Mr Andrew Geyl1
1Sydney Children's Hospital Randwick, Randwick, Australia
Biography:
Andrew Geyl has more than 30 years experience as an audiologist, and 20 of those involved with the NSW neonatal hearing screening, SWISH. He has a special interest in neonatal hearing diagnostics and management.
Abstract
Background:
Sydney Children’s Hospital is one of the three centres performing neonatal diagnostic assessment in NSW. In the more than twenty years of SWISH we have assessed many thousands of babies using tone burst and click stimulus of the Auditory Brainstem Response (ABR).
Jewett wave peak latencies are an important measure of waveform morphology, however without normative values for comparison, clinicians must rely on experience or more experienced clinicians.
For much of the past twenty years there have been no published few normative values for toneburst ABR waveform latencies for neonates, those available are often using different equipment or parameters to that typically used in Australia.
We have investigated our data in detail for over 1700 patients, almost 1500 patients with normal hearing, almost 200 with conductive hearing loss (CHL) and almost 200 with sensorineural hearing loss (CHL).
Method:
Retrospective review of patient records, including only neonates with normal hearing or a SNHL or CHL for one or both ears, up to 3 months corrected age.
We investigated our initial hypothesis wave V latency would be related to:
• SNHL, CHL or normal hearing
• Intensity of the stimulus and the ABR threshold at that intensity (ie sensation level)
• The changes that occur to interpeak latencies due to intensity or frequency of the tone burst stimulus.
Results:
Wave V latency is related to both intensity and sensation level of the stimulus, and the lack of change in interpeak latencies due to intensity or frequency of the tone burst stimulus.