Abstract
Detection of BAER waveforms in the neonatal ICU is hampered by the large size of the typical "pediatric earphone" normally used (TDH-39). Earphone size prevents adequate stability of sound intensity under all ICU conditions without disrupting or handling the infant during a BAER test. Also, large speaker coils must operate at higher currents; this induces stimulus artifacts which distort the cochlear microphonic and the auditory nerve response components (CM and Wave I). This is especially true at the intensities needed to test infants. We found that essentially the same BAER waveform, without significant stimulus artifacts, is produced using miniture ultra-lightweight earphones made with samarium cobalt magnets (<0.2 oz.) (Sony or Recoton). To insure reproducibility of click intensity, the earphone was mounted in a standard feeding nipple that had cotton stuffed loosely in the nipple stem. An "acoustic chamber" formed by the application of micropore tape placed around the nipple flange permitted the earphone to rest lightly over the external auditory canal without introducing mechanical distortions. These methods allowed us to test reliably all infants in isolettes, head boxes and on ventilators without the need to handle the infant excessively during data acquisition. We believe that these simple and inexpensive earphones significantly improve results obtained from BAER tests performed in the Neonatal ICU.
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Karmel, B., Brown, E. ULTRA-LIGHT EARPHONES IMPROVE NEONATAL BRAINSTEM AUDITORY EVOKED RESPONSE (BAER) TESTING. Pediatr Res 18 (Suppl 4), 378 (1984). https://doi.org/10.1203/00006450-198404001-01709
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DOI: https://doi.org/10.1203/00006450-198404001-01709