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BACKGROUND
Cochlear implantation is a well-established treatment modality for adults with bilateral sensorineural hearing loss (SNHL). Unaided pure tone audiometry, speech reception thresholds, and word recognition scores are widely accepted as the initial audiometric workup before recommending amplification. At the discretion of providers, patients with moderate to profound SNHL, poor word recognition, and/or dissatisfaction with hearing aids may be referred for cochlear implant evaluation (CIE). Many patients who would likely benefit from implantation are never referred due to poor regional access, unfamiliarity with the technology, and, perhaps most importantly, lack of established CIE referral guidelines. Several authors have proposed strategies for optimizing patient selection for CIE referral (see Table 1).
BEST PRACTICE
The existing literature supports the conservative recommendation that patients with an unaided 3-frequency pure tone average (3FPTA) (0.5, 1, and 2 kHz) of 70 dB hearing level or worse and/or unaided word recognition scores of 40% or less in the ear to be implanted are highly likely to be cochlear implant candidates when tested in quiet and should be referred for CIE. Institutions must consider an acceptable percentage of false-negative and false-positive referrals, as well as their perspective on testing in noise to determine candidacy. If a higher false positive referral rate is acceptable, and/or if candidacy is determined by testing in noise, patients with 3FPTA or worse than 60 dB hearing level and word recognition scores up to 60% in the better ear should be considered for CIE. Additional prospective studies are needed to develop a widely validated referral criteria guideline.
Table 1: Summary of Recommendations for Identifying Potential Adult Cochlear Implantation Candidates.
| Study | Level of Evidence | Number of Subjects | Recommendation |
|---|---|---|---|
| Lupo et al., 2020 | IIb | 100 | Patients with bilateral moderate-to-profound sensorineural hearing loss and 3FPTA (0.5, 1, and 2 kHz) ≥70 dB HL who are dissatisfied with bilateral hearing aids should be considered for CI evaluation referral. |
| Hoppe et al., 2015 | IV | 185 | The 4FPTA (0.5, 1, 2, and 4 kHz) and PBmax can be used to determine likelihood of audiologic CI candidacy using the inequality PBmax[%] > 4FPTA [dB]-8 for either ear. |
| Hoppe et al., 2020 | IV | 128 | Patients with 4FPTA (0.5, 1, 2, and 4 kHz) ≤80 dB HL with insufficient aided WRS (< 50%) should be considered for CI evaluation referral. |
| Gubbels et al., 2017 | IV | 139 | Patients with individual pure tone thresholds (0.25, 0.5, 1 kHz) of ≥75 dB HL and/or a monosyllabic WRS of ≤40% in the better ear have a high likelihood of meeting audiologic criteria for CI. |
| Zwolan et al., 2020 | IV | 529 | A 3FPTA (0.5, 1, and 2 kHz) of ≥60 dB HL and an unaided monosyllabic word score ≤60% in the better ear may be used as a screening measure for referral for CI with 96% sensitivity and 66% specificity. |
3FPTA = 3-frequency pure tone average; 4FPTA = 4-frequency pure tone average; CI = cochlear implant; HL = hearing level; PBMax = maximum speech scores for monosyllabic word list; PTA = pure tone average; WRS = word recognition score.