Dos potenciais evocados miogênicos vestibulares nas orelhas comprometida e assintomática na Doença de Ménière unilateral

Abstract

Aim:To verify whether vestibular evoked myogenic potentials can present abnormalities in the affected ear and in the asymptomatic ear in patients with diagnosis of unilateral Ménière's disease. Study design: Transversal cohort. Material and Method:The vestibular evoked myogenic potentials of 20 patients with unilateral Ménière's disease were analyzed. The selection of individuals was based on the history and in clinical evaluation suggestive of unilaterally defined Ménière's disease, and with electrocochleography abnormalities in the affected ear. Vestibular evoked myogenic potentials were evaluated in both ears of each patient through absolute latencies of p13 and n23, interaural difference of latency of peaks p13 and n23 and amplitude p13-n23 asymmetry rate. Results: Vestibular evoked myogenic potentials were altered in 35.0% of the affected ears and in 25.0% of the asymptomatic ears. The alterations were: absence of responses in seven cases, prolongation of p13 latency in three cases, and increase in interaural amplitude difference ratio in one case. Conclusion: The vestibular evoked myogenic potentials can present abnormalities in the affected and asymptomatic ears in patients with diagnosis of unilaterally defined Ménière's disease.

Potenciais miogênicos evocados vestibulares: metodologias de registro em homens e cobaias

“…However, using two or more channels can provide extra resources, such as the possibility to compare records between two sides [9][10][11] . This joint analysis of the two brain hemispheres can be carried out through the possibility of averaging out monoaural and binaural stimuli, through the use of earphones 9,12 or through bone vibrators (placed on the mastoid, directly behind the pinna) 13 .…”

“…However, in some cases, we saw recordings in the following windows: 50, 60 and 80ms 10,[16][17][18][19] .…”

“…The stimuli may be averaged by means of tone bursts (in the frequencies of 250Hz25, 500Hz 13,15,19,[25][26][27][28] , 1000Hz 25,28 , 3000Hz 10 , 5000Hz 15,21 ) or clicks 2,9,11,14,16,17,19,21,22,24 ,29 , which shall be employed at intensities above 75 dBHL. Currently, stimuli above 90 dBHL are used 2,[8][9][10][11][14][15][16]18,19,24,[28][29][30][31] .…”

“…Currently, stimuli above 90 dBHL are used 2,[8][9][10][11][14][15][16]18,19,24,[28][29][30][31] . However, in many studies, the threshold is surveyed by means of stimuli of different intensities (with ascending or descending techniques) until the lowest stimulus intensity capable of triggering a response is found 2,21,25,32 .…”

“…The recording is done by means of averaging or adding, and the parameters used in most studies are equal to or higher than 200 stimuli 2,[8][9][10]14,17,20,26,27,30,31 . In general, the higher the number of stimuli and the lower the shooting rate (number of stimuli per second), the better the recording quality.…”