Clinical Presentation of Vestibular Schwannoma in Patients with Baseline Cognitive Disability

Background/Objective: The majority of patients with vestibular schwannoma (VS) initially experience asymmetric audiovestibular complaints prompting medical evaluation. Owing to increasing disease awareness, greater access to radiological testing, and the routine use of gadolinium with magnetic resonance imaging (MRI), the incidence of VS has increased, while the average tumor size at diagnosis has decreased substantially. Over the past several years the authors have noticed a significant disparity in clinical presentation and tumor size among patients with pre-existing cognitive impairment compared with the general population. The objective of the current study is to review the clinical presentation of 5 consecutive patients with varying severities of baseline mental retardation who were ultimately diagnosed with VS.

Design: Retrospective chart review

Setting: Two tertiary academic referral centers

Participants: Consecutive subjects with baseline cognitive impairment who were evaluated for VS between 2010 and 2013

Main Outcome Measures: Presenting symptoms and tumor characteristics

Results: Five adult subjects (4 females; median age 33 years) were identified. Two patients were diagnosed with syndromic mental retardation (LEAPARD syndrome, Macrocephaly-capillary malformation syndrome), 1 with extreme prematurity and grade 4 intraventricular hemorrhage, and in 2 cases the cause for cognitive delay was not known. The most common reasons for seeking medical care included worsening balance/coordination and headaches, despite the fact that the 4 patients who were able to complete behavioral audiometry all demonstrated profound hearing loss in the ipsilateral ear. Additionally, after further prompting 2 patients endorsed facial numbness and 1 had partial facial palsy on physical examination. MRI revealed a median preoperative tumor size of 4.5cm (4.3–5.7cm) and all patients had varying degrees of hydrocephalus and peritumoral vasogenic edema.

Conclusions: Preexisting cognitive impairment is a risk factor for late presentation of VS. In the current series, the median tumor size at time of diagnosis was 4.5cm (4.3–5.7cm) and all subjects presented only after developing advanced symptoms associated with hydrocephalus. Patients with normal cognitive function most commonly seek medical care following unilateral hearing loss and tinnitus. In contrast, individuals with poor cognitive capacity may be unable to acknowledge such symptoms, communicate their presence, and caregivers may initially dismiss complaints. In such patients, the diagnosis of VS is elusive and clinicians should maintain a low threshold for imaging to avoid further delays in diagnosis and treatment.