INSTRUCTION: Large prospective studies have established an independent association between hearing impairment and cognitive decline (Lin FR et.al. 2011, Gallacher J et.al. 2012). Individuals with mild to severe hearing loss have a 2- to 5-fold increased risk of developing dementia compared with those with normal hearing (Lin FR et.al. 2011). Moreover, neuroimaging studies (Peelle JE 2011, Lin FR et.al. 2014) report an association between peripheral hearing impairment and temporal lobe cortex and whole brain atrophy. A combination of several interdependent mechanisms could account for this association, such as vascular risk factors, neurodegenerative processes affecting both peripheral auditory pathways and the cerebral cortex, social isolation, and reduced cognitive stimulation. Based on these reports, hearing rehabilitation using conventional hearing aids has logically been proposed as a treatment to help improve neurocognitive performance; however, the impact of the rehabilitation generated controversial results, with a beneficial effect reported in only half of the elderly groups presented in the published analyses (Mulrow CD et.al. 1990, Tesch-Römer C 1997, Acar B et.al. 2011, Choi AY et.al. 2011, Lin FR et.al. 2013, Van Hooren SA 2005). In cases of acquired severe to profound hearing loss with no benefit from conventional amplification, cochlear implantation that uses direct electrical stimulation of the auditory nerve has proved to be successful; patients 80 years or older are one of the groups receiving benefit (Carlson ML et.al. 2010, Williamson RA, et. al. 2009). Moreover, similar to younger patients with cochlear implants, most elderly patients who have received implants show an increase in social activities and improved confidence (Vermeire K et.al. 2005, Clark JH et.al. 2012, Olze H et.al. 2012). To the best of our knowledge, the relationship between hearing benefit following cochlear implantation and cognitive abilities in elderly patients has not been investigated. The longitudinal multicenter study was to assess speech perception, cognitive abilities, and quality-of-life scores before implantation and at 6 and 12 months after cochlear implant activation inpatients 65 years or older (Isabelle Mosnier MD et.al. 2015). So we aimed to determine these benefits on Alzheimer's Disease. CASE HISTORY: A 81 year old woman presented for evaluation of postlingual bilateral hearing loss which had been increased progressively during 25 years. She had been used hearing aid on left ear for 24 years. She had been diagnosed with Alzheimer's Disease for 15 years. Preoperative Evaluation: The case's preoperative evaluation included audiologic, otolaryngologic, linguistic - rehabilitative (included Ling's sound, three syllables - one syllable -- sentences discrimination tests), cognitive, quality of life, depression and neurological assessments. Surgical Procedure: A left cochlear implantation of a nucleus 22 CI24RE (ST) device was performed without difficulty. Radiologic findings confirmed that the implant had been properly positioned. The patient was discharged from the hospital the following day. Postoperative Evaluation: After one month an operation, the case's implant was connected to Nucleus 5 speech processor. Impedance levels of all electrodes were normal. NRT of the default electrodes (included 22, 16, 11, 6) were normal, but there was no NRT on first electrode. Mapping and aural rehabilitation procedures were performed according to standard guidelines. Audiologic tests, mapping procedure were repeated at 1, 3, 6 months, 1, 2 years postoperatively, and results were compared with the preoperative findings. Rehabilitation procedure was repeated at 3, 6 months, 1, 2 years postoperatively, and results were compared with the preoperative findings. Conclusion: Epidemiologic studies demonstrate that the anticipated number of people aged 60 years or older will double by the year 2050. As a consequence, the number of people with cognitive impairment and dementia will dramatically increase, reaching more than 100 million worldwide by 2050. Because there is no curative treatment available for cognitive decline, clinical research is needed that focuses on identification of risk factors to establish preventive measures that may reduce the burden of the disease. Further research is needed to evaluate the longterm influence of hearing restoration on cognitive decline and its effect on public health (Prince M et.al. 2009, Brookmeyer R et. al. 2007). [ABSTRACT FROM AUTHOR]