Hearing thresholds for speech using insert earphones versus supra-aural earphones

Area of Science:

• Audiology and Hearing Science
• Speech and Language Pathology

Background:

• Accurate measurement of speech recognition thresholds (SRT) is crucial for diagnosing and managing hearing impairments.
• Different headphone types, such as supra-aural and insert earphones, may influence SRT results due to variations in acoustic coupling and frequency response.

Purpose of the Study:

• To compare the speech recognition thresholds (SRT) obtained using Telephonics TDH-39 supra-aural earphones and EARTONE 3-A insert earphones.
• To determine the interchangeability of these two transducers in audiological assessments across different hearing statuses.

Main Methods:

• Speech recognition thresholds (SRT) were measured in two groups: normal hearing and hearing-impaired subjects.
• Testing was conducted on one ear per subject using spondee words.
• Both Telephonics TDH-39 supra-aural and EARTONE 3-A insert earphones were utilized.

Main Results:

• The mean difference in SRT between the two transducers was 1 dB, which was not statistically significant.
• No significant differences in SRT were observed between subjects with normal hearing and those with hearing loss when using either transducer.
• The study found the two transducers to be interchangeable for SRT measurement.

Conclusions:

• Telephonics TDH-39 supra-aural earphones and EARTONE 3-A insert earphones can be used interchangeably for speech recognition threshold testing.
• While measurable differences in frequency response exist, they do not impact SRT outcomes.
• For precise calibration of insert earphones, a 1 dB lower test level adjustment is recommended compared to TDH-39 earphones in standardized setups.