Introduction: Neurofibromatosis type 2 (NF2) patients commonly have bilateral vestibular schwannomas with progressive hearing loss. Auditory brainstem implants (ABIs) improve their hearing by stimulating proximal to the damaged vestibulocochlear nerve. This review re-analyzes available individual patient data to describe the impact of ABIs in NF2.
Methods: All three studies (total of 111 patients) in a multi-database search with access to repeated individual hearing outcomes after ABI insertion over time in adults with NF2 were included. Abstracted data included hearing ability with different complexities of sound (sounds to speech) and with different aids (ABI +/- lip reading) plus demographics (age/gender). Random effect multi-level mixed linear modelling was used separately for each study due to methodology differences to analyze how hearing changes over time and interactions between variables.
Results: Hearing consistently improved over time after ABI (p<0.0001) overall and with all complexities of sound. Hearing improved best with ABI together with lip reading and lip reading alone results stayed stable, suggesting ABIs can improve hearing beyond patient function without ABI. Vowels were better comprehended than consonants and same with words compared to sentences (p<0.0001), likely related to sound complexity. Age and gender did not predict hearing outcomes.
Conclusions: ABI use in NF2 improves hearing beyond a baseline of lip reading alone and these continue over time from ABI. Our findings may aid in resource allocation for ABI and to inform patient counseling about treatment options.
Patient Care: Patients with NF2 and bilateral vestibular schwannoma have progressive bilateral hearing loss and our review suggests that auditory brainstem implantation significantly improves their hearing. Our results also suggest that hearing improves over time with the implant and their lip reading ability fluctuates, which is useful in guiding hearing rehabilitation in these patients.
Learning Objectives: 1) To understand the impact role for auditory brainstem implantation in NF2
2) To understand the impact of auditory brainstem implantation
3) To educate patients who may benefit from implantation or on what to expect afterwards