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Brainstem response in cerebellopontine angle tumors.
1Department of Otorhinolaryngology, Albert-Ludwigs-University, Freiburg, Germany.
Summary
Auditory brainstem response (ABR) testing is not sufficient for early detection of small cerebellopontine angle (CPA) tumors. While normal ABR results were found in 18.4% of CPA tumors, smaller tumors showed a higher incidence of normal ABR.
Area of Science:
- Otolaryngology
- Neurology
- Diagnostic Imaging
Background:
- Cerebellopontine angle (CPA) tumors can affect auditory pathways.
- Auditory brainstem response (ABR) is a diagnostic tool used to assess these pathways.
Purpose of the Study:
- To evaluate auditory brainstem response (ABR) findings in patients with cerebellopontine angle (CPA) tumors.
- To specifically analyze cases with normal ABR results.
Main Methods:
- Retrospective evaluation of ABR findings in 309 patients with radiographically confirmed CPA tumors.
- Patients underwent audiologic examination, electronystagmography, ABR testing, and electrocochleography.
- Tumors were categorized by ABR results, histology, and size (via MRI).
Main Results:
- Normal ABR results were observed in 18.4% of CPA tumors, with 50.2% showing no response.
- Small vestibular schwannomas (under 15 mm) had a higher incidence of normal ABR (41.7%).
- CPA tumors with normal ABR often presented with no hearing loss, symmetrical hearing loss, or cochlear deafness.
Conclusions:
- The increasing detection of small CPA tumors with MRI may lead to a higher incidence of normal ABR results.
- Auditory brainstem response (ABR) sensitivity decreases with smaller tumors.
- ABR alone is insufficient for the early detection of small CPA tumors.