The remediative effect of galvanic vestibular stimulation (GVS) was
investigated in a patient who, following right hemisphere damage, is
profoundly unable to recognize faces. We administered a two-alternative
forced choice match-to-sample task in which the patient had to choose
which of two faces matched a sample face presented directly above, while
bipolar, transcutaneous current was applied to the left and right
vestibular nerves at a level below the patient's sensory threshold.
Performance improved beyond the chance-level observed prestimulation, and
relied on reversing the electrode polarity across two separate blocks of
trials, such that each mastoid received positive current for one block and
then negative charge for the next. Although our study involved only a
single case, the data provide preliminary evidence that a deficit in
perceptual face matching can be reduced by GVS. This raises the intriguing
possibility that other unilateral visual disorders may also respond in
such a manner. (JINS, 2005, 11, 925–929.)