The aim of the author's research described in this thesis was to obtain abetter understanding of a number of the fundamental characteristics of brainstem potentials and to establish normal values. This aim is described in chapter I, following a discussion of the possibilities and limitations of objective and subjective audiometry, an outline of the development of electroaudiometry and a description of the regions of origin of brain stem potentials and their nomenclature. The experimental set-up is discussed in chapter II, where the signal-tonoise ratio receives special attention. The description of the clinical application of brain stem audiometry in chapter VIII is based on both the literature and personal research. Chapter IX gives some practical suggestions for the application of brainstem audiometry. The author's own research, which is described in chapter III-VII, deals with the following subjects: 1. The aceurenee of and normal values for brain stem potentials. The occurrence of brain stem potentials and their normal values were investigated in 20 healthy subjects, 19 men and 1 woman, with normal hearing and ages varying from 20-53 years. The stimulus used had a wide frequency spectrum, with an intensity of 70 dB HL and a repetition rate of 10 Hz. The responses were filtered with a high-pass filter, cut-off frequency 300 Hz, 24 dB/oct., and a !ow-pass filter, cut-offfrequency 3000Hz, 24 dB/oct. After averaging 16,000 responses to binaural stimulation it was possible to identify the peaks P2 to P5 inclusive, for 75, 70, 85 and 100°/o of the test subjects respectively, while after averaging 4,000 responses to manaural stimulation the proportions were 65, 63, 78 and 98% respectively. The amplitudes of the responses were highly variable. The latendes were constant within narrow limits (table 3.1). The average latency for peak P5 was 7.0 ms with a standard deviation of0.35 ms. The interaurallatency difference averaged 0.02 ms and had a standard deviation of0.27 ms. 2. The distribution of brainstem potentials over the scalp. The distribution of brainstem potentials over the scalp was investigated to establish whether there are any electrode positions where the response originates primarily from the left or the right half of the brain stem. In order to do this the responses were recorded at 5 points on the nasion-vertex-inion line and the vertex-mastoid process line. The responses on the latter were obtained after ipsi- and contralateral stimulation with respect to the active electrode.

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E.H. Huizing
Erasmus University Rotterdam
Erasmus MC: University Medical Center Rotterdam

van Olphen, A.F. (1983, July). Auditieve hersenstampotentialen bij de mens : een studie van enkele fundamentele eigenschappen en hun klinische toepassing. Erasmus University Rotterdam. Retrieved from