BIOPAC® Systems, Inc. Logo

105 – Auditory Brainstem Response (ABR) Testing

This Application Note details setup and measurements for Auditory Brainstem Response (ABR) measurements using an MP160/MP150 data acquisition system and AcqKnowledge 4.1 or above software.

Whenever a sound wave is detected by the ear, it triggers a number of neuro-physiological responses along the auditory pathway. An action potential is conducted along the eighth nerve, the brainstem, and finally to the brain.

About one third of a second after initial stimulation, the signal evokes a response in the area of the brain where sounds are interpreted. These response signals are so small that they are frequently masked by the “background noise” of electrical activity in the brain. This interference is random with respect to the initial stimulation.

If you find an average of this interference signal, it will approach zero. However, since the evoked response is dependent on the stimulus, it should occur at the same time relative to the stimulus when the process is repeated. Therefore, if you repeat this stimulus-response process many times the “background noise” will disappear and what will be left is the neuro-physiological response of principal interest.

The ABR Calibration Guide outlines precise test equipment calibration to ensure proper signal-to-noise levels (S/N) and signal time delays for Auditory Brainstem Response (ABR) measurements.

For ABR studies, calibrate the OUT101 Tubephone with an Etymotic ER-7C Probe Microphone—this microphone provides a calibrated output voltage which is a function of applied Sound Pressure Level (SPL). The sensitivity is 50 mV/Pascal (-46 dB re: 1 V/uBar): 0 dB SPL = 0 dBuV. Place the Probe Microphone insert tube in the auditory canal prior to the insertion of the OUT101 foam tip. The OUT101 Tubephone sound delivery tube and the Probe Microphone sound input tube will then be exposed to the same auditory chamber. Accordingly, the SPL is recorded, via the Probe Microphone, simultaneously with applied auditory stimulus from the OUT101 Tubephone.

Associated Applications

Spotlight On
Ventilator Validation Kit

Ventilator Validation and Test Equipment

The Ventilator Validation Kit supports new prototype development, existing design validation for production testing, mobile field testing and verification, and other uses where accurate pressure and flow measurements are critical. The Ventilator Validation Kit provides ventilator manufacturers and prototype developers with a complete solution for validating new medical/hospital-grade ventilator products intended for human use. The VVK100-SYS includes […]

View All
Latest News

New Citations | Logic Games and Meditation: the Key to Unlocking our Brains?

Studying Cognitive Activity with fNIR! The age-old game of chess is known as a thinking man’s game, where foresight, critical thinking, and strategy are required to become a good chess player, and the terms “genius” or “brilliance” are bestowed upon the chess masters of the world. As such, chess is an excellent cognitive tool to […]

Electrocardiography Guide Now Available

BIOPAC’s comprehensive Introductory ECG Guide addresses fundamental to advanced concerns to optimize electrocardiography data recording and analysis. Topics include: ECG Complex; Electrical and Mechanical Sequence of a Heartbeat; Systole and Diastole; Configurations for Lead I, Lead II, Lead III, 6-lead ECG, 12-lead ECG, precordial leads; Ventricular Late Potentials (VLPs); ECG Measurement Tools; Automated Analysis Routines for extracting, […]

Read All
Request a Demonstration
Request a Demonstration