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[Highpass filtering of auditory evoked brain stem potentials (author's transl)]
Archives of Oto-Rhino-Laryngology
|January 1, 1981
Summary
Highpass filtering auditory brain stem potentials affects wave latency and amplitude. Moderate filtering aids neurological assessments, but broadband settings are best for objective threshold determination.
Area of Science:
- Neuroscience
- Audiology
Context:
- Auditory evoked brain stem potentials (ABR) are crucial for assessing auditory pathway function.
- Highpass filtering is commonly applied to ABR signals to remove low-frequency noise.
Purpose:
- To investigate the impact of varying lower cut-off frequencies (100, 200, 300 Hz) of Bessel filters on ABR characteristics (latency, amplitude, shape).
- To analyze the spectral composition of ABRs using Fast Fourier Transformation (FFT).
Summary:
- Increasing lower cut-off frequencies reduced the latency and amplitude of the negative wave between Jewett V and VI.
- Higher cut-off frequencies attenuated wave V amplitude relative to wave IV, suggesting significant brain stem activity below 300 Hz.
- Moderate highpass filtering can improve the identification of ABR waves (I-V) and interpeak latencies in neurological evaluations.
Impact:
- Highpass filtering alters the original ABR signal, necessitating careful consideration of filter settings.
- For neurological assessments, moderate highpass filtering can be beneficial for signal clarity.
- For objective threshold determination, broadband filter settings are recommended to ensure better correlation with audiometric hearing loss at 3 kHz.