on return to Earth. Aims of this project are to better
understand the pathophysiology of Space Adaptation Syndrome so
that treatment and performance of astronauts could be improved.
Considerable Earth benefit may also be derived in terms of
understanding the relationships between increased ICP and
imbalance, headache, motion sickness, and cognitive performance.
Appeal for Collaborators
We are keen to find collaborators to assist in development of these
methods. We are aware that greater involvement of audiologists to
support and undertake normative trials, clinical and field
measurements is critical. We are also seeking support to trial user
interfaces and seeking guidance as to methods of improving
information extracted from the data by use of appropriate signalprocessing methods.
All pictures from the ‘African Malaria Partnership’
photo library. http://www.gsk.com/malaria
It is believed that close collaboration between applied mathematics,
clinicians and signal processing experts will provide the opportunity
for publications in principal medical journals and collaborative
research on an international basis.
In addition to providing an evidence base for current clinical practice, the work undertaken will provide an insight into the causes of certain
hearing and balance disorders,4
If you are interested in collaborating with us, or discussing the potential application of signal processing techniques to
this problem, please contact us via [email protected],
1. Samuel, M., Marchbanks, R.J. and Burge, D.M. (1998) Tympanic membrane displacement test in regular assessment in eight children with shunted hydrocephalus. J Neurosurg 88:983-995.
2. Intracranial and Intralabyrinthine Fluids: Basic Aspect and Clinical Applications’. Editors A. Ernst, R Marchbanks, M.Samii. Springer Verlag, ISBN 3-540-60979-2, 1996.
3. Klose et al (2000) Detection of a Relation Between Respiration and CSF Pulsation With an Echoplanar Technique. J of Magnetic Resonance Imaging, 11:438-444.
4. Intracranial and Inner ear physiology and pathophysiology. Editors A. Reid, R Marchbanks, Whurr Publishers, ISBN 1 86156 066 4, 1998.