Cognitive Changes Up to 4 Years After Cochlear Implantation in Older Adults: A Prospective Longitudinal Study Using the RBANS-H
Authors: Vandenbroeke Tinne , Andries Ellen , Lammers Marc J. , Van de Heyning Paul , Hofkens-Van den Brandt Anouk , Vanderveken Olivier , Van Rompaey Vincent , Mertens Griet 
Published: September 2024

Objectives:
Hearing loss is a worldwide health problem that currently affects around 20% of the world’s population. Untreated hearing loss can have a significant impact on daily life, it can cause social isolation, loneliness, frustration, and higher anxiety and depression rates. Furthermore, older adults with hearing impairment have a higher risk for accelerated cognitive decline compared with normal-hearing individuals. Previous research indicated a positive effect of cochlear implantation on Health-related Quality of life (HRQoL) and cognitive functioning 1 year after cochlear implantation. The aim of this study was to evaluate the long-term effect of cochlear implantation on cognition and HRQoL in older adults with severe-to-profound hearing loss.

Design:
All included subjects were 55 years or older with postlingual, bilateral, severe-to-profound hearing loss, and received a unilateral cochlear implant. Cognition was evaluated using the Repeatable Battery for the Assessment of Neuropsychological Status for Hearing Impaired Individuals (RBANS-H), and HRQoL was evaluated using the following five questionnaires: Nijmegen Cochlear Implant Questionnaire (NCIQ); Hearing Implant Sound Quality Index (HISQUI); Speech, Spatial, and Qualities of Hearing Scale (SSQ12); Hospital Anxiety and Depression scale (HADS); and Type D questionnaire (DS14). Individuals were evaluated preoperatively, and annually up to 4 years after CI activation.

Results:
After cochlear implantation an improvement in hearing, cognition, and HRQoL was observed. When comparing preoperative and 12 months postoperative results a significant improvement was observed in the total RBANS-H score (mean [SD], 92.78 [±15.08] versus 98.35 [±14.18], p < 0.001) and the subdomain scores for “Immediate Memory” (94.13 [±18.75] versus 105.39 [±19.98], p = 0.005), “Attention” (86.17 [±19.02] versus 91.57 [±15.35], p = 0.048), and “Delayed memory” (97.91 [±14.51] versus 103.83 [±14.714], p = 0.017). When comparing preoperative results with 4 years postoperative results, a significant improvement was observed in “Immediate Memory” (94.13 [±18.75] versus 101.91 [±16.09], p = 0.020) and a significant decline was observed in “Visuospatial Memory” (97.04 [±17.47] versus 87.26 [±13.41], p = 0.013). Compared with the preoperative results, no significant improvement was observed in the total RBANS-H score 4 years after implantation. A significant improvement was observed for the HRQoL questionnaires, that is, NCIQ, HISQUI19, SSQ12, HADS, and DS14, 1 year after cochlear implantation. When comparing preoperative results with 4-year postoperative results, significant improvement was observed for the NCIQ and DS14 social inhibition scores. Long-term results of the SSQ12 and HISQUI19 were lacking.

Conclusions:
Unilateral cochlear implantation in an adult population with bilateral severe-to-profound sensorineural hearing loss has a positive effect on cognitive functioning and HRQoL 1 year after activation. This positive effect on cognitive functioning was no longer observed 4 years after cochlear implantation. Further research is needed to explain individual variation in the evolution of cognitive functioning.