Prospective Evaluation of Cognitive Functions After Rehabilitation With Cochlear Implant or Hearing Aids: Preliminary Results of a Multicentric Study on Elderly Patients

Abstract

Objective Recent literature has shown a growing interest in the relationship between presbycusis and cognitive decline, but significant evidence about the long-term benefit of rehabilitation on cognitive functions has not been reported yet. The aim of the study was to analyze audiological and neuropsychological performances in patients with cochlear implant (CI) or hearing aids (HAs) over time. Materials and Method Forty-four bilaterally deaf patients aged more than 60 years (25 with CI candidacy and 19 with HA candidacy) were enrolled. Patients were subjected to audiological evaluation, to a battery of neuropsychological tests (Mini-Mental State Examination [MMSE], Rey Auditory Verbal Learning Task [RAVLT], Rey–Osterreith Complex Figure Test, Digit/Corsi Span Forward and Backward, Multiple Features Target Cancellation, Trail-Making Test, Stroop Test, and Phonological and Semantic Word Fluency), and to a quality of life assessment (Short Form 36, Glasgow Benefit Inventory, Glasgow Health Status Inventory) at the baseline and after a long-term follow-up (6–12 months). Results Speech recognition scores in quiet and in noise were significantly improved even 6 months after auditory rehabilitation. Significant differences between pre- and post-rehabilitation scores were reported in physical and emotional impacts in life, general global health, vitality, and social activities. MMSE and RAVLT scores were significantly improved in both groups after 6 months of follow-up, suggesting a global involvement of memory domain. Mnesic performances remained unchanged between the first and second follow-up, but a further significant improvement in executive functions (Stroop Test) was detected in patients with CI reevaluated 12 months after implantation. A significant correlation of the RAVLT with signal-to-noise ratio at +10 dB speech-in-noise scores and the MMSE with signal-to-noise ratio at 0 dB speech-in-noise scores suggests the pivotal role of executive functions in recognition in noisy environment. Conclusions Our preliminary data confirm that hearing deprivation in aged patients represents a truly modifiable risk factor for cognitive decline, which can be positively faced by acoustic rehabilitation. The improvement of short- and long-term memory performances and the amelioration of executive and attentive functions suggest that hearing restoration with both HAs and CI may provide a recovery of superior cognitive domains probably through a reallocation of cortical resources altered by hearing deprivation.