Behavioral Pure-Tone Threshold Shifts Caused by Tympanic Membrane Electrodes

Area of Science:

• Audiology
• Neuroscience
• Otoacoustic Emissions

Background:

• Tympanic membrane (TM) electrodes are utilized in audiological assessments.
• Understanding potential artifacts from electrode placement is crucial for accurate hearing threshold determination.

Purpose of the Study:

• To investigate whether tympanic membrane (TM) electrodes induce behavioral pure-tone threshold shifts.
• To assess the impact of TM electrode placement on hearing sensitivity across different frequencies.

Main Methods:

• Pure-tone thresholds were measured in two groups: a test group (n=18) with TM electrodes and a control group (n=10) without electrodes.
• Thresholds were measured twice, with TM electrode placement occurring between measurements in the test group.
• The effect of TM electrode contact location on threshold shifts was analyzed.

Main Results:

• TM electrodes significantly elevated average low-frequency thresholds (7.5 dB at 250 Hz, 4.2 dB at 500 Hz).
• Individual ears showed threshold shifts as large as 25 dB.
• No significant variation in threshold shifts was observed based on TM electrode contact location.

Conclusions:

• The use of TM electrodes in conjunction with insert earphones can lead to low-frequency hearing threshold shifts.
• These findings have implications for the interpretation of electrocochleography (ECoG) responses, especially to low-frequency auditory stimuli.