Analog and zero phase-shift digital filtering of the auditory brain stem response waveform

Area of Science:

• Neuroscience
• Audiology
• Signal Processing

Background:

• Auditory brain stem response (ABR) is crucial for assessing auditory pathway function.
• Analog filters can introduce phase-shift distortion, potentially affecting ABR waveform analysis.
• Digital filtering offers a precise method for evaluating signal integrity.

Purpose of the Study:

• To systematically evaluate the impact of phase-shift distortion on auditory brain stem response waveforms.
• To compare the effects of digital versus analog filtering on ABR signal fidelity.
• To provide recommendations for analog filter parameter settings.

Main Methods:

• Analysis of ABR waveforms from normal ears using a computer-based digital filtering program.
• Application of Butterworth-type filters with varying high-pass and low-pass frequencies and filter slopes.
• Comparison of standard analog filtering with zero phase-shifting digital filtering.

Main Results:

• Phase-shift distortion, particularly from analog filters, was identified as a significant cause of ABR waveform distortion.
• Latency and amplitude of ABR waveforms were substantially altered by phase-shift distortion.
• Digital filtering demonstrated superior precision in preserving waveform characteristics.

Conclusions:

• Digital filtering is essential for accurate analysis of auditory brain stem response waveforms.
• Phase-shift distortion from analog filters can lead to misinterpretations of auditory function.
• Careful selection of analog filter parameters is necessary to minimize waveform distortion.