Auditory Brainstem Response Wiring Configuration using gTec equipment 1. Equipment used in ABR acquisition:

i. g-USB amp ii. g-trig box iii. active electrode iv. g-PAH (attenuator) v. 2 laptops or PC (for acquisition and audio stimulation player-separately) vi. Headphone/earphone

2. Wiring configuration

The above block diagram shows the acquisition method for the ABR signal. We can see that there are 2 part connection being made from the g-USB amp which is:

i. From the electrode ii. From a trigger box signal

The purpose is to let the computer can cut the EEG data into frames by following the trigger signal in parallel manner. The trigger signal will signal for each repetition.

3. Wiring connection

can cut the EEG data into frames by following the trigger signal in will response to the audio stimulation and then produce

can cut the EEG data into frames by following the trigger signal in a then produce triggered

i. First, we start the connection from USB-amp. The output of the USB-amp connects to the computer through USB cable.

ii. In the input part, there are 2 port used, Port A and Port C. In Port 1, we connect the 4 attach electrode to the Channel 1, Channel 2, and their GND and REF channel.

iii. In Port C, we connect the trigger output to Channel 9, GND and REF. iv. From both connections (in port A and C) we can cut the EEG recorded based on triggered signal

from input in channel 9. We call that framing or windowing. v. We record until 2000 frames or triggered referred to from the stimulus onset. vi. The input of the g-TrigBox is connected with the second computer, which played the audio

stimulation. The stimulation is played at the same frequency or duration (about 20 Hz). The trigger box is functions to trigger when it detects every repetition sound to let computer frames the EEG signal in a synchronous manner.

vii. From the same audio stimulation player (second computer), we connect it to g-PAH to attenuate the stimulation sound into desired dB programmed in MATLAB. That’s why you see there are two divisions being connected in a parallel manner from the stimulation player; one to trigger box and the other one to attenuator.

viii. The output of g-PAH is connected to the headphone to let subject hear the sound in the desired dB.

ix. The laptop 1 is connected to the g-PAH through dB24 wire connection. This is where the program to attenuate the dB level is transferred.