Auditory brainstem implants in neurofibromatosis Type 2: is open speech perception feasible?

Area of Science:

• Neurosurgery
• Auditory Neuroscience
• Biomedical Engineering

Background:

• Auditory brainstem implants (ABIs) offer a potential solution for hearing restoration in patients with bilateral auditory nerve destruction.
• Despite advancements, ABI hearing quality remains variable, necessitating identification of factors influencing speech perception.

Observation:

• A prospective study evaluated 18 neurofibromatosis Type 2 patients undergoing ABI surgery with neuromonitoring.
• Speech perception was assessed using word recognition (MTPa) and open-set sentence tests (HSM) at 24 months.

Findings:

• Successful ABI activations yielded average MTPa scores of 89% and HSM scores of 41%.
• Shorter deafness duration (ipsilateral and bilateral) and a higher number of active electrodes correlated with better HSM outcomes.
• Early MTPa scores at 3 months strongly predicted 24-month HSM results.

Implications:

• Open-set speech recognition is achievable with ABIs, even in cases of large tumor volumes.
• Optimizing ABI outcomes requires considering deafness duration and electrode count.
• Early auditory assessments can predict long-term speech perception capabilities in ABI patients.