The discovery of active mechanisms in the cochlea (otoacoustic emissions, or; OAE) is currently producing a revolution in the theory on hearing and in practical `management of hearing assessment. The power of the OAE method is such that, for the first time, universal hearing screening programmes based on objective tests can at present be considered feasible. In general terms, the aim of this project is to advance the field in the European Union and to maintain its leadership.
Although otoacoustic emissions and especially transient evoked otoacoustic emissions (TEOAE) can be considered to be a rather well established technique, this teclmology has not yet achieved its full potential. Theoreticians are only beginning to explore the implications of these "nonlinear and active processes" and have not yet been able to synthesise the new experirnental data and concepts into a workable model. -
On more practical ground, otoacoustic emissions can be measured with several different recording techniques (spontaneous emissions; transient evoked emissions; emission produced by simultaneous continuous tones). All these techniques are in use in auditory research and are playing an increasingly important role in the audiological test battery to assess and monitor hearing function in neonates, children, adults as well as in the elderly.
There are many important aspects of this method to be developed and there is a growing need for some standardisation. There is a need for improved methods of OAE recording and response analysis, in order to reach unambiguous test results, particularly in large scale clinical trials and in mass neonatal hearing screening programmes. In keeping with its high sensitivity. in fact, OAE recorded with present techniques and recording protocols lacks adequate specificity, i.e. it fails a number of ears whose hearing is, in fact, normal. Data from a few research laboratories (partners in this project) indicate that there is room to improve to about 0.5% technical failure rate. Hence, the objective of improving realisable sensitivity is genuinely tractable and can be achieved by a mixture of engineering and training initiatives.
Four closely interconnected areas will be addressed: technical aspects: generation of emissions; clinical applications; hearing screening programmes.
In general terms, aims of the AHEAD project are sharing of scientific and technical knowledge; testing of instruments; comparison and evaluation of methods and results; evaluation and standardisation of recording protocols; education and targeted training of scientists, clinicians and technicians.