Vestibular Tests Related to Tumor Volume in 137 Patients With Small to Medium-Sized Vestibular Schwannoma.

OBJECTIVE: The video head impulse test (vHIT) and cervical and ocular vestibular evoked myogenic potentials (cVEMP and oVEMP) are new methods for measuring peripheral vestibular function. The objectives of this study were to compare these tests and the traditionally used caloric test in patients with small and medium-sized untreated vestibular schwannoma (VS) and to measure the correlation between the tests' results and tumor volume. STUDY DESIGN: National cross-sectional study. SETTING: Tertiary university clinic. METHODS: Prevalence of abnormal cVEMP, oVEMP, caloric test, and 6-canal vHIT results on the tumor side and the nontumor side were compared and related to tumor volume with regression analyses in 137 consecutive VS patients assigned to a wait-and-scan protocol in the period 2017 to 2019. RESULTS: The sensitivity of 6-canal vHIT, caloric test, cVEMP, and oVEMP to detect vestibulopathy in VS patients was 51%, 47%, 39%, and 25%, respectively. Normal tests were found in 21% of the patients. The results of vHIT and caloric test were related to tumor volume, but this was not found for cVEMP and oVEMP. CONCLUSION: The caloric test and 6-canal vHIT showed the highest sensitivity in detecting vestibulopathy in untreated VS patients. vHIT, and particularly the posterior canal, was limited with a high prevalence of abnormal results on the nontumor side. A combination of cVEMP and caloric test was favorable in terms of a relatively high sensitivity and low prevalence of abnormal results on the nontumor side. Larger tumors had a higher rate of pathology on caloric testing and vHIT.

Postural Sway Predicts Growth in Untreated Vestibular Schwannoma: A Retrospective Volumetric Study.

BACKGROUND: One in three vestibular schwannomas (VS) will grow within 3 years after diagnosis, but no reliable baseline parameter has been found to predict such growth. OBJECTIVE: To determine if postural sway is associated with growth of untreated VS. METHODS: Patients with newly diagnosed sporadic VS assigned to a wait-and-scan protocol were identified from a prospectively maintained database. Postural sway was measured by posturography at baseline and patients were classified as steady or unsteady. Observer-blinded volumetric tumor measurements were performed on the diagnostic MRI and a 3-year control MRI. Tumor growth quantified as relative growth (%) and volume-doubling time (VDT and VDT-1) were investigated as dependent variables against baseline parameters. RESULTS: Out of 204 VS patients, 53 (26%) were classified as unsteady on the platform at baseline. Median tumor volume was 0.32 cm3 (range 0.02-4.79), and 51% demonstrated significant growth within 3 years. Unsteady patients had significantly faster-growing tumors, with a mean relative growth of 172.5% compared to 79.5% in steady patients (p < 0.006). Seventy-seven percent of unsteady patients had >20% volume increase, compared to 42% in steady patients (p < 0.001). Mean VDT-1 was 0.65 doublings per year for unsteady patients, and 0.22 for steady patients (p < 0.001). Multivariate regression analysis including demographic and clinical parameters showed an OR of 5.6 (95% CI 2.6, 11.8) for growth in unsteady patients. CONCLUSIONS: This is the first demonstrated association between a measurable parameter and future growth in untreated VS. Our findings may help clinicians identify patients with a higher risk for tumor growth and provide closer monitoring or early treatment.

Long-term Effects of Conservative Management of Vestibular Schwannoma on Dizziness, Balance, and Caloric Function.

OBJECTIVES: To study the development of dizziness, caloric function, and postural sway during long-term observation of untreated vestibular schwannoma patients. STUDY DESIGN: Retrospective review of a prospectively maintained longitudinal cohort. SETTING: Tertiary referral hospital. SUBJECTS AND METHODS: Patients with vestibular schwannoma undergoing wait-and-scan management were included-specifically, those who did not require treatment during a minimum radiologic follow-up of 1 year. Baseline data and follow-up included magnetic resonance imaging, posturography, bithermal caloric tests, and a dizziness questionnaire. Main outcomes were prevalence of moderate to severe dizziness, canal paresis, and postural instability at baseline and follow-up, as compared with McNemar's test. RESULTS: Out of 433 consecutive patients with vestibular schwannoma, 114 did not require treatment during follow-up and were included. Median radiologic follow-up was 10.2 years (interquartile range, 4.5 years). Age ranged from 31 to 78 years (mean, 59 years; SD, 10 years; 62% women). Median tumor volume at baseline was 139 mm3 (interquartile range, 314 mm3). This did not change during follow-up (P = .446). Moderate to severe dizziness was present in 27% at baseline and 19% at follow-up (P = .077). Postural unsteadiness was present in 17% at baseline and 21% at follow-up (P = .424). Canal paresis was present in 51% at baseline and 56% at follow-up (P = .664). CONCLUSIONS: There was no significant change in the prevalence of dizziness, postural sway, or canal paresis during conservative management of vestibular schwannoma, while tumor volume remained unchanged. This indicates a favorable prognosis in these patients with regard to vestibular symptoms.

Predictors of vertigo in patients with untreated vestibular schwannoma.

OBJECTIVES: Previous studies have shown that vertigo is the most powerful negative predictor of quality of life in patients with vestibular schwannomas, but the variability in vertigo symptom severity is still poorly understood. We wanted to find out whether vertigo could be related to objective parameters such as tumor size, location, vestibular nerve function, hearing, and postural stability in patients with untreated vestibular schwannomas. STUDY DESIGN: Baseline data from prospective cohort study. SETTING: Tertiary referral center. PATIENTS: Four hundred thirty-four consecutive patients with unilateral VS diagnosed on MRI. Mean age 56 years (range 16-84 yr). Fifty-three percent women. INTERVENTION: Diagnostic, with a medical history, otolaryngological examination, pure-tone and speech audiometry, MRI, posturography, and videonystagmography with bithermal caloric tests. MAIN OUTCOME MEASURE: Dizziness measured on a 100-mm visual analog scale (VAS). Secondary outcome measures were canal paresis and postural imbalance (static and dynamic posturography). RESULTS: Three hundred three patients (70%) completed the VAS. Severe dizziness, defined as VAS 75 or greater, was reported by 9% of the patients. Larger tumors were associated with higher risk of postural instability and canal paresis. Moderate to severe dizziness was associated with postural imbalance and canal paresis, and possibly with small to medium-sized tumors. Postural instability was related to tumor size and canal paresis when measured by dynamic, but not with static, posturography. CONCLUSION: A minority of VS patients experience severe vestibular symptoms related to canal paresis and postural instability. A curvilinear relationship is hypothesized between tumor size and dizziness.