A Comparison of Montreal Cognitive Assessment Scores among Individuals with Normal Hearing and Cochlear Implants

The Montreal Cognitive Assessment (MoCA) is a cognitive screening tool that has 4 of 10 test items heavily dependent on auditory input, potentially leaving hearing-impaired (HI) individuals at a disadvantage. Previous work found that HI individuals scored lower than normal-hearing (NH) individuals on the MoCA, potentially attributed to the degraded auditory signals negatively impacting the ability to commit auditory information to memory. However, there is no research comparing how cochlear implant (CI) recipients perform on the MoCA relative to NH and HI individuals. This study aimed to (1) examine the effect of implementing three different hearing-adjusted scoring methods for a group of age-matched CI recipients and NH individuals, (2) determine if there is a difference between the two groups in overall scores and hearing-adjusted scores, and (3) compare scores across our CI and NH data to the published HI data for all scoring methods. We hypothesized that (1) scores for CI recipients would improve with implementation of the hearing-adjusted scoring methods over the original method, (2) CI recipients would score lower than NH participants for both original and adjusted scoring methods, and (3) the difference in scores between NH and CI listeners for both adjusted and unadjusted scores would be greater than that reported in the literature between NH and HI individuals due to the greater severity of hearing loss and relatively poor spectral resolution of CIs.

A total of 94 adults with CIs and 105 adults with NH were initially enrolled. After age-matching the two groups and excluding those who self-identified as NH but failed a hearing screening, a total of 75 CI participants (mean age 61.2 y) and 74 NH participants (mean age 58.8 y) were administered the MoCA. Scores were compared between the NH and CI groups, as well as to published HI data, using the original MoCA scoring method and three alternative scoring methods that excluded various auditory-dependent test items.

MoCA scores improved for all groups when two of the three alternative scoring methods were used, with no significant interaction between scoring method and group. Scores for CI recipients were significantly poorer than those for age-matched NH participants for all scoring methods. CI recipients scored better than the published data for HI individuals; however, the HI group was not age matched to the CI and NH groups.

MoCA scores are only partly affected by the potentially greater cognitive processing required to interpret degraded auditory signals. Even with the removal of the auditory-dependent items, CI recipients still did not perform as well as the age-matched NH group. Importantly, removing auditory-dependent items significantly and fundamentally alters the test, thereby reducing its sensitivity. This has important limitations for administration and interpretation of the MoCA for people with hearing loss.