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New stimuli for infant audiometry may be too wide in their frequency composition.
What is it about?
Infants who did not pass their newborn hearing screening must be tested using the Auditory Brainstem Response (ABR) test to determine hearing levels for each ear at low, middle and high frequencies. It is important the stimuli used to elicit the ABR stimulate only a narrow frequency region. Recently, many audiologists are using a new stimulus called "narrowband chirps" rather than more-standard tones ("2-1-2" or "5-cycle" tones). This study shows these new stimuli contain a much wider range of frequencies than standard tones. More research is needed to see if these new stimuli result in less-accurate threshold estimates.
Why is it important?
Our study provides a detailed comparison of the frequency spectra for narrowband chirps and 2-1-2 stimuli. Results show narrowband chirp stimuli contain a much wider range of frequencies than standard 2-1-2 tones. In some cases, this may result in less-accurate threshold estimates.