Galvanic Reaction

GALVANIC REACTION (vertige voltaique), a term introduced into clinical diagnosis by Babinski and uniting a group of subjective and objective phenomena observed in humans when the inner ear is irritated by galvanic current. If electrodes of a galvanic battery are applied to the temples or to the mastoid processes, then in individuals with an intact labyrinth upon closing the circuit with a current of 1-3 mA (as was first established by Breuer, Hitzig, and others), there appears a sensation of dizziness, nausea, and deviation of the head toward the positive pole (anode), and in addition, nystagmus in the opposite direction. According to Babinski's observations, the galvanic reaction changes in cases of inner ear damage: in inflammatory diseases of the labyrinth, the reaction intensifies, and all phenomena arise vigorously with currents of much lesser strength than in normal conditions; conversely, in processes that destroy the labyrinth, the reaction diminishes to complete disappearance of all symptoms, while the current strength can be increased even to 15-20 mA. In deaf-mutes, the galvanic reaction (Ewald and Pollak) is absent in 30%. It is recommended that the galvanic reaction be investigated with caution.