The purpose of the study is to determine whether vestibular and postural compensation following schwannoma surgery is improved by ablating vestibular function prior to surgery, even if vestibular function is absent according to modern assessment techniques

Patients subjected to vestibular schwannoma surgery most often suffer from vertigo after surgery, even if no vestibular function can be found in pre-surgical assessment. According to retrospective data about 33% of patients scheduled for surgery do not have any measurable vestibular function. Even the occurrence of spontaneous nystagmus has been recorded in patients with no or very little function prior to surgery (Parietti-Winkler et al. 2008 JNNP). This indicates that despite new methods of measuring vestibular function, remaining vestibular function can be present and patients might benefit from pre-treatment of gentamicin (Tjernström et al. 2009 JNNP)

Inclusion Criteria:

• Vestibular schwannoma advised to surgical treatment
• No measurable remaining vestibular function

Exclusion Criteria:

• impaired decision making
• neurofibromatosis
• signs for central dysfunction
• remaining vestibular function
• Patients are advised not to participate in the gentamicin arm if
• hearing is better than 30 deciBel (dB) in pure tone average (500, 1000, 2000, 3-4000 Hz) and speech discrimination better than 70%
• the neurosurgeon aim at hearing preservation surgery and do not want to risk gentamicin associated hearing loss