On the Possible Overestimation of Cognitive Decline: The Impact of Age-Related Hearing Loss on Cognitive-Test Performance.

Christian Füllgrabe

doi:10.3389/fnins.2020.00454

Abstract

Individual differences and age-related normal and pathological changes in mental abilities require the use of cognitive screening and assessment tools. However, simultaneously occurring deficits in sensory processing, whose prevalence increases especially in old age, may negatively impact cognitive-test performance and thus result in an overestimation of cognitive decline. This hypothesis was tested using an impairment-simulation approach. Young normal-hearing university students performed three memory tasks, using auditorily presented speech stimuli that were either unprocessed or processed to mimic some of the perceptual consequences of age-related hearing loss (ARHL). Both short-term-memory and working-memory capacities were significantly lower in the simulated-hearing-loss condition, despite good intelligibility of the test stimuli. The findings are consistent with the notion that, in case of ARHL, the perceptual processing of auditory stimuli used in cognitive assessments requires additional (cognitive) resources that cannot be used toward the execution of the cognitive task itself. Researchers and clinicians would be well advised to consider sensory impairments as a confounding variable when administering cognitive tasks and interpreting their results.

Highlights

IntroductionThere has been increasing interest in the role of cognition in (the decline of) speech processing across the adult lifespan (see Figure 1 in Füllgrabe and Rosen, 2016b)
Over the past decades, there has been increasing interest in the role of cognition in speech processing across the adult lifespan
The observed results are consistent with the “effortfulness hypothesis” originally proposed by Rabbitt (1968, 1991)2 that suggests that, in suboptimal listening conditions, the early stages of speech processing require additional efforts, thereby limiting the remaining cognitive resources available for the encoding in memory what was heard

Summary

Introduction

There has been increasing interest in the role of cognition in (the decline of) speech processing across the adult lifespan (see Figure 1 in Füllgrabe and Rosen, 2016b). Many studies in hearing science nowadays use inclusion or exclusion criteria based on performance in cognitive screening tests, and/or assess cognitive abilities as covariates when trying to explain speech-processing abilities. In clinical audiology, it is being debated (e.g., Shen et al, 2016) whether cognitive screening should be part of the standard assessment for a more individualized rehabilitation (American Speech-Language-Hearing Association, 2018). It is important to remember that cognitive testing constitutes the very basis of the study of the lifespan trajectory of cognitive abilities in healthy and pathological aging

Methods

Results

Conclusion