Recording Techniques for Transtympanic Electrocochleography in Clinical Practice

Abstract

Enhancement of the signal-to-noise ratio is a central issue in electrically evoked response techniques. Transtympanic electrocochleography requires careful methodological considerations as responses from the cochlea may easily be affected by various sources of electromagnetic noise. The final electrophysiological waveforms are acquired by advanced signal processing which influences the content of the recordings. A standard method of transtympanic electrocohleography is presented here to increase the feasibility of the measurements in daily clinical use and to facilitate uniform interpretation of the recordings. The electrocochleographic recordings were carried out in 61 patients with a clinical diagnosis of Meniere's disease and in 15 ears of normal hearing subjects. The electrophysiological data are presented and set in relation to the results reported by other laboratories under equivalent recording conditions. Methodological factors of consequence for the quality of the recordings, such as testing environment, properties of the equipment, mode to produce and deliver stimuli and properties of the electrodes, are analysed.

Electrocochleographic recording in Asian adults: Preliminary normative data and demographic analyses

“…As expected, the mean amplitudes of SP and AP in the present study are lower than that of TT-ECochG studies ( Ferraro, 2010 , Sass et al., 1998 ) and higher than the reported ET-ECochG results obtained with ear canal electrodes ( Chatrian et al., 1985 , Padilla La Rosa and De Vinatea, 1999 ). For SP/AP ratio, the upper limit of 90% range value (0.40) agrees well with the findings from the previous studies ( Margolis et al., 1995 , Kim et al., 2005 ).…”

Ups and Downs in 75 Years of Electrocochleography

“…Inclusion of the 2 kHz tone burst had no further effect on sensitivity or specificity. Sass et al (1998) added the latency difference for condensation and rarefaction clicks, which was significantly larger in Ménière’s disease compared to normal and non-Ménière hearing loss (as was also found by Orchik et al, 1998; Ge and Shea, 2002), and found that “the sensitivity of TT ECochG, obtained by using measurements of SP/AP ratios and the SP amplitude at 1 kHz burst stimulation, increased from 83% to 87% by addition of the condensation-rarefaction shift measurement”. The specificity of TT ECochG obtained by this combination of variables was 100%.…”

Comparing the sensitivity and specificity of cervical vestibular-evoked myogenic potentials and electrocochleography in the diagnosis of Ménière’s disease

“…A tone burst will test a more specific region of the cochlear than a click and it is possible that the 1000 Hz frequency is more specific to MD than the range of frequencies tested with a click. Sass, Densert, and Arlinger (1998) found that the sensitivity of TT ECochG obtained by using measurements of SP/AP amplitude ratio and SP amplitudes at 1000 Hz tone-burst increased from 62 to 82%, without changing specificity. As yet few other studies have explored the sensitivity of SP/AP measurements to MD using tone-burst stimuli.…”