The impact of cochlear implantation on cognition in older adults: a systematic review of clinical evidence

Long-term cognition and speech recognition outcomes after cochlear implantation in the elderly

OBJECTIVE

The purpose of this study is to investigate how cognition, as measured using the Self-Administered Gerocognitive Examination Test (SAGE), and age affect speech recognition scores in older adults (age > 65) at one year and two years after cochlear implantation.

STUDY DESIGN

This is a prospective study.

SETTING

This study was conducted at a single institution.

METHODS

Unilateral cochlear implantation was performed by two surgeons on adult patients (>65 years) with postlingual bilateral sensorineural hearing loss. There were 230 patients who underwent cochlear implantation from January 2016 to June 2023. Fifty-five of these patients completed the SAGE questionnaire before implantation, one year after implantation, and 2 years after implantation. Paired t-test analysis was used to evaluate pre- and post-operative speech recognition scores (CNC, AzBio in Quiet).

RESULTS

Patients who had normal preoperative cognition on SAGE showed greater improvement in postoperative speech recognition tests at 1 year and 2 years after implantation compared with patients who showed preoperative cognitive impairment. There were no significant differences in postoperative speech outcome between age group 1 (between 65 and 80 years old) and age group 2 (over 80 years old) cochlear implant recipients. There were no changes in cognitive SAGE scores after 2 years implantation.

CONCLUSION

Cognitive function, as measured by SAGE, is a more reliable predictor than age in determining speech recognition improvement after cochlear implantation. Cochlear implantation did not improve postoperative cognition.

Neuropsychological Functions and Audiological Findings in Elderly Cochlear Implant Users: The Role of Attention in Postoperative Performance

Objectives: The present study aimed to investigate in a group of elderly CI users working memory and attention, conventionally considered as predictors of better CI performance and to try to disentangle the effects of these cognitive domains on speech perception, finding potential markers of cognitive decline related to audiometric findings. Methods Thirty postlingually deafened CI users aged >60 underwent an audiological evaluation followed by a cognitive assessment of attention and verbal working memory. A correlation analysis was performed to evaluate the associations between cognitive variables while a simple regression investigated the relationships between cognitive and audiological variables. Comparative analysis was performed to compare variables on the basis of subjects’ attention performance. Results: Attention was found to play a significant role in sound field and speech perception. Univariate analysis found a significant difference between poor and high attention performers, while regression analysis showed that attention significantly predicted recognition of words presented at Signal/Noise +10. Further, the high attention performers showed significantly higher scores than low attentional performers for all working memory tasks. Conclusion: Overall findings confirmed that a better cognitive performance may positively contribute to better speech perception outcomes, especially in complex listening situations. WM may play a crucial role in storage and processing of auditory-verbal stimuli and a robust attention may lead to better performance for speech perception in noise. Implementation of cognitive training in auditory rehabilitation of CI users should be investigated in order to improve cognitive and audiological performance in elderly CI users.

Is there benefit from the use of cochlear implants and hearing aids in cognition for older adults? A systematic review

Objectives

The aim of the study was to assess whether hearing aids (HA) and cochlear implants (CI) bring benefits to cognition or mitigate cognitive decline in older adults.

Methods

This is a systematic literature review registered on the International Prospective Register of Systematic Reviews (PROSPERO) and based on the criteria recommended by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). The Population, Intervention, Comparison, Outcome, and Study type (PICOS) strategy was used to define eligibility. Studies that met the criteria were included in the qualitative synthesis. We assessed the risk of bias through the Joanna Briggs Institute Critical Appraisal Checklists.

Results

A total of 3,239 articles, found in eight databases, addressed the relationship between HA, CI, and cognition. We selected 30 experimental articles reporting measures of cognitive outcomes for older adults to include in the qualitative analysis. Of those, 23 studies reported a significant improvement in outcome and seven reported no significant change.

Conclusions

This systematic review indicates that CI and HA can bring benefits to cognition in older adults.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021273690.

Retomando los sonidos: Prevención de la hipoacusia y rehabilitación auditiva en las personas mayores

La hipoacusia representa una de las principales causas de discapacidad a nivel mundial y su prevalencia aumenta a medida que se envejece. Representa un tipo de discapacidad que, en la mayoría de los casos, puede ser potencialmente prevenible y tratable, por lo que su prevención, identificación temprana y rehabilitación integral deberían ser algunos de los puntos de acción a nivel local ya que se ha relacionado con numerosos desenlaces adversos en salud, incluyendo los dominios físico, mental, social y económico de las personas mayores. El objetivo de este artículo es resaltar la importancia de la prevención de la hipoacusia y promover su rehabilitación a lo largo del curso de vida, especialmente en personas mayores, y describir estrategias que se han planteado desde la Organización Mundial de la Salud y la Organización Panamericana de la Salud.

Association of hearing loss and tinnitus symptoms with health-related quality of life among long-term oropharyngeal cancer survivors

BACKGROUND

This study investigated the association of hearing loss and tinnitus with overall health-related quality of life (HRQoL) among long-term oropharyngeal cancer (OPC) survivors.

METHODS

This study included OPC survivors treated between 2000 and 2013 and surveyed from September 2015 to July 2016. Hearing loss and tinnitus were measured by asking survivors to rate their "difficulty with hearing loss and/or ringing in the ears" from 0 (not present) to 10 (as bad as you can imagine). Hearing loss and tinnitus scores were categorized as follows: 0 for none, 1-4 for mild, and 5-10 for moderate to severe. The primary outcome was the mean score of MD nderson Symptom Inventory Head & Neck module interference component as a HRQoL surrogate dichotomized as follows: 0 to 4 for none to mild and 5 to 10 for moderate to severe interference.

RESULTS

Among 880 OPC survivors, 35.6% (314), reported none, 39.3% (347) reported mild, and 25.1% (221) reported moderate to severe hearing loss and tinnitus. On multivariable analysis, mild (OR, 5.83; 95% CI; 1.48-22.88; p = 0.012) and moderate (OR, 30.01; 95% CI; 7.96-113.10; p < 0.001) hearing loss and tinnitus were associated with higher odds of reporting moderate to severe symptom interference scores in comparison to no hearing loss and tinnitus. This association of hearing dysfunction was consistent with all domains of HRQoL.

CONCLUSIONS

Our findings provide preliminary evidence to support the need for continued audiological evaluations and surveillance to detect hearing dysfunction, to allow for early management and to alleviate the long-term impact on QoL.

Changes in cognitive performance after cochlear implantation in adults and older adults: a systematic review and meta-analysis

OBJECTIVES

To conduct critical assessment of the literature on the effects of cochlear implantation on adults' cognitive abilities.

DESIGN

PubMed, Scopus, Lilacs, Web of Science, Livivo, Cochrane, Embase, PsycInfo, and grey literature were searched. Eligibility criteria: age 18 or over with severe-to-profound bilateral hearing loss, cochlear implantation, cognitive test before and after implantation. Risk of bias was assessed using ROB, ROBINS-I and MASTARI tools. Meta-analysis was performed.

STUDY SAMPLE

Out of 1830 studies, 16 met the inclusion criteria.

RESULTS

On AlaCog test, significant improvement was found after implantation [MD = -46.64; CI95% = -69.96 to -23.33; I² = 71%]. No significant differences were found on the Flanker, Recall, Trail A and n-back tests (p > 0.05). For MMSE, no significance was found [MD 0.63; CI 95% = -2.19 to 3.45; I² = 88%]. On TMT, an overall significant effect with a 9-second decrease in processing speed post-implantation [MD = -9.43; CI95% = -15.42 to -3.44; I² = 0%].

CONCLUSION

Cognitive improvements after cochlear implantation may depend on time and the cognitive task evaluated. Well-designed studies with longer follow-up are necessary to examine whether cochlear implantation has a positive influence on cognitive abilities. Development of cognitive assessment tools to hearing-impaired individuals is needed.

Cognition and Cognitive Reserve in Cochlear Implant Recipients

At present, dementia is a hot topic. Hearing loss is considered to be a modifiable risk factor for cognitive decline. The underlying mechanism remains unclear and might be mediated by socioeconomic and psychosocial factors. Cochlear implantation has been shown not only to restore auditory abilities, but also to decrease mental distress and to improve cognitive functions in people with severe hearing impairment. However, the promising results need to be confirmed. In a prospective single-center study, we tested the neurocognitive abilities of a large group of 71 subjects with bilateral severe hearing impairment with a mean age of 66.03 (SD = 9.15) preoperatively and 6, 12, and 24 months after cochlear implantation using a comprehensive non-auditory computer-based test battery, and we also assessed the cognitive reserve (CR) [Cognitive Reserve Index (CRI)], health-related quality of life (QoL) (Nijmegen Cochlear Implant Questionnaire), and depression (Geriatric Depression Scale-15). Cognitive functions significantly increased after 6 months in attention (p = 0.00004), working memory (operation span task; p = 0.002), and inhibition (p = 0.0002); and after 12 months in recall (p = 0.003) and verbal fluency (p = 0.0048), and remained stable up to 24 months (p ≥ 0.06). The CR positively correlated with cognitive functions pre- and post-operatively (both p < 0.005), but postoperative improvement in cognition was better in subjects with poor CR (p = 0.003). Depression had only a slight influence on one subtest. No correlation was found among cognitive skills, quality of life, and speech perception (each p ≥ 0.05). Cochlear implantation creates an enriched environment stimulating the plasticity of the brain with a global positive impact on neurocognitive functions, especially in subjects with poor preoperative cognitive performance and low cognitive reserve.

Effect of cochlear implantation on cognitive decline and quality of life in younger and older adults with severe-to-profound hearing loss

Purpose

(a) To measure the change in cognition, the improvement of speech perception, and the subjective benefit in people under and over 60 years following cochlear implantation. (b) To assess the relationship between cognition, demographic, audiometric, and subjective outcomes in both age groups.

Methods

28 cochlear implant (CI) users were assigned to the < 60y group and 35 to the ≥ 60y group. Cognition was measured using the Repeatable Battery for the Assessment of Neuropsychological Status for Hearing impaired individuals (RBANS-H); subjective benefit was measured using the Nijmegen Cochlear Implant Questionnaire (NCIQ); the Glasgow Benefit Inventory (GBI); the Hearing Implant Sound Quality Index (HISQUI₁₉); Speech, Spatial and Qualities of Hearing Scale (SSQ₁₂); and the Hospital Anxiety and Depression Scale (HADS).

Results

Prior to surgery: the RBANS-H total score positively correlated with the domains “Advanced sound”, “Self-esteem”, and “Social functioning” of NCIQ, and negatively with HADS scores. 12 months post-implantation: the RBANS-H total score increased in the < 60y (p = 0.038) and in the ≥ 60y group (p < 0.001); speech perception and subjective outcomes also improved; RBANS-H total score positively correlated with “Self-esteem” domain in NCIQ. Age and the RBANS-H total score correlated negatively in the ≥ 60y group (p = 0.026).

Conclusions

After implantation, both age groups demonstrated improved cognition, speech perception and quality of life. Their depression scores decreased. Age was inversely associated with cognition.

Cochlear implant outcomes in the very elderly

PURPOSE

Managing hearing health in older adults has become a public health imperative, and cochlear implantation is now the standard of care for aural rehabilitation when hearing aids no longer provide sufficient benefit. The aim of our study was to compare speech performance in cochlear implant patients ≥80 years of age (Very Elderly) to a younger elderly cohort between ages 65-79 years (Less Elderly).

MATERIALS AND METHODS

Data were collected from 53 patients ≥80 years of age and 92 patients age 65-79 years who underwent cochlear implantation by the senior author between April 1, 2017 and May 12, 2020. The primary outcome measure compared preoperative AzBio Quiet scores to 6-month post-activation AzBio Quiet results for both cohorts.

RESULTS

Very Elderly patients progressed from an average AzBio Quiet score of 22% preoperatively to a score of 45% in the implanted ear at 6-months post-activation (p < 0.001) while the Less Elderly progressed from an average score of 27% preoperatively to 60% at 6-months (p < 0.001). Improvements in speech intelligibility were statistically significant within each of these cohorts (p < 0.001). Comparative statistics using independent samples t-test and evaluation of effect size using the Hedges' g statistic demonstrated a significant difference for average improvement of AzBio in quiet scores between groups with a medium effect size (p = 0.03, g = 0.35). However, when the very oldest patients (90+ years) were removed, the statistical difference between groups disappeared (p = 0.09).

CONCLUSIONS

When assessing CI performance, those over age 65 are typically compared to younger patients; however, this manuscript further stratifies audiometric outcomes for older CI recipients in a single-surgeon, high-volume practice. Our data indicates that for speech intelligibility, patients between age 65-79 perform similarly to CI recipients 80-90 years of age and should not be dismissed as potential cochlear implant candidates.

The Impact of Cochlear Implantation: Cognitive Function, Quality of Life, and Frailty in Older Adults

This review examines the relationship between cochlear implantation and cognition and quality of life in older adults, as well as how frailty affects outcomes for older patients with cochlear implants. A growing body of evidence suggests that there is a strong association between hearing loss and cognitive impairment. Preliminary studies suggest that cochlear implantation in older adults may be protective against cognitive decline. While studies have observed a positive impact of cochlear implantation on quality of life, currently it is unclear what factors contribute the most to improved quality of life. Frailty, as a measurement of general health, likely plays a role in complication rates and quality-of-life outcomes after cochlear implantation, though larger prospective studies are required to further elucidate this relationship.

Evaluating the Impact of Cochlear Implantation on Cognitive Function in Older Adults

OBJECTIVES/HYPOTHESIS

We hypothesize that treating hearing loss through cochlear implantation in older adults will improve cognitive function.

STUDY DESIGN

Prospective, interventional study.

METHODS

Thirty-seven participants aged 65 years and older who met criteria for cochlear implantation were enrolled. Subjects underwent preoperative cognitive testing with a novel arrangement of standard neuropsychological tests, including tests of general cognition and mood (Mini-Mental Status Exam [MMSE]), tests of verbally based stimuli and responses (Digit Span, Stroop, Hopkins Verbal Learning Test-Revised [HVLT-R], Hayling Sentence Completion), and comparable visually based tests (Spatial Span, d2 Test of Attention, Brief Visuospatial Memory Test [BVMT], Trails A and B). Testing was repeated 12 months postoperatively.

RESULTS

One year postoperatively, subjects showed a statistically significant improvement in hearing and on the following tests of cognitive function: concentration performance of the d2 Test of Attention, Hayling Sentence Completion Test, HVLT-R (total and delayed recall), Spatial Span (backward), and Stroop Color Word Test. A subgroup analysis was performed comparing 13 participants with preoperative cognitive impairment (MMSE ≤ 24) to 24 participants with normal cognition (MMSE ≥ 25). In this subgroup analysis, a greater magnitude of improvement was seen in those with impaired cognition, with statistically significant improvement in Digit Span (scaled score), Stroop Word (T-score), Stroop Color-Word (residual and T-score), HVLT-R, and Hayling (overall). All verbally based test scores improved, and 75% of the visually based test scores improved.

CONCLUSIONS

This study demonstrates the cognitive benefits of cochlear implantation in older adults 1 year after surgery. For older adults with cognitive impairment prior to cochlear implantation, the cognitive benefits were even greater than in subjects with normal cognition.

LEVEL OF EVIDENCE

3, nonrandomized controlled cohort Laryngoscope, 2021.

Improvement of Working Memory and Processing Speed in Patients over 70 with Bilateral Hearing Impairment Following Unilateral Cochlear Implantation

Several studies demonstrated the association of hearing disorders with neurocognitive deficits and dementia disorders, but little is known about the effects of auditory rehabilitation on the cognitive performance of the elderly. Therefore, the research question of the present study was whether cochlear implantation, performed in 21 patients over 70 with bilateral severe hearing impairment, could influence their cognitive skills. The measuring points were before implantation and 12 months after the first cochlear implant (CI) fitting. Evaluation of the working memory (WMI) and processing speed (PSI) was performed using the Wechsler Adult Intelligence Scale 4th edition (WAIS-IV). The audiological assessment included speech perception (SP) in quiet (Freiburg monosyllabic test; FMT), noise (Oldenburg sentence test; OLSA), and self-assessment inventory (Oldenburg Inventory; OI). Twelve months after the first CI fitting, not only the auditory parameters (SP and OI), but also the WMI and PSI, improved significantly (p < 0.05) in the cohort. The presented results imply that cochlear implantation of bilaterally hearing-impaired patients over 70 positively influences their cognitive skills.

Hearing Impairment and Cognition in an Aging World

With the increasing number of older adults around the world, the overall number of dementia cases is expected to rise dramatically in the next 40 years. In 2020, nearly 6 million individuals in the USA were living with Alzheimer's disease, the most common type of dementia, with anticipated growth to nearly 14 million by year 2050. This increasing prevalence, coupled with high societal burden, makes prevention and intervention of dementia a medical and public health priority. As clinicians and researchers, we will continue to see more individuals with hearing loss with other comorbidities including dementia. Epidemiologic evidence suggests an association between hearing loss and increased risk of dementia, presenting opportunity for targeted intervention for hearing loss to play a fundamental role in dementia prevention. In this discussion, we summarize current research on the association between hearing loss and dementia and review potential casual mechanisms behind the association (e.g., sensory-deprivation hypothesis, information-degradation hypothesis, common cause). We emphasize key areas of research which might best inform our investigation of this potential casual association. These selected research priorities include examination of the causal mechanism, measurement of co-existing hearing loss and cognitive impairment, and potential of aural rehabilitation. Addressing these research gaps and how results are then translated for clinical use is paramount for dementia prevention and overall health of older adults.

White Matter Lesions as Possible Predictors of Audiological Performance in Adults after Cochlear Implantation

The presented prospective study investigated whether structural brain damage, measured with the Fazekas score, could predict hearing rehabilitation outcomes with cochlear implantation (CI). With a follow-up period of 24 months, this study included 49 bilaterally, postlingually hearing impaired CI candidates for unilateral CI (67.3 ± 8.7 years; 20 men, 29 women) older than 50 at the time of implantation. The differences in the predictive value between two age groups, 50-70 year-olds (mid-age; n = 26) and over 70-year-olds (elderly; n = 23), were analyzed. The patients were evaluated using speech perception (SP) measured in quiet (Freiburg monosyllabic test; FMT) and noise (Oldenburg sentence test; OLSA). The subjective hearing ability was assessed using Oldenburg inventory (OI). The Fazekas PVWM score predicted postoperative speech perception two years after CI in the mid-age population. The periventricular white matter lesions (PVWM) could explain 27.4% of the speech perception (FMT) variance. Our findings support the hypothesis about the influence of pre-existing WMLs on CI outcome. We recommend the evaluation of Fazekas score as a predictive factor for post-implantation hearing ability.

Age-Related Hearing Loss and the Development of Cognitive Impairment and Late-Life Depression: A Scoping Overview

Age-related hearing loss (ARHL) has been connected to both cognitive decline and late-life depression. Several mechanisms have been offered to explain both individual links. Causal and common mechanisms have been theorized for the relationship between ARHL and impaired cognition, including dementia. The causal mechanisms include increased cognitive load, social isolation, and structural brain changes. Common mechanisms include neurovascular disease as well as other known or as-yet undiscovered neuropathologic processes. Behavioral mechanisms have been used to explain the potentially causal association of ARHL with depression. Behavioral mechanisms include social isolation, loneliness, as well as decreased mobility and impairments of activities of daily living, all of which can increase the risk of depression. The mechanisms underlying the associations between hearing loss and impaired cognition, as well as hearing loss and depression, are likely not mutually exclusive. ARHL may contribute to both impaired cognition and depression through overlapping mechanisms. Furthermore, ARHL may contribute to impaired cognition which may, in turn, contribute to depression. Because ARHL is highly prevalent and greatly undertreated, targeting this condition is an appealing and potentially influential strategy to reduce the risk of developing two potentially devastating diseases of later life. However, further studies are necessary to elucidate the mechanistic relationship between ARHL, depression, and impaired cognition.

Impact of Hearing Rehabilitation Using Cochlear Implants on Cognitive Function in Older Patients

OBJECTIVE

To assess the effects of hearing rehabilitation with cochlear implants on a subset of cognitive domains in older patients (≥65 yr).

STUDY DESIGN

Prospective observational study.

SETTING

Department of Oto-Rhino-Laryngology, Goethe-University Frankfurt/Main.

PATIENTS

Patients aged between 65 and 86 years who have received unilateral cochlear implant (CI) therapy.

INTERVENTION

Unilateral cochlear implantation.

MAIN OUTCOME MEASURES

The dementia screening test (DemTect) and the trail making test (TMT) were carried out on three occasions: previous to the surgery, at the initial fitting (about 1 month after surgery) and 6 months after surgery.

RESULTS

The average overall score on the DemTect scale increased significantly within 6 months of CI treatment (p = 0.049), with verbal aspects improving particularly markedly. The results of the trail making test showed that within 6 months of CI treatment, processing speed increased significantly (TMT A: p = 0.003; TMT B: p = 0.001).

CONCLUSION

A pre-post comparison showed that aural rehabilitation with a CI results in an improvement in cognitive subdomains. Further comprehensive randomized-controlled studies may be necessary to evaluate possible confounding variables and to assess long-term results.

How Does Cochlear Implantation Lead to Improvements on a Cognitive Screening Measure?

Purpose Cognitive screening tools to identify patients at risk for cognitive deficits are frequently used by clinicians who work with aging populations in hearing health care. Although some studies show improvements in performance on cognitive screening exams when hearing loss intervention is provided in the form of a hearing aid or cochlear implant (CI), it is worth examining whether these improvements are attributable to increased auditory access to test items. This study aimed to examine whether performance and pass rate on a cognitive screening measure, the Montréal Cognitive Assessment (MoCA), improve as a result of CI, whether improved performance on auditory-based test items drives changes in MoCA performance, and whether postoperative MoCA performance relates to post-CI speech perception ability. Method Data were collected in adult CI candidates pre-implantation and 6 months postimplantation to examine the effect of intervention on MoCA performance. Participants were 77 CI users between the ages of 55 and 85 years. Participants completed the MoCA, administered audiovisually, and speech perception testing with monosyllabic (CNC) words at both intervals. Results Compared to 31 participants pre-operatively, 45 participants passed the MoCA postoperatively, which was a significant difference in pass rate. An improvement in MoCA scores could be attributed primarily to improvement in the "Delayed Recall" test domain, which was auditory based. Post-CI MoCA performance was related to post-CI CNC speech perception performance. Conclusions Improved performance and pass rates were demonstrated on the traditional MoCA test of cognitive screening from before to 6 months after CI. Improvements could primarily be attributed to better performance on a delayed recall task dependent on auditory access, and post-CI MoCA scores were related to post-CI speech perception abilities. Further studies are needed to investigate the application of cognitive screening tools in patients receiving hearing loss interventions, and these interventions' impact on patients' real-world functioning.

The Association Between Early Age-Related Hearing Loss and Brain β-Amyloid

OBJECTIVES/HYPOTHESIS

To analyze the association between early audiometric age-related hearing loss and brain β-amyloid, the pathologic hallmark of Alzheimer's disease (AD).

STUDY DESIGN

Cross-sectional analysis of a prospective cohort study.

METHODS

A cross-sectional analysis was performed on 98 participants in a cohort study of hearing and brain biomarkers of AD. The primary outcome was whole brain β-amyloid standardized uptake value ratio (SUVR) on positron emission tomography (PET). The exposure was hearing, as measured by either pure-tone average or word recognition score in the better ear. Covariates included age, gender, education, cardiovascular disease, and hearing aid use. Linear regression was performed to analyze the association between β-amyloid and hearing, adjusting for potentially confounding covariates.

RESULTS

The mean age ± standard deviation was 64.6 ± 3.5 years. In multivariable regression, adjusting for demographics, education, cardiovascular disease, and hearing aid use, whole brain β-amyloid SUVR increased by 0.029 (95% confidence interval [CI]: 0.003-0.056) for every 10 dB increase in pure-tone average (P = .030). Similarly, whole brain β-amyloid SUVR increased by 0.061 (95% CI: 0.009-0.112) for every 10% increase in word recognition score (P = .012).

CONCLUSIONS

Worsening hearing was associated with higher β-amyloid burden, a pathologic hallmark of AD, measured in vivo with PET scans.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:633-638, 2021.

Assessment of Speech Understanding After Cochlear Implantation in Adult Hearing Aid Users: A Nonrandomized Controlled Trial

Importance

Cochlear implants were approved for use in adults in the 1980s, but use remains low owing to a lack of awareness regarding cochlear implantation candidacy criteria and expected outcomes. There have been limited, small series examining the safety and effectiveness of cochlear implantation in adult hearing aid (HA) users with and without mild cognitive impairment (MCI).

Objective

To investigate the safety and effectiveness of a single-ear cochlear implant in a group of optimized adult HA users with and without MCI across a variety of domains.

Design, Setting, and Participants

In this nonrandomized controlled trial, a multicenter, prospective, repeated-measures investigation was conducted at 13 US institutions. The setting was academic and community-based cochlear implant programs. Eligible participants were 100 adults (aged >18 years) with postlinguistic onset of bilateral moderate sloping to profound or worse sensorineural hearing loss (≤20 years' duration). Fluent English speakers underwent an optimized bilateral HA trial for at least 30 days. Individuals with aided Consonant-Vowel Nucleus-Consonant (CNC) word score in quiet of 40% or less correct in the ear to be implanted and 50% or less correct in the contralateral ear were offered cochlear implants. The first participant was enrolled on February 20, 2017, and the last participant was enrolled on May 3, 2018. The final follow-up was on December 21, 2018.

Interventions

Participants received the same cochlear implant system and contralateral HA.

Main Outcomes and Measures

The primary outcome measure was speech understanding in quiet (CNC word score) using both the cochlear implant and opposite ear HA. Secondary outcome measures included the following: adverse events; speech understanding in noise (AzBio signal-to-noise ratio of +10 db [+10 SNR]) Health Utilities Index Mark 3 (HUI3); Speech, Spatial, and Qualities of Hearing Questionnaire 49 (SSQ49); and Montreal Cognitive Assessment (MoCA).

Results

The median age at cochlear implantation of the 96 patients included in the trial was 71 years (range, 23-91 years), and 62 patients (65%) were male. Three serious adverse events requiring revision surgery occurred, and all resolved without sequelae. By 6 months after activation, the absolute marginal mean change in CNC word score and AzBio +10 SNR was 40.5% (95% CI, 35.9%-45.0%) and 24.1% (95% CI, 18.9%-29.4%), respectively. Ninety-one percent (87 of 96) of participants had a clinically important improvement (>15%) in the CNC word score in the implant ear. Mild cognitive impairment (MoCA total score ≤25) was observed in 48 of 81 study participants (59%) at baseline. Speech perception marginal mean improvements were similar between individuals with and without baseline MCI, with values of 40.9% (95% CI, 35.2%-46.6%) and 39.6% (95% CI, 31.8%-47.4%), respectively, for CNC word score and 27.5% (95% CI, 21.0%-33.9%) and 17.8% (95% CI, 9.0%-26.6%), respectively, for AzBio +10 SNR. Statistically significant and clinically important improvements in the HUI3 and SSQ49 were evident at 6 months.

Conclusions and Relevance

The findings of this nonrandomized controlled trial seem to indicate that cochlear implants are safe and effective in restoring speech understanding in both quiet and noise and improve quality of life in individuals with and without MCI.

Trial Registration

ClinicalTrials.gov Identifier: NCT03007472.

Does Treating Hearing Loss in Older Adults Improve Cognitive Outcomes? A Review

Hearing loss is the third most prevalent health condition in older age. In recent years, research has consistently reported an association between hearing loss and mental health outcomes, including poorer cognitive performances. Whether treating hearing loss in elders improves cognition has been directly or indirectly addressed by several studies. This review aims at providing a synthesis of those results. Regarding the literature on hearing aids’ use and cognition, although the lack of interventional studies has to be underlined, observational data suggest that hearing aids positively impact long-term cognition, even though more research is necessary to ascertain this statement and provide information on the length or frequency of use required in order to observe benefits. Regarding cochlear implants in elders experiencing more severe auditory deprivation, the literature is scarcer. The available studies have many limitations and do not allow the drawing of clear conclusions. Taken together, the results are encouraging. Nevertheless, because hearing loss is suspected to account for 9% of dementia cases, and also because hearing loss is one of the few potentially modifiable factors from a dementia prevention perspective, the need to stimulate research to have clearer knowledge of the benefits of treating hearing loss on cognitive outcomes is urgent.

The Effect of Age at Cochlear Implantation on Speech and Auditory Performances in Prelingually Deaf Children

To understand the effect of age at implantation on speech and auditory performances of 74 prelingually deaf Indian children after using cochlear implants for 3, 6 and 12 months. We also evaluate the causes of late implantation in this population. Seventy four children who underwent cochlear implantation from December 2013 to December 2015 in the Department of Otorhinolaryngology and Head Neck Cancer in SMS Medical College, Jaipur were participated in this study. To compare the efficacy of cochlear implant, candidates are classified into 2 groups according to the age at the time of implantation: 1-4 years and 4.1-7 years. The sample size is 37 in both age groups. Their auditory performance and speech intelligibility were rated using the Revised Categories of Auditory Perception scales, Speech Intelligibility Rating scales and Meaningful Auditory Integration Scale. The evaluations were made before implantation and 3, 6 and 12 months after implantation. The scores when compared in both the groups revealed that the results were comparable and significant after 12 months of follow up while the scores were not significant after 3 and 6 months. The results were statistically significant when baseline is compared with different postoperative stages. The children implanted before the age of 4 years had significantly better auditory and linguistic performances. At least 12 months of audio-verbal rehabilitation and speech and language therapy are required to compare the effects of cochlear implant in any set of children. Our study shows that hearing impaired children who receive cochlear implantation below 4 years of age acquires better auditory ability for developing language skills.

Effects of Bimodal and Bilateral Cochlear Implant Use on a Nonauditory Working Memory Task: Reading Span Tests Over 2 Years Following Cochlear Implantation

Purpose A growing body of evidence indicates that treatment of hearing loss by provision of hearing aids leads to improvements in auditory and visual working memory. The purpose of this study was to assess whether similar working memory benefits are observed following provision of cochlear implants (CIs). Method Fifteen adults with postlingually acquired severe bilateral sensorineural hearing loss completed the prospective longitudinal study. Participants were candidates for bilateral cochlear implantation with some aidable hearing in each ear. Implantation surgeries were carried out sequentially, approximately 1 year apart. Working memory was measured with the visual Reading Span Test (Daneman & Carpenter, 1980) at 5 time points: pre-operatively following a 6-month bilateral hearing aid trial, after 6 and 12 months of bimodal (CI plus contralateral hearing aid) listening experience following the 1st CI surgery and activation, and again after 6 and 12 months of bilateral CI listening experience following the 2nd CI surgery and activation. Results Compared to the preoperative baseline, CI listening experience yielded significant improvements in participants' ability to recall test words in the correct serial order after 12 months in the bimodal condition. Individual performance outcomes were variable, but almost all participants showed increases in task performance over the course of the study. Conclusions These results suggest that, similar to appropriate interventions with hearing aids, treatment of hearing loss with CIs can yield working memory benefits. A likely mechanism is the freeing of cognitive resources previously devoted to effortful listening.

Age-related hearing loss and tinnitus, dementia risk, and auditory amplification outcomes

Age-related hearing loss (ARHL) or presbycusis, as the third leading cause of chronic disability in older adults, has been shown to be associated with predisposing cognitive impairment and dementia. Tinnitus is also a chronic auditory disorder demonstrating a growth rate with increasing age. Recent evidence stands for the link between bothersome tinnitus and impairments in various aspects of cognitive function. Both ARHL and age-related tinnitus affect mental health and contribute to developing anxiety, stress, and depression. The present review is a comprehensive multidisciplinary study on diverse interactions among ARHL, tinnitus, and cognitive decline in older adults. This review incorporates the latest evidence in prevalence and risk factors of ARHL and tinnitus, the neural substrates of tinnitus-related cognitive impairments, hypothesized mechanisms concerning the association between ARHL and increased risk of dementia, hearing amplification outcomes in cases with ARHL and cognitive decline, and preliminary findings on the link between ARHL and cognitive impairment in animal studies. Given extensive evidence that demonstrates advantages of using auditory amplification in the alleviation of hearing handicap, depression, and tinnitus, and the improvement of cognition, social communication, and quality of life, regular hearing screening programs for identification and management of midlife hearing loss and tinnitus is strongly recommended.

Can Hearing Aids Delay Time to Diagnosis of Dementia, Depression, or Falls in Older Adults?

OBJECTIVE

To examine the association between hearing aids (HAs) and time to diagnosis of Alzheimer disease (AD) or dementia, anxiety or depression, and injurious falls among adults, aged 66 years and older, within 3 years of hearing loss (HL) diagnosis.

DESIGN

Retrospective cohort study.

SETTING

We used 2008 to 2016 national longitudinal claims data (based on office visit, inpatient, or outpatient healthcare encounters) from a large private payer. We used Kaplan-Meier curves to examine unadjusted disease-free survival and crude and adjusted Cox regression models to examine associations between HAs and time to diagnosis of three age-related/HL-associated conditions within 3 years of HL diagnosis. All models were adjusted for age, sex, race/ethnicity, census divisions, and prior diagnosis of cardiovascular conditions, hypertension, hypercholesterolemia, obesity, and diabetes.

PARTICIPANTS

The participants included 114 862 adults, aged 66 years and older, diagnosed with HL.

MEASUREMENT

Diagnosis of (1) AD or dementia; (2) depression or anxiety; and (3) injurious falls.

INTERVENTION

Use of HAs.

RESULTS

Large sex and racial/ethnic differences exist in HA use. Approximately 11.3% of women vs 13.3% of men used HAs (95% confidence interval [CI] difference = -0.024 to -0.016). Approximately 13.6% of whites (95% CI = 0.13-0.14) vs 9.8% of blacks (95% CI = 0.09-0.11) and 6.5% of Hispanics (95% CI = 0.06-0.07) used HAs. The risk-adjusted hazard ratios of being diagnosed with AD/dementia, anxiety/depression, and injurious falls within 3 years after HL diagnosis, for those who used HAs vs those who did not, were 0.82 (95% CI = 0.76-0.89), 0.89 (95% CI = 0.86-0.93), and 0.87 (95% CI = 0.80-0.95), respectively.

CONCLUSIONS

Use of HAs is associated with delayed diagnosis of AD, dementia, depression, anxiety, and injurious falls among older adults with HL. Although we have shown an association between use of HAs and reduced risk of physical and mental decline, randomized trials are needed to determine whether, and to what extent, the relationship is causal. J Am Geriatr Soc 67:2362-2369, 2019.

The Effect of Cochlear Implants on Cognitive Function in Older Adults: Initial Baseline and 18-Month Follow Up Results for a Prospective International Longitudinal Study

In older adults, hearing loss is independently associated with an increased rate of cognitive decline, and has been identified to be a modifiable risk factor for dementia. The mechanism underlying the cognitive decline associated with hearing loss is not understood, but it is known that the greater the hearing loss, the faster the rate of decline. It is unknown whether remediation of hearing loss with hearing devices can delay cognitive decline. This 5-year international longitudinal study is investigating the impact of cochlear implants on cognitive function in older people with severe-profound hearing loss, and whether remediation of hearing loss could delay the onset of cognitive impairment. This is the first study to examine the major primary risk factors associated with dementia in the same cohort. Participants were assessed before cochlear implantation and 18 months later using an identical battery including a visually presented cognitive assessment tool (Cogstate battery) that is highly sensitive to small changes in cognition and suitable for use with people with hearing loss. Hearing and speech perception ability were assessed in sound-treated conditions by an audiologist, and a range of questionnaire tools was administered to assess self-perceived ease of listening, quality of life, physical activity, diet, social and emotional loneliness, isolation, anxiety, and depression. A detailed medical health history was taken. Pre-operatively, despite the small initial sample size (n = 59), increased hearing loss and age predicted significantly poorer executive function and visual attention, while tertiary education predicted better executive function. Better self-reported quality of life was correlated with better visual learning performance, and engaging in frequent vigorous physical activity was correlated with poorer visual learning performance. At 18 months, for the first 20 participants, significant benefits of cochlear implants were seen in terms of speech perception, communication ability, and quality of life. Multiple linear regression modeling showed executive function improved significantly for non-tertiary educated males, while cognitive function remained stable for other participants. Further follow-up at 18 month intervals with a larger sample will reveal the effects of cochlear implant intervention on all outcomes, and whether this can delay cognitive decline.

[Hearing rehabilitation with cochlear implants and cognitive abilities]

The relevance of assessing cognitive functioning is increasing against the background of the continuing demographic changes. Up to a few years ago the focus was on the effects of cochlear implantation in children born deaf in comparison to healthy individuals. Currently, the question arises whether hearing rehabilitation in the elderly, e.g. by postlingual cochlear implantation, has a protective effect on cognitive functioning and therefore on the risk of onset of dementia. This review describes the association of cognitive functioning with hearing disorders and cochlear implantation. Historical aspects of intelligence testing are illustrated. Knowledge on cognitive aspects in elderly persons with hearing disorders and cochlear implants is rare in the currently available literature. Initial findings indicate a positive correlation between hearing improvement and cognitive functioning. Further studies are urgently required in order to elucidate appropriate guidelines for the treatment of patients with cognitive deficits and hearing impairment.

Geriatric Syndromes in People Living with HIV Associated with Ageing and Increasing Comorbidities: Implications for Neurocognitive Complications of HIV Infection

Long-term survival of treated people living with HIV (PLWH) currently approaches that of the general population. The average age of PLWH is currently in the mid-50s in resource-rich countries and is predicted that over 40% of PLWH will be older than 60 within a decade. Similar trends have been confirmed in all communities of PLWH with access to antiretroviral therapies. However, the positive impact on survival has been challenged by several developments. Ageing PLWH have clinical features similar to the general population about 5-10 years older. In addition to the earlier occurrence of common age-related conditions common geriatric syndromes have also impacted this population prematurely. These are often difficult to evaluate and manage conditions usually of multifactorial aetiology. They include polypharmacy, frailty, impaired mobility and falls, sarcopenia, sensory impairment, and increasingly, non-dementing cognitive decline. Cognitive decline is of particular concern to PLWH and their care providers. In the general geriatric population cognitive impairment increases with age and occurs in all populations with a prevalence of over 25% in people over 80. Effective treatments are lacking and therefore minimizing risk factors plays an important role in maintaining healthspan. In the general population geriatric syndromes may increase the risk of cognitive decline. The corollary is that decreasing the risk of their development may limit cognitive impairment. Whether a similar status holds in PLWH is uncertain. This chapter will address the question of whether common geriatric syndromes in PLWH contribute to cognitive impairment. Common risk factors may provide clues to limit or delay cognitive decline.

Can cochlear implantation improve neurocognition in the aging population?

Introduction

The relationship between cognition and the ability to hear is well known. Due to changes in demographics, the number of people with sensorineural hearing loss and cognitive impairment is increasing. The aim of this study was to identify the impact of hearing rehabilitation via cochlear implantation on cognitive decline among the aging population.

Patients and methods

This prospective study included 60 subjects aged between 50 and 84 years (mean 65.8 years, SD=8.9) with a severe to profound bilateral hearing impairment. A computer-based evaluation of short- and long-term memory, processing speed, attention, working memory and inhibition was performed prior to surgery as well as 6 and 12 months after cochlear implantation. Additionally, speech perception at 65 and 80 dB (Freiburger monosyllabic speech test) as well as disease-related (Nijmegen Cochlear Implant Questionnaire) and general (WHOQOL-OLD) quality of life were assessed.

Results

Six months postimplantation, speech perception, quality of life and also neurocognitive abilities significantly increased. The most remarkable improvement after 6 months was detected in executive functions such as attention (p<0.001), inhibition (p=0.025) and working memory (n-back: p=0.002; operation span task: p=0.008), followed by delayed recall (p=0.03). In contrast, long-term memory showed a significant change of performance only after 12 months (p=0.021). After 6 months, most cognitive domains remained stable, except working memory assessed by the operation span task, which significantly improved between 6 and 12 months (p<0.001). No correlation was found between cognitive results and duration of deafness, speech perception or quality of life.

Conclusion

Cochlear implantation does not only lead to better speech perception and quality of life, but has also been shown to improve cognitive skills in hearing impaired adults aged 50 years or more. These effects seem to be independent of each other.

Does Otovestibular Loss in the Autosomal Dominant Disorder DFNA9 Have an Impact of on Cognition? A Systematic Review

Background and Purpose: Cognitive impairment has been observed in patients with bilateral vestibular loss (BVL) and in patients with sensorineural hearing loss (SNHL). DFNA9 is an autosomal dominant disorder that causes a combination of both sensory deficits by the 3rd to 5th decade. We therefore hypothesize a combined detrimental effect on cognition. The aim of this systematic review was to identify studies related to DFNA9 in general and its relationship with cognitive impairment more specifically.

Materials and Methods: Several databases including Medline, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, ISI Web of Knowledge, and Web of Science were searched to accumulate information about DFNA9-mutations, including phenotype, genotype, pathophysiology, quality of life (QOL), and imaging in general and cognitive function more specifically. A qualitative analysis was performed on the 55 articles that qualified.

Results: The clinical features of DFNA9 are different along the 24 COCH mutations, described up to now. Vestibular symptoms generally present themselves a few years after SNHL onset in mutations associated with the vWFA-domain although they can precede SNHL onset in other mutations associated with the LCCL-domain. QoL has not been studied extensively in DFNA9, although scarce work is available on the positive impact of cochlear implantation to rehabilitate hearing. No studies were found evaluating cognition in DFNA9 patients.

Conclusion: Although cognitive impairment has been demonstrated in patients with hearing loss as well as in patients with BVL, no studies have been reported on the combination of both sensory deficits, such as in DFNA9. Further research is warranted to correlate otovestibular status with cognition.

A review of new insights on the association between hearing loss and cognitive decline in ageing

Age-related hearing loss (ARHL) has a multifactorial pathogenesis and it is an inevitable hearing impairment associated with reduction of communicative skills related to ageing. Increasing evidence has linked ARHL to more rapid progression of cognitive decline and incidental dementia. Many aspects of daily living of elderly people have been associated to hearing abilities, showing that hearing loss (HL) affects the quality of life, social relationships, motor skills, psychological aspects and function and morphology in specific brain areas. Epidemiological and clinical studies confirm the assumption of a relationship between these conditions. However, the mechanisms are still unclear and are reviewed herein. Long-term hearing deprivation of auditory inputs can impact cognitive performance by decreasing the quality of communication leading to social isolation and depression and facilitate dementia. On the contrary, the limited cognitive skills may reduce the cognitive resources available for auditory perception, increasing the effects of HL. In addition, hearing loss and cognitive decline may reflect a 'common cause' on the auditory pathway and brain. In fact, some pathogenetic factors are recongised in common microvascular disease factors such as diabetes, atherosclerosis and hypertension. Interdisciplinary efforts to investigate and address HL in the context of brain and cognitive ageing are needed. Surprisingly, few studies have been adressed on the effectiveness of hearing aids in changing the natural history of cognitive decline. Effective interventions with hearing aids or cochlear implant may improve social and emotional function, communication, cognitive function and positively impact quality of life. The aim of this review is to overview new insights on this challenging topic and provide new ideas for future research.

The EXPRESS Study: Exercise and Protein Effectiveness Supplementation Study supporting autonomy in community dwelling frail older people-study protocol for a randomized controlled pilot and feasibility study

Background

Research has repeatedly demonstrated that exercise has a positive impact on physical function and is beneficial in the treatment of physical frailty. However, an even more effective strategy for managing physical frailty might be the combination of multicomponent exercise with the intake of high-quality protein supplements, but the efficacy remains unclear for older adults who are already pre-frail and frail. The aim is to examine the feasibility of recruiting frail older adults to participate in a trial designed to determine the potential effects of a 6-month exercise and nutrition intervention on physical function. The feasibility objectives will include frail older peoples’ compliance, the safety and tolerability of the trial, the estimation of estimates to aid sample size calculation, and the potential efficacy. Primary outcomes for the main trial will include gait speed, grip strength and physical performance. Secondary outcomes will include frailty status, muscle mass, nutritional intake, physical activity levels, cognitive performance and quality of life.

Methods/design

A randomised, parallel, control pilot and feasibility study will be conducted. All participants will be randomly assigned to either (a) an exercise program + high-quality protein supplement or (b) an exercise program + low-quality protein supplement. Both protein supplements will be matched closely in colour, flavour and packaging so that both the participants and the research staff are blinded. The exercise program will be the same in both groups. Assessments will be conducted at baseline and at 3 and 6 months and include gait speed, grip strength, the Short Physical Performance Battery, Timed Up and Go Test, FRAIL Screen, bioelectrical impedance analyses, 24-h dietary recall, Katz Activities of Daily Living, Lawton Instrumental Activities of Daily Living, the Trail Making Test, Short Form Health Survey-36, and 1 week accelerometer quantification. The data will be analysed using an ANCOVA model.

Discussion

This study is expected to provide much needed insight into the feasibility of recruiting and retaining frail older adults into community-based intervention programs, while providing knowledge relating to the safety, tolerability and benefits of a combined exercise and protein supplement program designed to halt or reverse the transition of physical frailty in the community. If shown to be effective, this strategy could be included in the best practice clinical guidelines for community-dwelling older adults who are pre-frail or frail.

Trial registration

Australian New Zealand Clinical Trials Registry, ACTRN12616000521426

Exploring Technology Evolution Using Patent Classification: A Case of Cochlear Implant Technology Patents

Understanding technology evolution through periodic landscaping is an important stage of strategic planning in R&D management. In fields like that of healthcare, where initial R&D investment is huge and good medical products serve patients better, activities of periodic landscaping become crucial for planning. Approximately 5% of the world’s population has hearing disabilities. Current hearing aid products meet less than 10% of the global needs. Patent data and classifications on cochlear implants from 1977–2010 show the technology evolution in the area of such an implant. We attempt to highlight emergence and disappearance of patent classes over a period of time indicating changes in growth of cochlear implant technologies. Using network analysis technique we explore and capture the technology evolution in patent classes by showing what emerged or disappeared over time. Dominant classes are identified. The sporadic influence of university research in cochlear implants is also discussed.

Cochlear implantation in post-lingually deafened adults and elderly patients: analysis of audiometric and speech perception outcomes during the first year of use

The aim of this study was to analyse audiometric and speech perception outcomes after cochlear implantation (CI) in adult and elderly patients in the first year post-CI activation. We evaluated 42 subjects who underwent CI at the Otorhinolaryngological Clinic of Padua Hospital. The subjects enrolled were post-lingually deafened patients who were unilaterally implanted for bilateral, severe-to-profound hearing loss. The overall sample was divided into three groups according to the age at the time of implantation: group A (35-49 years), group B (50-64 years) and group C (≥ 65 years). The subjects were assessed, both before and after surgery (at months 1, 3, 6 and 12), using pure tone audiometry, speech audiometry and speech perception tests and the CAP questionnaire. Statistical analysis of outcomes was using a Student's t-test for paired data. In all study groups a significant improvement was demonstrated in auditory performance examinations post-CI compared to the pre-operative scores. All subjects in all age groups obtained significant improvements in PTA scores before surgery and post-CI activation. Comparison of PTA values among the three age groups did not reveal any significant difference. Considerable improvement was obtained even in the speech audiometry thresholds in all groups at follow-up, with no significant differences between groups. The speech perception examination and CAP questionnaire showed good progress in all study groups, although younger patients tended to achieve more complex categories than older ones. In conclusion, CI is an effective treatment for severe-to-profound hearing loss with no significant differences in auditory performances between older and younger CI recipients. Even if somewhat slower, subjects older than 65 reached good performance and therefore are good candidates for a cochlear implant.

The Repeatable Battery for the Assessment of Neuropsychological Status for Hearing Impaired Individuals (RBANS-H) before and after Cochlear Implantation: A Protocol for a Prospective, Longitudinal Cohort Study

Background: Currently, an independent relationship between hearing loss and cognitive decline in older adults is suggested by large prospective studies. In general, cochlear implants improve hearing and the quality of life in severely to profoundly hearing impaired older persons. However, little is known about the effects of cochlear implantation on the cognitive evolution in this population. Aim of the study: The primary goal of this prospective, longitudinal cohort study is to explore the cognitive profile of severely to profoundly postlingually hearing impaired subjects before and after cochlear implantation. In addition, the current study aims to investigate the relationship between the cognitive function, audiometric performances, quality of life, and self-reliance in these patients. Methods: Twenty-five patients aged 55 or older, scheduled for cochlear implantation, will be enrolled in the study. They will be examined prior to implantation, at 6 and 12 months after implantation and annually thereafter. The test battery consists of (1) a cognitive examination, using the Repeatable Battery for the Assessment of Neuropsychological Status adapted for Hearing impaired persons (RBANS-H), (2) an audiological examination, including unaided and aided pure tone audiometry, speech audiometry in quiet and speech audiometry in noise, (3) the administration of four questionnaires evaluating quality of life and subjective hearing benefit and (4) a semi-structured interview about the self-reliance of the participant. Discussion: Up until now only one study has been conducted on this topic, focusing on the short-term effects of cochlear implantation on cognition in older adults. The present study is the first study to apply a comprehensive neuropsychological assessment adapted for severely to profoundly hearing impaired subjects in order to investigate the cognitive capabilities before and after cochlear implantation. Trial registration: The present protocol is retrospectively registered at Clinical Trials (ClinicalTrials.gov) on June 9th, 2016. The first participant was enrolled on June 22nd, 2015. The protocol identifier is NCT02794350.