Paying attention to proprioception: age affects ankle proprioception and the attentional demand of proprioceptive processing in sedentary adults.

Ankle proprioception and attentional resources are crucial for maintaining balance and safely driving. However, research exploring the age-related integrity of ankle proprioception has yielded conflicting results, while the attentional demand of proprioceptive processing in seniors remains underexplored. We investigated how aging affects the interaction between proprioception and attention in healthy sedentary adults using a novel dual-task paradigm. Sedentary old and young adults performed an ipsilateral proprioceptive-matching task with a long target encoding time and a cognitive-attentional subtraction task. These tasks were performed alone (single-task) or simultaneously (dual-task). Older adults showed significantly lower ankle proprioceptive accuracy and consistency in dorsiflexion compared to young adults under the single-task condition. Hence, the matching inaccuracies of seniors were more pronounced relative to young adults, when performing the proprioceptive and cognitive-attentional tasks simultaneously. Importantly, both age groups demonstrated similar cognitive performance in the single-task. However, while younger adults maintained their performance during dual-tasking, seniors showed markedly lower cognitive-attentional scores in the dual compared to the single-task condition. Thus, their dual-task costs were higher than those of young adults. Our findings of impaired ankle proprioception in sedentary older adults in the single-task underline the importance of controlling participants' physical lifestyles and demonstrate that this novel paradigm is highly sensitive to age-related proprioceptive changes. Furthermore, the substantial decline in both proprioceptive and cognitive performance during dual-tasking suggests that sedentary older adults mobilize increasingly large cognitive-attentional resources to process proprioception. This dual-task paradigm may serve as a useful biomarker to predict falls and driving accidents in older populations.