Journal: Ear and Hearing
Article Title: Detection of Extracochlear Electrodes in Cochlear Implants with Electric Field Imaging/Transimpedance Measurements:
doi: 10.1097/AUD.0000000000000837
Figure Lengend Snippet: Methods for automatizing the detection and quantification of extracochlear electrodes. EL1 (electrode 1) refers to the most apical electrode, while EL16 (electrode 16) refers to the most basal electrode. A, Example of the calculation of the SCINSEV sum. A SCINSEV for a full insertion in a fresh-frozen cadaveric head is shown. The red markers show the datapoints as collected from recording electrode 3, while stimulating all the other electrodes, that is, 1–2 and 4–16 in this example. In the calculation of the SCINSEV sum, the value of all these datapoints (voltages induced at electrode 3 by stimulation of all other electrodes) are summed to form the SCINSEV sum for that electrode. This is repeated for each recording electrode. B, Example of the calculation of the SCINSEV sum 3 extracochlear electrodes in 1.0% saline in a fresh-frozen human cadaveric head. The blue markers show the datapoints as collected from recording electrode 3 and 15. In the calculation of the SCINSEV sum, the value of all these datapoints (voltages induced at electrode 3 and 15 by stimulation of all other electrodes) are summed to form the SCINSEV sum for that electrode. This is repeated for each recording electrode. C, Example of polynomial fit of the SCINSEV sum for 3 extracochlear electrodes. The sum of a SCINSEV (equal to Figure B) is flipped, shown here as a red dashed line. The changepoints are calculated using the findchangepts function (MATLAB (vR2018A, MathWorks Inc., Massachusetts, USA). The four segments are fitted to a polynomial, displayed with the corresponding polynomial function.
Article Snippet: In all cases, this was due to the findchangepts MATLAB (vR2018A, MathWorks Inc., MA) function not correctly identifying the most basal changepoint and therefore this basal segment with one extracochlear electrode had less influence on the mean and slope of the polynomial fit of the SCINSEV sum than with two or more extracochlear electrodes.
Techniques:
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