Audiologic presentation of vestibular schwannomas in neurofibromatosis type 2.

OBJECTIVE

The audiologic presentation of vestibular schwannoma (VS) associated with neurofibromatosis type 2 (NF2) has not been well characterized. The goal of this study was to investigate the audiologic features of NF2-associated VS and to determine their relationship to the size of the tumor.

STUDY DESIGN

A retrospective case review.

SETTING

Quaternary governmental medical research institute evaluating patients fitting specific criteria for ongoing clinical studies.

PATIENTS

Audiologic and magnetic resonance imaging data were available for 40 patients (25 males, 15 females), with an average age of 32 years, who had been recruited for ongoing clinical and genetic studies of NF2.

MAIN OUTCOME MEASURES

The audiologic profile and magnetic resonance imaging characteristic of tumor were retrospectively reviewed.

RESULTS

The average size of the tumor at presentation was 7.26 +/- 16.58 cm3 and measured 1.2, 1.6, and 1.1 cm in the anterior/posterior, lateral/medial, and superior/inferior dimensions, respectively. An increase in lateral/medial size of the tumor most significantly correlated with deterioration in mid- (1,000-2,000 Hz) and high- (4,000-8,000 Hz) frequency hearing levels, elevated speech reception threshold, and prolonged auditory brain stem response waves III and V latency.

CONCLUSIONS

Patients with NF2 demonstrate a more predictable audiologic profile for a given size tumor than has been previously described with spontaneous or sporadic VS.