Optimalizace měřicího řetězce přístroje ECLIPS pro přesný a spolehlivý záznam BERA signálu

Abstract

This master’s thesis deals with the measurement of Auditory Brainstem Responses (ABR/BERA) and the optimization of the measurement chain of the Interacoustics ECLIPS system. Because diagnostically significant waves reach very low amplitudes, often below 0.5 μV, this neurophysiological signal is highly susceptible to being masked by physiological artifacts such as EMG and EEG and technical noise, primarily EMI and power-line interference. The aim of the thesis was to propose and experimentally verify a set of measures to achieve the most favorable signal-to-noise ratio (SNR) and increase the statistical reliability of the recording. Through a series of real-world measurements, the effects of skin preparation, patient position, stimulation parameters, and grounding topology were tested. Based on the obtained data, a practical methodological manual for acquisition optimization was formulated. The results demonstrate that thorough preparation of the physical layer achieving impedance below 5 kΩ, absolute patient relaxation in a supine position, and equipotential bonding of the device and the examination bed lead to a residual noise reduction of more than 50% and a more than threefold increase in statistical reliability (Fmp) compared to standard clinical practice. Offline analysis using Pearson’s correlation coefficient confirmed high waveform similarity with the reference curve (r > 0.93); a paired t-test further identified a significant effect of patient position on residual noise (p = 0.021).