Novel slow- and fast-type drug release round-window microimplants for local drug application to the cochlea: an experimental study in guinea pigs.

Novel drug release microimplants (0.8 x 1.14 mm; custom-made by Leiras, now Schering OY, Finland) of slow- and fast-release types containing either 0.

Middle ear and cochlear disorders result in different DPOAE growth behaviour: implications for the differentiation of sound conductive and cochlear hearing loss.

Input/output functions of distortion product otoacoustic emissions (DPOAE I/O-functions) give an insight into the compressive, non-linear sound processing of the cochlea. With an inner ear dysfunction a steeper I/O-function is observed. Due to the linear sound processing of the middle ear, one can assume that the DPOAE growth behaviour remains unaltered with a sound conduction dysfunction.

Optimum primary tone level setting for measuring high amplitude DPOAEs in guinea pigs.

A special stimulus paradigm needs to be applied when distortion product otoacoustic emission (DPOAE) input/output functions are used to investigate the loss of sensitivity and loss of compression of outer hair cell cochlear amplifiers during noise exposure, drug treatment, etc. This stimulus paradigm should be able to reflect cochlear non-linear compressive sound processing known from direct basilar membrane measurements. Such a paradigm has already been established for humans that accounts for the different compression of the primary tones at the DPOAE generation site at f2 with L1 = 0.