Can Size or Type of the Pontocerebellar Tumor Be Predicted by an ABR Finding?

Abstract

ABR waveforms were analyzed in 63 subjects with tumors of the pontocerebellar angle. The tumors were diagnosed by CT scan and the diagnoses were surgically confirmed. According to the latency changing and amplitude size, the ABR waveforms were classified into seven types (0, A, B, C, D, E and F). All tumors were divided into groups (depending on size), and into subgroups (depending on type). Types 0–E were found in tumors of all sizes. Type C of the brain stem response (BSR) waveform (only 1 deflexion present) was revealed in 75 % of tumors greater than 20 mm. In this case tumor size may be predicted with the significance level of 5 %. Type F of the BSR waveform was found in tumors other than neuromas. Contralateral BSR is affected by tumors greater than 20 mm, and from the statistic point of view significantly more often by neuroma (significance level 5 %) than by other tumors.

False-positive MRI in a patient with otoneurological pathology

“…This is the case for pure tone audiometry (Portmann et al, 1989), subjective tests for recruitment (Pfaltz et al, 1991) and stapedius reflex testing (Gilain etai, 1991), not always been in agreement with the expected findings. Nowadays it is well established that both evoked response audiometry (ERA) and electrocochleography play a significant role in diagnostic testing for acoustic Accepted for publication: 30 September 1992. schwannoma, giving important clues for its detection (Portmann et al, 1989;Gilain et al, 1991) and size (Haralampiev and Ribaric, 1991). However, in several cases, such as the one presented in this paper, these tests are less reliable or cannot even be performed, owing to technical problems, i.e.…”

Sensitivity of Auditory Brainstem Response in Acoustic Neuroma Screening

“…Compression of the cochlear nerve and the brainstem would occur later if the posterior fossa is large. The incidence of normal ABR AN ranges from 2.1 to 24% (10,11). It was 8% in our study.…”