Brain stem evoked response audiometry versus magnetic resonance imaging in the detection of CPA lesions

Abstract

Introduction. When a patient is suspected of having a retrocochlear lesion, several diagnostic procedures are available to detect acoustic neuromas. In the early detection of acoustic neuromas a test with a high sensitivity (i.e. few false-negative tests) is important. It is desirable nowadays to use the least expensive test. In the Netherlands, magnetic resonance imaging (MRI) is 5× more expensive than brainstem evoked response audiometry (BERA). The aim of this study was to investigate the sensitivity of BERA in the detection of acoustic neuromas. Material and methods. In 1993 and 1994 1132 patients were suspected of having a retrocochlear lesion. In 174 patients the BERA was pathological. In 145 patients MRI was carried out. In 12% of the patients with a normal BERA, MRI was also performed. Results. In 74 patients a lesion was seen with MRI. In three of these patients the BERA was normal. In 103 patients with a pathological BERA no lesion was seen with MRI. We found a sensitivity of 96% and a specificity of 90% for BERA. Conclusion. In our hospital with approximately 500 new patients a year suspected of having retrocochlear lesions, the sensitive and less expensive BERA is the first diagnostic test. When the BERA is pathological an MRI is undertaken.