Divisions >> Otolaryngology-Head & Neck Surgery >> Otolaryngology Surgery Update e-newsletter >> September 2014 Issue >> Clinical Care - Hybrid Cochlear Implantation: Progress in the Treatment of High Frequency Sensorineural Hearing Loss
Hybrid Cochlear Implantation: Progress in the Treatment of High Frequency Sensorineural Hearing Loss
By Dr. Samuel Gubbels
High frequency sensorineural hearing loss is a challenging condition to manage for patients, audiologists and otolaryngologists alike. Patients with HF-SNHL describe problems with speech comprehension and appreciation of environmental sounds, particularly in the presence of ambient noise. Hearing aids are the primary treatment option for HF-SNHL, however, effectively providing selective amplification to the high frequencies can be challenging. A number of strategies have been developed to optimize amplification for patients with HF-SNHL, such as frequency compression, transposition and frequency lowering 1.
In the last 10 years investigators have reported promising results using cochlear implants as a treatment for HF-SNHL 2, 3. With refinements in surgical techniques and electrode designs, it has become possible to place a modified cochlear implant (CI) in patients with HF-SNHL while preserving a usable level of residual acoustic hearing in approximately 70% of patients 4. This allows the patient to use hearing aids in both ears in combination with electrical stimulation of the high frequencies from the cochlear implant; an approach called Hybrid cochlear implantation or electric-acoustic stimulation. The operative procedure is similar to standard cochlear implantation and utilizes a cochlear implant with a shorter and thinner electrode placed only into the basal turn of the cochlea.
Recently, Cochlear Corporation™ received FDA approval of the Nucleus Hybrid L24 system for the treatment of HF-SNHL 5, and this technology is now available for implantation at the University of Wisconsin. Candidacy for this device includes:
Pre-clinical studies of the Hybrid L24 device have demonstrated promising results 6. At six months postoperatively, patients using a combined stimulation mode (CI with bilateral hearing aids) achieved an average of >33% improvement in their CNC word recognition scores compared to their preoperative testing (p<0.001). Notably, this improvement was consistent in both quiet and noisy conditions (Figure 2). At six months, 100% of patients, even those who lost some residual low-frequency hearing with implantation, performed equal to or better than they did preoperatively with appropriately fitted bilateral hearing aids. Other reported benefits include maintenance of music perception abilities, positive self-reported outcomes and increased patient satisfaction in the majority of cases 6.
In summary, HF-SNHL remains a common and challenging clinical entity for patients and hearing health specialists. Hearing aids continue to be the primary treatment modality for this condition. Patients who fail to benefit from amplification with HF-SNHL of appropriate severity may now qualify for treatment with a novel cochlear implant to be used with bilateral hearing aids. Recent FDA approval of a device based upon this strategy offers otolaryngologists a new and welcomed opportunity to improve the listening abilities of patients with HF-SNHL.
1 Simpson A. Frequency-lowering device for managing high-frequency hearing loss: A review. Trends Amplif. 2009 Jun;13(2):87-106.
2 von Ilberg CA, Baumann U, Kiefer J, Tillien J, Adunka OF. Audiol neurotol. 2011;16 Suppl 2:1-30.
3 Woodson EA, Reiss LA, Turner CW, Gfeller K, Gantz BJ. The Hybrid cochlear implant: a review. Adv Otorhinolaryngol. 2010;67:125-34.
4 Talbot KN, Hartley DE. Combined electro-acoustic stimulation: a beneficial union? Clin Otolaryngol. 2008 Dec;33(6):536-45.