Vesitbular

Between January 1981 and February 1992, 102 non-NF-2 patients underwent removal of a unilateral vesitbular schwannoma. There were 54 women and 48 men. Eighty-six percent of patients with normal facial function preoperatively retained normal function (House score 1 or 2) postoperatively. Of the 64 patients with a functional cochlear nerve preoperatively, five had normal hearing (PTA < 25 dB, SB > 70%), five had near normal hearing (PTA < 45 dB, SD > 70%), four patients had preserved hearing (PTA < 50 dB, SD > 50%), and three patients had preserved cochlear nerve function (PTA > 50 dB, SD < 50%) after surgery...

Galvanic stimulation of the vestibular system provokes a nystagmus as well as a tendency to fall. The direction of these phenomena depends on the localization of the anode. In this study the value of the minimal current strength (threshold), which is able to provoke nystagmus with a constant frequency during at least 30 sec was determined. Also the effects of the lesions in the vestibular system on these threshold values were measured. The method of bipolar-biaruricular stimulation showed to be the most sensitive one...

Of the vestibulo-spinal reactions, the "stepping test" is considered to be the most important, especially for unilateral peripheral vestibular disturbances. Electronystagmography was performed on seven patients after transtemporal neurectomy of the vestibular nerve, 17 patients with a nearly compensated vesitbular defect after vestibular neuronitis, and seven patients after suboccipital removal of acoustic neuromas. These results were then compared to the spontaneous stepping test. The test could not be performed on six of the seven patients with the operated acoustic neuroma, and on three other patients...

Nystagmus as a reaction on vestibular stimulation is influenced by many factors which are difficult to control. One of the most important parameters correlating best with the excitability of the peripheral vestibular apparatus is the speed of the slow phase of the nystagmus. This can be registered directly by use of the nystagmometer (or Blauert System), together with the speed of the fast phase. All parameters of the nystagmus can be easily described when recorded. However, an exact description of the nystagmic reaction should not be considered as a complete diagnosis by itself alone; the diagnosis can only be the result of combining nystagmometry, audiometry and other otoneurological or neurological findings with the patient's presenting complaints (or history of the disease involved)...

On the ground of cytoarchitectonic investigation and planimetric measurements a volumetric comparison between the systems of truncal formations of auditory and optical analysers were made in the representatives of artiodactyla (deer, elk, gazelle, sheep, wild boar, hippopotamus) and perissodactyla orders (horse). The data obtained demonstrated a great quantitative predominance of the system of optical formation in comparison with that of auditory, which correlates to the leading role of the optical system in these animals...