Cerebellar-pontine angle tumors. Results of quantitative vestibulo-ocular testing

A new quantitative vestibulo-ocular test battery was evaluated in 12 patients with surgically confirmed cerebellar-pontine angle tumors. The battery consisted of precise vestibular and visual stimuli and digital computer analyses of responses. Eleven of 12 patients, including all patients with acoustic neurolemmomas, had significant vestibular deficits on the tumor side (P less than .01). Contrary to previous reports, rotatory tests (impulse and sinusoidal acceleration) reliably identified the side and magnitude of vestibular deficit. Eight of nine patients with surgically confirmed brain stem compression had significantly impaired smooth pursuit (P less than .05). Optokinetic nystagmus was impaired in five of nine patients with brain stem compression (P less than .05). By combining the results of the entire test battery with standard clinical evaluation, a good prediction of tumor size, location, and type was possible.