Diagnostic value of auditory brainstem responses in cerebellopontine angle tumours

Abstract

Conclusion. Auditory brainstem responses (ABRs) associated with other audio-vestibular examinations and a thorough clinical examination should allow detection of the majority of cerebellopontine angle (CPA) lesions (99.2–100%). Objective. The increasing quality of MRI in the detection of CPA lesions, and the reports of false negative ABRs have raised issues concerning the value of ABR in the diagnosis and preoperative assessment of CPA lesions. The aim of this work was to assess the value of the ABR in the diagnosis of vestibular schwannomas (VS) and other CPA lesions. Patients and methods. This retrospective study included 676 solitary VS (548 operated on and 128 followed up) and 70 other CPA tumours (72% meningiomas, 11% cholesteatomas, 3% ependymomas, 15% miscellaneous) managed between 1990 and 2001. All patients underwent clinical examination, audiometry, ABR, vestibular caloric tests and MRI. Results. ABRs were normal in 4.8% of VS. Association of normal ABR, vestibular caloric tests and audiometry (AAO-HNS class A) represented only 0.7% of VS. In other CPA lesions, ABR were normal in 15% of cases and the association of the three above-mentioned examinations was encountered in 10%. However, in the latter cases the clinical examination showed an abnormality in all cases.