STUDIES AT A GLANCE 

New scientific studies summarized for you 

Study: Long-term Hearing Preservation in Electric Acoustic Cochlear Implant Candidates 

(Original title: Long-term Hearing Preservation in Electric Acoustic Cochlear Implant Candidates Otol Neurotol. 2020 Jul;41(6):750-757, Sprinzl GM et al.) 

Take-home message: 

Long-term preservation of residual acoustic hearing is possible for patients undergoing cochlear implant surgery with electric-acoustic stimulation (EAS). Special flexible electrodes and a cautious surgical technique are key factors for successful hearing preservation. 

Background: 

Cochlear implant surgery is often associated with a loss of residual hearing due to trauma to the cochlea. 

The number of patients with severe sensorineural hearing loss in the high frequencies and usable residual hearing in the low frequencies is increasing. Candidates meeting these criteria can use a cochlear implant technology with simultaneous electric-acoustic stimulation (EAS). 

Residual hearing that can be preserved postoperatively can contribute to enhanced performance with the CI. 

Method: 

This study evaluated whether cochlear implantation with electric-acoustic stimulation leads to stable results and long-term hearing preservation. 

21 ears were included in the study, 10 of which were observed in the long-term group (12-58 months), the rest in the short-term group (up to 12 months). 

Key points: 

• Special electrode arrays mainly used in the study, MED-EL FLEX electrodes, are shorter and more flexible than standard cochlear implant electrodes. They cause less trauma during the insertion process and are less likely to protrude into the scala vestibuli. 
• Electrode insertion through the round window has proven to better preserve residual hearing long-term than a cochleostomy. 
• Slow electrode insertion causes less trauma to the cochlea. 
• Lateral wall placement leads to better hearing preservation than perimodiolar electrode placement. 
• Intraoperative application of steroids and antibiotics additionally foster low-frequency hearing preservation. 

Results: 

Taking both groups into account, almost half the ears (=47,6%) were rated as complete hearing preservation; for the rest but one, residual hearing was preserved to some extent. 

Speech perception for all subjects improved significantly after surgery, with patients using electric and acoustic stimulation benefitting more than those using just electric stimulation with their cochlear implant. 

Read the study here: https://www.sciencedirect.com/science/article/pii/S0165587621002895?via%3Dihub