Eclipse Support
The auditory brainstem response (ABR) is an evoked potential that originates at the auditory nerve (Cranial Nerve VIII). This test is used to assess the auditory system’s function from the cochlea through the brainstem. The response is identified by “peaks” that occur typically between 1 and 15 milliseconds from the stimulus onset. The ABR peaks are measured and marked traditionally as I, II, III, IV, and V. Each peak has an expected latency to be considered “normal”. Delayed or missing peaks are consistent with abnormal auditory function.
The amplitudes and latencies (both absolute and inter-peak) are used to diagnose certain auditory pathologies.
ABR testing is traditionally used to help determine the degree of hearing loss in pediatric or difficult to test populations. It is also used for testing the auditory pathway as related to acoustic neuromas and some nervous system abnormalities.
The patient should be relaxed or sleeping in a quiet environment. It is preferable that the patient lie down during the procedure to facilitate a calm and comfortable environment. The electrode sites must be prepared and cleaned in order to obtain acceptably low skin impedance. It is recommended to have impedance values be 3kΩ or lower. The impedance values between one another should be balanced or similar in value.
The electrodes must be placed as indicated below. The must be a few centimetres between each electrode. The same electrode placement for ABR is used for ASSR allowing for easy switching between the test types.
Check the impedance on the preamplifier and place the transducers. Make sure the patient is relaxed prior to starting the test. You can monitor this by watching the EEG Window on the top right of the recording window.
The Eclipse comes with pre-programmed protocols so the system is ready to use immediately. Protocols can be created or modified easily to fit your clinical needs. Consult your Additional Information to learn how to create or modify a protocol. The procedure discussed on the next page is simply a suggested process to be used as a guideline.
Choose ABR Threshold e.g. Threshold CE-Chirp LS
