Main theme: Otology
Intraoperative electrocochleography (ECochG) is increasingly used to monitor cochlear function during hearing preservation cochlear implantation (HPCI), yet no agreed framework exists for interpreting trace changes, even in adults. We aimed to characterise intraoperative ECochG trace patterns during paediatric HPCI, and to describe their relationship with short-term hearing preservation outcomes in a population where such data are especially scarce.
Prospective observational cohort at a single UK paediatric cochlear implant centre. Children undergoing HPCI had intraoperative ECochG. Trace patterns at 250 Hz were classified by cochlear microphonic amplitude into five categories (A: stable/rising; B: rise-then-drop; C: drop-then-recovery; D: progressive decline; E: uninterpretable), a ≥30% sustained drop defining an ECochG event. HEARRING graded preservation as Complete, Partial, Minimal or Loss.
Of 26 attempted recordings, 5 failed technically and 2 had software access issues. Of 19 analysed at 250 Hz, 32% were Type E. An ECochG event occurred in 69% of interpretable recordings. HEARRING outcomes: 29% Complete, 71% Partial, none Minimal or Loss. Complete preservation was achieved in 0 of 2 Type A, 3 of 6 Type B and 1 of 3 Type C ears.
Intraoperative ECochG was feasible in paediatric HPCI, though a third of recordings were uninterpretable. Cochlear microphonic drops of ≥30% did not consistently indicate poor preservation, and uninterpretable traces did not preclude favourable outcomes. Amplitude alone should not be the sole indicator of cochlear trauma in this population; combined amplitude and phase analysis, larger multi-centre cohorts, and longer-term data are needed.
References
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Buechner A, Bardt M, Haumann S, Geissler G, Salcher R, Lenarz T. Clinical experiences with intraoperative electrocochleography in cochlear implant recipients and its potential to reduce insertion trauma and improve postoperative hearing preservation. Fu QJ, editor. PLOS ONE. 2022 Apr 22;17(4):e0266077. doi:10.1371/journal.pone.0266077