Systematic review of compound action potentials as predictors for cochlear implant performance.
The variability in speech perception between cochlear implant users is thought to result from the degeneration of the auditory nerve. Degeneration of the auditory nerve, histologically assessed, correlates with electrophysiologically acquired measures, such as electrically evoked compound action potentials (eCAPs) in experimental animals. To predict degeneration of the auditory nerve in humans, where histology is impossible, this paper reviews the correlation between speech perception and eCAP recordings in cochlear implant patients.



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We performed a systematic search for articles containing the following major themes: cochlear implants, evoked potentials, and speech perception. Two investigators independently conducted title-abstract screening, full-text screening, and critical appraisal. Data were extracted from the remaining articles.



Twenty-five of 1,429 identified articles described a correlation between speech perception and eCAP attributes. Due to study heterogeneity, a meta-analysis was not feasible, and studies were descriptively analyzed. Several studies investigating presence of the eCAP, recovery time constant, slope of the amplitude growth function, and spatial selectivity showed significant correlations with speech perception. In contrast, neural adaptation, eCAP threshold, and change with varying interphase gap did not significantly correlate with speech perception in any of the identified studies.



Significant correlations between speech perception and parameters obtained through eCAP recordings have been documented in literature; however, reporting was ambiguous. There is insufficient evidence for eCAPs as a predictive factor for speech perception. More research is needed to further investigate this relation. Laryngoscope, 2016 127:476-487, 2017.
Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Ruben H M
RH
van Eijl
Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.
Patrick J
PJ
Buitenhuis
Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Inge
I
Stegeman
Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Sjaak F L
SF
Klis
Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.|Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands.
Wilko
W
Grolman
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003054:Cochlear Implants; D003056:Cochlear Nerve / Q000503:physiopathology*; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000502:physiology*; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology* / Q000534:rehabilitation*; D006801:Humans; D008875:Middle Aged; D009410:Nerve Degeneration / Q000503:physiopathology*; D013067:Speech Perception / Q000502:physiology*; D013223:Statistics as Topic; D055815:Young Adult
Systematic review; cochlear implant; deafness; electrically evoked compound action potential; hearing loss; speech perception