High Resolution Auditory Brainstem Response System

摘要

Auditory Brainstem Response (ABR) can be described as the early part of auditory Evoked Potential (EP). EP is an electrical response of the brain which is recorded from the scalp and obtained from acoustical stimuli. ABR signal often difficult to capture since it is small relative to the ambient noise. Electrodes placed on the scalp not only pick up ABR potential, but also any other physiological potential from multiple sources such as Electrooculogram (EOG), Electrocardiogram (ECG) and Electromyogram (EMG). The noise can be reduced by implementing high-resolution analogue to digital converter (ADC) into signal acquisition circuit. In this project, a high resolution ABR measurement circuit has been developed and evaluated with ABR signals. The signal acquisition circuit consists of AT91SAM3X8E in Arduino Due as microcontroller and ADS1299 as integrated amplifier and also ADC. The microcontroller is programmed to control the serial peripheral interface (SIM) connections and send the signal to computer through USB connection. The signal is displayed, processed and saved in MATLAB environment. With the used of high-resolution ADC, it gives advantage to higher signal to noise ratio of the prototype. Furthermore, the system has low input-referred noise which means it possess only small deviation from ideal ADC. The system is able to show the ABR signals with low number of trials which is less than 300. Thus, the prototype has high potential for further development to become a reliable device.