Vestibular function and quality of life in vestibular schwannoma: does size matter?

Judith Wagner

doi:10.3389/fneur.2011.00055

Abstract

Objectives: Patients with vestibular schwannoma (VS) frequently suffer from disabling vestibular symptoms. This prospective follow-up study evaluates vestibular and auditory function and impairment of quality of life due to vertigo, dizziness, and imbalance in patients with unilateral VS of different sizes before/after microsurgical or radiosurgical treatment. Methods: Thirty-eight patients with unilateral VS were included. Twenty-two received microsurgery, 16 CyberKnife radiosurgery. Two follow-ups took place after a median of 50 and 186.5 days. Patients received a standardized neuro-ophthalmological examination, electronystagmography with bithermal caloric testing, and pure-tone audiometry. Quality of life was evaluated with the Dizziness Handicap Inventory (DHI). Patient data was grouped and analyzed according to the size of the VS (group 1: <20 mm vs group 2: ≥20 mm). Results: In group 1, the median loss of vestibular function was +10.5% as calculated by Jongkees Formula (range −43 to +52; group 2: median +36%, range −56 to +90). The median change of DHI scores was −9 in group 1 (range −68 to 30) and +2 in group 2 (−54;+20). Median loss of hearing was 4 dB (−42; 93) in group 1 and 12 dB in group 2 (5; 42). Conclusion: Loss of vestibular function in VS clearly correlates with tumor size. However, loss of vestibular function was not strictly associated with a long-term deterioration of quality of life. This may be due to central compensation of vestibular deficits in long-standing large tumors. Loss of hearing before treatment was significantly influenced by the age of the patient but not by tumor size. At follow-up 1 and 2, hearing was significantly influenced by the size of the VS and the manner of treatment.

Highlights

Vestibular schwannoma (VS) is a benign tumor arising from the Schwann cells surrounding the vestibular nerve
Caloric testing was performed in 17 patients at the first and 19 patients at the second follow-up. Patients in this group had a median reduction of vestibular function of 38%
The patients had a moderate deterioration of vestibular function [52% (18; 100%) reduction at the first and 53% (9; 100%) at the second follow-up], resulting in a complete vestibular paresis in four patients (Figure 1)

Summary

Introduction

Vestibular schwannoma (VS) is a benign tumor arising from the Schwann cells surrounding the vestibular nerve. With an annual incidence of 9.4/1,000,000, it is one of the more common benign intracranial tumors (Tos et al, 1992). Vestibular deficits have been shown to severely affect quality of life (Pérez et al, 2003; Kammerlind et al, 2005). Most patients with a chronic loss of vestibular function regain their balance due to the process of central vestibular compensation. Central vestibular compensation consists of multiple processes of perceptual, vestibulo-ocular, and vestibulo-spinal readjustment after unilateral and bilateral vestibular loss. It has been shown to be rapid and mostly complete for static conditions. For dynamic conditions (i.e., associated with high-frequency head movements) it is often incomplete (for review see Brandt, 2000)

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