Classification of Acoustic Hearing Preservation After Cochlear Implantation Using Electrocochleography

Abstract

The objective to preserve residual hearing during cochlear implantation has recently led to the use of intracochlear electrocochleography (ECochG) as an intraoperative monitoring tool. Currently, a decrease in the amplitude of the difference between responses to alternating-polarity stimuli (DIF response), predominantly reflecting the hair cell response, is used for providing feedback. Including other ECochG response components, such as phase changes and harmonic distortions, could improve the accuracy of surgical feedback. The objectives of the present study were (1) to compare simultaneously recorded stepwise intracochlear and extracochlear ECochG responses to 500 Hz tone bursts, (2) to explore patterns in features extracted from the intracochlear ECochG recordings relating to hearing preservation or hearing loss, and (3) to design support vector machine (SVM) and random forest (RF) classifiers of acoustic hearing preservation that treat each subject as a sample and use all intracochlear ECochG recordings made during electrode array insertion for classification. Forty subjects undergoing cochlear implant (CI) surgery at the Oslo University Hospital, St. Thomas’ Hearing Implant Centre, or the University Hospital of Zurich were prospectively enrolled. In this cohort, DIF response amplitude decreases did not relate to postoperative acoustic hearing preservation. Exploratory analysis of the feature set extracted from the ECochG responses and preoperative audiogram showed that the features were not discriminative between outcome classes. The SVM and RF classifiers that were trained on these features could not distinguish cases with hearing loss and hearing preservation. These findings suggest that hearing loss following CI surgery is not always reflected in intraoperative ECochG recordings.

ZH-ECochG Bode Plot: A Novel Approach to Visualize Electrocochleographic Data in Cochlear Implant Users

“…Instead, they showed the growth functions of the amplitude of ECochG, ECochG responses recorded from a single location before and after insertion, or ECochG thresholds for different stimuli, amongst others. The remaining 74 studies [ 9 , 10 , 11 , 12 , 13 , 15 , 17 , 18 , 19 , 20 , 21 , 24 , 25 , 34 , 35 , 37 , 39 , 40 , 41 , 42 , 48 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 ...…”

“…Instead, they showed the growth functions of the amplitude of ECochG, ECochG responses recorded from a single location before and after insertion, or ECochG thresholds for different stimuli, amongst others. The remaining 74 studies [9][10][11][12][13]15,[17][18][19][20][21]24,25,34,35,37,[39][40][41][42]48, were included for review and are described in detail in Table S1 in the Supplementary Materials (https://github.com/OtoBM). The included articles contained 60 (81.1%) human studies, 11 (14.9%) animal studies, 1 study including both human participants (adults) and animals (guinea pigs), 1 study including only simulated data, and 1 study including both human (adults) and simulated data.…”

“…The responses can be measured at both extracochlear and intracochlear sites, whereby the latter is now achievable through direct recordings with the CI’s electrode array. ECochG recordings in cochlear implants have demonstrated potential relevance in monitoring cochlear function during and after insertion of the CI electrode [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ], detecting intracochlear trauma [ 20 , 21 , 22 , 23 ], optimizing the electrode’s placement [ 24 , 25 ], estimating hearing thresholds [ 26 , 27 , 28 , 29 ], investigating different etiologies of hearing loss [ 30 , 31 , 32 , 33 ], and predicting postoperative preservation of hearing [ 12 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 ] and CI speech perception outcomes [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ].…”