Vestibulo-oculomotor disturbances in trigeminal neuralgia and hemifacial spasm.

Patients with hemifacial spasm and trigeminal neuralgia later treated with microvascular decompression and surgical interposition for their vascular loop disturbance were investigated preoperatively with electronystagmography, saccade test and audiometry. Some of them underwent an extended investigation including computerized broad-frequency rotatory test with visual suppression and a computerized smooth pursuit test, both tests using sinusoidal as well as randomized movement patterns as stimulus. The patients showed a high frequency of vestibulo-oculomotor disturbances indicating that the vascular loop, in addition to pressure on the trigeminal and facial nerves, also exerted pressure on the statoacoustic nerve and/or the brain-stem. It can be deduced that the vascular loop may give purely VIII nerve disturbances treatable with surgery, the problem being, however, to establish the diagnosis.