Objective: Considerable unexplained variability and large individual differences exist in speech recognition outcomes for postlingually deaf adults who use cochlear implants (CIs), and a sizeable fraction of CI users can be considered “poor performers.” This article summarizes our current knowledge of poor CI performance, and provides suggestions to clinicians managing these patients. Method: Studies are reviewed pertaining to speech recognition variability in adults with hearing loss. Findings are augmented by recent studies in our laboratories examining outcomes in postlingually deaf adults with CIs. Results: In addition to conventional clinical predictors of CI performance (e.g., amount of residual hearing, duration of deafness), factors pertaining to both “bottom-up” auditory sensitivity to the spectro-temporal details of speech, and “top-down” linguistic knowledge and neurocognitive functions contribute to CI outcomes. Conclusions: The broad array of factors that contribute to speech recognition performance in adult CI users suggests the potential both for novel diagnostic assessment batteries to explain poor performance, and also new rehabilitation strategies for patients who exhibit poor outcomes. Moreover, this broad array of factors determining outcome performance suggests the need to treat individual CI patients using a personalized rehabilitation approach.

Unexplained outcome variability exists among adults with cochlear implants (CIs). Two significant predictors are age and duration of deafness, with older patients and those with longer durations of deafness generally demonstrating poorer speech recognition. However, these factors are often highly correlated. Thus, it is unclear whether poorer outcomes should be attributed primarily to age-related declines or to the experience of auditory deprivation. Our aim was to examine the effects of aging and duration of hearing loss on outcomes for postlingually deaf adults with CIs. Retrospective review of adults who received CIs from 1983 to 2014. Tertiary adult CI program. Sixty-four adult patients with postlingual hearing loss beginning after age 12 years, full electrode insertion, normal cochlear anatomy, and availability of postoperative outcome measures. Cochlear implantation with 12 months or greater of device use. Postoperative pure-tone averages (0.5, 1, 2, and 3 kHz) and recognition of words in sentences (Hearing in Noise Test and AzBio). Age at postoperative testing had a negative partial correlation with AzBio scores, when controlling for duration of deafness, whereas duration of deafness had a positive partial correlation with AzBio scores, when controlling for age. No other effects were identified. Older age at testing was associated with poorer recognition of words in difficult sentences, suggesting that cognitive aging may negatively impact CI outcomes. Further studies are needed to examine how a long duration of auditory deprivation affects CI outcomes.

Purpose: Models of speech recognition suggest that “top-down” linguistic and cognitive functions, such as use of phonotactic constraints and working memory, facilitate recognition under conditions of degradation, such as in noise. The question addressed in this study was what happens to these functions when a listener who has experienced years of hearing loss obtains a cochlear implant. Method: Thirty adults with cochlear implants and 30 age-matched controls with age-normal hearing underwent testing of verbal working memory using digit span and serial recall of words. Phonological capacities were assessed using a lexical decision task and nonword repetition. Recognition of words in sentences in speech-shaped noise was measured. Results: Implant users had only slightly poorer working memory accuracy than did controls and only on serial recall of words; however, phonological sensitivity was highly impaired. Working memory did not facilitate speech recognition in noise for either group. Phonological sensitivity predicted sentence recognition for implant users but not for listeners with normal hearing. Conclusion: Clinical speech recognition outcomes for adult implant users relate to the ability of these users to process phonological information. Results suggest that phonological capacities may serve as potential clinical targets through rehabilitative training. Such novel interventions may be particularly helpful for older adult implant users.

Objective: Unexplained variability in speech recognition outcomes among postlingually deafened adults with cochlear implants (CIs) is an enormous clinical and research barrier to progress. This variability is only partially explained by patient factors (e.g., duration of deafness) and auditory sensitivity (e.g., spectral and temporal resolution). This study sought to determine whether non‐auditory neurocognitive skills could explain speech recognition variability exhibited by adult CI users.Study Design: Thirty postlingually deafened adults with CIs and thirty age‐matched normal‐hearing (NH) controls were enrolled.Methods: Participants were assessed for recognition of words in sentences in noise and several non‐auditory measures of neurocognitive function. These non‐auditory tasks assessed global intelligence (problem‐solving), controlled fluency, working memory, and inhibition‐concentration abilities.Results: For CI users, faster response times during a non‐auditory task of inhibition‐concentration predicted better recognition of sentences in noise; however, similar effects were not evident for NH listeners.Conclusions: Findings from this study suggest that inhibition‐concentration skills play a role in speech recognition for CI users, but less so for NH listeners. Further research will be required to elucidate this role and its potential as a novel target for intervention.

Objectives/Hypothesis: Aural rehabilitation is not standardized for adults after cochlear implantation. Most cochlear implant (CI) centers in the United States do not routinely enroll adult CI users in focused postoperative rehabilitation programs due to poor reimbursement and lack of data supporting (or refuting) the efficacy of any one specific approach. Consequently, patients generally assume a self‐driven approach toward rehabilitation. This exploratory pilot study examined rehabilitation strategies pursued by adults with CIs and associated these strategies with speech recognition and CI‐specific quality of life (QOL).Study Design: Cross‐sectional study of 23 postlingually deafened adults with CIs.Methods: Participants responded to an open‐ended questionnaire regarding rehabilitation strategies. A subset underwent in‐depth interviews. Thematic content analysis was applied to the questionnaires and interview transcripts. Participants also underwent word recognition testing and completed a CI‐related QOL measure. Participants were classified as having good or poor performance (upper or lower quartile for speech recognition) and high or low QOL (upper or lower quartile for QOL). Rehabilitation themes were compared and contrasted among groups.Results: Five rehabilitation themes were identified: 1) Preimplant expectations of postoperative performance, 2) personal motivation, 3) social support, 4) specific rehabilitation strategies, and 5) patient‐perceived role of the audiologist. Patients with good speech recognition and high QOL tended to pursue more active rehabilitation and had greater social support. Patient expectations and motivation played significant roles in postoperative QOL.Conclusion: Postoperative patient‐driven rehabilitation strategies are highly variable but appear to relate to outcomes. Larger‐scale extensions of this pilot study are needed.