To identify primary biographic and audiologic factors contributing to cochlear implant (CI) performance variability in quiet and noise by controlling electrode array type and electrode position within the cochlea.
Although CI outcomes have improved over time, considerable outcome variability still exists. Biographic, audiologic, and device-related factors have been shown to influence performance. Examining CI recipients with consistent array type and electrode position may allow focused investigation into outcome variability resulting from biographic and audiologic factors.
Thirty-nine adults (40 ears) implanted for at least 6 months with a perimodiolar electrode array known (via computed tomography [CT] imaging) to be in scala tympani participated. Test materials, administered CI only, included monosyllabic words, sentences in quiet and noise, and spectral ripple discrimination.
In quiet, scores were high with mean word and sentence scores of 76 and 87%, respectively; however, sentence scores decreased by an average of 35 percentage points when noise was added. A principal components (PC) analysis of biographic and audiologic factors found three distinct factors, PC1 Age, PC2 Duration, and PC3 Pre-op Hearing. PC1 Age was the only factor that correlated, albeit modestly, with speech recognition in quiet and noise. Spectral ripple discrimination strongly correlated with speech measures.
For these recipients with consistent electrode position, PC1 Age was related to speech recognition performance. Consistent electrode position may have contributed to high speech understanding in quiet. Inter-subject variability in noise may have been influenced by auditory/cognitive processing, known to decline with age, and mechanisms that underlie spectral resolution ability.
Department of Otolaryngology Head and Neck Surgery, Washington University School of Medicine in St. Louis, St. Louis, Missouri
Address correspondence and reprint requests to Laura K. Holden, Au.D., Department of Otolaryngology Head and Neck Surgery, Washington University School of Medicine in St Louis, 660 South Euclid Avenue, Box 8115, St. Louis, MO 63110; E-mail: firstname.lastname@example.org
This study was funded in part by Cochlear Americas (Centennial, CO) and by the National Institute on Deafness and Other Communication Disorders Grant R01 DC009010 (JBF).
Laura Holden, AuD, is a member of the audiology advisory board for Advanced Bionics and receives a consulting fee. Jill Firszt, PhD, is a member of the audiology advisory board for Cochlear Americas and Advanced Bionics and receives a consulting fee. WUSM has received payment from Cochlear Americas for work performed by Timothy Holden specific to research studies at Cochlear Americas. For the remaining authors, none were declared.