Comparison of Residual Hearing Preservation and Auditory Based Performance after Paediatric Cochlear Implantation by Round Window Insertion versus Cochleostomy Technique: An Ambispective Cohort Study

Abstract

Background: Cochlear implantation (CI) has revolutionized the treatment of sensorineural deafness. The aim of the study was to compare auditory based performance in cochlear implants who underwent round window insertion and cochleostomy.

Methods: Ambispective cohort study was done among the children who underwent perilingual cochlear implant in a tertiary care hospital for period of 1 year. Children who satisfied the inclusion criteria were selected and randomly subdivided into 2 groups: group A- round window insertion and group B-cochleostomy. Pre- and post-operative pure tone average (PTA) and residual hearing preserved were evaluated among the cochleostomy and round window insertion groups separately. Post-operatively, children were evaluated, from three months to 1 year from the activation of cochlear implant, with the use of scores such as Category of Auditory Performance (CAP), Meaningful Auditory Integration Scale (MAIS), Speech Intelligibility rating (SIR) and Meaningful use of speech scale (MUSS score) to measure speech production skills by auditory verbal therapist.

Results: A total of 80 patients were included in the study. Complete hearing preservation (within 10 dB) was significantly high in round window insertion group compared to cochleostomy technique (p<0.001). None the subjects had complete loss of residual hearing. On evaluating the post CI performance, MAIS score in the round window insertion group (9.34, 18.21, 27.79) were significantly better compared to cochleostomy group during the 3 months, 6 months and 12 months follow-up.

Conclusions: Round window insertion technique is significantly more successful in complete hearing preservation at low frequencies compared to cochleostomy technique. Among the auditory scores, only MAIS in the round window insertion group was found to be significantly better compared to cochleostomy group.