Developing Clinical Normative Data for Neonates Using Auditory Brainstem Response at Korle Bu Teaching Hospital

ABSTRACT

Background: Undetected hearing loss in neonates and children compromises optimal speech and language development and personal achievement. Auditory brainstem response (ABR) test consists of eliciting and recording waveforms generated within the auditory nerve region to the brainstem. These waveforms are compared with normative data to determine normal and abnormal responses. The use of ABR in identifying, and managing infants with congenital hearing impairment is crucial to their academic, social and personal wellbeing.

Aim: The aim of the study was to develop an ABR clinical normative data for neonates within the age bracket of 2 to 8 weeks to ensure objective and valid interpretation of test results.

Methods: A prospective study design was used to develop clinical normative data from 30 normal hearing neonates within the age bracket of 2 to 8 weeks. The ABR tests were performed using the smart EP equipment in an acoustically treated room. The ER 3A insert earphones were used, and recordings of responses were made using surface electrodes (disposable), positioned according to the international 10-20 system (Cz: front; A1: right lobe, and A2: left lobes), adapting the impedance below 3 kΩ. All examinations were performed with the babies in natural sleep. A presentation level of 80 to 30 dBHL in 10 dB decrements was utilized.

Results: The results of the study revealed that the absolute and inter-peak mean latencies for the normative data established by the present study were within 2 standard deviations of the published data. The present study showed statistically significant effects of gender on mean absolute latencies for wave V at 30, 40, 50 and 60 dBnHL and also on inter-peak I-III at 70 dBnHL. However, there was no significant effect of gender on other absolute and inter-peak mean latencies.

Conclusion: The study concluded that the developed normative data was appropriate and useful for ABR testing and recommended the need for further investigations to be conducted on the effect of gender on neonatal ABR latencies.

Keywords: Auditory Brainstem Response, Neonates, Latency, Inter-peal Latency, Evoked Potential