Ipsilateral and contralateral acoustic brainstem response abnormalities in patients with vestibular schwannoma
Received 3 March 2009; received in revised form 16 September 2009; accepted 21 September 2009.
Abstract
Objective
To analyze auditory brainstem response (ABR) data in patients with vestibular schwannomas (VS) in an effort to identify correlations between abnormal ABR parameters and tumor size.
Study Design
Cross-sectional study with chart review.
Setting
Tertiary referral hospital.
Subjects and Methods
Retrospective chart review and analysis of bilateral ABR records in patients with VS. Interaural latency differences of interpeak I-V (ILD-I-V) and ILD-V longer than 0.2 ms were used as abnormal criteria.
Results
Thirty patients with a mean age of 50 ± 14 years were included in this study. The most frequent changes in ABR parameters included those of ILD-I-V (100%), wave V latency (96.7%), ILD-V (93.3%), and interpeak I-V latency (90%). Average VS tumor size was 2.48 ± 1.31 cm. For patients with VS greater than or equal to 2 cm, the prevalences of abnormal ipsilateral interpeak III-V latency, contralateral wave V latency, and interpeak III-V latency showed statically significant differences (P = 0.0035, P = 0.0267, and P = 0.0273, respectively) compared to those in patients with VS less than 2 cm. Tumor size was positively correlated with pure-tone average (P = 0.0106) and with the total number of bilateral abnormal ABR parameters (P = 0.004).
Conclusions
We identified a correlation between ABR parameters and VS tumor size. An ipsilateral ILD-I-V greater than 0.2 ms was sensitive for detecting VS. Abnormal contralateral wave V and interpeak III-V latency indicated a tumor size potentially larger than 2 cm. Further studies are needed to confirm these findings.
aDepartment of Otolaryngology, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan
bDepartment of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
cDepartment of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
dDepartment of Otolaryngology, Tai-Tung Christian Hospital, Tai-Tung, Taiwan
Corresponding author: Yuh-Shyang Chen, MD, Department of Otolaryngology, Tai-Tung Christian Hospital, No. 350, Kai Feng Street, Tai-Tung, Taiwan
No sponsorships or competing interests have been disclosed for this article.
ABSTRACT