Background: There is a growing body of evidence demonstrating hearing loss in middle-aged and older adults is independently associated with an increased risk of developing cognitive-decline and dementia. Verbal memory is one of the most common functions to decline early in Alzheimer's disease, the most common form of dementia Whilst the exact mechanisms underlying this association remain unclear, poorer test performance may reflect an overarching sensory deficit, as, for instance, most verbal memory tests are predominantly delivered auditorily. Therefore, this study aimed to investigate whether different modes of presentation (i.e., visual, or auditory) influence verbal memory screening test performance in those who failed a hearing screener.
Method: The study was conducted via online video-conferencing due to the COVID-19 pandemic. Participants (N= 63) completed a validated hearing screener, which was a digit-in-noise test delivered via the hearWHO smartphone application. Three cognitive tests were also administered: (1) the Modified Telephone Interview for Cognitive Status (TICS-M), presented auditorily; (2) the Hopkins Verbal Learning Test (HVLT), presented visually; and (3) a verbal fluency task as a control. All tests have been used as dementia screening tests.
Result: Separate ANCOVAs revealed that, when controlling for age, gender, and education level, adults who failed the hearing screener performed more poorly on the TICS-M compared to individuals who passed (p<.001). No differences between hearing groups were found for the other cognitive tests administered (p≥ .132).
Conclusion: This study provides support for the notion that the presentation mode of cognitive tests may account for some of the deficits observed in older adults with hearing loss. As such, researchers and clinicians should be mindful of the sensory deficits experienced by individuals when interpreting cognitive test performance, to avoid the overestimation of cognitive deficits and dementia in adults with hearing loss.
© 2021 the Alzheimer's Association.