The benefits of preserving residual hearing following cochlear implantation: a systematic review

Systematically review the current literature for evidence on the “real-life” benefits of hearing preservation cochlear implantation (HPCI) for children and adults. Systematic search of Pubmed, MEDLINE, EMBASE, CINHAL and Cochrane Library for MesH terms <i>hearing</i>¸ <i>preservation</i> and <i>cochlear implantation</i>. Inclusion criteria were the “real-life” benefit of HPCI i.e. other than pre- and post-operative pure tone thresholds. Exclusion criteria were non-English language, conference abstracts, reviews and animal and cadaveric studies. Risk of bias was assessed using the Evidence Project Tool. 37 studies that matched criteria for review with 8/37 including children and 29/37 including adults. HPCI was associated with better <i>speech perception in noise</i> in 18/26 papers and better <i>music perception</i> in 4/5 papers. There was no significant benefit reported in <i>speech perception in quiet</i> (14/20 papers) or <i>binaural cues</i> (3/4 papers), nor was there convincing evidence of HPCI outperforming bimodal users (5/7 papers). <i>QoL scores</i> were high amongst HPCI patients (2/2 papers). Interpretation of findings was hindered by small study groups and significant heterogeneity in various parameters. Current literature on the “real-life” benefit of HPCI, although limited, supports the existence of meaningful benefit, especially in <i>speech perception in noise</i> and <i>music perception</i>.