Criteria of candidacy for unilateral cochlear implantation in postlingually deafened adults III: prospective evaluation of an actuarial approach to defining a criterion.
OBJECTIVE
Outcomes from unilateral cochlear implantation in postlingually deafened adults are variable and difficult to predict precisely from data gathered before surgery. The objective was to derive and validate a method for specifying criteria of candidacy for implantation that takes this variability into account.


METHODS
Accuracy of identifying words in prerecorded sentences without lipreading was measured in 480 users of unilateral multichannel cochlear implants. These patients had all scored zero before surgery on prerecorded open-set tests of word recognition in sentences with acoustic hearing aids. Statistical models were derived that calculated the odds that a patient would score higher with an implant than a criterion score, given knowledge of the duration of profound deafness in the implanted ear. The accuracy of the models was evaluated prospectively with two new groups of patients who scored between 1% and approximately 50% correct before surgery in one or both ears with acoustic hearing aids. Group I (N=53) was implanted in an ear that scored zero. Group II (N=31) was implanted in an ear that scored above zero. Benefits from implantation, measured as changes in word recognition performance and in health utility, were compared with the odds calculated by the statistical models.


RESULTS
The preferred model was based on data from 376 subjects. It made accurate predictions of the proportion of patients in group I, and, disregarding minor exceptions, accurate predictions of the proportion of patients in group II, who improved on their preoperative word recognition score. Benefit from implantation was low for patients implanted with odds less favorable than 4:1 (4 chances out of 5).


CONCLUSIONS
Adoption of odds of 4:1 as the criterion of candidacy for unilateral cochlear implantation would be likely to maintain acceptable benefit and cost-effectiveness while being explicit and informative for patients, clinicians, and commissioners of health care.
D000206:Actuarial Analysis / Q000592:standards*; D000328:Adult; D019929:Cochlear Implantation / Q000191:economics / Q000592:standards*; D003198:Computer Simulation; D003362:Cost-Benefit Analysis; D003638:Deafness / Q000191:economics / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D016017:Odds Ratio; D018579:Patient Selection; D011446:Prospective Studies; D013065:Speech Intelligibility; D013067:Speech Perception; D016896:Treatment Outcome; D006113:United Kingdom