Fast acquisition of otoacoustic emissions by means of principal component analysis

Transient-Evoked Otoacoustic Emissions (TEOAE) are nonstationary acoustic signals coming from the inner ear after acoustic stimulation by clicks and they are applied as tools in newborn hearing screening programs to allow the early identification of hearing loss and the consequent diagnosis and intervention. In any screening program, the duration of each test is a crucial parameter. For TEOAE, it is strongly influenced by the acquisition procedure, typically based on classical synchronous averaging technique over 260 sweeps, with an average acquisition time of about 2-3 minutes. This paper present an application of Principal Component Analysis (PCA) to rapidly-acquired TEOAE (averaged over only 10, 60 or 100 sweeps) for the detection of this type of cochlear response. The PCA approach is shown to be able to enhance the signal-to-noise ratio (SNR) and, in turn, to allow a correct detection of the responses. Results of the application of this approach in comparison with responses recorded, from the same ears, with classical technique will be shown. The reduction of the acquisition time to about one forth with respect to Its typical value and with approximately the same final signal-to-noise ratio will be discussed.