Vestibular end-organ and balance deficits after meningitis and cochlear implantation in children correlate poorly with functional outcome

Abstract

Objective: Assess vestibular and balance function in meningitis-induced profound sensorineural hearing loss (SNHL).

Study design: Prospective cohort study.

Setting: Tertiary pediatric referral center.

Patients: Nine pediatric participant with profound SNHL after bacterial meningitis with (8) and without (1) unilateral Cochlear implant.

Main outcome measure(s): Horizontal canal function in response to caloric and high-frequency rotation (0.25-5 Hz). Saccular function assessed by the vestibular evoked myogenic potential. Static and dynamic balance performance on the balance subset of the Bruininsk-Oseretsky Test of Motor Proficiency 2. Labyrinthine ossification on computed tomography preimplant, with follow-up imaging in a subset (n = 7).

Results: Horizontal canal function in response to caloric stimulation was abnormal in all children, with 5 of 8 demonstrating bilateral areflexia and 3 of 8 having asymmetric hypofunction with better function on the implanted side. In response to rotation, horizontal canal function was abnormal in all but 1 child (8 of 9). Saccular function, assessed by VEMP, was intact in most of the children (5 of 7). Static and dynamic balance (Bruininsk-Oseretsky Test of Motor Proficiency 2 scores) were significantly poorer in the meningitis group compared with both normal-hearing controls (p < 0.01) and children with SNHL of variable etiology and Cochlear implant (p < 0.01). Labyrinthine ossification was present in all cases, with variable extent, location, and progression.

Conclusion: Vestibular function and balance are compromised in children with SNHL after meningitis. Whereas vestibular loss seems well compensated at low frequency through an overreliance on visual inputs, deficits surface during high-frequency rotation, particularly in dark. Saccular function seems less susceptible to damage from meningitis. Extent, location, and progression of ossification were variable. Despite profound dysfunction on objective testing, subjective limitations in functional balance were not reported, demonstrating the significant ability of children to compensate for even the most severe vestibular losses.