The Optimization of Galvanic Vestibular Stimulation according to Evoked Nystagmus

ABSTRACT

BACKGROUND AND OBJECTIVES:The aim of this study were to observe the nystagmus of normal general populations on galvanic vestibular stimulation, to set a new korean standard for galvanic vestibular stimulation. MATERIALS AND METHOD:We recruited 10 healthy adults and they were stimulated by 1,2,3 mA monaural monopolar, monaural bipolar, binaural monopolar, binaural bipolar galvanic vestibular stimulation through carbon-rubber electrode and Ag-AgCl electrode. We evaluated galvanic stimulating nystagmus and after galvanic stimulating nystagmus on sitting position through Frenzel goggle and video-nystagmography. RESULTS:We detect stimulating and after-stimulating nystagmus on 1,2,3 mA monaural monopolar, monaural bipolar, binaural monopolar, binaural bipolar galvanic vestibular stimulation. The nystagmus on galvanic vestibular stimulation was directed to the negative electrode side and after-galvanic stimulating nystagmus was directed to opposite side. The greater current, the more occurrence of nystagmus was found. We detect nystagmus mostly on monaural bipolar vestibular stimulation through carbon-rubber electrode. We thought most effective Galvanic vestibular stimulation was 2 mA monaural bipolar vestibular stimulation through carbon-rubber electrode in consideration of increased pain and discomfort on 3 mA monaural bipolar vestibular stimulation in spite of high occurrence of nystagmus. CONCLUSION:Galvanic vestibular stimulation evoked different nystagmus according to stimulation, stimulated site. We thought 2 mA monaural bipolar vestibular stimulation through carbon-rubber electrode was most effective, stable galvanic stimulation. Specifity and sensitivity of 2 mA monaural bipolar vestibular stimulation were 100%, 100% respectively. Galvanic vestibular stimulation is useful to evaluate vestibular function.