Difference between the default telecoil (t-coil) and programmed microphone frequency response in behind-the-ear (BTE)...

Area of Science:

• Audiology
• Hearing Aid Technology
• Acoustics

Background:

• Telecoils (t-coils) are crucial for hearing aid users on telephones to prevent microphone feedback.
• Clinicians may prioritize microphone response over t-coil performance for telephone use.
• Limited research exists on matching t-coil and microphone frequency responses for optimal telephone listening.

Purpose of the Study:

• To determine statistically significant differences between hearing aid microphone and t-coil program outputs.
• To assess the feasibility of measuring microphone and t-coil frequency responses using real-ear measures.
• To compare the frequency response of t-coil and microphone programs in hearing aids.

Main Methods:

• A repeated-measures design was used with behind-the-ear hearing aids from a single manufacturer.
• Hearing aid output was measured in a 2-cc coupler and via real-ear measures.
• Mixed-model repeated-measures ANOVA and Tukey's HSD post hoc test were employed for analysis.

Main Results:

• No significant overall difference in mean output between t-coil and microphone programs across all tested frequencies.
• A significant transducer-by-frequency interaction was observed.
• T-coil output was significantly lower at 200 and 400 Hz, and higher at 4000, 5000, and 6300 Hz compared to microphone output.

Conclusions:

• Mean t-coil output was significantly lower than microphone output at 400 Hz, within the typical telephone bandwidth.
• This frequency-specific difference may contribute to patient complaints of insufficient loudness during telephone communication.
• Further investigation into optimizing t-coil performance for telephone use is warranted.