Mood disorder following DBS of the left amygdaloid region in a dystonia patient with a dislodged electrode

Continuous high-frequency stimulation of the globus pallidum internum (GPi) is an accepted treatment for patients with primary dystonia. In a series of 18 consecutive dystonia cases that were successfully treated by bilateral GPi stimulation, 1 patient had an adverse event involving the downward migration of the electrodes. He developed remarkable behavioral complications and was found to have dislodgement of the left electrode to a position close to the left amygdala. The patient developed behavioral changes consisting of depression, psychotic symptoms, and heightened pain perception. This syndrome reverted when the left electrode was removed and a new one inserted in the correct position. We describe in detail the clinical features associated with left amygdala dysregulation induced by high-frequency stimulation through the displaced electrode.