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Indexed/Abstracted in: EMBASE, Scopus
Online ISSN 1827-188X
From the Otolaryngology Department of Medical University, Lódz, Poland (Chairman: Prof. B. Latkowski)
Background. The method called vestibular evoked myogenic potentials (VEMPs) allows exciting vestibular receptor-saccular receptor and receiving response on neck muscles. It seems to be a promising method for objective examination of vestibular organ. The study in a personal modification is presented to record muscle activity inhibition after sound stimulation with higher insensitivity. The main purposes of this study were the recording of VEMPs in normal volunteers using available equipment, arrangement of parameter values of VEMPs (latency, amplitude) and arrangement of influence of initial muscle tension, magnitude intensity of sound and number of repeated stimuli on the recording legibility.
Methods. Experimental design: the 90 healthy ears of volunteers were stimulated by sound and there is received VEMPs findings. Two ipsilateral and two contralateral VEMPs were recorded in each subject. Medelec-Sapphire 2ME produced by Medelec Ltd was used in this study because it generated repeated acoustic sound in the form of clicks and allowed the recording of muscle activity in the form of averaged electromyograms. Setting: studies were undertaken in the Otorhinolaryngology Department of Medical University of Lódz, Poland.
Results. Healthy people demonstrated short latency responses to click stimuli during tonic neck flexor activation. VEMPs were recorded as biphasic, positive-negative waves, that were described by lower case letters (p, n). Mean latency for p-wave was 14 ms and n-peak was 21 ms. Later waves were not analysed because of their inconstant appearance. There was a statistical difference between ipsilateral and contralateral tracings in regard to peak latency but there was no statistical difference in regard to peak-to-peak amplitude. Mean values of latency for ipsi-p14 were 12,77 ms and for contra-p14-19.72 ms. Mean values of latency for ipsi-n21 were 20.97 ms and for contra-n21-26.47 ms. Mean value of amplitude for ipsi-p14 was 4.11 µV. Mean value of amplitude for contra-p14 was 2.31µV. Mean value of amplitude for ipsi-n21 was 3.34 µV. Mean value of amplitude for contra-n21 was 2.27 µV. Mean amplitude of p14n21 was dependent on the level of the initial tonic muscle activation. Morphology of VEMP recordings related to increasing of stimulus intensity and the number of repeated stimuli.
Conclusions. VEMPs is full objective, safe and simple method of testing vestibular organ and vestibular tracts to neck muscles, so it should be used in pathologic states to confirm its diagnostic value.