Untersuchung der Frequenzspezifität akustisch evozierter Potentiale früher und mittlerer Latenz mit Hochpaßmaskierung

Abstract

In contrast to auditory brainstem potentials (ABR), a more apically defined generation of middle latency evoked potentials (MLR) can be assumed due to the longer integration time present. To date, the effect of stimulus frequency spectra on MLR has not been completely known. By using masking with high-pass filtered white noise in 12 normal-hearing adults, we measured the dependence of amplitude and latency of ABR and MLR on filter frequency. No differences were found between the masking effects for ABR and MLR evoked by tone bursts of 0.5 and 2 kHz. The high-pass masking of click stimuli showed a greater influence on the amplitude and latency of the ABR than on MLR. These different qualities have to be considered clinically when evaluating the methods and results of hearing testing with acoustic evoked potentials. Our findings show that MLR evoked by tone bursts should be used for the frequency selective diagnosis of hearing thresholds, especially in low-frequency ranges.

Amplitude Modulation Following Responses (AMFR) in der audiologischen Diagnostik

“…So besitzen die Hirnstammpotenziale aufgrund der zu ihrer Stimulation erforderlichen hohen Anstiegssteilheiten des Reizes nur eine sehr geringe Frequenzspezifität. Um dennoch den Verlauf der Hör-schwelle einschätzen zu können, wurden in der Vergangenheit hauptsächlich Verfahren auf Basis der selektiven Maskierung benutzt [1].…”