Question
It is my understanding that the use of TDH 39 earphones can result in electrical noise during ABR testing. Is this true?
Answer
This is true, but typically only at high intensities. Below are some screen shots showing this occurrence using reuseable electrodes and TDH 39s. Note the very large spikes at time 0-1 ms, especially on curves with high intensities.
The solution to this issue would be to use a shielded TDH39 headphone, but even then you still could see an artifact at intensities above 90 dB SPL. At that point you can simply move the recording window to start after the artifact. You could also switch to the use of an insert earphone. These also have the advantage of being more comfortable for the patient to wear.
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David Speidel is the director of audiology for Interacoustics USA. Beginning his career with a clinical practice and moving into sales and service, David now has over 25 years of experience in sales of diagnostic equipment. He has worked with several top manufacturers and has been instrumental in their product development, strategic planning and product support.