Differential diagnosis of cerebellopontine angle tumours with special reference to the galvanic test

In the present paper an attempt to evaluate the diagnostic importance and reliability of the various vestibular tests was made. Special attention was paid to the galvanic test and its typical patterns of retrolabyrinthine lesions. The galvanic test is an important diagnostic method allowing a differentiation between a lesion of the vestibular endorgan and its peripheral neuron at an early stage. 40 surgically confirmed cases (24 acoustic neuromas and 16 cerebellopontine angle tumours) were analysed. In 36 cases the neurootologic diagnosis was correct while 4 cases of acoustic neuroma were not recognized as such. The diagnostic failure and some common pitfalls in the neuro-otological diagnosis of CPAT are discussed.