A Comparison of Intracochlear Pressures During Ipsilateral and Contralateral Stimulation With a Bone Conduction Implant.
Jameson K Mattingly, Renee M Banakis Hartl, Herman A Jenkins and 3 others
PMID 31389846WHAT IT FOUND
Contralateral bone conduction stimulation loses 10–15 dB at high frequencies compared to ipsilateral.
This attenuation worsens to 25–30 dB with transcutaneous implants and thicker skin flaps. Direct bone conduction implants preserve high-frequency audibility better in single-sided deafness.
Key findings
01Contralateral stimulation attenuates high-frequency signals by 10–15 dB compared to ipsilateral stimulation.
02Transcutaneous implants with 9 mm skin flaps increase contralateral attenuation to 25–30 dB at high frequencies.
03Contralateral stimulation introduces a delay of over 100 μs in intracochlear pressures compared to ipsilateral stimulation.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study used cadaveric tissue, which lacks the active physiological responses and varying tissue properties of living patients. Measurements were taken at high stimulus levels (100–120 dB SPL equivalent) to ensure signal quality, which may not reflect everyday listening levels. The single-axis laser vibrometry could not fully capture complex three-dimensional skull vibrations. Possible motion artifacts from the pressure probes sealed with alginate cannot be entirely ruled out.
Declared interests
One author is a consultant for Cochlear Corporation, the manufacturer of the implants tested.
The easy way to misread this
Do not assume these attenuation values apply directly to live patient performance without considering individual anatomical variations and the lack of neural processing in cadaveric models.