Background: The increasing diffusion of newborn hearing screening programs has brought about the need for diagnostic tools providing a reliable assessment of hearing threshold in the early period of life, within 6 months of age, in order to plan proper therapeutic interventions. The diagnostic evaluation of children with a suspect of hearing loss has to be completed within 6-8 months of age (JCIHS 2007 Pediatrics 2007), a period in which behavioural audiometry techniques lack of precision in determining hearing threshold. Moreover it must be considered that a misdiagnosis can lead to irreversible therapeutic decisions, such as cochlear implantation or the use of high power hearing aids. Study design: In this paper we report the results of a retrospective survey involving 1463 children (2880 ears) who underwent electrocochleography in the period between 1973 and 2011. In all the patients we performed a complete battery of tests, including, according to different periods: - 1st group (1973-1982): 973 pts (1833 ears): ECochG and Impedence testing - 2nd group (1983-1990): 171 pts (342 ears): ECochG-Impedence-ABR - 3rd group (1995-2011): 319 pts (705 ears): ECochG-Impedence-ABR-OAEs The first group has not been included in this study, since ABR wasn’t available before 1980. Considering that ABR represents the first choice and the main diagnostic tool for the assessment of hearing threshold, in this work we tried to find out clinical and diagnostic variables which can reduce the reliability of ABR in establishing hearing threshold. Results: We performed ABR and ECochG testing under general anaesthesia in the same diagnostic session, in a total number of 470 children. The better ear ECochG threshold and the ABR threshold were compared for each patient and for single ears. The patients were then divided into subgroups according to the presence or absence of OAE and to the presence of signs and symptoms of CNS pathology. A more than 20 dB difference between better ECochG and ABR thresholds was found in 328 ears (31,3%). Small differences were found in the three periods considered, likely related to the substantial changes regarding the etiology of preverbal hearing loss, and to the progressive development and application of advanced NICU procedures. In the ‘90s a positive correlation came out between ECochG-ABR difference and the detection of OAEs, that represent a main diagnostic criterion for auditory neuropathy. In this case, however, the clinical significance of CAP threshold, and its relationship with audiometric threshold, are still uncertain. A strong correlation was found between an ECochG-ABR difference≥ 20 dB and the presence of signs and symptoms indicating a possible CNS damage. Conclusion: ABR has to be considered the first choice in hearing assessment strategy, either for screening or diagnostic purposes. According to the results of this study, the diagnosis of hearing loss must be considered with caution in those patients displaying detectable OAEs with absent wave V in ABR recording, and in presence of a possible damage of central auditory nervous pathways. In these cases, ECochG may be the only reliable diagnostic tool for hearing assessment in uncooperative subjects.

Differences between ABR and ECochG in the hearing threshold assessment in children

ARSLAN, EDOARDO;SCIMEMI, PIETRO;SANTARELLI, ROSAMARIA
2012

Abstract

Background: The increasing diffusion of newborn hearing screening programs has brought about the need for diagnostic tools providing a reliable assessment of hearing threshold in the early period of life, within 6 months of age, in order to plan proper therapeutic interventions. The diagnostic evaluation of children with a suspect of hearing loss has to be completed within 6-8 months of age (JCIHS 2007 Pediatrics 2007), a period in which behavioural audiometry techniques lack of precision in determining hearing threshold. Moreover it must be considered that a misdiagnosis can lead to irreversible therapeutic decisions, such as cochlear implantation or the use of high power hearing aids. Study design: In this paper we report the results of a retrospective survey involving 1463 children (2880 ears) who underwent electrocochleography in the period between 1973 and 2011. In all the patients we performed a complete battery of tests, including, according to different periods: - 1st group (1973-1982): 973 pts (1833 ears): ECochG and Impedence testing - 2nd group (1983-1990): 171 pts (342 ears): ECochG-Impedence-ABR - 3rd group (1995-2011): 319 pts (705 ears): ECochG-Impedence-ABR-OAEs The first group has not been included in this study, since ABR wasn’t available before 1980. Considering that ABR represents the first choice and the main diagnostic tool for the assessment of hearing threshold, in this work we tried to find out clinical and diagnostic variables which can reduce the reliability of ABR in establishing hearing threshold. Results: We performed ABR and ECochG testing under general anaesthesia in the same diagnostic session, in a total number of 470 children. The better ear ECochG threshold and the ABR threshold were compared for each patient and for single ears. The patients were then divided into subgroups according to the presence or absence of OAE and to the presence of signs and symptoms of CNS pathology. A more than 20 dB difference between better ECochG and ABR thresholds was found in 328 ears (31,3%). Small differences were found in the three periods considered, likely related to the substantial changes regarding the etiology of preverbal hearing loss, and to the progressive development and application of advanced NICU procedures. In the ‘90s a positive correlation came out between ECochG-ABR difference and the detection of OAEs, that represent a main diagnostic criterion for auditory neuropathy. In this case, however, the clinical significance of CAP threshold, and its relationship with audiometric threshold, are still uncertain. A strong correlation was found between an ECochG-ABR difference≥ 20 dB and the presence of signs and symptoms indicating a possible CNS damage. Conclusion: ABR has to be considered the first choice in hearing assessment strategy, either for screening or diagnostic purposes. According to the results of this study, the diagnosis of hearing loss must be considered with caution in those patients displaying detectable OAEs with absent wave V in ABR recording, and in presence of a possible damage of central auditory nervous pathways. In these cases, ECochG may be the only reliable diagnostic tool for hearing assessment in uncooperative subjects.
2012
Abstracts of Collegium Oto-Rhino-Laryngologicum Amicitiae Sacrum Meeting
Meeting of Collegium Oto-Rhino-Laryngologicum Amicitiae Sacrum Meeting
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2526278
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