Study on galvanic eye movement and galvanic body sway test

The Combined Galvanic Test (abbr. CGT) based on simulataneous recording of both galvanic nystagmus (Galvanic eye movement : GEM) and galvanic body sway (GBS) was developed in our clinic for differential diagnosis od the vertigo, especially due to the retrolabyrinthine origin from the peripheral labyrinthine origin. The purpose of this study was to determine the normal range od the CGT and to compare the peculiatrity of CGT responsed in each disease entities, and furthermore to discuss both the acailability for the differential diagnosis and the speculated mechanism in the galvanic stimulation in the vestibulo-ocular and in the vestibulo-spinal reflexes. The findings were as follows in the healthy subjects in anodal stimulation : In GEM, the small eye movement toward the anodal electrode (named as ”Initial eye movement”) followed by the slow phase of nustagmun toward the same direction and quick phase of the nystagmus toward the opposite side (”Initial nystagmus”) are observed. When the cathodal stimulation, the direction of responses were inverted. Meanwhile, in GBS, the fast small body sway (named as ”Initial wave”) and large bodysway (named as ”deviation” or maximumdeviation point) aooeared. Meniter's disease showed a similar finding closely to the healty subjects. In the cases with vestibular neuronitis, GEM and GBS showed a similar finding closely to the healthy subjects. In the cases with vestibular nouronitis, GEM and GBS showed slow sluggish response, In the acoustic tumor, GEM and GBS were diminished. In the brainstem infarction, GEM and GBS finding did not coincide. It is sonsluded from these findings that CGT might be a uniwue test for diffetentiating the retrolabyrinthine origin vertigo from the peripheral origin.