IntroductionThe 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 methodsThis 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.ResultsSix 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.ConclusionCochlear 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.

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 &lt; 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.

<b><i>Introduction:</i></b> Age-related hearing loss affects about one-third of the population worldwide. Studies suggest that hearing loss may be linked to cognitive decline and auditory rehabilitation may improve cognitive functions. So far, the data are limited, and the underlying mechanisms are not fully understood. The study aimed to analyze the impact of cochlear implantation on cognition in a large homogeneous population of hearing-impaired adults using a comprehensive non-auditory cognitive assessment with regard to normal-hearing (NH) subjects. <b><i>Material and Methods:</i></b> Seventy-one cochlear implant (CI) candidates with a postlingual, bilateral severe or profound hearing loss aged 66.3 years (standard deviation [SD] 9.2) and 105 NH subjects aged 65.96 years (SD 9.4) were enrolled. The computer-based neurocognitive tool applied included 11 subtests covering attention (M3), short- and long-term memory (recall and delayed recall), working memory (0- and 2-back, Operation Span [OSPAN] task), processing speed (Trail Making Test [TMT] A), mental flexibility (TMT B), inhibition (cFlanker and iFlanker), and verbal fluency. CI patients underwent a neurocognitive testing preoperatively as well as 12 months postoperatively. Impact of hearing status, age, gender, and education on cognitive subdomains was studied. Additionally, after controlling for education and age, cognitive performance of CI subjects (<i>n</i> = 41) was compared to that of NH (<i>n</i> = 34). <b><i>Results:</i></b> CI users achieved significantly better neurocognitive scores 12 months after cochlear implantation than before in most subtests (M3, [delayed] recall, 2-back, OSPAN, iFlanker, and verbal fluency; all <i>p</i> &#x3c; 0.05) except for the TMT A and B. A significant correlation could be found between the postoperative improvement in speech perception and in the attentional task M3 (<i>p</i> = 0.01). Hearing status (<i>p</i> = 0.0006) had the strongest effect on attention, whereas education had a high impact on recall (<i>p</i> = 0.002), OSPAN (<i>p</i> = 0.0004), and TMT A (<i>p</i> = 0.005) and B (<i>p</i> = 0.003). Inhibition was mainly age-dependent with better results in younger subjects (<i>p</i> = 0.016). Verbal fluency was predicted by gender as females outperformed men (<i>p</i> = 0.009). Even after controlling for age and education NH subjects showed a significantly better performance than CI candidates in the recall (<i>p</i> = 0.03) and delayed recall (<i>p</i> = 0.01) tasks. Postoperatively, there was no significant difference between the 2 groups anymore. <b><i>Conclusion:</i></b> Impact of cochlear implantation on neurocognitive functions differs according to the cognitive subdomains. Postoperatively, CI recipients performed as good as age- and education-matched NH subjects.

IntroductionDue to demographic changes, the number of people suffering not only from dementia illness but also from hearing impairment with the need for hearing rehabilitation have increased noticeably. Even with the association between hearing, age, and cognitive decline being well known, this issue has so far not played an important role in daily clinical Ear Nose Throat settings. The aim of the present study was to evaluate the use of a computer-based battery of tests of neurocognitive abilities in older patients with and without hearing loss.Patients and methodsA total of 120 patients aged 50 years and older were enrolled in this prospective clinical study: 40 patients suffered from severe bilateral hearing loss and were tested before cochlear implantation and 80 patients showed normal hearing thresholds between 500 and 4,000 Hz bilaterally. The test battery covered a wide range of cognitive abilities such as long- and short-term memory, working memory (WM), attention, inhibition, and other executive functions. Individuals with severe depression or cognitive impairment were excluded.ResultsHearing status was a significant predictor of performance on delayed recall (P=0.0082) and verbal fluency after adjusting for age (P=0.0016). Age predominantly impacted on inhibition (P=0.0039) and processing speed (P<0.0001), whereas WM measured by the Operation Span task (OSPAN) and the attention were influenced by both age and hearing. The battery of tests was feasible and practical for testing older patients without prior computer skills.ConclusionA computerized neurocognitive assessment battery may be a suitable tool for the elderly in clinical practice. While it cannot replace a thorough neuropsychological examination, it may help to draw the line between cognitive and hearing impairment in the elderly and enable the development of individual strategies for hearing rehabilitation.