Theoretical Evaluation and Experimental Validation of Localized Therapeutic Hypothermia Application to Preserve Residual Hearing After Cochlear Implantation.
Ilmar Tamames, Curtis King, Chin-Yuh Huang and 3 others
PMID 29240567WHAT IT FOUND
A cooling probe lowered cochlear temperatures toward mild hypothermia in human cadaveric temporal bones and a computer model, mainly at the round window, without cooling the mastoid surface.
The paper reports temperature changes, not hearing preservation results.
Key findings
01In the computer model, 18 minutes of probe cooling lowered the round window by about 6°C, the oval window by about 3.5°C, and the mastoid by 0.5°C.
02With the probe placed through the facial recess, 18 minutes of cooling lowered the round window by 5.41°C and the oval window by 4.36°C, while the mastoid surface changed by about 1°C.
03In cadaveric temporal bones, the total change in temperature at the cochlear round and oval window locations was significant compared with the mastoid (p<0.001).
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study reports temperature measurements, not hearing or speech outcomes. The authors state that further study is needed before transferring the model and temperature recordings into a clinical application. The computer model did not include movement of inner ear fluids or blood flow, which can affect heat transfer. The model used simplified tissue properties and did not account for differences between soft and hard tissues in the ear. In cadaveric bones, the mastoid surface was affected by room temperature, so it may not match conditions in a living patient. The cooling period took 16 to 18 minutes in the model and cadaver work, longer than in a previous rat study, and may need to be shortened for clinical use. The facial recess may need to be modified to place the probe.
Declared interests
The publication types list research support from NIH extramural and non-U.S. government sources. The article text does not include an author conflict-of-interest declaration.
The easy way to misread this
Do not conclude that localized therapeutic hypothermia preserves residual hearing after cochlear implantation. This paper measured temperature changes in a computer model and cadaveric temporal bones, not hearing outcomes in patients.