Galvanic Test In Central Vestibular Lesions

Abstract

1. Brainstem lesions without presence of a spontaneous vestibular nystagmus generally do not show any particular change of the pattern of the galvanic nystagmus reactions.

2. In brainstem lesions with presence of a spontaneous nystagmus the threshold of the galvanic nystagmus is mostly normal whereas supra-liminar tests invariably show a pathological reversal phenomenon. Sometimes a relatively high incidence of abnormally increased amplitude and frequency values can be found, a phenomenon which is not observed among other groups.

3. Cerebello-pontine angle tumours (acoustic neuroma excluded) show either a normal or only moderately raised nystagmus threshold.

4. In supratentorial lesions of the brainstem the pattern of liminar and supraliminar galvanic responses is not characteristic.

5. In lesions of the cerebral cortex threshold values are normal among the majority of the cases but supraliminar tests reveal a relatively high incidence of pathological directional preponderance towards the side of the lesion, which may also be combined with a corresponding directional preponderance of optokinetic nystagmus.