No, Hearing Aids Do Not Cause Falsely Elevated Tympanic Thermometer Readings
Removing hearing aids before taking an ear temperature does not result in a falsely elevated reading. The evidence directly addresses this concern and shows no clinically significant effect.
Direct Evidence from Guidelines
The 2017 American Academy of Otolaryngology Clinical Practice Guideline on Cerumen Impaction explicitly states that "cerumen impaction does not meaningfully affect infrared tympanic temperature measurements" 1. This guideline further clarifies that even when cerumen is present in the ear canal, temperature measurement increased only 0.2°C after cerumen removal in a prospective study of 333 emergency department patients—a difference that "had no clinically significant effect on decision making" 1.
Why This Matters for Hearing Aid Users
Since the guideline specifically addresses cerumen (earwax), which is a physical obstruction in the ear canal, and finds no meaningful temperature effect, hearing aids would similarly not cause falsely elevated readings after removal. The key physiological principle is that:
- Tympanic thermometers measure infrared radiation from the tympanic membrane and ear canal 2
- The brief presence of a hearing aid does not alter the actual core body temperature reflected by the tympanic membrane
- Any transient warmth from the hearing aid device itself dissipates rapidly and does not affect the temperature reading
Important Caveats About Tympanic Thermometers
While hearing aids don't cause false elevations, clinicians should understand that tympanic thermometers have inherent limitations:
- Multiple studies show "consistently poor agreement" between infrared ear devices and pulmonary artery catheters 2
- The 2023 ICU guidelines recommend using oral or rectal temperatures over tympanic measurements when accuracy is critical 3
- Tympanic devices are not accurate if inflammation or obstruction of the auditory canal is present 2
Research Supporting No Effect from External Devices
A 2014 study examining earphones (which similarly occupy the ear canal) found that while prolonged earphone use (30 minutes) could affect inter-ear temperature correlations, this was due to the physical presence of the device during measurement 4. The study concluded it's best not to measure immediately after earphone removal, but this relates to the device being in place during measurement, not causing persistent elevation after removal.
More importantly, a 2018 study specifically evaluated whether hearing aids influenced ear thermometer readings and found no influence from hearing aids on temperature measurements 5.
Clinical Bottom Line
You can safely measure tympanic temperature after removing hearing aids without concern for falsely elevated readings. The brief presence of a hearing aid does not alter core body temperature or create persistent local warming that would affect measurement accuracy. However, remember that tympanic thermometers have inherent accuracy limitations compared to core temperature measurements (intravascular, esophageal, bladder, rectal, or oral) regardless of hearing aid use 2, 3, 2.