Objectives: To determine how patients who did not meet UK TA166 NICE criteria for cochlear implantation (CI) but were subsequently found to have cochlear dead regions (DRs) performed with CI.Methods: A retrospective review of medical records was performed on CI recipients: 152 controls and 40 in the DR group. Of these, 34 pairs were matched by pre-operative Bamford-Kowal-Bench (BKB) scores and compared.Results: The forty DR patients had a median age at implantation of 56 years. Their mean pre-operative BKB score of 23% increased to 78% after CI. Thirty-seven experienced improvements in BKB scores. In matched case-control analysis, the improvement in mean BKB score with CI was no different (p = 0.19) between the DR group and control group; a similar proportion of patients benefitted in each group.Discussion: This study is the largestreport to date of performance of patients with DRs, before and after CI. The DR group gain similar benefit as the controls.Conclusion: Patients with DRs, who did not meet TA166 NICE criteria, received the same benefit as those who did. TEN testing to detect DRs should be included in routine CI work-up where standard criteria are not met.