The major finding of our study is hearing loss >45 dB HL in infants who passed screening with AABR. Unfortunately, in-ear calibration is available only in some of the AABR devices. Daily auto-calibrations, followed by regular earphone cleansing or replacement when required, are crucial for the accuracy of the hearing screening procedure. However, periodical calibrations are not sufficient. These checks are routinely held and documented by the hospital's medical engineering department. This comparison in such a short time interval has never been reported before and should be performed more often.Ĭalibration - A yearly calibration is performed on all our diagnostic audiology devices. Our patients underwent a battery of hearing tests, as required however, for the purpose of this study, the focus was on the click-evoked ABR threshold measurements because these are the only measurements that can be directly compared with the click AABR screening results. Validation - The only way to validate the sensitivity of an automated screening device is to compare it with a diagnostic device preforming the same test. A TEOAE-based hearing screening in well infants is approved by the joint committee on infant hearing. The normal TEOAE remained a required criterion for passing in our hearing screening procedure. Because of this and the low refer rate at the TEOAE screening, we decided that, in infants who failed the TEOAE screening, an AABR test would be performed at 45 dB HL only to obtain additional information and not as an optional pass criterion. Actually, an intensity that could serve both of these conflicting purposes does not exist. While 35 dB HL is too high to ensure a normal hearing threshold, it is also too low for the exclusion of all possible transient conductive hearing loss. We initiated the follow-ups because we felt that telling the parents that this result corresponds to normal hearing was not a viable option. Therefore, in the absence of a normal TEOAE and an ABR recorded at 35 dB HL, the interpretation of "normal hearing" is inadequate. This is well-established evidence-based clinical knowledge. Stimulus intensity - In a normal hearing ear, a response to an ABR click stimulus at a level of 0-20 dB HL is expected, in addition to a normal TEOAE response. The infants were included in our study because their hearing loss was evident at birth, at 10-30 days and at the hearing evaluation at 1-3 months therefore, by definition, these infants' hearing loss could not be considered to be transient. Therefore, the AABR screening test cannot distinguish between sensory and conductive hearing loss or between transient and permanent hearing loss. Inclusion criteria - Some conductive hearing loss can be permanent, while sensory hearing loss can be of a mild severity or confined to a high tone loss. We would like to clarify the following issues: We thank Professor Hall for noting these important issues.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |