Dowling, Eric M.

AbstractA cochlear implant (CI) is a surgically implanted device for the treatment of severe to profound sensorineural hearing loss in children and adults. It works by transducing acoustic energy into an electrical signal, which is used to stimulate surviving spiral ganglion cells of the auditory nerve. The past 2 decades have witnessed an exponential rise in the number of CI surgeries performed. Continual developments in programming strategies, device design, and minimally traumatic surgical technique have demonstrated the safety and efficacy of CI surgery. As a result, candidacy guidelines have expanded to include both pre and postlingually deaf children as young as 1 year of age, and those with greater degrees of residual hearing. A growing proportion of patients are undergoing CI for off-label or nontraditional indications including single-sided deafness, retrocochlear hearing loss, asymmetrical sensorineural hearing loss (SNHL) in adults and children with at least 1 ear that is better than performance cut-off for age, and children less than 12 months of age. Herein, we review CI design, clinical evaluation, indications, operative technique, and outcomes. We also discuss the expanding indications for CI surgery as it relates to lateral skull base pathology, comparing CI to auditory brainstem implants, and address the concerns with obtaining magnetic resonance imaging (MRI) in CI recipients.

Objective: To characterize the risk of progression to nonserviceable hearing in patients with sporadic vestibular schwannomas (VS) who elect initial observation. Study Design: Retrospective case series. Setting: Two tertiary care centers. Patients: VS patients with serviceable hearing who underwent at least two audiograms and two MRI studies before intervention or loss to follow-up. Main outcome measure(s): Serviceable hearing, defined as the pure tone average ≤ 50 dB HL and word recognition score ≥ 50%. Results: Four-hundred sixty-six patients (median age of 57 yr and median tumor diameter of 7.3 mm) had serviceable hearing at presentation and were followed for a median of 2.3 years (IQR 1.0 – 4.0). Kaplan–Meier estimated rates of maintaining serviceable hearing (95% CI; number still at risk) at 1, 3, 5, 7, and 10 years following diagnosis were 94% (91–96; 357), 77% (73–82; 172), 66% (60–73; 81), 56% (49–65; 31), and 44% (33–59; 10), respectively. Each 10-dB increase in pure-tone averages at diagnosis was associated with a 2-fold increased likelihood of developing nonserviceable hearing (hazard ratio 2.07; p < 0.001). Each 10% decrease in word recognition score was associated with a 1.5-fold increased likelihood of developing nonserviceable hearing (hazard ratio 1.48; p < 0.001). Conclusions: Among patients with sporadic VS, good baseline word recognition score and low pure-tone average are jointly associated with maintenance of serviceable hearing. These data may be used to guide patient counseling and optimize management.