ABSTRACT. Purpose: Various directional hypotheses for the observed links between aging, hearing, and cognition have been proposed: (a) cognitive load on perception hypothesis, (b) information degradation hypothesis, (c) sensory deprivation hypothesis, and (d) common cause hypothesis. Supporting evidence for all 4 hypotheses has been reported. No studies have modeled the corresponding 4 causal pathways into 1 single model, which would be required to evidence that multiple directional hypotheses apply. The aim of the current study was to tease out which pathways apply for 5 different cognitive measures. Method: Data from 1,029 respondents of the Longitudinal Aging Study Amsterdam were used spanning a maximum follow-up of 7 years (3 measurements). Speech-innoise recognition ability (digit triplet speech-in-noise test) was included as a measure of auditory function. Cognitive measures included global cognitive functioning, fluid intelligence, information processing speed, and verbal memory (immediate recall and retention). Bivariate dual change score modeling was used to model the causal pathways between hearing, cognition, and baseline age. Results: For information processing speed, global cognitive functioning, fluid intelligence, and memory-immediate recall, all pathways except for the sensory deprivation pathway were supported. For memory-retention, only the common cause and the sensory deprivation pathways were supported. Conclusions: Causal pathways corresponding to all 4 hypotheses were supported. Support for the common cause hypothesis, the information degradation hypothesis, and the cognitive load on perception hypotheses was found for 4 of 5 cognitive measures. This was unexpected in some cases (e.g., support for the information degradation pathway for cognitive measures that do not rely on auditory stimuli). The sensory deprivation pathway that emerged for memory-retention might point toward processes related to early stages of dementia. In summary, the results show that the links between decline in auditory function, cognition, and aging are complex and most likely are captured by pathways belonging to various directional hypotheses.
