[Evoked potentials--effect of filter type on the results]

Area of Science:

• Audiology
• Occupational Medicine
• Signal Processing

Background:

• Occupational hearing loss diagnosis is a key area in occupational medicine.
• Existing data on ready-made filters for brainstem auditory evoked potentials (BAEPs) is limited.
• Filter characteristics and their impact on BAEP interpretation require verification.

Purpose of the Study:

• To characterize ready-made filters used in processing BAEPs.
• To evaluate the effects of different filters on BAEP signal integrity and interpretation.
• To provide insights for accurate diagnostic methods in occupational hearing loss.

Main Methods:

• Utilized a Nicolet Spirit 2000 Unit and a custom-designed phantom simulating physiological responses.
• Verified filter characteristics in two stages: electromagnetic induction and a precise composite signal source.
• Tested neuronal, linear, and arithmetical averaging filters on simulated brainstem responses.

Main Results:

• Arithmetical averaging filter provided the most accurate representation of the reference signal.
• Linear filters caused phase shifts in high-amplitude signals.
• Neuronal filters induced phase shifts in low-amplitude signals.

Conclusions:

• Ready-made filters can distort the input signal during BAEP analysis.
• The type of filter and its specific effects on the signal must be considered for accurate interpretation.
• This research highlights the importance of filter selection in diagnosing occupational hearing loss.